MK5 Golf GTI
All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: RedRobin on September 01, 2009, 04:57:28 pm
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I have it on good authority (AP Racing) that the Golf GTI does about 85% of its braking on the front wheels and consequently most big brake upgrades are front kits. For normal road use it's considered fine to leave the rear brakes as oem, but for trackday use it's advisable to at least upgrade your rear pads. If you don't, you may experience fade on them quite quickly and without fully realising.
Many of us have front brake kits using the ubiquitous Ferodo DS2500 pad and so a DS2500 pad is wanted to fit the oem rear brake calipers. My initial attempts to source some discovered that they don't appear to be listed as such for the Mk5 GTI but with Kate's help at JKM I found that their Ferodo part# is FCP1636 (she wanted some for her car too).
Unless you want it as eye-candy you don't really need to change the rear discs on the Mk5 GTI to something grooved and/or drilled - For the 15% work they do the plain discs are quite sufficient.
If anyone needs some rear DS2500's I recommend contacting JKM - 023 9263 9933 - They supply at the best prices for Ferodo products and can supply quickly.
HTH :happy2:
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Top man - thanks for this Robin!
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Spot on Robin :happy2:
Still considering rear TAR-OX grooved discs for the ED30 beastie, but this could be a quick fix for now :smiley:
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never had a problem with them on track and don't really see the point . braided hoses will help tho
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Spot on Robin :happy2:
Still considering rear TAR-OX grooved discs for the ED30 beastie, but this could be a quick fix for now :smiley:
....I nearly added something in my original post to cover the likes of your goodself who have modified cars somewhat beyond most others. Especially with the power you're going to be having 'a la Garrett', methinks you'll need some big rear stoppers even if only ~15%.
Am I right in thinking that any increase in rear braking capability will keep the ESP more at bay?
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never had a problem with them on track and don't really see the point . braided hoses will help tho
....Weeeell, I'm inclined to take AP Racing's advice.
Perhaps adding braided hoses to the rear may also help but I won't bother with that until my next brake fluid change and also until speaking with AP and VWR again.
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never had a problem with them on track and don't really see the point . braided hoses will help tho
....Weeeell, I'm inclined to take AP Racing's advice.
Perhaps adding braided hoses to the rear may also help but I won't bother with that until my next brake fluid change and also until speaking with AP and VWR again.
I remember asking T_T (Sean) about braided hoses in the past. He said that the OEM hoses are banded internally anyway and that they are more than up to the job. :happy2:
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I'd be very surprised if the bias figure was 85/15, the figure for the Mk4 was calculated at 74/26 and with the Mk5 Gti having 286 rear discs as opposed to 256's then the bias would probably be rearward from the Mk4
This despite the fact that the MK5's front piston is 1.5mm bigger on radius than the Mk1 TT/Mk4 setup, same rear piston, same MC
if the number was 85/15 then the car would feel absolutely awful to drive with excessive wear put on the front suspension to alleviate the massive dive that it would generate.
Whilst I appreciate the advice came from AP (who sell brakes...front brakes.....) I would be sceptical that its actualy that bad in reality, sometimes generic flippant remarks come out with no real substance......
Now having said all that if that figure arrived from a conversation that took into account disc size, piston surface area,pad surface area, master cylinder piston stroke and surface area, pad material and piston rollback measurements then I stand to be corrected and please accept my apologies
If the bias was indeed as bad as that the first thing on my shopping list would be a huge rear brake kit IMHO
Braking is about balance - 85/15 sound right to you???
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@ DaveB,
My AP Big Brake Kit was fitted by their Senior Engineer at Coventry with myself present. At that time in 2006, I asked him whether he thought it was worth also fitting their AP brakes to the rear and he said no, saying that about 85% of braking on the Mk5 Golf was done by the front brakes and the power of the front AP's would 'do the job'.
The 85% value has been mentioned by him again since 2006 in our conversations and also yesterday when I specifically asked for his advice about what would be best to do now that I occasionally track (Nurburgring).
Now, it is of course possible that his use of the term "85%" is more to emphasise that the rear brakes do relatively little. "85%" possibly over emphasising? But "flippant"? - I very much doubt it. In our chat yesterday he also made the comment that the oem rears on the GTI were more designed for 'street' stopping as opposed to a workout on The Ring.
AP Racing (once known as Lockheed) do far more than sell brakes - They design and test brakes and clutches for car manufacturers (they are an autonomous arm of Brembo), F1 (first 9 of the finishers at Spa last weekend), and NASCAR etc etc. When I first visited them they were 24/7 bench testing calipers for the Bugatti Veyron for example.
Now having said all that if that figure arrived from a conversation that took into account disc size, piston surface area,pad surface area, master cylinder piston stroke and surface area, pad material and piston rollback measurements then I stand to be corrected and please accept my apologies.
....I'm confident that his knowledge as AP's Senior Engineer will have taken such technical factors into account.
The question is whether his "85%" comment is to be taken literally or as emphasis - I would have to ask him when we next speak.
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R32's have vented 312mm discs on rear which are larger than a standard GTI fronts!
Also it's a cheap oem upgrade (I gave £280 for a complete F&R setup).
I think the rear pads are the same also, just the caliper carrier is moved out in comparison to accomodate the larger disc size.
....Do you know how much R32 312mm discs weigh?
Are you saying you bought a new set of front and rear R32 brakes for £280?
One of the reasons for upgrading the pads to DS2500's on oem GTI rears is to reduce generated heat and its ramifications.
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Dave also knows his stuff Robin :wink:
This could be a good thread to look in on as some decent technical info could come out of it :happy2:
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Dave also knows his stuff Robin :wink:
....So I'm told.
I'm just piggy-in-the-middle trying to help people (and myself) by posting and sharing information which can only ever be to the best of my knowledge.
T_T Sean knows his stuff too, but all these experts don't always agree - Brake fluid for example.
The bottom line for me is that I run AP Racing front brakes and I'd be a fool not to take their advice about brake related subjects on my car, especially considering their indisputable experience and reputation. The AP kit I run has been designed by them for Performance Road as opposed to eyeballs-out Competition.
:happy2:
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R32's have vented 312mm discs on rear which are larger than a standard GTI fronts!
Also it's a cheap oem upgrade (I gave £280 for a complete F&R setup).
I think the rear pads are the same also, just the caliper carrier is moved out in comparison to accomodate the larger disc size.
....Do you know how much R32 312mm discs weigh?
Are you saying you bought a new set of front and rear R32 brakes for £280?
One of the reasons for upgrading the pads to DS2500's on oem GTI rears is to reduce generated heat and its ramifications.
More friction = More heat?
Since i fitted my S3 rears the car is a joy to drive, the car feels balanced under braking, and the rear never gets "tail happy" under braking.
i was asked by an independent engineer as to what brakes I have fitted, he was impressed by the overall feel of the car, and he has the pick of any braking system, being in the 'race preparation' enviroiment.
I therefore rate the S3 rears was the 2nd best mod behind fitting my RNS510.
This is my opinion, and I would do the same again.
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^^^^
Now, it is of course possible that his use of the term "85%" is more to emphasise that the rear brakes do relatively little. "85%" possibly over emphasising? But "flippant"? - I very much doubt it. In our chat yesterday he also made the comment that the oem rears on the GTI were more designed for 'street' stopping as opposed to a workout on The Ring.
Now having said all that if that figure arrived from a conversation that took into account disc size, piston surface area,pad surface area, master cylinder piston stroke and surface area, pad material and piston rollback measurements then I stand to be corrected and please accept my apologies.
....I'm confident that his knowledge as AP's Senior Engineer will have taken such technical factors into account.
The question is whether his "85%" comment is to be taken literally or as emphasis - I would have to ask him when we next speak.
robin 85/15 would drive crap and thats the sort of split I would expect from a ford fiesta with rear drums.....
emphasis/flippant - tomayto/tomarto - its not 85/15 maybe it would be worthwhile asking your senior engineer mate to clarify.
Front end dive is not a good trait - wherever possible 60/40's ///// 70/30 is the figure normally aspired to (depending on configuration) , mid engined cars can have 50/50 - I've had many pairs of Ferrari 360 calipers the psiton sizes are the same at 38/42 front and rear, discs sizes are 330mm front and rear, Audi R8 rears are big at 38/42 as examples
The rears should be encouraged to share the load, redistribute the forward energy in to heat front and rear if you're brakes are really 85/15 then you should get it sorted you'll be amazed at what it'll do for your lap times.
