Vacuum Brake - TEAM COTTON'S PERFORMANCE TURBO BUICK ONLINE FORUMS

gnvader · #1 09-09-2008, 05:00 PM

Hi Jack,

Getting ready to install your CPT61.

I just converted to Vacuum Brake and cant hold boost more than 3 Lbs. I hear you have also converted to Vacuum. What can I do to improve it. I don't like the response as well compared to Power Master. However, it'll be a pain to go back to PowerMaster.

Thanks in Advance,

Virgil Tordera

BrianHynes · #2 09-09-2008, 07:44 PM

Trans brake

JCotton1 · #3 09-10-2008, 10:22 AM

There ya go, trans brake.... of course that may not work so well on the street. I really don't have any tips to help there Virgil. Are you saying that the 3lbs is with your old turbo with the vacumn brakes? If so what turbo is it?

WSLN 6 · #4 09-10-2008, 01:37 PM

If you have decent vacuum at idle (which you should, 15" or so) you should have plenty of power with vacuum brakes. I have always been able to hold 15psi on the footbrake, no matter what turbo I had.
A couple things that will help:
Looser converter (something over 2800 rpm at 0psi)
S-10 rear brake cylinders (nice increase)
Good rear brake shoes (some guys use both long shoes and return the short ones lol)
Boxed rear control arms (I gained 5psi by doing this)
Vacuum resevoir (Comp Cams $60)

gnvader · #5 09-10-2008, 05:17 PM

Jack,

I have the stock Turbo. I am afraid that with your turbo, I will not see the gains if I cannot hold boost. Looking more for street performance.

I was thinking of putting my old PowerMaster back, since it had better response time than vacuum.

WLN6..Thanks for your replies. I guess upgrading with S-10 cylinders and longer brakes is not a bad idea regardless of the types of brakes.

Thx, Virgil

WSLN 6 · #6 09-11-2008, 03:22 AM

One thing to mention, try some practice stops on dry pavement with the S-10 cylinders. They will be a tad touchier in the rain out back, so be careful....

JCotton1 · #7 09-11-2008, 01:02 PM

Virgil, don't let the brakes hold you back, get that turbo on, work with it from there.. Sean is right on with what he is saying.

gnvader · #8 10-05-2008, 12:22 AM

Quote:

Originally Posted by WSLN 6

If you have decent vacuum at idle (which you should, 15" or so) you should have plenty of power with vacuum brakes. I have always been able to hold 15psi on the footbrake, no matter what turbo I had.
A couple things that will help:
Looser converter (something over 2800 rpm at 0psi)
S-10 rear brake cylinders (nice increase)
Good rear brake shoes (some guys use both long shoes and return the short ones lol)
Boxed rear control arms (I gained 5psi by doing this)
Vacuum resevoir (Comp Cams $60)

WSLN 6;

Can you send me a picture of where you placed the vacuum reservoir?

Thx, Virgil

waGoN · #9 10-05-2008, 04:42 PM

I never have trouble holding any decent boost. Of course I have the power master, but there are ther things that I have done. I used to have the 4 long shoes, but don't think you really need those. Definately get the S10 wheel cylinders. Then snug up on the brakes until they drag. Then take it for a spin, then snug up on them again, then take them for a spin. Do it a few times. This will wear the shoes so they make alot more contact with the drums. Speaking of which, put on new drums or get yours turned. This should improve them. Check out the wear on the shoes, and see how much contact they are making. Then see how it is and if you still have a problem, get the vacuum reserve canister, but make sure that you have a check valve between it and the engine, or it won't help any.