Any issues with AutoX with Vacuum brakes and High Stall converter?

UNGN

Can't Re- Member
Joined
May 24, 2001
My 16 year old son loves my TTA and convinced me to get it running and now wants to prep it for AutoX. On paper it appears to be the hot setup for ESP... it just too bad there aren't many choices in 16" street tires any more.

I figure that in stock form brakes won't be a problem, but if I put in the Vigilante Converter that has been sitting on my shelf for 15 years in combo with the stock turbo, vaccum might be an issue.

Does anyone have experience AutoXing a TTA or with vacuum brakes?
 
I run a 9.5 3300-3500 non-L/U stall here with a vacuum brake conversion and it works fine under braking. When getting on the gas it comes on a little too fast/hard... the car was more predictable with 2000 non-L/U stall.

 
Autocrossing mine with the vacuum brakes was always problematic. No matter what kind of check valve I put on the booster, it got pressurized, resulting in no power assist after going WOT. Compensating for it on the course was a nightmare.

Now, the TTA may have a better setup, and if yours is still stock, it'll probably do OK. A TTA won FS at Nationals way back in the early 1990s, and 1LE Camaros of the same vintage were competitive until the latest batch of stupid-fast muscle cars came out, so the platform will do just fine. Especially for a 16 year old just getting started.

I don't think the convertor is going to hurt the braking. As long as the check valve and booster aren't leaking, you're going to have enough vacuum stored for one good stop, and as soon as he takes his foot off the go pedal, he'll drop back into vacuum and empty the booster back out.

Where you'll run into problems is if you spring a leak or starting raising the boost and overpowering the check valve. I just switched my GN over to manual, and couldn't be happier. It works the same every time and there's less crap to break now.
 
Huh... my car is tuned for 30psi and I have never experienced any of those symptoms. But, then again the brakes on my car are upgraded.

Run it and report back.
 
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