MK5 Golf GTI
All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: rex on January 02, 2013, 07:44:28 pm
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Hello,
I am opening a new thread concerning brake ducting. I am aware that there is another similar thread in the "General Area" but after reading it, it does not seem to answer my questions.
So... After having a NQSBBK for a couple of years I came to the conclusion that this is not enough for tracking even a 160bhp Golf. I find the kit awesome but I think that what I need to have a complete car (from the brakes point of view) is to have proper brake venting. I installed the RS3/TTRS brake vents but I want more.
I will try to explain what I am thinking about and if you guys think I am not on the right path or I might be doing something different please intervene.
After much consideration I think NeilM's solution
(https://live.staticflickr.com/65535/51243562780_e16e43c1c8_o.png)
is only partially ok because I would like the ducting to be closer to the discs.
1. Where does the air come from?
Well, I think the best way to get air to the brakes is to get it from the open fog grilles. I, unlink a normal GTI driver, don't have the normal GTI (or opened GTI) fog grilles.
I have the RLine fog grilles (these can also be fitted to a GTI fender):
(https://live.staticflickr.com/875/27739904998_48a9a7d1dd_o.jpg)
(https://live.staticflickr.com/789/40876998334_84c22045e2_o.jpg)
As you can see in the picture above, these fog grilles have a cover next to the fog light hole. This cover can be taken out or left in place depending on the driver preferences. This cover makes it really easy to create a brake ducts hole. I just cut a hole (the red circle)
(https://live.staticflickr.com/817/27739904818_f53b6b1c07_o.jpg)
(https://live.staticflickr.com/933/40898141094_d9b3bc60ec_o.jpg)
and attach the brake ducts.
This is a very clean solution and without a negative impact on the looks of the car, because, personally, I do not like this:
(https://live.staticflickr.com/931/27739715828_de629d671b_o.jpg)
2. Well, one end is done and another end remains. Now I have to attach the brake duct to the brake assembly. I am thinking that the best way to go is for the air to exist the brake duct and enter the disc vanes, thus cooling both regions of the disc. Something like this:
(https://live.staticflickr.com/887/27735818578_14e7faef8f_o.jpg)
(https://live.staticflickr.com/65535/51242720478_558fe039a5_o.png)
I saw that some people are not concerned by sending the air into the disc vanes and just redirect the air to one side of the disc:
(https://live.staticflickr.com/811/39801209530_0fc4f7bb99_o.jpg)
(https://live.staticflickr.com/882/39800873520_94c3b11aed_o.jpg)
I tried to find information about the right way to do it but I found nothing so I might be mistaking but this way makes no sense to me... By sending air to one side of the disc, that side of the disc will be cooler than the other one so no quite optimal in my opinion (again, if I am mistaking please correct me).
So, I am thinking of manufacturing a piece that will be attached to the mud guard (I do not want to take the mud guard off because this is still my daily drive) and will have an opening to let the air out and direct it to the disc vanes. Unfortunately I have almost no Photoshop skills (and I do not have a hub + disc + mud guard assembly yet in order to make photos and explain) but I hope you know what I am trying to say...
(https://live.staticflickr.com/828/27739904728_e3d4612bf3_o.jpg)
This is pretty much what I have in mind. What do you think?
Oh.... and one more thing... Since this is still my daily drive and since I have (and hopefully will still have) seen some track day action with cold weather (~4 degrees) I think I need a way to "cancel" the brake ducts with minimal effort. I saw some people duck tapping the intake of the brake ducts but I am looking for a more elegant and permanent solution. I am thinking of putting another piece between the brake duct itself and the final piece (the one attached to the mud guard) this piece can be taken out whenever I change the wheels and setup the suspension for a trackday. This piece will either allow or block the flow of air to the brakes. Is this a good idea?
Thanks!
P.S. Sorry for the long post.
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The setup in that first picture wont do diddly squat!
It needs trunking all the way to the back of the disc to stand a chance of working.
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(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi1237.photobucket.com%2Falbums%2Fff469%2Fvladpanut%2FBrakevent2_zps3da3a8e1.jpg&hash=9bbe13c6fcc683315b99193479b8b96d7c401552)
I agree its far from the perfect solution, although it will fill the wheel arch with cool air which has no where else to go but through the alloys and arch gaps and maybe underneath. But its better than nothing.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi1237.photobucket.com%2Falbums%2Fff469%2Fvladpanut%2Fbrakes_e46_backingplate_installed_lg_zpsf262e20e.jpg&hash=c16faf307318eeed0b7fc3cecb900dea6fa456cd)
This looks to be a good idea. Forcing air into the central hub area and then out through the cooling vents. My only question is which way do the vents work. Does it suck cool air into the central hub area at the rear of the disc then push it out through the vents in the disc or does the air get drawn in from the outer points of the disc as it rotates and forced out through the cental hub at the rear of the disc? If its the latter the above method might be wrong.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi1237.photobucket.com%2Falbums%2Fff469%2Fvladpanut%2FP8066749.jpg&hash=9fed74c47f63e3de732e734be3f0ced0b6b4029e)
This was my plan. Its probably the simplest option and will no doubt be effective, but, your only cooling one side of the disc so will have a temperature gradient present between both sides of the disc so the pads will no doubt wear unevenly due t the difference in the temperatures etc.
Would like to see what DaveB has to say about this.
You also dont want to cool them down too much either, as you could then lose performance on your pads.
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richwig83 as I said above that is what NeilM has done to his car. I think that solution is better than no brake ducts at all. I am thinking that redirecting air in the wheel arch will create an area of high pressure thus forcing the air out of that area, cooling the brakes. As you say, and as I sail above I would like the ducting to be closer to the disc.
Janner_Sy we have similar opinions.
