Using a BBK from a 'normal' M3

Porter · 24-10-2011, 08:01 PM

Hi guys - I'm after some brake know-how, please.

I used to have a normal E46 M3. The best thing I did to that car was to put a StopTech BBK on the front. It's a 4-piston caliper and 355mm disc set up.

I've been emailing StopTech in the 'states, who have said that I should fit a different StopTech kit to retain the correct front/rear balance. They say that, as the rear caliper pistons on the CSL are larger (46 vs 42mm?), I need calipers with larger pistons on the front. This all makes eminent sense so far.

My quandry comes when I look at other manufacturers' kits (including AP, as far as I can make out). They seem to offer only one front BBK, for both the M3 and the CSL. So I am left wondering how much difference there is between the 2 StopTech kits and whether I really need to buy different front brakes.

I am happy with the other options (pads/fluid/brake less etc), but I tried all those on the M3 and I am sure that I will eventually go for a BBK on the CSL.

Thanks for taking the time to read all this rubbish. Grateful for any ideas - the wife will have a hissy seizure if I tell her I want new brakes.

24-10-2011, 08:01 PM	#1
Porter S4 - Getting the hang of it Join Date: May 2011 Posts: 135 Casino cash: $4767	Using a BBK from a 'normal' M3 Hi guys - I'm after some brake know-how, please. I used to have a normal E46 M3. The best thing I did to that car was to put a StopTech BBK on the front. It's a 4-piston caliper and 355mm disc set up. I've been emailing StopTech in the 'states, who have said that I should fit a different StopTech kit to retain the correct front/rear balance. They say that, as the rear caliper pistons on the CSL are larger (46 vs 42mm?), I need calipers with larger pistons on the front. This all makes eminent sense so far. My quandry comes when I look at other manufacturers' kits (including AP, as far as I can make out). They seem to offer only one front BBK, for both the M3 and the CSL. So I am left wondering how much difference there is between the 2 StopTech kits and whether I really need to buy different front brakes. I am happy with the other options (pads/fluid/brake less etc), but I tried all those on the M3 and I am sure that I will eventually go for a BBK on the CSL. Thanks for taking the time to read all this rubbish. Grateful for any ideas - the wife will have a hissy seizure if I tell her I want new brakes.