300ZX Brake Swap...Problem

[SingleCamSam]

I finished the 300ZX brake swap this weekend. I installed a set of 26mm front calipers, rotors, KVR pads, stainless lines, and a 1" MC. My setup before this just the KVR pads and stainless lines front and rear. To make a long story short a friend and i decided to do some before and after tests. Before installing the brakes yeserday, we went out to the local air-field in Culpeper and decided to do a "before" test to get some data on stopping distance/fade/etc. "Cold" stop from 60mph on stock setup was 122' give or take. After the third hard stop we did a hot test, and came with 131'. Now granted we are not professional testers, but we did make sure all the tests were uniform (cone every 30' with stop beginning from 60 at the first cone). Here's the results we got today at the airport with the 300Z brakes. Cold stop: 123'. Hot (took much longer to heat those suckers up): 129'. Also, temperatures today were much the same as they were yesterday.

Now i know that i did this install correctly, but i would have thought my cold stop would have been more improved than it was. Especially considering the 4 piston calipers up front. I was very impressed with the resistance to fade and heating up, but from what i see now, unless you're autocrossing/road racing, save the money and get yourself some nice pads and lines for your stock brakes. This is an 89 S13 BTW. Any thoughts?

[Exar-Kun]

yeah, like i've always said, the benifit of larger brakes is not the decreased stopping distance, its their ability to dissipate heat. I think I even told you that directly.

I keep getting blown off when I try and say this, but I'll say it again:

if you can lock your tires, your stopping power is more than adequate.

SCC found the same thing you just did(and I've repeated this 3 times, at a minimum) with a supra...they gained 2 feet hot stopping distance with brembo GT brakes than the stock system....

you just found out what I've been trying to explain toe veryone who thingsk bigger brakes stop you faster, they dont. they're just better at dissipating high heat better.-chet

[SingleCamSam]

Nah man, i don't think you told me this directly. I definitely would have listened if you did since your always more than helpful with my questions.

Don't get me wrong, i'm not dissapointed in the least. It took 7 runs of some HARD braking to get them hot, and pedal feel was much improved.

[Exar-Kun]

should make it much better braking for any autocross or really hard driving

plus, the pedal feel is worth the upgrade alone

I think I should stikie the pysics article on why bigger brakes do not mean less stopping distance...-chetgood to hear ya like it.

[Q45tech]

All cars are optimized for single stop braking distances from the factory, then what ever trade off the ABS creates.Tires are the major variable in 100,80,60 to zero distances........other than camber and toe changes.

I'll bet the upgrade stops better from 120 mph.

KVR pads are tilted towards warm/hot stops. Measure your rotor temperatures........roughly 120F increase FRONT for each 60 to zero stop.If you start at 100F>220F>340F >460F...........not really warm yet!but a single 120 to zero would be 100>550F.

[BadMojo]

Maybe we need a dedicated Sticky for brakes? This is all really good info.

[Q45tech]

If an 15 pound rotor increases by 120F for a SINGLE 60 to zero stop then a 17.5 pound rotor will only increase by [17.5/15= 1.1666..120/1.666=102 F.I've reduced the complicated math to a simplistic form which should be usable by everyone.

Braking force braking torque can be thought of in the same way. Use the same calipers but [via new mounts new larger diameter rotors] move them outwards. A 13" rotor will have 18% more torque than a 11" rotor.