The disc vanes take the air from the hub:
(https://live.staticflickr.com/882/39796989260_d7184e3e86_o.png)
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Intresting thread rex, I would be interested in improving the cooling to my nqsbbk
I think the disc vaines take air from the hub so forcing air into this area would be the best solution.
If the vaines were to vent air towards the hub i think this would cause problems bit brake dust being forced towards the hub which could cause problems in the long term.
How easy would it be to make up some ducts around the hub and test it out to see if there is a noticeable improvement?
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If the vaines were to vent air towards the hub i think this would cause problems bit brake dust being forced towards the hub which could cause problems in the long term.
How easy would it be to make up some ducts around the hub and test it out to see if there is a noticeable improvement?
Because of their circular movement and their shape the air must be taken from the hub (I think it is impossible the other way)...
I am thinking of buying a hub + mud guard (already have discs) and try to make a prototype for the air duct, but I can't test the design to have an objective result and see the benefits.
I am hoping for some improvement and only a small improvement is needed for a nqsbbk and a 160bhp Golf. Hopefully when I have the air ducts and some feedback you can try the solution and see if it works for you...
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Have you seen the oe Phaeton brake cooling set up?
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Yes, but not on a MK5 (as I remember Dave said he could not make that setup work for a Mk5). And also the air is not taken from the front grille but from underneath the car.
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Have you seen the oe Phaeton brake cooling set up?
Nope, any pics?
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ETKA images were useless so Googled and found this - v interesting!
http://www.audiworld.com/tech/wheel60.shtml (http://www.audiworld.com/tech/wheel60.shtml)
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Oh just realised - phaeton has a trailing caliper - we have leading.... :confused: :fighting: :sad1:
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Yup... they have a "double arm" (hope this is the English name) suspension and we have a MacPherson one.
All the audis (a4/a5/a6...)/vws (Passat B5, Phaeton) I know that have double the arm suspension, have a trailing caliper.
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Great thread, Rex !! To make things short:
Please do remove the shields. You'll never regret it. :wink:
:drinking:
On a side note:
The issue is the trailing caliper + FWD incl. drive shafts making it hard to route a hose from front to hub.
Open fog grills into the wheel well + removed shields can decrease rotor temperature significiently by,
say, 50° C and more.
Don't mind about brake cooling in the winter. It doesn't realy matter if the pads have -10° or +50° C
compared to 500°C on the track. I even never felt any delay in the wet + salt.
BTW - engine bay, under bottom frontal area and wheel well are high pressure zones. Besides the car
(at your doors) there are low pressure zones. Knowing this you can easily imagine the average air flow.
:driver:
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Please do remove the shields. You'll never regret it. :wink:
The car is still a daily drive (I bought a Seat Ibiza as daily drive but I will still occasionally use the Golf also) and the roads in Romania have a lot of dirt. So, for the moment, taking the dust shields off is not an option... :drinking:
Don't mind about brake cooling in the winter. It doesn't realy matter if the pads have -10° or +50° C compared to 500°C on the track.
It is very had to get some heat in the brakes to make them work properly (as a daily drive) in winter...
Regarding the progress... I found a spare hub (didn't want to pay for a new one) and when I get my hands on it I will start with the brake ducts.
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Today I got some time and parts and I started working on the brake ducts...
First, here are the brake ducts (3m of them):
(https://live.staticflickr.com/818/41588066801_262ee41fb0_o.jpg)
And the air inlet for them:
(https://live.staticflickr.com/873/40717198385_f904e76405_o.jpg)
(https://live.staticflickr.com/813/39780050370_d68e1e924d_o.jpg)
Then, I took one of my wheels off the car and I wanted to see where the brake ducts will fit best.
(https://live.staticflickr.com/861/40695774895_b1fc3389ed_o.jpg)
As you can see, there are 2 possible mounting points:
(https://live.staticflickr.com/854/41588067291_24d4ae9a0c_o.jpg)
Above the sensor (I think this is the ABS sensor):
(https://live.staticflickr.com/809/40695775125_4967a14d94_o.jpg)
Or below the sensor:
(https://live.staticflickr.com/849/39780051800_215a748c93_o.jpg)
Unfortunately when steering the car, if the brake vent is below the sensor, there is not enough room. So, only the position above the sensor is ok.
Next, I put the parts together in order to build a prototype...
Hub + bearing:
(https://live.staticflickr.com/784/41588065971_6fe4d36949_o.jpg)
Nqsbbk J hook rotors:
(https://live.staticflickr.com/786/41547534832_4e351f6c4a_o.jpg)
As you can see, the air is not directed to the center of the rotors (and vanes). So I have to create a piece to direct the air towards the vanes:
(https://live.staticflickr.com/831/27739950358_bab65aeaa8_o.jpg)
(https://live.staticflickr.com/876/41568738302_0a30622368_o.jpg)
And the finished piece:
(https://live.staticflickr.com/894/39780046880_cff6fe752a_o.jpg)
(https://live.staticflickr.com/877/41608741311_46607a7390_o.jpg)
Because the air inlet for the ducts is Aluminium I think I will make this piece out of Aluminium also and weld it to the inlet.
Next I will need to get my hands on a dust shield and see how I can attach the air inlet to it.
I will keep you posted!
Any advice is welcomed! :drinking:
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Hey mate !!
Nice job, but I need to make some remarks:
1. By doing it this way you are blocking half of the area of your ducts >> a bad idea !!
2. Better fit one or two "air guides" / "deflectors" inside the inlet similar to my figure below.
3. I still believe you loose performance if you don't remove most of the brake shield (I know I'm boring).
At least the two black marked deflectors (even better add the green):
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fup.picr.de%2F13504111ck.png&hash=772ff70e77a4ab94017cc1ae6dddf5bbaa454f4b)
Many ducts (intakes etc.) have similar guides inside. In this windtunnel similar deflectors are used:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fup.picr.de%2F13504110wh.jpg&hash=5030e55b29c4f16381c2d53b65571525997ff63e)
Pardon me, I didn't find proper pics on the web showing these deflectors in ducts and also didn't want
to take photos from Joseph Katz' "race car aerodynamics" book.
