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Posted: Sun Jun 26, 2005 5:04 am
by Mats
Micke wrote: BTW, are U sure you have enough braking power rear as well?
If the fronts lock up in a corner under heavy braking (when you already have lateral load transfer) you probably need more rear bias. Remember, the OE thing is designed for 150% safety.
Exactly, big bias on the front in the standard setup. One way of finding the "almost too much" point is to gradually increase pressure in the rear until the car starts to waggle the rear during hard braking and then back off again until you feel comfortable. :twisted:
Check out my video from Knutstorp, quite loose during braking at the end of the straight.
Maybe should have a little more front bias but I didn't wanna adjust it during the race as I always forget which way to turn that stupid knob, the guys at Wilwood must have had a hang over when they labelled it "increase" <--> "decrease"... :roll:

Bias

Posted: Mon Jun 27, 2005 5:23 am
by Reale
You know, this is exactly why I plumbed gauges into the front and rear systems. When I go to set the bias, I stand on the brake pedal until I have 1000psi on the front system (I do this in the paddock with the car stopped, of course :lol: ). Then I read the rear gauge (600psi seems to work well), and have a baseline for setup. The OEM setup used some kind of differential pressure to set the rear bias, since it took a reference off the front system.
Also, I definitely agree about trying to figure out which way to turn the knob during a race. I usually get it set during practice or qual, then leave it alone.
-Al

Posted: Mon Jun 27, 2005 5:40 am
by Mats
Interesting, I've thought about gauges but have never done it because of KISS/cost/weight. Does the pressure bias change anything after a stint? Going out cold and coming in hot I mean, is the readings repeatable or is it only for baseline setups?
Same pads front/rear?

Bias gauges

Posted: Mon Jun 27, 2005 6:05 am
by Reale
The way I see it is this:
If you (or someone else) turns the knob accidently, or you don't recall where you left it, you need to be able to return the settings to a "known good" point. That alone is worth the install. Weight is trivial, use the mini gauges. Plumbing is really the only issue, but is easily solved.
The readings do not seem to be significantly different cold/hot.
I have definitely found that different compounds demand different bias settings.
For example:
Carbotech XP9 front/rear: bias 1000/750
Carbotech XP10 front/XP9 rear: bias 1000/600

-Al

Posted: Mon Jun 27, 2005 6:12 am
by Mats
Yeah, thats reasonable, if the pads are heat sensitive they will need another setting compared to insensitive pads.
Sounds like a great tool for sizing master cylinders. :)

I tend to think: If it doesn't make the car go faster it makes it go slower.
Made me take away a lot of "could come in handy" stuff, I have never missed it. ;)

Posted: Mon Jun 27, 2005 6:36 am
by Jim K
Very interesting stuff Al! :wink:
I'm thinking of juggling the existing 75 factory valve short pipes next to the MC for connecting the gauges as I can't make those damn flared fittings. Now gauges...hmmm, I'll see if I can find somebody with half-decent small ones, maybe Speedway, I'll check.
Jim K.

Brake stuff

Posted: Tue Jun 28, 2005 2:29 pm
by Reale
Well, since we are on the subject . . .
What I did (back when I still used the stock Alfa MC), was to get adapters that converted the (as I recall) M10 x 1.0 fittings to 37 degree flares. Porterfield sells them, but I am sure they are available elsewhere. Then I either: a) made hardlines as I needed them, or b) got premade Teflon/SS flex lines.
I use AN-3 for brake, and AN-4 for clutch.
Now I have a Wilwood MC assembly, with 3/4" cylinders for the clutch and rear brakes, and 5/8" for the fronts, with a balance bar. I still use the gauges to set the balance bar correctly.
-Al