I do a 300mm S4 conversion for 4WD mk4's which upgrade them from 256mm - we've had tangible positive results reported at the first stop, trackers and ringers also reported flatter braking, less weight transfer and better turn in and into corner confidence.
I think the 310mm R32 rears are a worthy upgrade, for a given (similar) pad area and piston size.... in easy terms its the difference between trying to move the rear ABS locking wheel with a ratchet as opposed to a breaker bar. If the rear ABS is kicking in then you need a bigger disc - think about it
One of the reasons for upgrading the pads to DS2500's on oem GTI rears is to reduce generated heat and its ramifications.
The pads reason d'etre is to deal with the heat generated - they dont reduce or increase the amount of heat generated you adjust that by hard you press and for how long, the generation of heat is a positive thing..... its how your setup deals with that through cooling, materials that gives you a good installation. As you probably know pads are classified by their reccomended operating ranges.
heat is a good thing - no heat no stopping the energy has to go somewhere!
Dont know whether its an installation issue but the 2500 compund has been getting a bit of a slating recently over on uk-mkivs, the pad of choice over there at the moment seems to be the pagid blues
Just my £0.02
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My understanding is that the DS2500 pad performs better than the oem pad regarding whatever heat generation there is or isn't.
So, stokey, tell us more about your S3 rear brakes - Disc size, pads used, weight, any pics?
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I was under the impression the S3 and R32 rear set-ups are the same, might be wrong though :laugh:
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My understanding is that the DS2500 pad performs better than the oem pad regarding whatever heat generation there is or isn't.
So, stokey, tell us more about your S3 rear brakes - Disc size, pads used, weight, any pics?
Pads used are the std S3 rears, allied with 310 x 22 (i think) mm Discs. The pics are in the thread linked below. The weights are heavier, due to larger dia and thickness disc used, also the caliper is larger. heavier by how much, I dont know.
http://www.mk5golfgti.co.uk/forum/index.php?topic=2113.0 (http://www.mk5golfgti.co.uk/forum/index.php?topic=2113.0)
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@ DaveB,
Yes I definitely will be asking AP to clarify about the 85%. But whatever the braking distribution is, my car doesn't front end dive or handle badly as a result.
Whereas I can understand how a certain amount of heat generation is a good thing, I think we all know that too much heat is not a good thing!
It's well known that DS2500 pads, like tyres, need a bit of heat in them to work better but that's easily generated.
Dont know whether its an installation issue but the 2500 compund has been getting a bit of a slating recently over on uk-mkivs, the pad of choice over there at the moment seems to be the pagid blues
....I don't read the uk-mkivs forum but I'm not inclined to view such information as reliable. Someone posts a negative opinion which then starts others wondering and naturally it spreads. Whether the negative comment was right or wrong it happens everywhere on the internet (and elsewhere such as public confidence in the economy etc). What's more important is who expressed the opinion originally and on what basis. Another aspect of car forums is how so many are primarily led by cost considerations in their judgement of products - Perhaps Pagid Blues are cheaper (I don't know).
Do you have a link to this slating of the DS2500's please? [mine have just arrived in the post!]
Thanks :happy2:
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@ Quality Dave, aka stokeballoon - Thanks for that info and very helpful link about your S3 brakes.
:drinking:
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Just thinking aloud, but both the oem R32 and S3 rear brakes will surely have been designed to work on 'driven' rear wheels (be it Haldex or quattro).
Does this suggest that fitting them on the rear of the FWD Mk5 GTI may be overkill?
Please note that I'm only raising the question and not saying that this is the case.
Since i fitted my S3 rears the car is a joy to drive, the car feels balanced under braking, and the rear never gets "tail happy" under braking.
i was asked by an independent engineer as to what brakes I have fitted, he was impressed by the overall feel of the car, and he has the pick of any braking system, being in the 'race preparation' enviroiment.
I therefore rate the S3 rears was the 2nd best mod behind fitting my RNS510.
This is my opinion, and I would do the same again.
....But didn't you also fit S3 front brakes? So how are you able to judge the benefit of fitting only rear S3 brakes to a GTI/Ed30 as a mod?
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In my opinion i would just stick some decent pads in the back, front wheel drive cars shouldnt use much rear braking... when your trying to do everything through the front wheels the last thing you want to do it to make the back too stable!
In a mid engine car it is possible to have more rear braking... because thats where the weight is!
For front engined front wheel drive its alwase going to stand on the nose when braking, no matter what suspension setup you have... so the front wheels have the most amount of grip to put the braking force through!!
at the end of the day when VWR (or any touring car team) build a car if there was an advantage to fitting huge rear brakes on a front wheel drive car dont you think they would use it?
Thats my part anyway, and i dont really need to justify this...
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Just thinking aloud, but both the oem R32 and S3 rear brakes will surely have been designed to work on 'driven' rear wheels (be it Haldex or quattro).
Does this suggest that fitting them on the rear of the FWD Mk5 GTI may be overkill?
Please note that I'm only raising the question and not saying that this is the case.
Since i fitted my S3 rears the car is a joy to drive, the car feels balanced under braking, and the rear never gets "tail happy" under braking.
i was asked by an independent engineer as to what brakes I have fitted, he was impressed by the overall feel of the car, and he has the pick of any braking system, being in the 'race preparation' enviroiment.
I therefore rate the S3 rears was the 2nd best mod behind fitting my RNS510.
This is my opinion, and I would do the same again.
....But didn't you also fit S3 front brakes? So how are you able to judge the benefit of fitting only rear S3 brakes to a GTI/Ed30 as a mod?
Robin,
The way I judged is that the car feels far more stable. Sat in the drivers seat, you can feel the rear being braked, front brakes do not give that feeling. Thats how I judged.
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Robin,
The way I judged is that the car feels far more stable.
....I would suggest this is mainly due to the improved (S3 rather than oem GTI) front braking.
Sat in the drivers seat, you can feel the rear being braked. Thats how I judged.
....Then you must have a much more sensitive arse than I have! :laugh:
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to be fair i think even if the rear discs only cope with 15% of the overall brake bias moving from 256mm to 312 discs and bigger pistons and pads etc will still make a huge difference in the overall stopping power available.
I also agree that if the brakes were increased on the rear as well as the front(albeit not to the same extent) then the weight transfer and balance would be much improved especialy if braking mid corner, which does happen sometimes. ie coming around a bend to find stand still traffic, or carrying too much speed into a corner on a track and having to brake. both have happened to me before and ive felt the back step out a little.
However guys who have used the DS2500 on the std front 312 discs commented on the huge difference the pads made. So maybe that would prove to be more cost effective
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I also agree that if the brakes were increased on the rear as well as the front(albeit not to the same extent) then the weight transfer and balance would be much improved especialy if braking mid corner, which does happen sometimes. ie coming around a bend to find stand still traffic, or carrying too much speed into a corner on a track and having to brake. both have happened to me before and ive felt the back step out a little.
....Having to slam on the anchors extremely hard when coming round a blind bend has happened several times to me and I've been very glad to have the AP's - How my rear oem brakes behaved I have absolutely no idea! It was furthermost from my mind.
However, on a faster bend with open visibility or roundabouts, I tend to get all my braking done while the car is still straight even if I'm not going in as fast as I could be. At least with the Quaife it helps me get back on the power very early. But as you say, we can still get caught out.
However guys who have used the DS2500 on the std front 312 discs commented on the huge difference the pads made. So maybe that would prove to be more cost effective
....I'm looking forward (I think!) to seeing how just the DS2500 pads work on my oem rears at The Ring, if indeed I can feel a difference.
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In my opinion i would just stick some decent pads in the back, front wheel drive cars shouldnt use much rear braking... when your trying to do everything through the front wheels the last thing you want to do it to make the back too stable!
Thats my part anyway, and i dont really need to justify this...
Not necessary to justify anything mate, could you just elaborate on the bit Ive highlighted
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Guys, whilst this is all good discussion - I can't help feel confused.
I have a big brake kit arriving any time this week. Should I also look at upgrading my rear pads, or go for the plunge and upgrade the discs as well?
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Guys, whilst this is all good discussion - I can't help feel confused.
I have a big brake kit arriving any time this week. Should I also look at upgrading my rear pads, or go for the plunge and upgrade the discs as well?
