B7 RS4 brake conversion - should we?

[andrewneaves]

I've been running RS4 B7 front calipers with RS6+ discs for about eighteen months or so. The set up at the rear was standard S4 calipers with slotted (std. size discs). The brakes were a dramatic improvement on standard - which had been just too exciting (in a bad way) on too many occasions for comfort.

The front discs needed replacing just recently - the rears were in poor condition too - so I asked Doug (at MRC, for the uninitiated) to replace front discs with RS4 (B7) discs, RS4 (B7) OEM pads and fit a complete RS4 (B7) setup at the rear. The difference is astonishing - soooo much more power, modulation, sensitivity and pedal feel - if anyone tries to tell you that the rear brakes don't contribute much to the overall braking effect on these cars - don't just accept it. Brilliant - and another great job by Doug.

I had the geometry checked and a 4 wheel alignment done at the same time - all arranged and managed by Doug. The front, in particular, was some way out - the car is now transformed. It was money well spent.

[Peakz]

Interesting post Andrew, can you elaborate on the negative aspect of the standard S4 rear brakes?
Also how old were the rear discs/pads and how misaligned was the geometry?

I'm running B7 RS4 front discs/pads and S8 rear discs with standard S4 calipers/pads on my facelift car, got SRF brake fluid too.

[Blue_Thunder]

How come you went from RS6+ discs to RS4 ones?

[andream88]

what do you think 'bout these Wilwood calipers?
http://www.rallydesign.co.uk/product_in ... s_id=11370

Thanks

[Doug_S2]

B7 rears have larger calipers and larger pads so better braking than stock calipers. I have the B7 setup on the back of my S4 now.

[rolskii]

- if anyone tries to tell you that the rear brakes don't contribute much to the overall braking effect on these cars - don't just accept it

about time someone else praises large rear brakes ..... I was told it didnt really matter by some twats ..... sorry the un-knowing .....
I have rs4(b5) on rears and there great ... nicely balanced with the rs6+ on front end

[JDB]

how much does the rear kit cost and have you got any pics?? Doug maybe you have some to hand

[andrewneaves]

The deficits of the old system were that the braking tho powerful wasn't balanced and upset the handling of the car. The rear vented and slotted discs were about fifteen months old - calipers were original facelift S4 and the pads had been replaced just before this last Christmas.

My impression from driving the new setup is that there is a much less extreme weight transfer to the front - consequently the car handles better under braking and is less unstable. Why? I would think that it's because with such powerful brakes at the front unless the rears are very quickly responsive to brake input and reasonably powerful then very significant weight transfer will produce a situation in which they wouldn't be able to achieve much breaking effect anyway.

I changed to RS4 discs at the front because I have to run spacers with my widebody S4 and BBS CH's and was only able to use the OEM caliper and bracket setup with 4mm spacers inboard of the discs with the RS6+ discs (although that did not in fact cause any problems I thought it less than ideal). With the RS4 discs greater offset I can discard the inboard spacers and use only outboard spacers of moderate size.

The RS4 B7 rear calipers and discs I got nearly new for £400 and the pads were about £140, I think. I'll post some pics over the weekend.

[Peakz]

Thanks for the update Andrew, I found after the brake upgrade that the rear would occasionally come round in the wet on hard braking whilst on the road but around the track it was fine.
Having done a couple of trackdays and doing around 12,000 miles on the road (mostly town & motorway driving) the brakes are now pretty much perfect.
Brake pad/disc wear appears to be normal for the mileage on visual inspection but I'll get Doug to double-check the rear brakes this weekend.

Is yours the black widebody S4 with anthracite CH's that was at MRC last week?
Nice car

[andrewneaves]

Yes, Peakz, that was my car.
Pics enclosed