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Posted by: Elliot Cannon Apr 22 2003, 11:43 AM

Hi,
I'm fairly new to 914s and this web site, so I think this topic has probably been discussed before. I'm working to restore this 73 914 and have done the suspension and most of the brakes. All new brake lines, calipers and 19mm master cylinder. I installed BMW 320i calipers in the front. I would like to replace the rear brake proportioning valve with a "T" fitting. I finally have the engine out and will be finishing up the rear brake lines after some welding is done. What do you think of replacing the valve with the "T"??
I've seen some great discussions on this site and have learned a lot and hope to learn more. I can't wait to get this car back on the road. Thanks in advance for the advice.
Cheers, Elliot

Posted by: SirAndy Apr 22 2003, 12:04 PM

i just put the "T" into my car a week ago. no driving experience yet, but the word is that with a major brake upgrade (in my case '86 911 Carrera), the stock bias does not allow enough pressure to the rear brakes. therefore the "T" gives you a better overall brake performance.

Andy

Posted by: Brad Roberts Apr 22 2003, 03:26 PM

Elliot,

The T in place will balance out the new braking force you have in the front very well with the stock rears. I'm finding more and more stock prop valves heading towards failure.

B

Posted by: Anton Apr 22 2003, 03:40 PM

Have you read the Tech Articles on the Pelican Parts website concerning brake physics and practice? I personally would not discard of the prop. valve. In Europe it's even forbidden; a street car will not get its annual approval (MOT, TüV, APK; depending on where you live). There are after-market, adjustable proportioning valves; wouldn't that be better? I must admit that my own 914 braking experience goes as far as a revised stock set-up, apart from a 19mm master cylinder.

Posted by: airsix Apr 22 2003, 03:45 PM

Nobody has mentioned the best part - with the prop valve gone (or replaced with a modern one) spongy brakes are a thing of the past!

I love my brakes since I ditched that flaming piece of dog poop.

-Ben M.

Posted by: Brad Roberts Apr 22 2003, 03:52 PM

Anton,

We have found when installing an adjustable valve... we end up running them wide open...so why spend the money on an adjustable one when I end up with it wide open ?? Install the 8$ T. I do agree that the different brake combo's will require something in place of the T, but I have tested every possible brake caliper combo with the T without the T and with adj. prop valve. Your safe with the T in the USA unless you have bone stock size tires on the car.

I threw physics out the window. We test setups with digital pyrometers to read rotor temp. I have real numbers... not theories.

B

Posted by: bernbomb914 Apr 22 2003, 03:55 PM

I need to get a Tee for my Volvo conversion but cant find one around here. went to Glenns swap meet to pick one up but he was out of them. Volvo fronts are awesome and really pull down very smooth and with the Tee it should be better.

Bernie

Ps Muller is responsable for the idea of the installation. Very inexpensive.

Posted by: Elliot Cannon Apr 22 2003, 05:02 PM

Thanks for the info and opinions everyone. I am told that you can get these "T" fittings at a VW dealership. I think I'll look for one tomorrow.
Cheers, Elliot

Posted by: anthony Apr 22 2003, 05:05 PM

Here's one for $5 http://www.914world.com/classifieds/detail.php?cat=21&de=401&PHPSESSID=5498e275f87642dcce65be805db3e82b

Dominic is a good guy.

Posted by: drew365 Apr 22 2003, 05:15 PM

Could this be why I flat spotted my front tires last event? So for lack of a $8 T fitting I've got to replace $400 in tires. I think I'm going to try not to let this happen again.

Posted by: Brad Roberts Apr 22 2003, 05:18 PM

Sure.. all race drivers try and find a reason to describe flat spotted tires.


B

Posted by: drew365 Apr 22 2003, 05:37 PM

Well if I install a T it will eliminate one excuse. Besides, I'm still a member of the Ricky Racer Club. When I run out of excuses I might be a race driver.

Posted by: campbellcj Apr 22 2003, 11:27 PM

I did the tee a while back and once I got some good pads installed front+rear, the difference is pretty amazing. You can actually feel the rear brakes "working" where you couldn't before.

I got my tee from a local Bug shop in the SF valley. "Small Car" was the name, I think, in Reseda or thereabouts.

What brakes are you running Andy?

Posted by: Brad Roberts Apr 22 2003, 11:30 PM

I'm not Andy...

He has Carrera front calipers and stock rears with a 19mm MC.

B

Posted by: campbellcj Apr 22 2003, 11:42 PM

Pretty close to my setup - SC (A) calipers up front with SC vented rotors & Pagid Black pads; 914-4 front calipers in rear with 914-6 rotors and Pagid Orange pads; 19mm M/C; SS lines; ATE blue fluid. I haven't been to a really brake-intensive track yet, but they feel very good so far.

Posted by: Anton Apr 23 2003, 05:39 AM

Another question for me is whether the original prop. valve wears out and needs revision at some point.

Remarkably, revision parts for the prop. valve are nowhere to be found. So, is this not necessary? Or, if it is, might this be the reason for a poor rear brake performance (regardless of the superiority of a "T" as you all say)?

Most car parts simply need revision or replacement after 30 years of duty.

Posted by: drew365 Apr 23 2003, 08:28 AM

This Andy has early S front calipers and stock rear calipers and rotors. I'm not sure which pads are on it but I know they were supposed to be a combo street/track pad. I will probably use pagid when these wear out.
Chris; whats the difference between the Pagid orange and black?

Posted by: Brad Roberts Apr 23 2003, 11:30 AM

Anton,

I do agree that the prop valve probably needs rebuilding. Dont get me wrong, not all cars need a T in place. We went thru a ton of hassle on a factory 6 car in the shop to locate a good factory six valve. When I say a car needs a T... its when somebody has done a 6 conversion on a 4cyl car (the stock 6 prop valve is valved for more rear brake) or a V8 conversion in a 4cyl car....or someone has gone to sticky wider tires. It all comes down to your situation. If I was doing a concourse restoration.. I would go thru and find the proper pieces to rebuild the stock prop valve.

Unless you have driven a car with a T.. its hard to explain the benefits. ChrisC above got pretty close with his comments on "I can feel the rear brakes working now"

B

Posted by: James Adams Apr 23 2003, 11:48 AM

Hey Brad, don't you need less rear brakes (more prop valve) with stickier tires? You can transfer more weight to the front so the rears have less vertical load and less grip that the fronts.

What am I missing?

Posted by: Brad Roberts Apr 23 2003, 09:14 PM

Your not missing anything James.

I want the car to stop flat and not transfer so much weight forward. Our cars are pretty well balanced and they turn in really well. No need for more transfer (these are my thoughts on this) I have spent quite a bit time playing with adjustable prop valves in 4cyl cars and 6cyl cars. Each time they end up wide open... so I stopped buying them and starting going with the T.

Too much front brake makes the car feel really squirrely under heavy braking like the rear end wantsto swap ends with you.. the T adds just enough rear brake that the car is more stable when you stand on the binders.

B

Posted by: campbellcj Apr 23 2003, 11:18 PM

That's right..remember that I (and a lot of other guys) have much bigger front brakes than stock. We also have way more grip than stock. Think of what happens when you slam the front brakes on a sport-bike... woohoo. Serious excess front weight transfer. That's basically what you end up with on a 914 if you have bigger front brakes, sticky tires, and stock prop valve that wasn't set up with any of this in mind. Your rear brakes are practically "turned off".

Andy - the "RS14 black" compound is higher friction than orange. They are both high-temp "full race" pads.

Here's the info page on Pagid's site --

http://www.pagidusa.com/characteri.html