Daniel;290609 said:
SGD6k for that?
Isn't just cheaper and easier just to buy direct fitment Brembo/Stoptech/Wilwood/AP etc?
well, problem is.. you can't get the equivalent off the shelf from the after-market specialists..
a bit of research was done and in the spirit of DIY and modding, my friend wanted to try and build a customised kit of his own, & not be any backyard project, but a properly engineered brake kit specifically designed for his CAR
First of all.. some calculations.. this will be based on the E36 M3 / E46 M3 with the 25.4mm ATE master cylinder.. all other E36's used the smaller 23.8mm master cylinder so if you want to use his calculations factor in -13.8%..
the 2 most important things to consider when buying a brake kit are (1) mechanical brake torque/bias and (2) pedal feel/travel. Most people just buy an off the shelf kit.. sometimes it works and sometimes it doesn't work so good.. some people complain about longer pedal travel etc you can avoid all that buy building your own..
(1) Mechanical brake torque is calculated by multiplying the piston area (A) by the effective radius (R) multiplied by the line pressure (P) multiplied by the friction co-efficient of the brake pads (cf).. effective radius is usually defined as the distance from the center of the rotor to the center of the brake pad.. brake torque = A * R * P * cf.. so here is the calculation for the stock E36 M3 (note a single sliding piston counts as a 2 piston caliper):
The brake bias on a stock M3 is 2.06 which is very very good for a car with 50-50 weight distribution.. (Most EVO's and other nose-heavy AWD/FWD cars run a bias of 2.5 - 2.8.. if you put that kind of bias on our balanced cars.. we would nose dive and skid to a stop i.e. horrible braking) So to maintain the similar pedal feel and bias.. you'll need to match the piston areas.. in his case, it was made sure that the increase in braking power came from upsizing the rotors ONLY, and not from increasing the piston area, since that usually results in longer, sloppy pedal travel.. based on the calculations you would be looking for a 42/40 or 44/38 front piston calipers and 30/28 rear piston piston calipers
To cut a long story short, Brembo 44/38mm piston F40 calipers were chosen for front with the Porsche 996 Brembo monoblock 30/28mm piston calipers at the back.. this giving a mechanical brake bias of 2.09 which is within 1.5% of the stock M3 when using 345/328 rotors.. when choosing calipers.. make sure they are radial mount and not lug mounted... radial-mounted calipers give a lot more flexibility in fabricating the adapter plates
Here are some of the brake calipers tried for this experiment.. here you can see some of the selection AP Racing etc namely the CP5555 and CP5070 that the E46's guys like to use.. the problem with the AP Racing brakes is that
they do not have dust seals.. they are pure race calipers which require rebuilding from time to time.. this is unacceptable and cumbersome from a daily driver point of view. They are probably OK to run on the street for a few years but my friend did'nt want to have to deal with seal issues at
any point in time..
In the end it was deciding between the CP5555 vs the Brembo X20.4862.. they are roughly the same size.. the Brembo uses 4 pistons the CP uses 6.. the pad area is about the same.. In the end the Brembo's were chosen as they are not as loud and come with dust seals.. anyway, AP Racing is wayy overrated and overpriced)
For the rear calipers.. the Porsche 996 monoblocks were chosen as they have the correct differential piston size of 30mm and 28mm.. they are also extremely light and easily available.. both sets were bought from scrapyards in the USA..
the rest of the job was mainly working in the brake repair kit.. and fabricating the brackets...
Well, one could simply say its a lot of time/ money anf effort.. but the great thing about the 36 is that its a great car to do lotsa D.I.Y. projects on, without having to worry about too many hi-tech issues, that are way too common in newer car these days..
We're from the old shool kampung bang-bang-chop-chop d.i.y, fraternity... no better way to get up real close to the car.. than to know its bits very well..inside out!..
BiG bollocks BKKs
Brembo 44/38mm piston F40 calipers in front with the Porsche 996 Brembo monoblock 30/28mm piston calipers at the back FTW! :top:
