Braking System Dash Adjuster

[Ianthegypo]

We are running a conventional balance bar arrangement for the braking system on our car. Saw on the Wilwood website a dash adjuster that links to the balance bar, and adjusts proportionality on the go.

http://www.wilwood.com/Products/005-PedalAssemblies/004-RBBA/index.asp

Simple question really, has anyone actually used this on their car? Are they actaully any good, or is there really no point?

Ian Davis
Team Leader
City University, London

[Nate Notta]

Yeah we've run it two of the past three years... once on the dash, once just to the driver's side. If you have good drivers who will use it while tuning or on the track, of course it's good to have. You can make your own knob out of aluminum that's lighter than that Wilwood knob.

[jdstuff]

Ian,

I would say that this is a must have for any racecar! There was a recent thread about 'brakes not locking,' that would be good for you to read about why you should have adjustable bias (if you haven already). And if you're going to have adjustable bias, it only makes sense to have it driver adjustable. As Nate pointed out, I have regularly made slight bias adjustments over the course an endurance run. Chances are you won't need to....but if you do you'll be thanking yourself when it's there!

Tilton makes an excellent bais bar and remote adjuster system. They have two knobs, one plastic and one aluminum. I would reccomend the Al knob, as it has a smoother operation and a more positive feel. I would also reccomend placing the knob high in the cockpit, usually opposite of the shifter...somewhere that is easy for the driver to grab without really taking his eyes off the track. Here's some examples:

http://gozips.uakron.edu/~jdstuff/dash.jpg

This is a pic of our 2004 car.

http://gozips.uakron.edu/~jdstuff/dash2.jpg

This one is of the new Champ Car Atlantic cockpit....a little more difficult to see, but it's hiding behind the steering wheel. If you want a better pic, I can snap one the next time I'm at work for you.

Hope that helps....best of luck!

[kwancho]

I see those Ohlins sticking out there. Hot stuff.

[Ianthegypo]

thanks for the replies. The pedal box ive designed does indeed have a bias bar. Only problem I had was whether dash adjusters were actaully used much during the endurance races. If this is the case, then it sounds like a good idea.

[Chris Allbee]

in the past we've also run an electronic bias adjuster, didn't really work but it looked neat and the judges like gimicky things. we never really touch the bias adjustment while driving anyways. its usually set pretty well after testing in the practice area.

[drivetrainUW-Platt]

picts of the electronic bias setup??

[VinceL]

We ran a driver adjustable bias knob for the past 3 or 4 years. However this year we aren't running one. This is because we never use it at comp. We set the bias the first couple of days the car is running, and don't have to set it again.
However,I can think of two reasons why brake bias would have to be changed during the eduro. One the track conditions are changing i.e. from wet to dry, or two your front and rear brakes are heating up at different rates. This would be caused by different pad compounds front to rear.

[Steve Yao]

I've always tried to incorporate an adjust knob. On team/alumni drive days, we might switch out a dozen drivers. Some are a bit more top heavy than others, conditions change, etc. It saves a lot of time to have the knob, rather than having to stop everything, remove the nose, wrench around, and cross your fingers that you guessed the right # of turns on the balance bar.

A bias knob goes right along with the design goals of the competition for a weekend autocross racer. i.e. I don't see one person buying one car that they drive a dozen times a year at best. I see 2-4 people chipping together to share a car. And I am sure clients would rather be checking tire pressures than adjusting bia bars between their runs.

[Nate Notta]

Originally posted by tuccmasterflex:
I can think of two reasons why brake bias would have to be changed during the eduro. One the track conditions are changing i.e. from wet to dry, or two your front and rear brakes are heating up at different rates. This would be caused by different pad compounds front to rear.

Don't forget that drivers of different weights could need different proportioning.

[Superfast Matt McCoy]

Our electronic brake bias system that Allbee is talking about never actually worked. It was on the same board as the shifter timer, so that didn't work and also our temp/rpm display didn't work.

It's a simple setup, you just put 2 pressure transducers in your brake lines and run them to a pcb. a microcontroller reads the input and displays the pressure for the front and back. when you press the "front" button, the pcb turns a stepper motor that is attatched to the brake bias adjuster by a small incriment. same for the down button, but obviously in the other direction. you could even easily add other buttons to jump to presets.

it's probably one of those things that you could to with one of those BASIC Stamp DIY microcontroller kits. I would love to see it done properly, and i'm sure it would work great.
I think the only reason ours didn't get done is that our EE was never that commited to the team. When his wife wasn't yelling at him to leave the shop, he was telling us how he didn't have any reason to be there and how lucky we were to have him on the team.

In any case, I would recommend doing that in place of the knob adjustment if you're going to do any cockpit adjustment at all. the knob doesn't give you any feedback on what the ratio is or how much it's changed.