:wink:
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First of all, thank you for your advice!
1. By doing it this way you are blocking half of the area of your ducts >> a bad idea !!
Yes, the area where the air exists is smaller, but the same amount of air travels through there.
Because the exist is smaller than the intake, the air will travel faster through the exist.
2. Better fit one or two "air guides" / "deflectors" inside the inlet similar to my figure below.
I am not sure this way really solves what I want to do... I want to direct the air towards the disc vanes / disc bell and NOT directly on the inner side of the disc.
In the case proposed by you,here is the air flow through the brake ducts:
(https://live.staticflickr.com/858/40713132265_b8fca7af57_o.png)
As you can clearly see, some of the air is directed correctly and some is not directed correctly.
This is the way I am thinking of making that part:
(https://live.staticflickr.com/816/26720077997_d7487dfb54_o.png)
In this case, all of the air is going where I want it to go...
3. I still believe you loose performance if you don't remove most of the brake shield (I know I'm boring).
I agree, but the only reason to keep the dust/mud guard (shield) is that my car is is still a daily drive and a lot of dirt/dust will get to the discs and calipers...
Again, than you for your ideas!
:notworthy:
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Like what you are doing rex :happy2:
With regards to directing the air flow to the gains I agree with rex. I think that way it will cause a high pressure and accelerate the air out towards the veins. That's my understanding anyway.
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Like what you are doing rex :happy2:
With regards to directing the air flow to the gains I agree with rex. I think that way it will cause a high pressure and accelerate the air out towards the veins. That's my understanding anyway.
It might make the air leave the pipe quicker but it will reduce volume of air flowing out the end. Which ones most important?
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Thank you very much for your thoughts guys! :notworthy:
IMO, the more air I can get into the rotor vanes and/or in the disc bell, the better. I think that directing the air away from a disc face ans into the disc bell and/or vanes makes a lot of sense. In the pictures above you will see a couple of examples...
IMO, no matter how the air gets there, the main idea it has to go out, and I will go out, mostly, through the rotor vanes thus cooling the rotor.
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Yes, the area where the air exists is smaller, but the same amount of air travels through there.
Because the exist is smaller than the intake, the air will travel faster through the exist.
Unfortunately it will not be the same amount, Vlad. :sad1:
I am not sure this way really solves what I want to do... I want to direct the air towards the disc vanes / disc bell and NOT directly on the inner side of the disc.
Yes, of course. Directing the air flow into the bell is your major target, but the 2nd
one will be to get much air in as possible and even more so if you keep the shields
which inhibit the cooling of the rotors inner face.
That's why I suggested it that way keeping the full amount of air flow.
I agree, but the only reason to keep the dust/mud guard (shield) is that my car is is still a daily drive and a lot of dirt/dust will get to the discs and calipers...
I know. You won't need the shields in the summertime though. The better way would
be to remove them in the summertime (when your tracking) and fit them in the winter
if you feel a need. I didn't even miss them in the winter (you might know there's lots
of salt on German Autobahn).
It might make the air leave the pipe quicker but it will reduce volume of air flowing out the end. Which ones most important?
Agree. That's been my consideration. The air will accelerate at the narrow area, but
drag will increase at the same time (according to Bernoulli and Newton - continuity of
momentum). As a consequence there must be less volume in the end.
IMO, the more air I can get into the rotor vanes and/or in the disc bell, the better.
That's indeed the point. I'm pretty sure with deflectors similar to what I suggested
you will get at least the same amount of air into the bell as you get with the one
you proposed (I believe even more). The 2nd benefit would be the disc face also
gets some air.
Keep in mind if you keep the shields the inner face of the rotor will get hotter than
the outer face causing 'shielding' or even warping.
At higher temps in the 500° C area heat radiation plays a major role compared to
lower temps. With a dust shield on one side the disc will not just get hotter, it will
also have a very unequally temperature distribution.
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Some good work Rex, I can't help but think after enjoying your videos that you've outgrown the NQS kit and should maybe buy an AP offering.
Some thoughts....
Standard discs are straight vaned and not directional and curved.....this means they will distribute any air that's introduced in that area but they are ineffective at creating a low pressure area behind the disc to encourage flow....they blow but don't suck simply put
THIS WILL BE THE BIGGEST ISSUE....some directional discs without ducting will work similarly to straight vane discs with ducting
ANY cooling even the wheel arch mod is better than none
Any air introduced should ideally find itself behind the hub area only, only cool the back ace directly if you ave front face cooling too this can be via a device on the wheel or via vents milled onto the back of the bell which line up with the rotor vents
Ditch the dust shields
Regarding ducting I tried every which way to get the phaeton ducts to work, I ended up grinding that much of them away they didn't resemble ducts anymore. John from rally tech near us then decided to take pity on me after having a laugh at my creative skills and suggested a scoop/shield idea straight from the WRC cars that he does all the carbon for.
They've moved away from ducting generally and started using scoops, they're lighter and less complicated.
So i find myself with a 2011 TTRS front subframe complete down the side of my house which growls at me every time I walk my dog because I haven't done anything with it for three month, plan is to develop an integrated scoop/shield in carbon that's simple to bolt on ........problem is Rex it can only work from about 330-390mm rotor size.
I wouldn't worry too much about the volume of air and Mr Bernoulli this isn't Formula 1 and if it got to that stage where he featured then the pads would have given up 2 miles ago and all the rubber seals on the Calipers would have melted.
