Classic Audi Technical Mech/Tech Suspension & Brakes » Brake upgrade options for 15" 4 stud

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Old 28-09-17, 09:55 AM   #1
20vcqdriver
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Default Brake upgrade options for 15" 4 stud

I have decided that I am going to have to further improve the braking on my Cq when it comes off the road next month, but as I wish to retain the factory look need something that fits under the 15" Ronal wheels.
Present upgrade I installed 12 years ago has been OK but now I'm running around 400bhp its not good enough especially when I can virtually accelerate faster than I can stop :

So present set up at the rear took the discs from 245mm x 10 to 256mm x 12mm using modified Black Diamond discs from the front of a 90bhp 1.9TDi Golf (altered for centre hole and 4x108pcd.) retaining original calipers but moved outward 5.5mm. Works well and not looking at changing the rears any further.
The fronts went up from 256mm to 280mm using Corrado G60 discs, again altered for the centre hole and PCD. C&R provided a new carrier to allow the original calipers to be used without any further mods (although I did need to change front struts for the early series 3 that had larger mountings but otherwise identical.) And have found the best pads (after various tests) for the car are Ferodo DS2500 race pads.

I am about to see if the early A4 288mm discs will fit with their larger calipers (need to source a new carrier too). These have a much bigger pad area so should be enough to make a big difference over present setup.
I was wondering if anyone has a working setup on their cars (retaining the 15" wheels). All suggestions welcome. Also been told a Ford Focus setup would work but would need more info on this
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Old 28-09-17, 12:45 PM   #2
Colin Aitchison
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I did a post last week titled " Audi B2 Coupe Gt " after it was posted I saw my mistake and could not alter the title to add "big brake conversion", have a look, original 256mm x 20mm on front now have 280mm x 22mm with G60 twin piston calipers, I have had a few teething problems but the car stops now better than it ever did also have a 280mm x 10mm conversion for the rear but when on track running 256 x 20mm on front and 280 x 10 on the rear was tending to lock up in heavy braking areas, I also have a revised drop link for the front anti roll bar to wish bone link (no rubber bushes), also work in progress is a rear anti roll bar for the rear of the B2 coupe Gt, all fits behind 15" alloys, you may want to PM me your phone number or email address for more information.
Drop link post title " Audi Coupe Gt Front Anti Roll Bar Drop Link Upgrade "

Last edited by Colin Aitchison; 28-09-17 at 12:47 PM. Reason: Adding text at bottom
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Old 28-09-17, 01:02 PM   #3
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Hey Colin, I know your car is a FWD, so here's tip, I found that the bias valve spring attached to the rear axle had relaxed a touch over time, I found a guide on setting this up but I can't find it again just now, but this made a big difference, reduced front end dive, better stability under braking and just better stoppage in general. I have purposefully tried to lock up rears on snow & ice fronts ALWAYS go first, so I'm certain this isn't over adjusted, it is how it should be. This car has 280x22 With G54 calipers (single pot), 245 rears, EBC Yellow Stuff pads & Brembo OE discs all round. I found the discs made a huge difference compared to some of the cheaper brands.

I know this doesn't directly affect you 20vcqdriver but you may want to think about front/rear break line balance along with your upgrades.
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Old 29-09-17, 02:55 PM   #4
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Quote:
Originally Posted by Colin Aitchison View Post
I did a post last week titled " Audi B2 Coupe Gt " after it was posted I saw my mistake and could not alter the title to add "big brake conversion", have a look, original 256mm x 20mm on front now have 280mm x 22mm with G60 twin piston calipers, I have had a few teething problems but the car stops now better than it ever did also have a 280mm x 10mm conversion for the rear but when on track running 256 x 20mm on front and 280 x 10 on the rear was tending to lock up in heavy braking areas, I also have a revised drop link for the front anti roll bar to wish bone link (no rubber bushes), also work in progress is a rear anti roll bar for the rear of the B2 coupe Gt, all fits behind 15" alloys, you may want to PM me your phone number or email address for more information.
Drop link post title " Audi Coupe Gt Front Anti Roll Bar Drop Link Upgrade "
Quote:
Originally Posted by quattromnc View Post
Hey Colin, I know your car is a FWD, so here's tip, I found that the bias valve spring attached to the rear axle had relaxed a touch over time, I found a guide on setting this up but I can't find it again just now, but this made a big difference, reduced front end dive, better stability under braking and just better stoppage in general. I have purposefully tried to lock up rears on snow & ice fronts ALWAYS go first, so I'm certain this isn't over adjusted, it is how it should be. This car has 280x22 With G54 calipers (single pot), 245 rears, EBC Yellow Stuff pads & Brembo OE discs all round. I found the discs made a huge difference compared to some of the cheaper brands.

I know this doesn't directly affect you 20vcqdriver but you may want to think about front/rear break line balance along with your upgrades.
I have done all sorts of trials with the brakes and 256mm rear is about the max on a cq unless you start going for bigger wheels and upwards of 320mm fronts. As you discovered 280mm on the rear is too much for road use although as mentioned you can regulate on the 2WD cars so not as big an issue.
I Fitted a rear anti roll bar back in 1997 and already running modified drop links. Both well worth doing, especially on a Cq. All my mods have been articles in the VW/Audi magazine at the time and Audi Driver more recently. Had the old girl 27years now
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Audi A4 Saloon, 1.9tdi. 1997
Audi A4 2.5TDi Sport cabriolet (163bhp) 2004:- Remapped to 180bhp
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Old 29-09-17, 03:13 PM   #5
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20vqudriver, Nice to see there is someone like myself just trying to make the old cars better, not seen you drop link articles do you have any photos? working on a rear anti roll bar for the 2wd coupe Gt, looks like an S2 rear anti roll bar will fit with very short drop links, the reason for fitting the S2 ARB is I removed it from my S2 to fit a 18mm adjustable White line ARB and the White line ARB will be tested on the Coupe Gt at some point if the original S2 ARB is not up for the job. Did you see the drop link I made for the front of the Coupe Gt, photo below.

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Old 29-09-17, 04:21 PM   #6
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My Ur quattro, running standard 15x8" R8

Fronts.
986-351-421/422 calipers (Porsche Boxter)
Custom caliper brackets originally spec' by 'Harvey' and made by Bambridge.
288x25mm discs from c4 100

I was previously running a G60 twin pots upgrade with standard 276x25mm discs, as per MB.
Original setup on the ur was single pots with 280x22mm disc.

Rears.
269mm vented discs, same as 20v ur, urS6(?), V8, using oem parts.

If memory serves, a 4stud disc is available in both setups.
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Old 05-10-17, 11:42 AM   #7
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Quote:
Originally Posted by Hanuman View Post
My Ur quattro, running standard 15x8" R8


Rears.
269mm vented discs, same as 20v ur, urS6(?), V8, using oem parts.

If memory serves, a 4stud disc is available in both setups.
Are the rears using same caliper design as solid disc setup, just wider to take vented discs? Could be a worthwhile upgrade to go with my proposed 288 front discs
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Coupe quattro 1986:-~400bhp + loooong list of mods!
Audi A4 Saloon, 1.9tdi. 1997
Audi A4 2.5TDi Sport cabriolet (163bhp) 2004:- Remapped to 180bhp
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Old 05-10-17, 03:09 PM   #8
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Bmw 7 series Brembo and focus rs disc were great on a b3 q with aby I had but didn't go under 15". Were close on 17".
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