How many would be interested in a bolt on front brake uograd

914URY · Post by **914URY** » Fri Feb 01, 2002 7:05 pm

Ok - they're right, I take it back, don't use the SS lines on the street. Go with new rubber lines, replace the p-valve, bleed them and enjoy.

Rleog · Post by **Rleog** » Fri Feb 01, 2002 8:55 pm

Greetings again,
The more I checked back on this thread, the more I liked it. While waiting for spring and having the engine done, I'd rebuilt the calipers, went to a 19 mm master cylinder, and put new rubber hoses on. Then I started second guessing myself after reading so many posts in favor of the 911 brake upgrades. The thought of having one of Jake's 2270s behind my back was already making me a little nervous about not having enough brake to reign it in. So, I'm feeling a lot better about having rebuilt the stock calipers. One last question - do you guys have a preference among the proportioning valves? I know Dave said there were several out there, and Chris has no complaints about the Tilton. Thanks again - I'm figuratively grinning from ear to ear. Bob G. 70 (soon to be 2.3)

BobP · Post by **BobP** » Fri Feb 01, 2002 9:14 pm

I have enjoyed this entire thread too, just goes to prove that what you read elsewhere doesn't always play out in the real world.

As I said before I have had no problem with my brakes, I had new lines and pads put on when I bought the car and changed the fluid, I will change it again this year. I will be thinking about the proportioning valve and master cylinder upgrades when I do the tear down and repair I plan for next winter.

How much does the larger master cylinder increase the pedal effort?

Rleog, keep us posted on your new engine, I am considering the same thing for next winter. Or a 2563

[This message has been edited by BobP (edited 02-01-2002).]

Dave_Darling · Post by **Dave_Darling** » Fri Feb 01, 2002 9:49 pm

Chris--you can answer your own question about the brake pads: How do your race car's brakes feel in the first braking zone? Have you ever tried to really use them there?

Some of the locals tell me that with some pads (Ferodo Race pads was one example) you want to get on the brakes about double the distance back on the first corner, and hold them on as long as you can. That gets them heated up--and for the rest of the run session, they never cool down to where they don't like to work.

On the other hand, some of the carbon/kevlar pads do work well when cold. Their downsides are the fact that they generate a lot of dust, and their tendency to wear down rotors quickly.

Bob, the 19mm M/C has about 25% more area than the stock 17mm M/C. ( (19 X 19) / (17 X 17) ) Pedal travel will be about 25% shorter, but require about 25% more effort to get the same clamping force.

--DD

Racer Chris · Post by **Racer Chris** » Fri Feb 01, 2002 10:17 pm

OK, I really like the way my KFP pads feel even when cold, but I have never really put them to the test. I have 100 percent confidence in them after a slight warm-up. I use the medium compound. Maybe the autocross compound would be more appropriate for street use. KFP pads are available for the stock rear calipers, unlike many of the popular racing pads. Also, they do not seem to wear the rotors heavily.

Chris Foley

914URY · Post by **914URY** » Fri Feb 01, 2002 11:08 pm

Rleog,
I found that when I changed my p-valve I was able to bleed the rears much better. Before that it was as if the rears weren't working that hard, but the p-valve changed that. I would also go to the ss lines but they need to be checked out once and awhile. They are not maintance free. I did have a front one blow out on me once. I see no need for cooling ducts on a street car. Keep the fluid fresh and the air and water out. I tend to the think when people make the change to the BMWs, they are seeing the biggest increase in perforance due to the fact that they bleed the system completely and used new fluid. Good luck

Racer Chris · Post by **Racer Chris** » Sat Feb 02, 2002 12:02 pm

I don't think you could convince me to buy anything from Summit Racing, at any price, thank you very much. Especially not to install in a Porsche.

914URY · Post by **914URY** » Sat Feb 02, 2002 7:47 pm

Go with the Tilton p-valve. Leave the Summit stuff for the drag racers

BA914 · Post by **BA914** » Sat Feb 02, 2002 11:49 pm

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Racer Chris:
<B> A big problem is the proportioning valve on the firewall in the engine compartment. If you change that to an adjustable unit like a Tilton and adjust it so the front brakes lock up slightly before the rears you will have fantastic brakes unless you have a very big motor and drive very, very fast.
Chris Foley</B><HR></BLOCKQUOTE>

There is a device available that will aid this. I'm not sure what the name is but I have seen it used on drag cars as kinda a sudo ABS. It's a divice developed by NASCAR teams that installs inline with you rear brake lines. Under normal braking preasure, it allows normal preasure to the rear brakes. But, under hard braking, as the preasure is abruptly applied, it delays the preasure to the rear brakes for a fraction of a second and then graduates the preasure so the rear brakes do not lock up.
I have seen it in tech articals but not sure where you can purchase one. My guess is you can probably find em at Sumitt Racing.