There also doesn't seem to be much point in doing anything complex to straight vane discs.....its like spending a fortune on developing a turbo for a 650cc engine when you can just drop in a 2.0 and go,just as fast......when you turbo (duct) the 2.0 engine (directional rotors) is when you will see the results....make sense?
AP have some great pics of their GT and LMP ducting recommendations COMPLETELY impractical on a road car but they steer the thought process I'll try to,post them up
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From AP
A good source of cooling air should be supplied preferably through the upright to the disc throat. A typical venting cross section of 100cm² (16in²) is usually sufficient. The pick up should preferably be in an area of clean high pressure air flow and the ducting should be arranged to avoid sharp bends or changes in section which may choke the air flow.
Careful design of the Mounting Bell is important in achieving effective disc cooling and avoiding problems. Typically 80% of the airflow should be directed up the disc vents and 10% up each face of the disc. This ratio can vary considerably in practice but it is important that both disc faces are cooled equally by adjusting the air gaps. Unequal face temperatures can lead to disc distortion and a long pedal.
Lightening holes in the bells should be avoided as available cooling air can be lost without cooling the disc.
I'll find some more....
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Thank you very much guys for your information and implication! :notworthy:
There are some interesting thoughts...
1. Dust shields...
Holger, I know you always said to ditch the dust shield and for performance you are 100% right!
a. As far as I know, it is impossible to take the dust shields off the car without taking the disc down (and the caliper). Although this is not a complicated operation I prefer not to take the calipers off the car 2 times per year.
b. The dust shield also provide a good base for mounting the air inlet. Without them I would need to create a bracket to fix the air inlet.
c. The problem with the dust/dirt. In the pictures above you can see the dust/dirt accumulated on the dust shield. Wouldn't it be a problem if all this dirt entered the caliper pistons?
I will look into these problems closely too see if there are simple solutions.
I want to buy a dust shield today to have the hub assembly complete and see if I can solve point a.
2. Buying a new brake assembly (like AP).
Unfortunately my finances are very low and the nqsbbk is very very close to being perfect for my car. Please remember I only have 160bhp and down Hungaroring straight I reach 170kph apposed to fuscobal's 210kph (I think). I abuse the brakes (aka braking like I should) for 7-8 laps at a time and, only after 3-4 rounds, the pedal gets softer. This is why I want to improve the brakes slightly and I do not expect miracles from the brake ducts. Dave, from what you said, I understand that any cooling is good and that I should expect at least some improvement. Did I understand correctly?
Also the nqsbbk fits behind 16 inch rims that no bbk does (for the mk5), relatively cheap discs, pads and maintenance. So, if I can improve the brake fade slightly there are no reasons to go for AP.
3. Having directional vanes or not...
some directional discs without ducting will work similarly to straight vane discs with ducting
This means that ducting is doing something good for the OEM 312 discs...
By the way Dave, did you create that 315x25 AP rotor for the nqsbbk kit?
4. These ducts with other BBK...
Am I correct into thinking that the brake ducts as described above are useful for any BBK (AP PRO 5000 for example)? The way I "designed" these brake ducts they will fit the 312 rotor but can be fitted to any other rotor larger than this.
So if I create these brake ducts I can change the BBK and not have to start from scratch...
5. For street/winter use I intend to "disable" the brake ducts. There are 2 ways:
a. put something over the brake duct intake (from the fog grille).
b. put something to block the air next to the hub.
I am not sure which way I will go but, I hope I can created a cover for point a. Please keep in mind that I want the solution to be nice and tidy and I want to make it flexible so that I can take it off/ put it on in less then 5 minutes.
P.S. About making something complicated, I have some time to kill... And I also find it very rewarding actually doing something by myself for the car and not buying parts.
Any more thoughts/suggestions are welcomed and, again, than you guys very much for your implication so far!
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First of all, I agree with Dave. I remember reading AP's advice on brake ducting some
time ago. Of course Bernoulli's principle still applies to fluid dynamics, even in F1.
Thank you very much guys for your information and implication! :notworthy:
There are some interesting thoughts...
1. Dust shields...
Holger, I know you always said to ditch the dust shield and for performance you are 100% right!
a. As far as I know, it is impossible to take the dust shields off the car without taking the disc down (and the caliper). Although this is not a complicated operation I prefer not to take the calipers off the car 2 times per year.
b. The dust shield also provide a good base for mounting the air inlet. Without them I would need to create a bracket to fix the air inlet.
c. The problem with the dust/dirt. In the pictures above you can see the dust/dirt accumulated on the dust shield. Wouldn't it be a problem if all this dirt entered the caliper pistons?
I will look into these problems closely too see if there are simple solutions.
I want to buy a dust shield today to have the hub assembly complete and see if I can solve point a.
a) Right, you'd need to remove the caliper first, then the disc.
b) Yes, indeed. That's why I suggested cutting the shield to a minimum to just being
a kind of 'bracket' for the duct.
c) Guess not.
I'd give you my old dust shields for free. I shurely will never refit them. Shipping will
exceed the cost of new shields though.
2. Buying a new brake assembly (like AP).
Unfortunately my finances are very low and the nqsbbk is very very close to being perfect for my car. Please remember I only have 160bhp and down Hungaroring straight I reach 170kph apposed to fuscobal's 210kph (I think). I abuse the brakes (aka braking like I should) for 7-8 laps at a time and, only after 3-4 rounds, the pedal gets softer. This is why I want to improve the brakes slightly and I do not expect miracles from the brake ducts. Dave, from what you said, I understand that any cooling is good and that I should expect at least some improvement. Did I understand correctly?
Also the nqsbbk fits behind 16 inch rims that no bbk does (for the mk5), relatively cheap discs, pads and maintenance. So, if I can improve the brake fade slightly there are no reasons to go for AP.
