Quote:
Originally Posted by Snake2998
Interesting post - thanks. In general Cobras with Jag suspension and brakes are way under braked at the rear and either need much bigger rear caliper pistons or a much smaller rear MC to balance the brakes. Some in South Africa put the proportioning valve on the front circuit and say it makes a huge improvement to braking on the track (Generally not advised by makers of these valves so approach with caution and much careful testing)
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Snake
I would never put a Proportion Valve on the front Brake circuit......especially since 60% to 70% of braking is done on the front brakes......balancing the brakes on a road racing car is very important to the stopping as well as the handling of a car.....installing a Proportion Valve on the front circuit is automatically reducing the effectiveness of the front brakes.....and could effectively reduce the overall braking.....
A lot of guy’s crank in more rear brake bias to help the front of the chassis turn in faster....very common in all race cars....because you don’t transfer as much weight to the front when braking, thus, allowing better turn in the corner.....because there’s less push on the front tires......or less weight transferred to the front.
First you have to balance the Master Cylinders Front and Rear.....smaller Master Cylders provide more pressure but less volume.......larger Master Cylinders provide less pressure but more volume.....
For those with Single Master Cylinders...then you need the Proportion Valve in the Rear Circuit to assist in overall braking first ...then once they are balanced properly, you can start trying to add rear brake to help the front turn in better.
How do you know how the brakes are operating???
The easiest and most reliable method is to use temperature paint on the rotors....like paint a H pattern on the rotors starting at 900*degrees and then 1000*degrees, then 1100*degrees, then 1200* degrees.....on all of the rotors....then go out for some laps and use the brakes vigorously as normal.....when you come in and remove the tires & wheels.....look at the rotors and see what temperature the fronts are running and the rears are running....thus you will then know how hot the rotors are running .....
You shoot for about a 200* degree difference front to rear....like 1000* degrees on the front & 800* degrees on the rear.....in our racing on tracks we would run about 1150*-1200* degrees on front......and 900*-1000* degrees on the rears.....then if I needed to get more turnin on certain corners I’d crank in a couple turns on my brake balance bar.....none of you well reach these high numbers ...so maybe you should start with some lower numbers....and use the same ideas.....
Sorry for the long post ...but there is no short way to say all of this kind of info.....
Morris