....Personally I would get to know your front big brake kit first and then later think about your rears.
Unless you are going to be doing lots of trackdays you might only want to upgrade the pads on the rear. But take it all one step at a time so you can experience and learn from what each mod does.
Which front brake kit?
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In my opinion i would just stick some decent pads in the back, front wheel drive cars shouldnt use much rear braking... when your trying to do everything through the front wheels the last thing you want to do it to make the back too stable!
Thats my part anyway, and i dont really need to justify this...
Not necessary to justify anything mate, could you just elaborate on the bit Ive highlighted
no problem, when your fast road or track driving in a front wheel drive car the only way it's going to go quick is if you can be the last on the brakes and first on the power, the only way to do this is to have the car pointing in the right direction as early into the corner as possible with the least ammout of steering input a possible... This doesn't work if the back end is too settled! (we have tried it) you can brake much further into corners with very little rear brake.
I see what your saying that the more even braking should mean better stopping abuility... And on mid engined or rear engined cars this is correct, but it's not really the right direction for front engined front drive cars! In my opinion of course.
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Guys, whilst this is all good discussion - I can't help feel confused.
I have a big brake kit arriving any time this week. Should I also look at upgrading my rear pads, or go for the plunge and upgrade the discs as well?
....Personally I would get to know your front big brake kit first and then later think about your rears.
Unless you are going to be doing lots of trackdays you might only want to upgrade the pads on the rear. But take it all one step at a time so you can experience and learn from what each mod does.
Which front brake kit?
I've taken the plunge and gone for a big brake kit from HiSpec- 2-piece 360mm diameter discs, steel braided lines, 6 pot billeted calipers, 5.1 brake fluid, and some Ferodo DS2500 pads.
http://www.hispecbrake.co.uk/calipers.htm
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prices dont seem too bad in comparison to other available alternatives. although i would rather not have the EBC redstuff pads they supply.
Monster 4 335x32mm £1105.38 £1298.82
Monster 6 335x32mm £1246.38 £1464.50
however you can get 4 pot R8 calipers with larger 345mm R32 discs for £1000, the only other benefit i can see for the extra £300 is that they are 2 piece discs, so will help with cooling. could it not be cheaper and more cost effective to put some form of ducting through from the front to blast on the brakes.
@jabbalad, i dont see how you can brake much later for a corner with less rear brake. i know you a little tap on the brakes to bring the back round will get the front turning in more, but that also unsettles the car and you can lose traction on acceleration out of the corner with all the sudden weight transfer. surely for the large majority of drivers who are competent but not advanced drivers a settled car would be faster.
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however you can get 4 pot R8 calipers with larger 345mm R32 discs for £1000, the only other benefit i can see for the extra £300 is that they are 2 piece discs, so will help with cooling. could it not be cheaper and more cost effective to put some form of ducting through from the front to blast on the brakes.
....An easy mod to duct through from front.
@jabbalad, i dont see how you can brake much later for a corner with less rear brake. i know you a little tap on the brakes to bring the back round will get the front turning in more, but that also unsettles the car and you can lose traction on acceleration out of the corner with all the sudden weight transfer. surely for the large majority of drivers who are competent but not advanced drivers a settled car would be faster.
....I've always been taught that smoooother is always faster. It's easier on tyres and just about everything else!
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In my opinion i would just stick some decent pads in the back, front wheel drive cars shouldnt use much rear braking... when your trying to do everything through the front wheels the last thing you want to do it to make the back too stable!
Thats my part anyway, and i dont really need to justify this...
Not necessary to justify anything mate, could you just elaborate on the bit Ive highlighted
no problem, when your fast road or track driving in a front wheel drive car the only way it's going to go quick is if you can be the last on the brakes and first on the power, the only way to do this is to have the car pointing in the right direction as early into the corner as possible with the least ammout of steering input a possible... This doesn't work if the back end is too settled! (we have tried it) you can brake much further into corners with very little rear brake.
I see what your saying that the more even braking should mean better stopping abuility... And on mid engined or rear engined cars this is correct, but it's not really the right direction for front engined front drive cars! In my opinion of course.
I think we need to just quantify exactly what we're trying to achieve with our cars here, if we're setting our cars up tp be a lightweight racer - inside or around 1000kg with no interior, carbon/ali panels, exotic brake materials and touring car suspension, talented pro driver and a testing budget - then I'll take your word for it that asking the front wheels to handle 300BHP+, steer and handle the vast majority of braking and deal with the associated heat generated with little rear braking is a good thing.
I think the vast majority of us have also got a requirement to:
A) Go to Sainsbury's
B) Take the old dear out
C) Not kill ourselves on todays roads with a car set up purely for the track
D) Enjoy the drive to work
E) Enjoy track action at a reasonable cost - with out taking it all too seriously (with its associated cost)
I think setting our cars up so that they'll "scandinavian flick" a bit better is beyond most of us on here, in my opinion I want the best dynamic drive I can afford for the road, with a setup that cross polinates to a degree on the track so that the car holds its own and flatters my/our (amateurish - by definition) attempts to go fast.
If I buy a Mk5 Gti I would get a buzz from knowing that it brakes as well as an RS4, if I buy an RS4 I would like to thing I can get it dynamically on the road as good as an R8 isn't that whats moddings all about
So that being the case, improving the front rear bias so that it feels better/faster through my "arse" is a worthwhile mod and for £250 is well worth it. The flatter braking encountered improves confidence/flatters the driver and reduces the work/heat done by the fronts
Given an unlimited budget, a pro driver and another daily drive I could make the fastest golf in the world but isn't that why we watch and enjoy F1???
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has anybody here fitted any brake ducting to their cars, or seen any pics or internet links of it done. would be interested to see how and what they have used to do it and where they ran it. I havent had a look yet,
I was thinking hoover tubing and cable clips etc, but i want it too last
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i do have to agree with dave TBH,
I wouldnt want my wife loosing it on a bend if she had an emergency stop for some reason. £250 is pretty cheap as well all things considered, and even more so if you are due to renew your rear pads and discs
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I think we need to just quantify exactly what we're trying to achieve with our cars here, if we're setting our cars up tp be a lightweight racer - inside or around 1000kg with no interior, carbon/ali panels, exotic brake materials and touring car suspension, talented pro driver and a testing budget - then I'll take your word for it that asking the front wheels to handle 300BHP+, steer and handle the vast majority of braking and deal with the associated heat generated with little rear braking is a good thing.
I think the vast majority of us have also got a requirement to:
A) Go to Sainsbury's
B) Take the old dear out
C) Not kill ourselves on todays roads with a car set up purely for the track
D) Enjoy the drive to work
E) Enjoy track action at a reasonable cost - with out taking it all too seriously (with its associated cost)
I think setting our cars up so that they'll "scandinavian flick" a bit better is beyond most of us on here, in my opinion I want the best dynamic drive I can afford for the road, with a setup that cross polinates to a degree on the track so that the car holds its own and flatters my/our (amateurish - by definition) attempts to go fast.
....I think you are absolutely right in that it's important to quantify exactly what we are trying to achieve with our individual cars and consequently to plan our mods accordingly. However, in reality the slope of modding being slippery, usually causes us to move on the fly!
I'm not sure that the "vast majority" of us here fall into your requirements list at all - I know I most certainly don't! For what it's worth, I : -
A) Walk to Waitrose etc and never do a weekly big shop.
B) The oldest person who goes in my car is myself and I don't drive any differently whoever the passengers are.
C) My car is set up for 'Fast Road' and spirited driving whenever circumstances safely allow (surprisingly often).
D) I don't work.
E) Just starting to become addicted to the Nurburgring.
If I buy a Mk5 Gti I would get a buzz from knowing that it brakes as well as an RS4, if I buy an RS4 I would like to thing I can get it dynamically on the road as good as an R8 isn't that whats moddings all about
So that being the case, improving the front rear bias so that it feels better/faster through my "arse" is a worthwhile mod and for £250 is well worth it. The flatter braking encountered improves confidence/flatters the driver and reduces the work/heat done by the fronts
Agreed. Modding enhances a car because the manufacturer builds them to a lower common denominator. Example: The VW air intake is more of a hot air intake because VW have to cater for cold starts in colder climates [probably not the best example, but]. And then there's all the crap about emissions etc.