No doubt - ANY cooling is good. It's hard to tell specific numbers, but as a ball-park figure
I'd expect 50° C lower peak temperatures with proper cooling and a similar amount with
directional rotors.
The softer pedal may come from both fluid boiling and rotor distortion by some amount.
Again, the dust shield prevents the inner face of the rotor from being cooled equally to the
outer face.
A cooler running rotor will also cool the pad better and heat up both caliper and fluid less.
3. Having directional vanes or not...
some directional discs without ducting will work similarly to straight vane discs with ducting
This means that ducting is doing something good for the OEM 312 discs...
By the way Dave, did you, create that 315x25 AP rotor for the nqsbbk kit?
From what I remember Performance Friction made a small number of 312x25 discs for AWE.
Sadly they stopped making them. AP Racing still makes a "Strap Drive" kit for R32 & S3:
http://www.apracing.com/product_details/road_car_upgrades/oe_replacement_disc_kits/strap_drive_kits_and_system/vw_golf_mk5.aspx
4. These ducts with other BBK...
Am I correct into thinking that the brake ducts as described above are useful for any BBK (AP PRO 5000 for example)? The way I "designed" these brake ducts they will fit the 312 rotor but can be fitted to any other rotor larger than this.
So if I create these brake ducts I can change the BBK and not have to start from scratch...
Certainly it'll help with any BBK. Very large BBKs may even make it easier to fit a duct
between hub and caliper instead of the back side of the hub.
5. For street/winter use I intend to "disable" the brake ducts. There are 2 ways:
a. put something over the brake duct intake (from the fog grille).
b. put something to block the air next to the hub.
I am not sure which way I will go but, I hope I can created a cover for point a. Please keep in mind that I want the solution to be nice and tidy and I want to make it flexible so that I can take it off/ put it on in less then 5 minutes.
To me a) seems to be most practical. I even guess blowing some clean air to the rotor
may help to keep it free from salt and water. Keep in mind it's the tyre swirling up
water and salt.
P.S. About making something complicated, I have some time to kill... And I also find it very rewarding actually doing something by myself for the car and not buying parts.
Any more thoughts/suggestions are welcomed and, again, than you guys very much for your implication so far!
I guess we already covered most of the theme. Ducting is good, ducting + directional rotors
is better and a properly vented BBK is best. Now you know how to design the ducts correctly,
but however you do it - it will help lowering rotor (and pad + caliper) temperatures.
It's all right as long as you do any venting. :wink:
BTW,
Vlad consider to get some downforce as Fuscobal does. Your car will run slower on the straight
and faster on the corners. >> Less brake effort, less heat. :signLOL:
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Yup, I guess you summarized it correctly!
I already bought a new dust shield... It will arrive tomorrow... It was about 10 EURO (~8 GBP) and I had 50% discount so it was not worth to get it from other places... Thanks for the thought, though!
I will have it fitted tomorrow and see how it goes from there on.
OFFTOPIC.
Yes, I told fuscobal to keep the templates so it will be easier to have a wing mounted later on.
I also want to have a rear diffuser but this is a costly job since I want to change the whole exhaust with the new diffuser.
But both these chapters require spending money and I prefer to spend the money on going to Hungaroring and/or Nurburgring instead. There is enough time to do all the mods...
So, since the finances are limited I want to do these brake vents and also a baffled sump.
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Very nice topic Rex. I see 2 problems there :
1) There will be like 2 shims (plates) in the front grille right in front of the entrance to the duct. I don't know what they'll do to the air entering the duct (regarding speed and turbulence)
2) Having the diameter of the duct shrink just before the exit to the disc will accelerate air while the exact opposite should be done (at least that's how it works for the radiators). Don't know how this will interact with the disc's rotation and the cooling vanes. For a radiator, you'd want the air to slow down before hiting it. In Simon McBeath's book there were some comparisons with various guides in front of the radiators if I recall correctly ! Can't you try to make an ovaloid section there (like 2cm high and 10cm long or whatever gives an area larger than your 5cm diameter duct). Ap said "A typical venting cross section of 100cm² (16in²) is usually sufficient. The pick up should preferably be in an area of clean high pressure air flow and the ducting should be arranged to avoid sharp bends or changes in section which may choke the air flow". High pressure airflow equals low speed, meaning you'll have to enlarge the exit, not shrink it. Going even further, 100cm² is way more than what your 5cm duct gives you (19.6cm²)
If I were you, I'd use the brakes as they are but without the shields (my APs are not that dirty and remember I have no seals on my calipers) and I'd upgrade to some medium brake kit like 4 pots with 320-330mm sometime when possible !
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Thank you for your thoughts, fuscobal :notworthy: !
Well, those 2 points are problems only if the goal is to create the perfect brake ducts performance wise! So, great advice for anyone who will build some brake vents and want maximum performance!
But, I am aware that I want to make some esthetic and daily drive mods...
So those 2 problems are not quite problems as far as I am concern:
1. Yes, those 2 plates might affect the air flow but I also want my car to look OEM (OEMish) and nice. So they will stay on...
2. With the OEM 312mm discs there is not enough room to expend the exit. Restricting the air flow was done only because I had to redirect the air towards the disc bell (hub). If I had had enough space to make another exit I would have done it. For larger diameter rotors (like yours) the exist can be made differently (with a larger exit)....
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If I were you, I'd use the brakes as they are but without the shields (my APs are not that dirty and remember I have no seals on my calipers)....
Vlad, you see we won't stop forcing you to discard them. :evilgrin:
Your brakes will welcome the absence of these needless shields.*
:drinking:
* of course in this specific case you'd best cut them to a minimum able to provide fitment of the ducts
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:grin: We have a saying: "When everybody says you're drunk, it's time to go to bed" :grin: (since everybody is telling me to drop the dust shields :scared:)
I will install the shields for the template (Saturday or Sunday) and see how it goes from there on...
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Yesterday I got some more time to work on the brake ducts project...
I received and installed the dust shield (to fix the air inlet onto).
Here is how it will looks:
(https://live.staticflickr.com/875/41568730942_de37094b65_o.jpg)
And a closer look with the "exposed" area:
(https://live.staticflickr.com/940/41588057481_a25a6c0265_o.jpg)
Here is the back of the dust shield with some highlighted ares:
- red: this part has to be removed for the air to reach the disc/hub
- green: this is an elevated area that has to removed in order to have a flat spot to bolt the air inlet onto
- blue: this is the outline of the air inlet
(https://live.staticflickr.com/793/26741034967_1d19aaf0e4_o.jpg)
I have not made the cuts yet because I do not have cutting tools so this will take a few days (till I find the proper tools).
I also took the wheel of the car to make sure the air inlet will not interfere with the speed/ABS sensor and it's a tight fit but no rubbing and no issues.
Since the wheel was off, I took some time to investigate where the air hose would go (inner wheel arch):
Red: this is, I think the best method (if it fits). I want to squeeze the air duct between the TT Arm (lower part) and the drive shaft...
Blue: this is an alternative solution, where I have to make a hole in the inner wheel arch.
I will try to go with the red solution but if there is any rubbing with the drive shaft I will go with the blue on.
(https://live.staticflickr.com/821/40695759895_28ccdd22cb_o.jpg)
(https://live.staticflickr.com/939/41588056691_5535a4fb2a_o.jpg)
It turns out to be a much more complicated project than I thought but I really enjoy it and I hope to have some improvement after all...
Any comments are, as always, welcomed! :drinking:
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Today I was helped by a friend (aka he did most of the work) and the hub assembly is done.
I made the inner piece for the air inlet out of Aluminium (old registration plate :grin: ). This piece is now bolted to the air inlet by 2 bolts and is is glued with windshield sealant (I tested and there are no issues at temperatures above 400 degrees):
(https://live.staticflickr.com/809/41568728292_86910e24f3_o.jpg)
The final form for the dust guard (with 3 holes to attach the air inlet):
(https://live.staticflickr.com/883/41608733701_7eb74fb334_o.jpg)
And the painted assembly:
(https://live.staticflickr.com/822/41588056161_877649db48_o.jpg)
A peek through the air inlet:
(https://live.staticflickr.com/856/40695757735_1d1bc246c3_o.jpg)
I have a planned Hungaroring trip on the 30th of March so all has to be in place by then.
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Good job, curious on the outcome. You should be about the trustiest person to tell the difference :)
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Good job, mate, 10 points !!
:congrats: :congrats: :congrats: :congrats:
is glued with windshield sealant (I tested and there are no issues at temperatures above 400 degrees)
.....
Hungaroring trip on the 30th of March so all has to be in place by then.
Hope you will enjoy Hungaroring without any issues at all. :happy2:
:drinking:
If you notice some smell or smoke hopefully it's just the sealant.
:evilgrin:
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Good job, curious on the outcome. You should be about the trustiest person to tell the difference :)
Thank you, my friend! I am really curious of the outcome...
Good job, mate, 10 points !!
Hope you will enjoy Hungaroring without any issues at all. :happy2:
If you notice some smell or smoke hopefully it's just the sealant.
Thank you Holger! I hope so too...
I tested the sealant and there was minimal smoke. The sealant seems to melt away but without any drops and very few smoke...
There are 2 more things to do with the brake ducts:
1. Attach the brake duct to the fog grille and create a lid for the winter.
2. Find the proper way to connect the 2 ends... As I said about 2 posts before, I hope not to make any more holes for this.
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Some more photos...
The finished and painted air inlets:
(https://live.staticflickr.com/899/41608730231_f973358cf4_o.jpg)
(https://live.staticflickr.com/872/41608729541_ef40de5179_o.jpg)
Final fitment of the air duct:
(https://live.staticflickr.com/926/40898175814_0246358463_o.jpg)
(https://live.staticflickr.com/902/41608731271_c7cac0ca72_o.jpg)
The air duct is quite close to the speed sensor ( I designed it this way):
(https://live.staticflickr.com/908/40876973234_0b9be7ea12_o.jpg)
This is an above image of the hub. You can see that the air duct is very close to the horizontal part of the hub (as I wanted):
(https://live.staticflickr.com/828/27739934088_aff80488fd_o.jpg)
I have a small issue because the bolt for the air inlet are app 3.5mm from the discs. Do you suspect any issues because of this?
(https://live.staticflickr.com/847/41608728841_a814f39f38_o.jpg)
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I have a small issue because the bolt for the air inlet are app 3.5mm from the discs. Do you suspect any issues because of this?
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi1237.photobucket.com%2Falbums%2Fff469%2Fvladpanut%2Fsite_P3038558_zps22e7003f.jpg&hash=3aba14507dac9a49614ed285e9c2b43077aa1f13)
Guess not. :wink:
On the other hand, if you'd use rivets you not just save space,
there also wouldn't be any chance left to lose a nut (and bolt).
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Top advice!
I might just do that.... Although, this way I can still take the part off... Not sure yet which way to go.
Anyway, top advice! :notworthy:
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Work continues:
(https://live.staticflickr.com/865/27739933668_710af387f0_o.jpg)
(https://live.staticflickr.com/922/41568722942_4d5cf8be5f_o.jpg)
The air inlet will be painted black but this not the final form (I have to trim it a little bit).
The position of the air inlet is not in the middle because I plan to use another air inlet for the Cold Air Intake (left side of the car) and, maybe, for a oil cooler (right side of the car).
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Nice work here Rex.
