911 Rear Brake Tech help
12-31-2003, 08:50 AM
#1
Rennlist Member
Thread Starter
911 Rear Brake Tech help
Hi,
I am trying to increase the rear stopping power of my 76 911 race car. I do not want to go full blown big reds or the like because of weight.
I have modified 944 turbo calipers on the front and they work great. I love them, They have never faded or boiled the fluid. I would love to do the same to the rear, but the best I seem to be able to do is get them to mount with about 1/4" of the pad hanging off the top of the rotor because the rotor is not large enough in diameter.
The question is, is there any other rotor that bolts up to my hub directly that is a little larger. I already have the Carrera rotor on it (which I think is a little larger in diameter) but, is the 964 larger and bolt on, or is there some other rotor that will do the job.
Also, I have seen the page on rennlist that is brake tech and talks about the rotor diameter and width, but only the front. Is there a page that talks about the rear as well.
Thanks
Ed
I am trying to increase the rear stopping power of my 76 911 race car. I do not want to go full blown big reds or the like because of weight.
I have modified 944 turbo calipers on the front and they work great. I love them, They have never faded or boiled the fluid. I would love to do the same to the rear, but the best I seem to be able to do is get them to mount with about 1/4" of the pad hanging off the top of the rotor because the rotor is not large enough in diameter.
The question is, is there any other rotor that bolts up to my hub directly that is a little larger. I already have the Carrera rotor on it (which I think is a little larger in diameter) but, is the 964 larger and bolt on, or is there some other rotor that will do the job.
Also, I have seen the page on rennlist that is brake tech and talks about the rotor diameter and width, but only the front. Is there a page that talks about the rear as well.
Thanks
Ed
12-31-2003, 09:28 AM
#2
Race Car
Ed, I'm not too handy on rotor sizes for your application, but I'm guessing there's a decent solution out there and someone that could guide you in the right direction. 
ALSO, you might want to consider your brake bias. I'm not sure if the '76 911 had a rear brake bias/limit valve or not. If it does, I'm sure that it would be mounted right underneath the master cylinder or down where the brake lines route...is it the "smuggler's hatch"?? I seem to remember that's where my valve was, but I don't have my SC anymore.
In your case, you would need to identify the value on the valve, likely 33-55bar - just a guess...and at that point you would either want to remove it completely or go up in value, causing more bias to the rear.
Example: if it is a 33 bar unit, try 45 bar, if 45 go 55 and so on...I believe the factory makes them up to 60bar and then you just take the valve out if you need more bias.
ALSO, you might want to consider your brake bias. I'm not sure if the '76 911 had a rear brake bias/limit valve or not. If it does, I'm sure that it would be mounted right underneath the master cylinder or down where the brake lines route...is it the "smuggler's hatch"?? I seem to remember that's where my valve was, but I don't have my SC anymore.
In your case, you would need to identify the value on the valve, likely 33-55bar - just a guess...and at that point you would either want to remove it completely or go up in value, causing more bias to the rear.
Example: if it is a 33 bar unit, try 45 bar, if 45 go 55 and so on...I believe the factory makes them up to 60bar and then you just take the valve out if you need more bias.
12-31-2003, 12:39 PM
#3
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Are you sure you really want to do that??
Early truck style ABS systems only released the rear brakes from skidding since that was the primary danger. Too much braking in the rear can lead quickly to loss of control.
IF you have aproportioning valve, my 78 SC doesn't, you need to think really hard about why its there before you go removing it.
Early truck style ABS systems only released the rear brakes from skidding since that was the primary danger. Too much braking in the rear can lead quickly to loss of control.
IF you have aproportioning valve, my 78 SC doesn't, you need to think really hard about why its there before you go removing it.
