Great articles on automotive brakes in June 2006 Sport Compact Car

Among all automotive upgrades, the brake upgrade is among the most misunderstood. There're 2 great articles on the June06 SCC magazine. So happens a discussion on rear brake upgrades appeared in the Carma forum, so a reply was posted here: http://forum.carma.com.sg/showthread.php?p=17539814#post17539814

Excerpts:

Read these 2 articles:
Project Scion tCPart II: Bolt-on Brakes for Geeks

The TruthWe Bust a Dozen Common Street Tuning Myths

OK just a summary:

1) Braking distance is hugely a function of tyre friction. Changing pad helps little, because you can always press the brake harder. Most of the time, tyre friction is the bottleneck and the pad friction is far far greater than tyre friction, so solve the tyre friction first before going to brake.

2) There is only 1 way to shorten brake distance by brake upgrade, is to use the rear brakes a bit more so that the rear tyres' friction can be taken into consideration. But it must be a good balance, because if you up your rear brake torque too much, car will spin (this statement is subject to electronics, below). (edit: Incidentally, a hose upgrade from rubber-only to steel braided, will decrease braking distance by a couple of metres since most of the hose balooning will be eliminated, converting all pedal pressure to servo assisted braking pressure)

3) In order to correct badly off brake balance, many people use brake proportioning valve method. However, this is NOT TRUE for cars with Electronic Brake-Force Distribution systems.

4) For cars with EBD, you DO NOT NEED TO CARE SO MUCH ABOUT BRAKE BALANCE LIAO! All you have to do is to increase braking torque everywhere, starting with the rears, and the rear will NOT lock up in a way which will compromise stability. YOU WILL decrease the braking distance significantly because you will now be using maximum stopping potential of the rear tyres.

5) The major benefit of using big brake upgrade for front, is NOT to lower the braking distance, but rather so that if you brake on track, the heat dissipation will be better and you will not have so much brake fade problem.

So in a brake upgrade, please check whether your car got EBD or not. If not, I think better don't touch because once you go into brake proportioning valve is a nightmare without experienced hands helping you out. If got ABD, just upgrade the rear first for maximum bang for the buck, then do front so that you can go on track to race.