On my car I've removed dust shields and removed all arch liners and under tray and opened the side grills fully allowing a massive increase in air flow to the whole area. Ducting needs to flow to both sides of disc equally was my understanding as you wouldn't want one side cooler than the other.
Look forward to your end results
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Thank you for sharing your thoughts! :notworthy:
Your solution is much more radical... But that is not for me. If my care was only for track days than would make sense, but that is not the case.
Yes, I am trying not to cool only one part of the disc. This is why I will redirect the air towards the disc vanes.
Today, I prepared the car for the summer and I washed the inner wheel arch. I can not tell you how much dirt was in that part... It seems that, in Romania, we import dust and mud from other regions. So, for the moment, the mud/dust shields will stay on.
I also checked, again, where the brake duct should go. Now, I did this for both sides of the car (only did this for the left side). And there are a few surprises..
1. I found out that the brake duct will fit, easily, above the TT arm and below the drive shaft, on the left side. On the right side, no. This is because the drive shaft is thicker on the right side (probably because it is further away from the gearbox). On the right side there is only about 1 cm of clearance between the brake duct and the drive shaft, so the brake duct should be very well anchored.
2. I also found out that the blue solution, from the below pictures, will not work because, beneath the inner arch I found metal (body work) and I do not want to go through that.
So, I have to make the red solution work for both sides:
(https://live.staticflickr.com/821/40695759895_28ccdd22cb_o.jpg)
(https://live.staticflickr.com/939/41588056691_5535a4fb2a_o.jpg)
3. And the speed sensor is not the same as on the left and hopefully, the gap for the speed sensor is enough or, maybe, I can put turn the speed sensor 180 degrees...
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:happy2:
This is because the drive shaft is thicker on the right side (probably because it is further away from the gearbox).
On a side note:
The right drive shaft is thicker because it's hollow to be the same weight as the short but solid left one.
ps:
Can't see the first picture. :sad1:
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Thanks for the info Holger!
Fixed the photo issue :happy2:.
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Wednesday I fitted the new dust shields and the brake ducts:
(https://live.staticflickr.com/786/41568780132_1d76b31121_o.jpg)
Left side:
(https://live.staticflickr.com/916/41568778962_ba158a2b0c_o.jpg)
Right side:
(https://live.staticflickr.com/807/27739991068_c494259ff5_o.jpg)
(https://live.staticflickr.com/868/27739990838_fccc85cd68_o.jpg)
I found some clearance issues...
1. On the right side, when using the maximum steering angle (to the right) the brake duct just about touches the drive shaft. I will sort this problem a.s.a.p.
2. Had to do some mods to the air inlet piece to clear the speed sensor on the right side. Now the brake duct and the speed sensor touch but since none of the is a moving part it doesn't bother me that much.
I still have to finish the other part (front grille). The parts are 95% done I just have to put them all together.
If the weather is ok, I should be all done my Sunday.
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And the front grille part is done!
This is how the setup for winter looks like (the air duct is disabled). All I have to do is to undo a bolt in order to take the cover out:
(https://live.staticflickr.com/805/41608780941_fbed3317b3_o.jpg)
This cover is easily taken out and the brake ducts become "enabled":
(https://live.staticflickr.com/839/41568777212_33b808b8c7_o.jpg)
(https://live.staticflickr.com/893/41608780211_eb7075a370_o.jpg)
This is the part where the air duct will be fitted (all painted and ready to me installed):
(https://live.staticflickr.com/813/41568775722_4eba292020_o.jpg)
And with the cover above it (to restrict the air flow in winter or when I do not need the air ducts):
(https://live.staticflickr.com/798/40898206354_173610050b_o.jpg)
All I have to do is to connect the air duct to these pieces and I am done. I will hopefully do this tomorrow. Fingers crossed! :drinking:
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well done !! :happy2:
Just shut it on the backside with some piece of a trash can liner and a zip tie wasn't just good enough?
:evilgrin:
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Thanks :notworthy:
Well, it might work, but I find this solution better. This was the easiest way I could think of to have a cover over the inlet, that could be taken off in less then one minute (it takes about 15 seconds). It is also a permanent solution and I do not have to worry about rocks puncturing the cover...
I saw people covering the air ducts with duct tape. I guess that does the job, but I like my car to be both form and function.
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Today I managed to "close the circuit"! :pomppomp:
This is the front bumper seen from behind. You can see the 2 air inlets mounted:
(https://live.staticflickr.com/878/40898205284_eb10c37a54_o.jpg)
And a close up with the left side (there is an additional hole for the Cold Air Intake, that has to be fitted but I ran out of air inlets):
(https://live.staticflickr.com/871/41608777681_f60daa5be8_o.jpg)
And a close up with the right side:
(https://live.staticflickr.com/814/40717236025_f310172c5c_o.jpg)
Below are shots from the front.
The right side with the cover (the cover is black as the rest but because light from the flash bounces off it, it appears to be different)
(https://live.staticflickr.com/803/41608776271_9be818d524_o.jpg)
And with the brake ducts "active":
(https://live.staticflickr.com/862/40898201904_834652a2fa_o.jpg)
Left side (again with the cover):
(https://live.staticflickr.com/838/41547497252_db1e4b212a_o.jpg)
And the left side without the cover:
(https://live.staticflickr.com/861/41608775241_47f4cf893d_o.jpg)
I also checked for clearance on both sides and this is the final setup with no rubbing no matter the steering angle (hope I did not speak too soon):
Right side:
(https://live.staticflickr.com/851/41547495652_9d600189e3_o.jpg)
Left side:
(https://live.staticflickr.com/929/40898201124_d783f55b0b_o.jpg)
So, I am just about done, but I am very curious to see if (and what) effect this has on the track.
And to draw some conclusions:
1. it is very difficult to find a path for the brake vent (between the drive shaft, control arm, brake hoses, etc).
