Originally posted by bob547
Hi Vader, Let me tell you my experience with making boost and holding the car with the brakes. My fathers GN could make 10 lbs of boost by power braking at the line. When we changed to a bigger turbo, the car did not make any boost by power braking, the car was slower with the bigger Turbo because it was slow off the line. With all the modifications on your car, you need a higher stall speed converter, or a trans brake. My mother has an 89 turbo TA, when she blew the trans, I rebuilt it with all ART Carr parts and a new converter, the only problem was they sent the wrong converter, it stalled at only 1800 rpm! I thought something was wrong with the brakes. Art took back the converter and sent us a 9 inch non- lock up. The point is, your combination makes boost at a higher rpm, so there is no way to hold the car with the brakes and rev the engine to make boost. You need to go to the next step, a trans brake and a better converter.
Originally posted by Turbonut
FINALLY someone gave the correct answer!!!!!!! Yea! Thats why you need to know what rpm your at as well as boost. I don't give s#$% what the boost is unless you give rpm numbers to. The stock D5 converter is 24to 2600 stall period. Big turbos will not build much boost that low. It's simple science, I have vac. brakes and leave at 8psi, DS data shows 2850 when the MPH starts showing something going on. Sounds about right to me for a stock converter. 15psi launch with a stock conv is a bunch of $%$^% Maybe with slicks and a baby turbo. My 2cents worth.
Originally posted by c&cgn
Well, without messing with the prop valve at all, my car held 7psi @ 2050rpms on the stock D5. I can get it to 2500rpm easily, and usually flash it to 2800-3000rpm when I launch. If I crank up the prop valve I would guess I will be able to hold 12-15psi at 2800rpm+. No reason why not, I flash it to there already on a regular basis.
I seem to remember TTA89 saying he flashed his stock D5 to 4000rpms on several launches, but I suspect that would cook your convertor pretty quickly.