Need boost-building advice (long)

Black Box

Out cruisin'.
May 29, 2001
This is a multi-faceted question so I think it best belongs in this forum.

I'm just about finished all the winter mods (see my signature) to the GN and am ready to go racing, at least I think. Last year when I raced I was only able to hold 5psi on the radials before they would spin or I would push thu the lights. I want to be able to build more boost (10-15 psi) at the line, but I'm not quite sure what would be the best way to do it without tearing sh*t up or screwing with the driveability of the car. Here's the options I was thinking of:

  • S-10 brake cylinders and bigger brake shoes & line lock (cheap option)
  • vacuum brake conversion (a little more $$$ option)
  • E-brake launch (free workout for my left leg)

I think the S-10 cylinders and bigger shoes would probably work best, but I have heard that they can make the car react wierd during street driving/braking, which is what I primarily do with the car. But could someone answer the following questions:

  • Would the vacuum brake conversion allow me to hold more boost? Is the lack of brake holding power due to the weakness of the Powermaster?
  • How much boost can I realistically hold with the E-brake? Has anyone had any luck with this practice? Is it going to damage anything?
  • Should I try using both the E-brake and the footbrake at the same time?

I have sticky Hoosiers QT's now so I don't think spinning them once they're heated is going to be an issue.

I race with a bunch of F-body and Mustang guys. One of them INSISTS that a higher-stall torque converter is the answer. I've told him time and time again that with a stock turbo, intercooler, heads and cam I don't need anything but a stock D5, and that a $500-$700 converter is a damn expensive way to be able to build boost, and that brake mods or different launching techniques would be much more effective and less costly. He's stubborn as a mule and it's really starting to piss me off.
I'm convinced that he is just of the mindset that since a new Trans Am benefits from a converter, then a TR will too. Now I'm no genius when it comes to TR's, but I've done a lot more research about them in the past year than he has in his life. Not only do I think that he's dead wrong and that my car doesn't really need one, I am hesitant to put one in my stock (w/shift kit) 200R4. Also, I can't afford a converter, and I certainly can't afford a new tranny right now.

If I'm wrong them please say so. But can anyone shed some light on these subjects? Can someone provide me with some advice so I can (hopefully) shut this guy up once and for all?

Thanks for your help
I have the S10 cyls, the bigger shoes, line lock and an adjustable proportioning valve. The Adj prop valve allows you to send more pressure to the rear wheels for racing/launching and then you can dial it back to where it is suitable and safe for street driving. Then you won't even kow you have th big cyl's in there but you should be able to hold as much boost as you want.

Takes some playing around with the prop valve to figure out what works best for street driving, but then again what doesn't take some playing around on these cars?
I dont think the vacuum brakes would make any difference at all in the amount of boost you can build at the line. I would say stay away from using the e-brake cause its easily breakable. I would say just get the softer shoes in the rear and the s-10 wheel cylinders and you'll be fine. Just stick with the footbrake unless u want to get a trans-brake or a converter for big bucks.
Thanks for the advice. What do you think about putting a converter in the car? Will it substantially help build boost? Is it going to solve my problem? I told my friend that even if I put a converter in the car, if the brakes don't hold it now, they sure aren't gonna hold it if I start building higher amounts boost at the line.
Steve you are thinking correctly. Don't let your buddy's talk you out of what you know is correct for these cars. Stick with the D5 and work on the brakes. I think the bigger wheel cylinders and brake shoes is a 70/30 shot. I see too many people with them that still can't hold boost. I have come to the conclusion it is the proportioning valve in these cars and how hard you push on the brakes. I still have standard shoes and the stock w-cyl's but I push on my pedal LIKE I HATE IT and I hold over 15psi w/ slicks and 13psi with street tires.
I agree with c&cgn on the adj proportioning valve 100%!

another thread..

Thanks for your advice. I thought that was the case, but he would hear nothing of it. I think I'm gonna make an appoinment @ Cottons to have him install an adj prop valve and a line-lock.

Thanks again,
A line lock will be a big help at this point, as it'll keep the rear brakes form getting hot during your burnout. A cool brake drum & pad will hold a lot more boost than a hot one will!

I'm going to also suggest going for the s-10 cylinders & 4 "big" shoes (just get 2 set of the cheapest brake pads you local shop carries.) I have that exact combo (line lock, s-10 cylinders, 4 big shoes) on my car & can easily hold 10+ lbs of boost off the footbrake. Haven't noticed any driveability problems, but then again I usually only drive my T on the street during nice weather weekends & out cruising/prowling the local hot-rod hang outs.

A higher stall converter WILL help you hold more boost on the line, but is not NEEDED with your current combo. Wait until you need one to go with a bigger turbo, etc... :)

Doug C.
I have the stage right trans brake.Cant beat it for building boost.cost was $199 through ramchargers and about an hour and a half to install.No problems yet and I use it alot.You should make sure your trans is up to it though.I take off like a rocket with 10psi and can hold more if I want to,depending on traction.
it is a fresh rebuild with a hardened shaft,B&M shift kit,vigilante,stage right.Otherwise stock,yes.