performance differences between single and twin pot GT4 brakes?

[Jim-SR]

just out of curiousity (having already bought the single pot 277mm setup), how much better than standard is the smaller twinpot setup? in terms of disc diameter there is barely a difference from standard, the only gain over std is a thicker disc (thus more heat dissipation due to larger vents) and the twin piston caliper meaning slightly more efficient braking.

however ive never managed to fade the stock brakes, ive warped the discs through excessive heat, but not faded them. so heat obviously isnt a huge issue anyway, maybe due to the weight distribution of the car. i do struggle to lock the front brakes though unless i abolutely stand on them so the only room for improvement IMO is in outright stopping power, which i think could only be gained from more braking torque (e.g. larger discs) or increased friction on the existing setup (expensive brake pads)

just curious as to what gains over standard the twin pot setup actually makes (from peoples experiences), and how it compares with the larger single pot setup?

i have bought a single pot setup, but im still toying with 14" wheels and theres no way the 277mm discs will fit under them (theyre going to struggle underneath my 15's!!)

cheers
JIM

[lodgeman]

the only problem with the single pots is the size of disc is smaller 258mm which is the same as the mk1b, as you say the only advantage is the thickness. i run the single pot set up on mine but it has not been track tested, but in road conditions there is no fade at high speeds. as for cooling this was discussed by tom (x19) and it seems that wheel choice is a reason for a lot of heat buildup.

[Icsunonove]

as for cooling this was discussed by tom (x19) and it seems that wheel choice is a reason for a lot of heat buildup.

Jim, I believe this is the case. Originally I had some 16" TSW alloys on the car when I bought it. They are a very open pattern and I had no brake overheating issues. But after a while I couldn't stand the handling of my car on 16" wheels and bought some early 14" wheels. These are the triangle jobbies and are very enclosed. Ever since then I have tried everything to try and stop the brakes overheating, all to no avail.

I do have some Carbotech XP8 pads that I haven't tried yet though... I had them specially made but you should be aware that it cost me over £200 for the set!

I have driven on track with XP8 pads though, in Tim Cartledge's racecar. And I must say they were absolutely awesome!

I haven't totally given up on getting 14" wheels to work though. Last week I bought a set of 14" BBS wheels (the lightest you can get) but I haven't picked them up yet. These are the lattice design type and should flow a lot more air. I've also bodged a brake duct to funnel more air through the brakes. I'll update later with some pics...

If this doesn't work I'll have no option other than buying yet another set of wheels, this time 15", and fit some larger rotors....

EDIT! Oops! :blush: Just reread the first thread properly again. Please ignore everything I have said unless you are going to track the car. I may as well leave the post unedited as it may be of use to others... (Really should stop speed reading topics, it gets me into trouble both here and on IMOC :blush:)

[Jim-SR]

lol not entirely the answers i was looking for, but on topic none the less, and an insight into heat issues with 14" wheels!

ive currently got some fairly open 15" wheels on there and even if i absolutely hammer the brakes, i cant get them fading. the car spends 99% of its time on the road, but i intend to track it a handful of times a year, and my drive to work is quite involved, its a seriously twisty high speed A-road thus there are quite a few 60-20mph braking zones (i say 60 because that is the speed limit, but you can read between the lines ;))

i do love the handling of tiny wheeled cars though, and id really like to go to some wider 14" rims. ive currently got a set of the 277mm single pot ST185 brakes being prepared to go on, but i can get hold of a pair of twin pots simply by driving to a friends house to collect them, thus i was wondering how they compare to the standard mk1b setup assuming all other factors remain the same (e.g. same wheels, pad quality, etc)

and it wouldnt be hard to get some extra performance out of the smaller twin pots with better brakes pads either! and brake cooling wont be a major problem, im sure i can fabricate a replacement dust cover plate with build in ducting, and im going to run DOT 5.1 fluid anyway

anyone running ST165/185 twin pots who can offer their thoughts on performance compared to standard?

[OlberJ]

Nik runs them, but doesn't run his car much. Seein as he's in Dheli. I've got a set to fit but won't get them done till the V6 is sorted.

Sorry mate.