 Brake upgrade question, will I need a brake bias |
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| smrz914 |
 Jul 26 2005, 10:45 PM
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#1
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Soon to be brightening the life of the person behind you.  Group: Members Posts: 456 Joined: 21-April 03 From: Pleasant Hill, CA or Chico, CA Member No.: 596  |
So I dropped off my stuff at the platers today and orderd parts so I'm hoping that i'll have everything by the end of the week. I useto have a 911 front end with "A" calipers and stock rear calipers. I saw the threads on the 911 rear brake upgrades so I decided to do that. So all the stuff is coming together. I took the stock proportioning valve out when I put the 5.8L in the car because it wouldn't fit. I just have a T in there now.
So when I put the 911 front end on I got a 19mm master cylinder. My question is whether or not I need a proportioning valve with the bigger rear brakes? Will it be a trial and error thing for when I get the car back on the road? |
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Replies(1 - 6)
| lapuwali |
Jul 27 2005, 09:38 AM
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#2
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743  |
It would be a good idea. They're small, and they're not all that expensive. You'll go through a trial and error process of setting it once you have the car running again.
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| ewdysar |
Jul 27 2005, 10:48 AM
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What happens here, stays here. Group: Members Posts: 558 Joined: 29-October 04 From: Altadena, CA Member No.: 3,030 |
Most V8 conversions run the "T" with 911 fronts, 19mm masters and stock 914 rears. The extra weight near the rears seems to balance the brakes pretty well. Check the piston area on the new calipers compared to the old ones, if they're close, things shouldn't change much. Anything more than 10% different might call for a prop valve. If you're setting up for hard core racing, i.e. corner balancing, adjustable bars, etc. then an adjustable bias valve could be better. The drag is when you find that the proper adjustment is full open... (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)
I haven't locked a wheel in my car yet, so I don't know which will go first. Eric |
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| SirAndy |
Jul 27 2005, 11:07 AM
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#4
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Resident German Group: Admin Posts: 41,648 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
i have mid '80s carrera brakes on all 4 corners, 19mm MC and i run a "T" instead of a valve. the brake bias is perfect, fronts lock up just a tad before the rears ... (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) Andy |
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| smrz914 |
Jul 27 2005, 02:17 PM
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#5
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Soon to be brightening the life of the person behind you. Group: Members Posts: 456 Joined: 21-April 03 From: Pleasant Hill, CA or Chico, CA Member No.: 596 |
Trial and error it is!
So is there a way to get the exact year off the calipers without knowing the car they came off of? |
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| Eric_Shea |
Jul 27 2005, 02:47 PM
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#6
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PMB Performance Group: Admin Posts: 19,275 Joined: 3-September 03 From: Salt Lake City, UT Member No.: 1,110 Region Association: Rocky Mountains  |
Measure pistons and you can slot yourself in a model year ballpark.
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| smrz914 |
Jul 27 2005, 08:22 PM
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#7
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Soon to be brightening the life of the person behind you. Group: Members Posts: 456 Joined: 21-April 03 From: Pleasant Hill, CA or Chico, CA Member No.: 596 |
Fronts are ~48mm and rears are ~38mm, I didn't have my digital calipers on me so I used a ruler. Is there any gain in the back becides the vented rotor?
The plater wouldn't take the pistons. Said they would get damaged, so how should I protect the pistons from getting rusty (the part exposed to the outside not what is inside the caliper). |
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