Given an unlimited budget, a pro driver and another daily drive I could make the fastest golf in the world but isn't that why we watch and enjoy F1???
....Not why I enjoy watching F1 - It has absolutely nothing to do with my own car or driving - It isn't a substitute.
:happy2:
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has anybody here fitted any brake ducting to their cars, or seen any pics or internet links of it done. would be interested to see how and what they have used to do it and where they ran it. I havent had a look yet,
I was thinking hoover tubing and cable clips etc, but i want it too last
....I think NeilM has done so, or is it john_o?
There are durable duct hoses for cars on the market - I saw some recently and I'll see if I can find a link for you.
Google is your friend! Found these immediately - There will be others and doubtless in the UK.
Linky : - http://www.hrpworld.com/index.cfm?form_cat_id=59,7,363&action=category
And DemonTweeks in the UK : -
http://www.demon-tweeks.co.uk/products/ProductDetail.asp?cls=MSPORT&pcode=GLO025BLK
[Thanks for the Thanks!]
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I had already googled it, i was just interested to see how people might have secured these scoop ducts and piping etc
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Finally made a decision and after a little advice decided to go with uprated R32 rear set up. OEM ventilated discs, pads, calipers and carriers. Hopefully this should nail any chance of the rear "floating" under braking at the 'ring and having them ventilated should help with cooling over just solid ones. :jumpmove:
Going on next Monday.
Not a bad price fitted either :wink:
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I run some half the price of DS2500s Hawk fast road pads in the rear and they suffice, so long as they cope with the temps asked of them on a track day without crumbling then that'll do. They do this fine. Much as I love the DS2500s, they're a waste of money on the rear TBH.
The OEM rear pads I've had fall to bits on my MKIV on the track in the past, so I just bypassed them this time around and swapped them... they may well have been fine??, I don't know and didn't want to find out.
I thought about the upgraded rears to R32/S3 spec for a long time and I decided they weren't necessary on my car for my style of driving and its usage. I, like Jabbalad, like a loose rear - it isn't for everyone and its taken a long time to get the confidence to use it to my advantage, but I wouldn't like to change the dynamics I have now. For everyone else, then it's a perfectly good upgrade and in terms of value for money the best you can do to the rear.
Dave mentioned some DS2500 issues we've been talking about on UK-MKVs, this was just involving some of us who track our cars, not a 'free for all anecdotal moan'. Those with solid discs were finding that the pads were crumbling away and the compound changing thus damaging discs. Essentially it is down to the temps getting too high on them, they can't cope with a big heavy car and being stamped on constantly for seven sessions at 20 minutes at a time. They're excellent pads, but they can be taken past a limit of working effectiveness on a track. There's scoring and deposits left on the discs.
I haven't had this, but I have had the edge crumbling issues (see pic below from a set used at Oulton last month), it hasn't worried me enough to not replace mine with a fresh set of DS2500s, they're on the car now. The others are looking at the Pagid Blues (£200+ a set, so it isn't a cost factor) and some Mintex race pads simply to see if it suits them better? I've run out of my DS stockpile though, so I may look into some other options myself in the future.... getting a pad to do everything you ask of it road and track is extremely hard, a bit of experimenting is what's required. I may go to a 2 pad set up, road and track.
For the 'Ring, it isn't a brake heavy track, you use them a few times and there's plenty of cooling time in between - I haven't heard of anyone experiencing DS2500 issues there. For the road too, they're still my personal choice. There's nowt wrong with them and they're plenty better than 90% of others you can buy, but a track day is proving a bit much for them on some set ups.
Brake ducting is an avenue we're all going down to help that way, a detachable carrier mounted bracket to run it on the face of the disc, more on this when it is looking realistic/proven. Other options are being looked into too.
Right, the pad off my car. See how the edges are all crumbling away? The compound on the very edges has changed and is brittle, the others had this happen to the whole pad and big lumps were coming off... not good. Proves how much cooler a 2-piece disc runs though.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fe123%2Frobertsm2006%2FIMG_2171.jpg&hash=ce109e05374272cebae8d2757e2c038e16f4b9ce)
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^^^^
Great post and info, Mike! :happy2: 8) :happy2:
Trouble is I've just bought some DS2500 rear pads for my oem solid rear discs. Still, what little track work I've been doing so far is on the Nordschleife (though a day on a very fast track is scheduled).
I'll just have to keep a close eye on the state of things.
Thanks for that specific info about what others have been finding :drinking:
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You'll never get the rears hot enough to do that to them, I promise you.
Your fronts, I can't see you personally pushing your car to such a level that you'll experience crumbling either - so in your case the recommendation to use DS2500s is correct and sound judgement. You may no doubt get the same performance from some cheaper ones, but if you're comfortable, why change?
Considering how long they last on the rear, DS2500 cost isn't a biggie really, as you'll get tens of thousands of miles from them... but something to think about for others coming up for rear replacement.
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^^^^
Thanks, Mike - that's reassuring. :happy2: 8) :happy2:
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AS Robin has already said....great info Mike :happy2:
I'm going to try the OEM pads first as I think they may be enough with the larger R32 ventilated discs. If not, I still have that option in future. :smiley:
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Oh yeah, if you've got them, use them and see how you get on, Hurdy. You'll crumble them at worst, so just junk them and buy something a bit more suited.... so long as it isn't crap (cough EBC cough!!)
With the power you're running and considering they're going to be road brakes 300+ days of the year, I think your upgrade is a wise decision and will pay off well.
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Luckily I now have a couple of guys locally who can help me out with OEM stuff fairly cheap and this should pay dividends with getting stuff swiftly and at *cough* cost :happy2:
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....
I have it on good authority (AP Racing) that the Golf GTI does about 85% of its braking on the front wheels and consequently most big brake upgrades are front kits.
Oh, boy, you really do keep going on about that utter BS, from AP. As I have repeatly stated, the GTI, along with most road cars do NOT have an extreme bias like that. The Golf Mk5 platform cars are running around a 60:40 brake bias - and this is very EASY to prove!
For normal road use it's considered fine to leave the rear brakes as oem, but for trackday use it's advisable to at least upgrade your rear pads.
Nope, if you 'upgrade' the fronts, then the rears should also be upgraded, to maintain the balance. If you don't upgrade the rears, the rear end will become un-nervingly twitchy under heavy braking, in anything other than an arrow-straight direction, on billiard table smooth and level tarmac. And both you, and others have described this very situation.
If you don't, you may experience fade on them quite quickly and without fully realising.
That simply PROOVES just how hard the rear brakes are trying to work!!!!!! And it also proves that the rear bias is CONSIDERABLY more than the rubbish AP are spouting!
Unless you want it as eye-candy you don't really need to change the rear discs on the Mk5 GTI to something grooved and/or drilled - For the 15% work they do the plain discs are quite sufficient.
Nope, if you upgrade your fronts with 'bigger' discs, you really need enlarge the rear discs by the same relevent amount - to cope with the 40%, not 15% the rears have to deal with.
And you have completely failed to address the issue of the rear brakes working when the brake pedal isn't even pressed!
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never had a problem with them on track and don't really see the point . braided hoses will help tho
How do braided hoses improve brake efficiency? They do NOT. Just another 'snake oil' product. Braided hoses arn't even used in MotoGP, with their mighty carbon brakes, braking from 230mph!
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never had a problem with them on track and don't really see the point . braided hoses will help tho
....Weeeell, I'm inclined to take AP Racing's advice.
Perhaps adding braided hoses to the rear may also help but I won't bother with that until my next brake fluid change and also until speaking with AP and VWR again.
I remember asking T_T (Sean) about braided hoses in the past. He said that the OEM hoses are banded internally anyway and that they are more than up to the job. :happy2:
Correct. Braided hoses are only really usefull on rally cars, to prevent the hoses being cut from flying rocks and the likes.
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^^^^
Hey, T_T!! Helloooo!! I think my post was done here before we had our reasoned and calm convo about the same subject on the other forum.
:smiley:
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if the number was 85/15 then the car would feel absolutely awful to drive with excessive wear put on the front suspension to alleviate the massive dive that it would generate.
Agreed. If it did have an 85:15 bias, everytime you braked hard, the car would try and stand on its nose. But it doesn't. The Golf5 rear suspension has been designed with quite agressive 'anti-dive' geometry - an NEEDS quite a large rearwards brake bias. This is why Golf5s are fairly pitch 'neutral' when braking hard. :happy2:
Whilst I appreciate the advice came from AP (who sell brakes...front brakes.....) I would be sceptical that its actualy that bad in reality, sometimes generic flippant remarks come out with no real substance......
I fully agree! AP have NEVER backed up this statement! :stupid:
If the bias was indeed as bad as that the first thing on my shopping list would be a huge rear brake kit IMHO
Exactly, couldn't agree more! :happy2:
Braking is about balance - 85/15 sound right to you???
Not at all correct, by a long margin! :wink:
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My AP Big Brake Kit was fitted by their Senior Engineer at Coventry with myself present. At that time in 2006, I asked him whether he thought it was worth also fitting their AP brakes to the rear and he said no, saying that about 85% of braking on the Mk5 Golf was done by the front brakes and the power of the front AP's would 'do the job'.
The 85% value has been mentioned by him again since 2006 in our conversations and also yesterday when I specifically asked for his advice about what would be best to do now that I occasionally track (Nurburgring).
If AP are still standing by this bias rate, perhaps you can ask them to provide individual wheel braking effect readings from a rolling brake tester. But I honestly bet they wont be able to! :wink:
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As I have said, the car feels spot on with the FULL S3 upgrade, very well balanced front and rear braking. You can feel the rears working and for the money, I would rather have a system that was designed by the manufacturer to work on a similarly sized platform such as the S3.
The front may not be as 'Eye-candy' as AP, Tarox, or Brembo, but the system works very well. It is all about function for me. That is why I think the Audi S3 looks a far better car that the pictures of the golf R20.
But as always each to their own.
:happy2:
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robin 85/15 would drive crap and thats the sort of split I would expect from a ford fiesta with rear drums.....
And that would usually be with the assistance of a relatively 'dumb' pressure limiting valve in the rear hydraulic circuits.
Front end dive is not a good trait - wherever possible 60/40's ///// 70/30 is the figure normally aspired to
Agreed, and on modern cars with anti-dive rear suspension setups, they can often run closer to 55:45 front to rear.
And I don't know if you are aware, the new Renault Laguna has larger REAR brakes than it does up front, and that is a front engine, front wheel drive car. The rears really do play a massive part not only in traditional 'braking', but also in terms of vehicle stabilty, when controled by ESP systems.
Dont know whether its an installation issue but the 2500 compund has been getting a bit of a slating recently over on uk-mkivs, the pad of choice over there at the moment seems to be the pagid blues
Ferodo went through some very serious quality issues in the 1980s and early 90s! Anyway, are these Pagid Blues the same as Pagid RS pads? :confused:
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Just thinking aloud, but both the oem R32 and S3 rear brakes will surely have been designed to work on 'driven' rear wheels (be it Haldex or quattro).
Not really. When the brake pedal is pressed, the Haldex automatically disengages the drive to the rear wheels. Haldex only sends drive to the rears during acceleration, and then only after the fronts have lost traction. So that thought, whilst perfectly reasonable, is not technically correct! :wink: :smiley:
Does this suggest that fitting them on the rear of the FWD Mk5 GTI may be overkill?
Nope! :happy2:
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TT, what would you suggest to complement (i.e. rear brakes) the 360mm 6 pot front brakes I will be getting installed in a couple of weeks time?
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^^^^
I've said most of what I have to say on this subject on the other forum - I can't be arsed to drag it all up again. Likewise I wouldn't expect AP to be arsed to dig up info for a forum - You can see why most companies don't want to get involved in forum discussions and when they do it rarely lasts for very long.
All any of us can ever do is post info which we believe to be to the best of our knowledge - Sometimes it's spot on and sometimes it turns out to be bollox, no matter who we are.
Whichever brand of whatever mod we choose, we are each going to believe it's the best because it's what we chose for ourselves and it's also natural to justify our decisions to ourselves.
stokeballoon is very happy with his setup and I'm happy with mine.
[/end of]
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In my opinion i would just stick some decent pads in the back, front wheel drive cars shouldnt use much rear braking... when your trying to do everything through the front wheels the last thing you want to do it to make the back too stable!
In a mid engine car it is possible to have more rear braking... because thats where the weight is!
For front engined front wheel drive its alwase going to stand on the nose when braking, no matter what suspension setup you have... so the front wheels have the most amount of grip to put the braking force through!!
What utter nonsence! :sick:
at the end of the day when VWR (or any touring car team) build a car if there was an advantage to fitting huge rear brakes on a front wheel drive car dont you think they would use it?
Erm - that is because a RACING CAR is a massively different beast ot a road car! :stupid: :stupid: :stupid: :stupid:
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Guys, whilst this is all good discussion - I can't help feel confused.
I have a big brake kit arriving any time this week. Should I also look at upgrading my rear pads, or go for the plunge and upgrade the discs as well?
To maintain car stability, you really need to be looking at larger rears too. :happy2:
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Guys, whilst this is all good discussion - I can't help feel confused.
I have a big brake kit arriving any time this week. Should I also look at upgrading my rear pads, or go for the plunge and upgrade the discs as well?
....Personally I would get to know your front big brake kit first and then later think about your rears.
I'd have to strongly dispute that. What if he lost the rear round a corner whilst braking - which could be highly likely if you just go for 'bigger' fronts!
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The front may not be as 'Eye-candy' as AP, Tarox, or Brembo, but the system works very well. It is all about function for me. That is why I think the Audi S3 looks a far better car that the pictures of the golf R20.
But as always each to their own.
:happy2:
....Indeed each to their own but you appear to be saying that you think the Audi S3 is a far better car than the Golf R because you think the S3 looks better. To me, for example, the S3's looks don't appeal and neither do its looks say "I am better designed etc".
Are you saying that you think the S3 is a 'better' car because you prefer its aesthetic styling?
No car is perfect and I expect you'd also agree that no helicopter is perfect - They each have their individual strengths and weaknesses and appeal in very different ways to our individual senses on many levels - Just like women! (or men if you're gay).
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In my opinion i would just stick some decent pads in the back, front wheel drive cars shouldnt use much rear braking... when your trying to do everything through the front wheels the last thing you want to do it to make the back too stable!
Thats my part anyway, and i dont really need to justify this...
Not necessary to justify anything mate, could you just elaborate on the bit Ive highlighted
no problem, when your fast road or track driving in a front wheel drive car the only way it's going to go quick is if you can be the last on the brakes and first on the power, the only way to do this is to have the car pointing in the right direction as early into the corner as possible with the least ammout of steering input a possible... This doesn't work if the back end is too settled! (we have tried it) you can brake much further into corners with very little rear brake.
I see what your saying that the more even braking should mean better stopping abuility... And on mid engined or rear engined cars this is correct, but it's not really the right direction for front engined front drive cars! In my opinion of course.
But that is fine when used purely on the track. But for on highway use - it is NOT the best, nor safest way to set up the brakes! :fighting: :fighting:
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Guys, whilst this is all good discussion - I can't help feel confused.
I have a big brake kit arriving any time this week. Should I also look at upgrading my rear pads, or go for the plunge and upgrade the discs as well?
....Personally I would get to know your front big brake kit first and then later think about your rears.
I'd have to strongly dispute that. What if he lost the rear round a corner whilst braking - which could be highly likely if you just go for 'bigger' fronts!
....What, like everyone else who has only fitted a big brake kit to their fronts hasn't done?
[You wanna stay off the brakes mid corner anyway]
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I've taken the plunge and gone for a big brake kit from HiSpec- 2-piece 360mm diameter discs, steel braided lines, 6 pot billeted calipers, 5.1 brake fluid, and some Ferodo DS2500 pads.
http://www.hispecbrake.co.uk/calipers.htm
Hmmmm . . . . not really known on the VAG scene - and this shocking cock-up shows - http://www.hispecbrake.co.uk/Conversions/START%20audi.htm - do they REALLY think that an Audi S2 is the same as an A2 !!!! :scared: :scared: :scared: :scared: :sick:
And they don't know the difference between a Mk4 Golf and a Mk5 - http://www.hispecbrake.co.uk/Conversions/START%20vw.htm
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Agreed. Modding enhances a car because the manufacturer builds them to a lower common denominator.
Nope, they build them to appeal to the masses, at a reasonable price. Volkswagen are, afterall, a mainstream manufacturer, just like say F0rd, V@uxhall, Reno, etc, and NOT some high end sports car manufacturer!