2. the air inlets attached to the dust shield and to the fog grille are pretty simple and, if you want a similar solution the photos above will be conclusive. If these are not enough I made some drawings of the parts and I will send them to you.
3. I hope all this work is not in vane and this actually works on the track!
And I also hope this topic helps anyone who wants a similar method to cool the brakes.
All the best! :drinking:
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THX again for sharing all this. :happy2:
Just another idea, my friend: It might help to reinforce the hose with some gaffa tape or even shrinking hose
where the zip ties hold them in place. Permanent vibration and rubbing may wear the hoses prematurely.
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Top advice! :notworthy:
I will try that!
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Another idea if anyone plans on doing a similar ventilation.
Octavia with S3 hubs:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fup.picr.de%2F13985352gl.jpg&hash=9d9414d34a87e46a3de25ee5532f0a1c2393450e)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fup.picr.de%2F13985353dz.jpg&hash=fd3bcebcd7c943f27722bad422c87a948615d601)
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That is very interesting!
1. The mud/dust shield are still on
2. This solution seems to direct the air towards the side of the disc (not the hub/bell).
3. I am curious to see if the air hose has a hole in the bodywork....
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(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fwww.golfmkv.com%2Fforums%2Fattachment.php%3Fattachmentid%3D85236%26amp%3Bd%3D1339945821&hash=cd8b21c3314e61fffafb41e52d8ad4709771cae5)
http://www.golfmkv.com/forums/showthread.php?t=169796
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Excellent project :congrats:
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Another well made solution for S3 swivels:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fup.picr.de%2F14125585nq.jpg&hash=830ef2728c041be5274fd0ebe0b971da35ce62ed)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fup.picr.de%2F14125586bf.jpg&hash=9156299501df505eae64797fa88118ddf5a53b9d)
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Very nice, but I doubt it still has maximum steering angle! Not important for a track day car but very important for a street car...
But the mounting point on the hub is much more elegant!
The way I see it, the brake ducts should tick the following (besides the brake cooling itself):
1. not affect the turning radius
2. turn on/off for winter or cold trackdays
3. not be visible from the front of the car
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You're right. I'd suggest smaller hoses to solve this issue.
But the most significient point:
This guy did fit the rotors the wrong direction !! :evilgrin:
:signLOL:
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OMG! You are wright! I haven't noticed till now....
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No newbies, they should be pros:
http://www.roadraceautox.com/showthread.php?t=40959
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Well guys, a few weeks ago I got to test the brake ducts at Hungaroring:
The weather was quite cold (14 degrees the highest) and, thus, it is very difficult to have an objective comment about the brake ducts efficiency, but I hope this comment is still better than no comment... I have had this weather before, but there we NO trackdays (till this on), where I did not overcook the brakes (of course, different stages of overcooking)...
BUT, this time I had no issues with the brakes. Because of the weather it was harder to get the brakes and tires to temperature but once they were up to temperature were performed flawlessly (my setup for the last 2 years was NQSBBK + Pagid 4-4 Orange + Custom J Hook Rotors and Dunlop Direzza 03G)!
Unlike any other TrackDay I have done, this time I even had 2 sessions in a row without any bake fade (6 hot laps + one cooling lap + 6 hot laps). Also, after the sessions, the rotors were not as red as they usually were and did not radiate so much heat...
So, I think this mod clearly has an effect and I am very happy that it worked so well!
:drinking:
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Well, it's been a year since having this system in place and my friend Stefan (Acidutzul) pointed out a design flaw... Because the hose is not held in place by anything, over time, the screw connecting the subframe to the chassis will make a whole in the brake ducts:
(https://live.staticflickr.com/848/41608727841_922b42b576_o.jpg)
I use the car a few times a week and there was a lot I had to take into account when creating this. The car still has to use the full turning radius (not a problem for race cars), the brake ducts should be turned on/off really easy, the system should not show any signs of fatigue over a few years, etc.
I came to realize that, unfortunately not all those boxes are ticked. But since I saw an improvement with using the brake ducts (I can't tell how much the brake ducts helped or how much the Pagid Yellow helped) I would really like to tick all the boxes...
I came up with idea of creating a new mounting point using the same screw that was creating the problems.
So, I bought 2 of these
(https://live.staticflickr.com/889/41568784532_1915336441_o.jpg)
,4 air outlets and I started working. This is the end result:
(https://live.staticflickr.com/872/41608785781_22884c25ca_o.jpg)
When fitting I though that it was better to cut the pieces along the red line because the gap was too small and I didn't want to have clearance issues with the arms.
(https://live.staticflickr.com/861/40695739285_743493057a_o.jpg)
BUT, this solution not ideal, because there are clearance issues with the sway bar (once the brake hose is fitted). That shouldn't be much of a problem since the sway bar isn't moving a lot, but I decided to mount the remaining of the brake hose only before a track day (easy fitment) until I find a neat and permanent solution to avoid the sway bar.
Left side:
(https://live.staticflickr.com/919/41568781412_9b074e929f_o.jpg)
Right side:
(https://live.staticflickr.com/907/27717915918_ee997f4f64_o.jpg)
The final piece of the brake hose is not attached in the photos because, as I said, it will be attached only before a track day (I have to change the wheels so it's not quite a complicated task).
If someone wants to walk this path hopefully they will not go through the same trial and error path that I am going :smiley:.
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Nice workaround :congrats:! I'd say just stick a piece of rubber that would fit tight between the swaybar and the outlet/hose, and just let them move together. Worse case scenario the duct/hose will be slightly deformed, but I don't think that would happen. Even so, not any actually harm done, and there won't be any rubbin' involved anymore.
Good luck :happy2:
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Great thread Vlad! Likewise I had no track day without brake overheating problems, I really need to see how can I can build some brake ducts for my Cupra. :congrats: