All Things Mk5 > Performance Modifications
Rear Brake Pad Upgrades....
Hurdy:
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:
RedRobin:
--- Quote from: Hurdy on September 02, 2009, 11:06:14 am ---
Dave also knows his stuff Robin :wink:
--- End quote ---
....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:
QD MBE:
--- Quote from: RedRobin on September 02, 2009, 10:24:29 am ---
--- Quote from: monkgti on September 02, 2009, 06:17:44 am ---
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.
--- End quote ---
....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.
--- End quote ---
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.
DaveB@Vagbremtechnic:
--- Quote from: RedRobin on September 02, 2009, 10:07:59 am ---^^^^
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.
--- Quote from: DaveB1970 on September 02, 2009, 08:03:52 am ---
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.
--- End quote ---
....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.
--- End quote ---
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
--- Quote ---One of the reasons for upgrading the pads to DS2500's on oem GTI rears is to reduce generated heat and its ramifications.
--- End quote ---
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
RedRobin:
....
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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