Example: The VW air intake is more of a hot air intake because VW have to cater for cold starts in colder climates [probably not the best example, but].
What an utter load of BS. The standard GTI intake is probably in one of the most efficient areas, and is DEFINATELY a COLD air intake!!!! :booty:
And then there's all the crap about emissions etc.
Emissions may be 'crap' - but they are a legal requirement! :indifferent:
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Do you two ever give up????????
Can I ask this remains on topic please.
Just in case you have forgotten there is a clue in the title - Rear Brake Pad Upgrades.
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I must say that now I've upgraded the rear to an S3 set-up, with OEM S3 pads (on topic Steve :happy2:) the balance of the car is much better under heavy braking. The R888's did give me extra grip to stop faster, which for me showed up the imbalance more. Brakes can primarily only ever be as effective as the friction between the tyres and the braking surface, once this is broken then ABS and the other plethora of electronic controls help balance the braking with the available grip. So, with more available grip, my rears struggled more. Now the balance has been redressed I'm happy that the available braking power is much more stable than it was with just the TAROX upgrade at the front. :smiley:
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TT, what would you suggest to complement (i.e. rear brakes) the 360mm 6 pot front brakes I will be getting installed in a couple of weeks time?
The only real options would seem to be the S3/R32 set up. That is what I shall be going for.
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TT, what would you suggest to complement (i.e. rear brakes) the 360mm 6 pot front brakes I will be getting installed in a couple of weeks time?
The only real options would seem to be the S3/R32 set up. That is what I shall be going for.
....And it's what I might consider if I have any dodgy 'experiences' which suggest it's a good idea!
But meanwhile, as I stated in the original post of this thread, I'll try just the DS2500 pads and take it from there.
:smiley:
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^^^^
I've said most of what I have to say on this subject on the other forum - I can't be arsed to drag it all up again. Likewise I wouldn't expect AP to be arsed to dig up info for a forum - You can see why most companies don't want to get involved in forum discussions and when they do it rarely lasts for very long.
Huh, no one is specifically asking AP to get involved in the 'forum'! :stupid: :sad1:
However, the likes of Revo are more than happy to support the forum, and offer real help. :notworthy: :notworthy:
I just think that it is vitally important - because either AP just 'made up' the 85:15 figures, or they have it from 'real' testing - so I don't think that it is at all unreasonable for them to back up what they are saying. If they did not make up this wild statement - they should be able to offer proof. :popcornsoda:
Peeps wouldn't buy a remap if some tuner quoted wild figures (and APs claim of 85% is more than 'wild') without backing it up with some dyno plots! :fighting2:
All any of us can ever do is post info which we believe to be to the best of our knowledge - Sometimes it's spot on and sometimes it turns out to be bollox, no matter who we are.
I don't have a prob at all with that. And nor do I have a prob with anyone posting 'incorrect' info, if they themselves genuinely are unaware that there may be inaccuracies. :smiley: :drinking:
Whichever brand of whatever mod we choose, we are each going to believe it's the best because it's what we chose for ourselves and it's also natural to justify our decisions to ourselves.
Again, each to their own and all that. :smiley: However, I think peeps need also to be able to 'smell the coffee' when they have been sold something which doesn't match up to some hype! :chicken:
stokeballoon is very happy with his setup and I'm happy with mine.
[/end of]
And whilst that is all exceedingly important, I certainly don't think it should be so agressive as 'end of'. If you personally followed that ethos, then you'd have still been stuck with your Koni FSDs! :surprised:
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The only real options would seem to be the S3/R32 set up. That is what I shall be going for.
And perfectly suitable -going much bigger than 310mm on the rear quickly gets you into the realms of diminishing returns.
Any upgrade front and rear must always consider the size of the fairly small master cylinder on the Mk5, theres been a couple of people over on the Mk4 forum who have gone for S4 fronts on a Mk5, the problem being the piston size is bigger. The 286mm caliper and the 310mm caliper both share the 38mm piston so for all intents and purposes its rearward bias but without all the other baggage that would accompany either a 2 or 4 pot upgrade.
I drew and fabbed a bracket to use Evo 2 pot rears and compbrake handbrake calipers but quickly realised that the R32/S3 rear setup ticked all the boxes and more importantly wouldn't compromise hydraulically any front upgrades already done.
Ive got a fitting kit for RS4 rears here - but to go from the Mk5 38mm piston to the RS4 43mm piston whilst only 5mm is volumetically a country mile and would drive crap, looked into MC upgrades for the Mk4 with no joy but theres too much parts bin engineering in the Mk5 for there not to be a 25mm+ MC in group that would really open up some serious rear upgrade options.
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Ok guys... there's a lot of "fluff" flying around!
What's the rear setup that I should go for? TT?
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Guys, whilst this is all good discussion - I can't help feel confused.
I have a big brake kit arriving any time this week. Should I also look at upgrading my rear pads, or go for the plunge and upgrade the discs as well?
....Personally I would get to know your front big brake kit first and then later think about your rears.
I'd have to strongly dispute that. What if he lost the rear round a corner whilst braking - which could be highly likely if you just go for 'bigger' fronts!
....What, like everyone else who has only fitted a big brake kit to their fronts hasn't done?
YES, because virtually EVERYONE who has fitted big brakes just to the front, and who use their brakes earnestly - have reported very undesireable traits from the rear end!
Now if you personally are happy to take that risk, then fine - but in my humble but professional opinion - I consider it vital to warn others of the possible potential for a nasty surprise!
[You wanna stay off the brakes mid corner anyway]
I fully agree - but in the 'real world' - sh!t sometimes happens - no matter how good a driver you are. Furthermore, the vast majority of drivers have never recieved any 'advanced' driver training, and know how to correctly brake. This is exceedingly apparent when you are a motorcyclist - following a car mid corner, and it brakes mid-corner when there is absolutely no need!
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Do you two ever give up????????
Can I ask this remains on topic please.
Just in case you have forgotten there is a clue in the title - Rear Brake Pad Upgrades.
Erm - we ARE discussing 'rear brake pad upgrades' - and that happens to also consider other alternatives too! :nerd:
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I must say that now I've upgraded the rear to an S3 set-up, with OEM S3 pads (on topic Steve :happy2:) the balance of the car is much better under heavy braking. The R888's did give me extra grip to stop faster, which for me showed up the imbalance more. Brakes can primarily only ever be as effective as the friction between the tyres and the braking surface, once this is broken then ABS and the other plethora of electronic controls help balance the braking with the available grip. So, with more available grip, my rears struggled more. Now the balance has been redressed I'm happy that the available braking power is much more stable than it was with just the TAROX upgrade at the front. :smiley:
Well said, John! :grouphug: 8) :party:
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What's the rear setup that I should go for? TT?
R32=S3=TT= All the same
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The only real options would seem to be the S3/R32 set up. That is what I shall be going for.
And perfectly suitable -going much bigger than 310mm on the rear quickly gets you into the realms of diminishing returns.
Any upgrade front and rear must always consider the size of the fairly small master cylinder on the Mk5, theres been a couple of people over on the Mk4 forum who have gone for S4 fronts on a Mk5, the problem being the piston size is bigger.
Eeek - the S4 caliper, whilst being physically identical to the R32/S3 front caliper, has a 60mm dia piston, whereas the R32/S3 is 57mm. 3mm diameter difference doesn't sound much, but it has quite an effect on surface area!
So what size diameter is the Mk5 master cyl - 22mm? :confused:
The 286mm caliper and the 310mm caliper both share the 38mm piston so for all intents and purposes its rearward bias but without all the other baggage that would accompany either a 2 or 4 pot upgrade.
Are you sure on that? The 286mm rear caliper is 38mm, but according to all the data I have, the 310mm caliper for the S3/R32 uses a 41mm piston!
I drew and fabbed a bracket to use Evo 2 pot rears and compbrake handbrake calipers but quickly realised that the R32/S3 rear setup ticked all the boxes and more importantly wouldn't compromise hydraulically any front upgrades already done.
That's really good to know. :happy2:
Ive got a fitting kit for RS4 rears here - but to go from the Mk5 38mm piston to the RS4 43mm piston whilst only 5mm is volumetically a country mile and would drive crap, looked into MC upgrades for the Mk4 with no joy but theres too much parts bin engineering in the Mk5 for there not to be a 25mm+ MC in group that would really open up some serious rear upgrade options.
Tell me more! :wink: :smiley:
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What's the rear setup that I should go for? TT?
R32=S3=Cupra?=TT= All the same
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What's the rear setup that I should go for? TT?
R32=S3=TT= All the same
OK, that settles it. Gotta find a R32 rear kit to install.... thanks everyone.
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@TT
You are indeed correct sir :booty: 2 mins on google has found me out! 41mm is the figure!
So.....
R32/S3 Front is 57mm compared to 54mm for the Gti
R32/S3 rear is 41mm compared to 38mm for the Gti
Total surface area of all 4 pistons on the GTi = 6850 mm2
Total surface area of all 4 pistons on the R32/S3 = 7745mm2
A 13% increase on the same (23.8mm)??? master cylinder (confidently assuming 23.8mm as the Gti piston sizes are the same as the Mk4)
So 13% is the figure that we can hydraulically upgrade to and keep an OEM Pedal
TT you aware of any proportioning that goes on front to rear?
So just considering MC upgrades from within the VAG group, you could calculate as a percentage the master cylinder surface area against total piston area which works out for the GTi at 6.5% and for the R32/S3 5.75%. Interestingly enough the S4 with the 60/43mm pistons works out at a middlingish 6% dead with the 25.6mm master cylinder.
So assuming you could reduce that OEM 6% by 13% to 5.22% on the S4 or similar Master Cylinder in much the same way that VW did with the S3/R32 against the Gti it would give you a total piston surface area of approx 9850mm2 which would be handy and would maybe open up the possibility of some 4 pot rear conversions :laugh:
So im off to scour EKTA for a master cylinder within group that would suit, I normally try to find the servo/MC seal part number from the unit Im trying to replace and search for that as a starting point - anybody else any other ideas or candidates???
With the ESP sensor being downroute of the MC now Im thinking maybe something like a transporter van, we could also do with somebody with a Mk5 track slag that we could experiment with as opposed to a road car.
Its funny how history repeats itself - sticking a Mk2 Gti MC into a Mk1 Gti was a popular upgrade in the eighties :signLOL:
E&OE !!!!!!! Somebody for fecks sake check my maths
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I just did a quick calculation Dave and all your figures above are correct. :grin: :rolleye:
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I just did a quick calculation Dave and all your figures above are correct. :grin: :rolleye:
I thought so too Tom!
:happy2: :happy2:
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Interestingly enough the S4 with the 60/43mm pistons works out at a middlingish 6% dead with the 25.6mm master cylinder.
....Was at Brands Hatch today and one of the VW Cup teams was running S4 brakes but ALL the teams I saw were running oem brakes on the rears of the Mk5 GTI.
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Without locking horns again Robin and covering old ground, track cars no problem, no road ride height, uber stiff suspension.
The adverse dive can be dialed out when there are no other compromises to make
The S4 brakes just look like R32/S3 brakes from the front, you'd need to strip them and measure the piston to be sure...
Unless you asked of course in which case I'll stfu! :signLOL:
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Without locking horns again Robin and covering old ground, track cars no problem, no road ride height, uber stiff suspension.
The adverse dive can be dialed out when there are no other compromises to make
The S4 brakes just look like R32/S3 brakes from the front, you'd need to strip them and measure the piston to be sure...
Unless you asked of course in which case I'll stfu! :signLOL:
....No locking of horns - Just discussion. We don't have to agree about everything.
At least you've now written it in plain English I can understand :grin: (re track cars) - The highly detailed tech stuff goes over my head.
No I didn't ask about if they were S4 brakes - I would have felt a bit stupid as they had S4 written on them.
:drinking:
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Yeh sorry mate, they started putting S4 on them after they went B7. Just done some GT40 fronts onto a B6 S4 and they looked like scruffy R32 unpainted calipers
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DaveB1970 - good stuff about the master cylinders. Are they easy to change?
As I'm looking to upgrade the rear brakes with the ones from the Seat Cupra, I might as well do the master cylinders from the R32.
Are there two separate master cylinders, front and rear?
Presumably, the Seat's rear brake kit will be a straight fit on the GTi?
Part numbers for all this would be very helpful... Many thanks in advance.
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....
Back on the subject of rear brake pad upgrades, inspection of mine shows that whereas I wore my front DS2500's almost to the metal there is still loads of pad thickness on my rears, so I shan't be putting new pads on yet.
Any rear end 'twitchiness' I've experienced under harder driving is most definitely the ESP kicking in but I've found that it's best to ignore and drive through it, taking it on board as feedback information.
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If there is so much difference with the pad wear, do you think that you could get VWR or JKM to alter the brake bias to give more bite at the rear?
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If there is so much difference with the pad wear, do you think that you could get VWR or JKM to alter the brake bias to give more bite at the rear?
....Is this done via software? If so, then Keith at JKM would be best to do it.
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If there is so much difference with the pad wear, do you think that you could get VWR or JKM to alter the brake bias to give more bite at the rear?
....Is this done via software? If so, then Keith at JKM would be best to do it.
It's something T-T DEMANDED should be done, but as usual when asked to explain how you do it, he couldn't/wouldn't answer. I dont know anyone who knows anything about it or its parameters. I'm guessing it's a dealer version of VCDS job?
Worth finding out though.
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^^^^
I'll have a word with both my friendly VW dealer when I see them on Tuesday and with my mate Dan (ex VW techie) who is now a Revo agent and knows about software. I'm pretty sure it's something that a VW dealer will not be allowed to change from oem and can appreciate why.
Dear old T_T, eh? :laugh: Bless him! He and I have some wonderful exchanges but have met lots of times and it's never a problem.
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Bonjour....
Only soft coding available vis a vis brake wise is to tell the ABS what size wheels you're running. Its nothing to do with braking per se, its just so that it can intervene appropiately and "release" the disc properly
Imagine your brake disc clamped by your pads is a rusty bolt, you can either use a 6" ratchet (15" wheels) or a 24" breaker bar (18's) to turn it 18s will continue to turn your wheel where 15's would have locked them up for a given clamping force by the pads .
Its not about the braking systems ability to lock the wheels i.e.2/4/6/8 pot and big discs against 288's
I appreciate its all supposed to be the same rolling circle but invariably its not and I think there is soft coding to trim the MPH reading for different alloys as well
PS numbers totally random to demo the point
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Bonjour....
Only soft coding available vis a vis brake wise is to tell the ABS what size wheels you're running. Its nothing to do with braking per se, its just so that it can intervene appropiately and "release" the disc properly
I appreciate its all supposed to be the same rolling circle but invariably its not and I think there is soft coding to trim the MPH reading for different alloys as well
....Interesting!
So, for example, my GTI left Wolfsburg with Monza 17's and was therefore soft-coded accordingly. When I swopped to Monza 18's, although it was a factory option, my existing coding thinks I'm still running 17's.
Would the coding also take a weight of the wheel into account? - Surely that would be ignored as such and reacted to smartly according to lack of grip etc regardless of how it was caused.
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Robin heres a link to a brief thread over on Vortex
http://forums.vwvortex.com/zerothread?id=2739583 (http://forums.vwvortex.com/zerothread?id=2739583)
The part number 1K0 907 379 E can not be recoded 1K0 907 375 E can be apparently....
Maybe start a thread in the VDCs section - somebody somewhere has played with it probably with some success
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^^^^
Not for the feint hearted! Personally I'll be leaving such methods well alone. The car hasn't put me in a ditch so far with things as they are.
:happy2:
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....
Just to update this thread with the info that I am now buying some S3 rear brakes (whole kit) from DaveB.
Like most mods, they aren't absolutely essential but I have learnt a lot from the discussions on this thread and they appear to be a very good upgrade to better match my AP Racing front brakes, especially as I have started to do more trackdays/Nordschleife.
DaveB is a bit modest about being called a 'brakes guru' but he certainly knows his stuff and is also able to supply all sorts of brake components extremely competitively priced.
:drinking:
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....
Just to update this thread with the info that I am now buying some S3 rear brakes (whole kit) from DaveB.
Like most mods, they aren't absolutely essential but I have learnt a lot from the discussions on this thread and they appear to be a very good upgrade to better match my AP Racing front brakes, especially as I have started to do more trackdays/Nordschleife.
