brake bias/overbraking the car

[Acidburn]

I've had a look for some threads, out of interest has anyone got any comments about if the following setup would a)need a bias valve or the like) b) result in any issue's with locking up the rears/or the rear swapping ends easily.

fronts : 323mm discs with 4 pots
rears : 300mm discs with single pots

The car will be around the 1300kg mark once done so not the heaviest of cars but will atm have a full interior etc.

[s2_wot]

can you get me the piston diameters, and the approx tyre size.

[Acidburn]

I will try to but it will most likely be friday before I can find out. (unless they are mentioned in s2avants thread about the 300mm rear setup for the avants, the front piston sizes are just monobloc stock sizes)

And tyre size will most likely be a 235

[s2_wot]

Have the stock setup fronts & rears up in excel so just have to compare..

[Acidburn]

ok cheers, as soon as I can find out I will do, currently on the other side of the uk on a rubbish connection

[Gompa]

depends on the weight distribution as well i would guess stripped out mk1 golfs always used to lock there drums on the rear due to no weight being on them during hard braking.
are you re-doing brake pipes? if so it wouldnt take much to drop in an adjustable bias valve

[Acidburn]

Yes i'm hoping to do the brake pipes again as cheap enough, just depends where and how much hassle a adjustable b/valve would be.

[martinws]

It would be pretty good to be able to have a bias valve. Especially if you will be stripping out the car ever.
On the other hand, does your car have a compensator valve that puts more bias towards the rear when weight is added to the car? My coupe failed an MOT on a faulty compensator a few years back, I dont know the situation of if it was removed completely and replaced with a manual bias valve.

[Acidburn]

I will have to check on that. I went out in a very very rapid s2 saloon the other day that weighs under 1.3 ton and was stripped running this setup but that has a bias valve on it so not sure how much that was adjusted if at all.

[Gompa]

Its fairly simple you just have to run the brakelines inside the car to a bias valve (think there around 60-100quid?) to be honest im not sure if it would have to be in the car but i imagine it would have to be pretty even between the front and rears? ive only ever seen them in my friends mini and mk1 golf and they were both the other side of the handbrake.

[Acidburn]

Yeah thats where the one in the s2 saloon was. Tbh might have to have a word with the owner of that car or just have a go with it to be 100% sure.

forgot to add car won't have abs.

[urs4guy]

I've got a heavily modified B5 A4 that approximates your layout. The car weighs in at 3180 lbs which is 1442 kgs. Up front are Boxster S calipers and 2 piece 321mm rotors. In back are B5 calipers with 2 piece 300mm rotors. The overall braking capabilities of this car are outstanding. For pads I run Pagid Blacks in front and Porterfiel R4-S in the rear. At the track I go for a little pad bias by throwing on Pagid Orange up front. Everything seems to work just great.

My other car runs Cayenne 6 pots up front with 993tt in the rear with 355mm and 314 mm rotors respectively. It also weighs in a bit heavier at 3760 lbs. I run basically the same pad combo of the Blacks and R4-Ss.

Hap, wit dakine braking info not from Evahboost, Maguire