44cup.com Forums :: View topic - Q&A : Brakes, Wheels and Suspension

tim pruitt wrote:

So the Tilton Lever type valve as described below:

Tilton Lever Style Brake Proportioning Valve
The compact Tilton Brake Proportioning Valve allows a driver to rapidly select 7 distinct and repeatable settings for brake bias. The maximum reduction of output pressure is approximately 50% of the input pressure. The handle can be oriented in any direction with respect to the base for ease of installation. Complete instructions are included.

Is it legal or not?

What if it is mounted so that the driver cannot adjust it during competition?

In addition, having a quick way to adjust brake bias when rain arrives could also be considered a safety feature. For those that do not have anti-lock brakes it is safer to use more rear brake because there is less weight transfer to the front tires when braking in the rain.

Author:	Director [ Tue Mar 30, 2010 11:03 am ]
Post subject:	Q&A : Brakes, Wheels and Suspension
Q: Are brake bias valves free? A: Fully adjustable brake bias valves are permitted for cars using SCCA prep levels and with no limitation on location. For PCA Stock and Prepared the rules do not provide for any specific mods for brake bias valves. However, we have never checked to ensure the brake bias valve being used is specific for the model in question. There are numerous valves available for the 944 models but there location and design making it near impossible to determine which valve is in use. Plus there are other ways to adjust brake bias currently legal for PCA prepped cars such as pad selection or modification which are free. Considering the problems with inspection and other options for bias adjustment, we will allow any brake bias valve to be used for PCA cars; however, in line with the current PCA rules, the brake bias valve can not function as an adjustable valve.

Author:	tim pruitt [ Tue Mar 30, 2010 3:10 pm ]
Post subject:	Re: Q&A : Brakes and Suspension
So the Tilton Lever type valve as described below: Tilton Lever Style Brake Proportioning Valve The compact Tilton Brake Proportioning Valve allows a driver to rapidly select 7 distinct and repeatable settings for brake bias. The maximum reduction of output pressure is approximately 50% of the input pressure. The handle can be oriented in any direction with respect to the base for ease of installation. Complete instructions are included. Is it legal or not? What if it is mounted so that the driver cannot adjust it during competition? In addition, having a quick way to adjust brake bias when rain arrives could also be considered a safety feature. For those that do not have anti-lock brakes it is safer to use more rear brake because there is less weight transfer to the front tires when braking in the rain.

Author:	tom s #18 [ Tue Mar 30, 2010 8:44 pm ]
Post subject:	Re: Q&A : Brakes and Suspension
Dave: ITS cars are at a disadvantage to many PCA cars under the current rules with regard to the suspension and wheel/tire specs. Allowing adjustable brake bias on PCA cars takes away one of the few advantages for ITS. As for the 'safety feature' of quick adjustment, while true, others my just see it as a more costly performance advantage. Thanks, Tom

Author:	Director [ Tue Mar 30, 2010 11:02 pm ]
Post subject:	Re: Q&A : Brakes and Suspension
tim pruitt wrote: So the Tilton Lever type valve as described below: Tilton Lever Style Brake Proportioning Valve The compact Tilton Brake Proportioning Valve allows a driver to rapidly select 7 distinct and repeatable settings for brake bias. The maximum reduction of output pressure is approximately 50% of the input pressure. The handle can be oriented in any direction with respect to the base for ease of installation. Complete instructions are included. Is it legal or not? What if it is mounted so that the driver cannot adjust it during competition? In addition, having a quick way to adjust brake bias when rain arrives could also be considered a safety feature. For those that do not have anti-lock brakes it is safer to use more rear brake because there is less weight transfer to the front tires when braking in the rain. Not legal as the Tilton you describe functions as an adjustable bias valve. How safe or dangerous an adjustable bias valve does depend much on the driver. In the hands of an inexperienced driver, the adjustable bias valve makes for a very dangerous device. ps. On a slick or wet track you actually want less rear brake, as it would be easy to brake the rear free, resulting in a very quick swapping of the frt end of the car with the rear. A lesson not easily forgotten when done at over 100 mph during my first season in the number 44 car.

Author:	tim pruitt [ Wed Mar 31, 2010 7:43 am ]
Post subject:	Re: Q&A : Brakes and Suspension
So to clarify for me..... We are allowed to utilize any porsche (OEM) brake bias valves on the master cylinder to create whatever braking balance we want for our cars and we can change these OEM parts at will to change as we see fit?

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Q&A : Brakes, Wheels and Suspension http://forum.44cup.com/viewtopic.php?f=7&t=263	Page 1 of 2

Author:	Director [ Wed Mar 31, 2010 7:47 am ]
Post subject:	Re: Q&A : Brakes and Suspension
tim pruitt wrote: So to clarify for me..... We are allowed to utilize any porsche (OEM) brake bias valves on the master cylinder to create whatever braking balance we want for our cars and we can change these OEM parts at will to change as we see fit? Correct for the most part. The bias valve does not need to be OEM parts.

Author:	johntorg [ Wed Mar 31, 2010 9:38 am ]
Post subject:	Re: Q&A : Brakes and Suspension
My old (wrecked) 944Cup car, Formerly owned and raced by Eric Rupert to a National Championship had an adjustable brake bias valve. Does anyone know if it was an ITS prepped car?

Author:	Director [ Wed Mar 31, 2010 9:56 am ]
Post subject:	Re: Q&A : Brakes and Suspension
johntorg wrote: My old (wrecked) 944Cup car, Formerly owned and raced by Eric Rupert to a National Championship had an adjustable brake bias valve. Does anyone know if it was an ITS prepped car? Was wondering just the other day whatever happened to Rupert's car. Thanks for the update. Yes, Eric raced as a rare SCCA prepped car.

Author:	johntorg [ Wed Mar 31, 2010 10:28 am ]
Post subject:	Re: Q&A : Brakes and Suspension
Its sitting in my garage after hitting the wall in turn 9 at Road Atlanta at 107MPH after the steering wheel came off in my hands. The engine and transmission are in my current car.

Author:	tim pruitt [ Fri Apr 02, 2010 10:11 am ]
Post subject:	Re: Q&A : Brakes and Suspension
DD, While you may have had an end swapping issue in the rain.......Dave Murray suggested during his Enduro pre-race discussion on our rainy Sunday morning....that race cars without anti-lock brakes and those that have the ability to adjust brake bias should propbably move a little more braking to the rear because there is less weight transfer to the front tires when braking on a wet track. Made sense to me at the time and my data from traqmate also indicates lower G's during braking on the wet or semi-wet track versus the dry track we had on Saturday. Looks like I will be buying a bunch of valves and start the experimentation process. That is exactly what I needed....another race car project:)

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