DaveB is a bit modest about being called a 'brakes guru' but he certainly knows his stuff and is also able to supply all sorts of brake components extremely competitively priced.
:drinking:
I knew that once you had it in your head it wouldn't be long before your slope got a little slippy again :grin: :driver:
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I knew that once you had it in your head it wouldn't be long before your slope got a little slippy again :grin: :driver:
....You're not entirely blameless in spending my money on the S3 rear brakes either!
It was you who so graphically described how much better they are than oem rears with a front BBK. I think it will encourage me to use my brakes more than I do.
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I knew that once you had it in your head it wouldn't be long before your slope got a little slippy again :grin: :driver:
....You're not entirely blameless in spending my money on the S3 rear brakes either!
It was you who so graphically described how much better they are than oem rears with a front BBK. I think it will encourage me to use my brakes more than I do.
I try my best :evilgrin:
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How do the S3 Rears differ to the Cupra brakes? The cupra fronts are massive
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How do the S3 Rears differ to the Cupra brakes? The cupra fronts are massive
I'm not 100% sure, but the Cupra rears are the same as the GTI's....286mm solid.
The S3 ones are 310mm and vented :happy2:
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How do the S3 Rears differ to the Cupra brakes? The cupra fronts are massive
I'm not 100% sure, but the Cupra rears are the same as the GTI's....286mm solid.
The S3 ones are 310mm and vented :happy2:
Ta John, Ill be looking for an S3 upgrade then:)
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....
Another quezzie for our resident brakes guru........
:pomppomp: :pomppomp:....... DaveB !!!! :pomppomp: :pomppomp: :star:
Or perhaps everyone would prefer : -
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FRedRobin_05%2FHotties%2Fcheerleader.jpg&hash=67629c2c3651036e9fc86f44f090386cf6500027)
Anyway, the question is whether it's ok to use DS2500 pads on rear discs (S3) which are neither drilled nor grooved. My thinking is whether perhaps the DS2500 compound is kinder to the disc in some way if grooves are present.
:drinking:
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Camel-toe alert!
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^^^^
Oh dear! What have I started!? Friday night, eh! :jumpmove:
That song is just brilliant! :laugh: :laugh: :laugh: :laugh: :congrats: :congrats: :congrats: :congrats:.............. :star:
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Hi Robin.
They'll work well on the back of the S3 setup, wouldn't worry too much about the plain discs. I like the DS2500 it ticks a lot of boxes but just makes a mess when they go off.
Cheers Mate
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I am having these fitted 335 rotors TVr -AP- calipers and DS2500 pads to replace the 312/single pot set up on my Leon Fr.
http://i59.photobucket.com/albums/g284/mechanicalrepairs/vwbrakes001.jpg
what would be a sensible rear set up with brisk road work in mind?
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^^^^
Speaking only from the experience of having similar size front brakes on my Mk5 GTI (AP Racing 4-pot with DS2500's) and oem rear brakes and pads, I wouldn't put changing or modding your rear brakes high on your list of priorities. I'm changing to S3 rears now but have done about 50,000 miles with AP fronts and stock rear brakes on all sorts of roads and journeys and without any cause for alarm.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FOZ_13Oct09_front.jpg&hash=9ce48b636c5462755ba1a9a26497134c078d42ce)
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Thanks very much for a prompt and helpful reply- I was thinking of DS2500s for the rear as well- not as a priority but in oder to seek to maintain balance. Early on in this very entertaining and informative thread someone posted a part number for rear pads which had my creit card itching.....
Btw how do I give a thank you for a post- as I would like to.
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^^^^
Subject to the wear on the pads in the S3 rear kit I've bought (I haven't opened the packaging yet!) I intend to fit the DS2500's I've already got (still in their box but looked at!). Hence my question earlier.
DaveB is the resident brakes guru, so I would always listen what he has to say.
Just click the star Thank You on the top righthand side of the post you want to thank.
:happy2:
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I'm too new for pm's so will just hope he comes on here again!
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I'm too new for pm's so will just hope he comes on here again!
....He definitely will. The way it works is that if you 'subscribe' to a thread, you will recieve an email notification everytime someone posts a new reply in the thread (until you 'unsubscribe').
You can set it up so that you are automatically subscribed to every thread in which you post:
Go to your Profile > Modify Profile > Notifications and Email and tick the boxes as you want.
HTH (Hope This Helps) :smiley:
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I am having these fitted 335 rotors TVr -AP- calipers and DS2500 pads to replace the 312/single pot set up on my Leon Fr.
http://i59.photobucket.com/albums/g284/mechanicalrepairs/vwbrakes001.jpg
what would be a sensible rear set up with brisk road work in mind?
Where did you get this set up from mate. How much If you dont mind me asking? Slightly smaller discs than my cupra but more efficient calipers, lighter discs too. How do you find them?
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^^^^
Subject to the wear on the pads in the S3 rear kit I've bought (I haven't opened the packaging yet!) I intend to fit the DS2500's I've already got (still in their box but looked at!). Hence my question earlier.
DaveB is the resident brakes guru, so I would always listen what he has to say.
Just click the star Thank You on the top righthand side of the post you want to thank.
:happy2:
I am not to sure why, its probably just me Robin, but it makes me cringe when you ask for people to click your thank you. :sick:
Is it not enough that they say thank you very much in the post. :stupid: :ashamed:
I know your going to say you were just trying to help a new member out by pointing this out but you have done it on at least 3 other occasions. (https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Ftomashandmilly%2FDaft_stuff%2Fgeez.gif&hash=1e4ac29faa1caba17c45c7db8c69a9c4990b012c)
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^^^^
@ TC:
Yes, you're correct in realising what I'm going to say - I wonder why :grin: : -
I was directly asked how to use the Thank You feature and you should note that I wrote how to do so in a way which was purposely general and not specifically for myself.
Yes, of course I enjoy it knowing that I have helped someone enough for them to go as far as clicking the Thank You button and I'm not ashamed of that.
Instead of taking the opportunity to criticise what I posted, you, as a Moderator, really ought to be more grateful that a member (in this case myself) has bothered to help a newbie in response to their question. Perhaps you should click me a Thank You too :evilgrin:
Or is it my turn to be someone for you to have a go at..... Again. :rolleye:
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Dress it up how you want asking for thanks is like touching a slug. :fighting2:
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Go easy Top Cat- I did ask - as a newbie I was grateful for the help and wanted to do so but was too slow to work it out for myself-if you read my post you will see Robin just answered my request.
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@TT
You are indeed correct sir :booty: 2 mins on google has found me out! 41mm is the figure!
:happy2: :happy2:
TT you aware of any proportioning that goes on front to rear?
Don't think this was answererd.
Basically, the Golf Mk5, and just like all modern ABS (with EBD) - does NOT use any knid of 'mechanical' brake biasing or proportioning. All modern brake systems now have much greater 'default' bias to the rear - typically 60% front, 40% rear. The actual finite biasing is done on the fly via the electronics in the ABS - more specifically, the EBD, or 'electronic brake-force distribution'.
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Without locking horns again Robin and covering old ground, track cars no problem, no road ride height, uber stiff suspension.
The adverse dive can be dialed out when there are no other compromises to make
The S4 brakes just look like R32/S3 brakes from the front, you'd need to strip them and measure the piston to be sure...
Unless you asked of course in which case I'll stfu! :signLOL:
....No locking of horns - Just discussion. We don't have to agree about everything.
At least you've now written it in plain English I can understand :grin: (re track cars) - The highly detailed tech stuff goes over my head.
No I didn't ask about if they were S4 brakes - I would have felt a bit stupid as they had S4 written on them.
:drinking:
Just throw a spanner in the works - they could have fitted an S4 caliper spring to an identical looking S3 caliper - therefore had 57mm pistons. :wink:
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If there is so much difference with the pad wear, do you think that you could get VWR or JKM to alter the brake bias to give more bite at the rear?
....Is this done via software? If so, then Keith at JKM would be best to do it.
It's something T-T DEMANDED should be done, but as usual when asked to explain how you do it, he couldn't/wouldn't answer. I dont know anyone who knows anything about it or its parameters. I'm guessing it's a dealer version of VCDS job?
Worth finding out though.
Hey - that's a bit harsh! I may have strongly recommended doing it - but never 'demanded' anything. And I've regularly posted links to both the vortex thread and the RossTech wiki site. :smiley: