<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Brad Manhattan Beach & Stephen Yap:
Sean:
Who's brakes are you using on your set up? What performance numbers are you getting out of your brakes and do you need any other modifications like proportioning valves? How is the front and rear bias and pedal feel? Is this a streetable system, or just for track applications?
What are the possibilites for upgraded 2 piece rotors that last longer than the stock ones?
<HR></BLOCKQUOTE>
Most of Brad's questions can be answered by reading the product description on the website, but in a nutshell:
The components that make up the entire assembly are: AP Racing
www.apracing.com 6 piston front calipers; PBR 2 piston rear calipers; matched Delphi brake booster, master cylinder and oversized reservoir (so that the fluid level does not run low with all that pad and piston area when the pads are thin); Performance Friction brake pads; Earls -3 stainless braided hose and fittings (we cut and assemble the hoses here); Wilwood adjustable proportioning valve. Beyond that, all the mounting brackets are made here or at a CNC machine shop.
The braking G #'s are in the description on our website, but with 17" stock street tires: stock is about .77G; our rear upgrade gets it up to .9G,; the 4 wheel kit with street pads gets it up to 1.1G; with race pads 1.15G (stock street tire limited); with race tires, 14" rotors and race pads we expect 1.4G.
To answer your question about streetability, each caliper features dust seals, all parts used in the system are OE quality and we do still retain the orignial handbrake assembly. We have devised a special adapter that relocates the stock rear caliper which is then used as the handbrake mechanism.
Regarding the system feel, ask anybody who drove my car at VOI ( Dave Tittle of Dilusi, Matt from Stop-Tech, and about 15 other people)or any of the people who have it. At the point of lockup, it is the most controllable brake system available. With street pads (as it was at VOI), you don't need an adjustable proportioning valve and most people were braking at or over 1G as they were learning what the car was capable of with the stock street tires.
I worked very ******* achieving the correct feel and controllability. In my experience, the cars that only have a front upgrade seem great at first because it takes so much less pedal pressure to stop the car. That's all well and good and I could have stopped developing mine there as well. But, I'm a professional road racer and I know how important control, feel and a balanced system are.
In 1993, I upgraded the front brakes only on my 1992 LT1 Bridgestone Supercar Championship Corvette with a kit developed by GM Motorsports. The Vette had ABS and at first the brakes seemed great. During qualifying at Atlanta Motor Speedway (the first outing with the new brakes) the ABS computer set a code and disabled itself because. Going into the chicane they setup before NASCAR turn 1, you had to brake from 172mph down to about 80mph. Once the ABS went out and was not dumping enough pressure to keep the front brakes from locking up, I immediately locked my inside front wheel, flat spotted the tire through the cord and blew the tire all within about 2 seconds. This was all because the front and rear system were not matched and the booster and master cylinder were designed for the stock brakes, not the big fronts they sent me (which were $5,200 back then).So, I understand completely about balancing systems and in fact still have the help of the Delphi (GM) guys today in making sure our system is completely balanced. I sent them front and rear calipers and pads and they came up with the booster and master cylinder arrangements and reservoir size. Something that NO OTHER Viper brake upgrade supplier is doing.
Regarding the rotors, you can use stock Viper rotors as I did in SCCA World Challenge last year with our GTS. However, I am working on a front and rear rotor upgrade for the track cars. The 14" front rotor with aluminum hat is 5lbs lighter than the stock front rotor because of its large aluminum hat. the metalurgy of these rotors is far superior to stock and the life should be double to triple on the track. On the street and for occasional track use, the stock rotors are fine.
To upgrade the full 4 wheel system to 14" front rotors will only cost the price of the rotors as we designed the front caliper bracket offset on one side so you could run stock or bigger without buying other parts.
Once we have our 14" rotors on with the 18" wheels John Purner is making for us, I will challenge ANY other Viper brake system for performance and feel. This system on an ABS car will be incredible and because of the ABS's ability to reduce pressure, may not require the booster and master cylinder change.
We just sent Ken Adelbergs complete 4 wheel system out to California and he is having it installed along with our shocks, bushings and duct kit this weekend. Ken will be a good judge for you guys and he is getting the first production set of 14" front rotors and he did some testing for Stop Tech.
Regarding the adjustable brake proportioning valve (because I know some people are wondering about this) I supply it as part of the kit for tuning purposes. In the four wheel kit with race pads and 13" front rotors, the adjustable brake-proportioning valve will need to set at about 5 turns out from full increase. Once the system is bedded in, you'll need to perform some brake tests to final set the bias. Keep in mind that tires, temperature, pressure, surface, alignment, corner weights, shock settings and whether the car is in gear or in neutral when you're braking all are factors in setting the brake bias correctly. Ultimately, it is safer to have a little front lock up first when braking hard as the car will continue in a straight line with the front brakes locked. When the rear brakes are locked, the car can turn and is less controllable.
Here's a picture of the 14" front rotor I'm working on. The stock 13" front is on the left, the new 14" on the right.
You must be registered for see images
