Thread: b13 11" wilwood (BABK science)

Corrado rotors work fine and have nicely finished hats. You NEED hub rings for this however. Ask me how I know...xD

Mine came from the FB folks and do the trick just fine:

The real gain is "Fade Resistance"? No, not remotely true, especially not in autocross. The real gains are shorter braking distance, superior initial bite (higher coefficient of friction at the pad/rotor) and superior Modulation. Despite the CW "Brakes don't make you faster", well no, they don't - however they do allow you to GO faster AND still slow down in time, with later application.

Fade is caused first and foremost by heat. Heat changing the coefficient of friction at the pad to rotor surface, heat causing the fluid to boil prematurely, in extreme cases causing the rotor and pad surfaces to glaze. Heat is mitigated by larger surface areas, vented rotors, pad materials, more fluid volume, etc. Being able to lock the wheels as any measure of braking effectiveness is baloney. You can lock the wheels with drum brakes. Hell, I can stick a steel rod in the spokes and lock the wheel.

Modulation of the brakes is key in autocross and track, a mark of a mismatched set of components is wheels locking under hard braking, with the accompanying huge loss of traction of a sliding wheel. Being able to set the car into a turn with weight transfer, aided by precise pedal feel, huge plus in traction at very high speeds. I would never have thought I could take the first turn at Pocono Raceway at over 100 mph (no braking) without the brakes capable of handling the speed reduction needed for turn 2. That's where this kind of stuff really pays dividends. If my initial bite is lower, I have to brake sooner to allow time for the pad to rotor friction to ramp up to the level needed. That's time away from being on the throttle or just holding a higher speed later into a turn.

The whole justification for these brakes in autocross is superior initial bite, i.e. better braking with a higher coefficient of friction when you want it, sooner AND more effective braking after you do apply them. Fade is rarely even an issue in autocross, the problem is having a set of brakes you apply late enough, in a short enough distance to slow the car for a turn that do not fail at that task, and do not require so much time (distance) to perform that task that you have to slow down prematurely.

Stock B13 disc brakes take longer at this task, and yes, if the course is long enough and severe enough, you can overwhelm their fade resistance by the last gates. The real issue however is you can lose buckets of time because your brakes just do not allow for really late braking, trail-braking, and other time-shaving techniques.

Ben, have you ever personally actually run this Wilwood 11" front, with U13/B13 MC and Maxima/Atima rear caliper setup? Do you actually drive your car at autocross and track events? Because when I read this crap, I cannot help but say wth man, another person writing about what other people say and post, not their own actual experience...for what that's worth. *insert facepalm here*

Steve, I said the real gain of going with larger brakes is fade resistance. This is the truth. Nothing you wrote counters that from what I could see. I'm not sure what you're reading into what I've said?

I didn't say fade resistance was the only benefit, but it is the main benefit in my opinion.

If we're talking auto-cross and fade is not an issue, then larger brakes make little sense in my opinion. Maybe you'll disagree with me there. If you're going for initial bite, then pad choice is key, as is making sure there is no flex anywhere (lines, linkage, caliper). Making sure you avoid pad kick-back is almost highly important for initial bite. On an atuo-x course I would probably rather maximize those issues to get bite than to go with a heavier, higher rotational inertia brake setup.

I will concede the greater leverage provided by the larger diameter rotor has a prominent effect on bite. For that reason alone you may want to move to a larger brake setup even if fade is not your worry. That is a secondary benefit from larger brakes (in my opinion) which is why I failed to mention it. If that is the way you like to tackle the bite problem, then more power to you.
I also had no idea we were specifically talking auto-cross here in this thread. Were we?

Steve you've asked if I have "ever personally actually run this Wilwood 11" front, with U13/B13 MC and Maxima/Atima rear caliper setup?"

Yes, I have personally actually run this Wilwood 11" front, with U13/B13 MC and Maxima/Atima rear caliper setup.

You've asked "Do you actually drive your car at autocross and track events?"

The answer to that again, is yes. (Although not nearly enough.)

dodging all those little cones you would want high initial friction but you would want the smallest lightest setup possible to allow optimal handling and accel. track and autocross are very different and autox has never really appealed to me personally but I understand physics. but like i said before there is no reason to touch the back on any car not on r-compounds. I have literally seen rear sentra tires come off the ground during very hard breaking going downhill into oaktree at VIR. the fronts are doing 99% of the work at that point.

I see we've changed topics.
jjkamikaze, to go along with your anecdote, I've had both rear tires leave the ground under hard braking on the street. Shit was cray.

Unfortunately some of us don't have big tracks around us so we have to deal with dodging little cones. Autocross isn't that appealing to me either, compared to track, but you have to attain skills somewhere before you start racing at track speeds. The last few comments have done wonders for me, so thanks guys.

Most autox courses aren't long enough ( 2 min tops probably ) to need a brake system that will deter brake fad. I got my subliminal answer though. I agree with Ben, no need to go bigger than upgraded oem brakes for autox.

A bit off topic, but Eurokid, check out Gingerman racetrack up in South Haven, MI:
Gingerman Raceway, Ltd.
They have (had?) Test and Tune nights of untimed run what you brung for around $60. It'd be a long daytrip for you, but if you go in the summer months you can get several hours of "relaxed" lapping under your belt. Great for working on your skills.

Back on topic, since we are on the science of the BABK, the wilwoods have a larger rotor than NX rotors and therefore more rotational mass. But the caliper is significantly lighter than the AD22 caliper, lowering unsprung weight. Anybody know where that balances out?

Oh wow, I would so be up for that. I just need a trailer and a truck haha

Also check out Grattan Raceway for a more advanced course. Also in MI, near Grand Rapids. They have a lot of really cool car clubs that show up there. My favorite to go watch is the Lotus club.