So i am having a strange thing going on and im not sure if its me or the car yet haha. well the setup is built lsvtec turbo making 500hp with s300 with bbg. previously I was building about 8psi on 2 step at 6200rpm with 24.5x8.5x13 slicks at 9psi and a stg 5 clutch hitting 1.7 60fts at 7.1 in the 1.8th leaving power on the table in 1st and 2nd. Now i throw a twin disc in there and its bogging hard off the line. still getting 8 psi same everything. tried raising the 2 step up to 7k and tire pressure up to 17psi to get it to start acting sort of right again. my question is does this seem normal? Makes me wonder if the old clutch was slipping just enough at launch to help me and now this twin disc says nah bro learn to drive. should i turn the 2 step up to like 7k and start with tire pressure at 20psi and go down from there or what? i know at the track i can figure it out but before i get there just want some input from you folks who have kind of went through this already. Thank you

 

Your car will be quickest with the bare minimum amount of clutch that it takes to hold high gear. That's because something, either the tires or clutch (there is no third option), needs to slip until the car is going fast enough that a solid connection between the engine and track does not bog the engine. The slower the clutch pulls the engine down, the more time the car has to gain speed before the clutch locks up. Also the slower the clutch pulls the engine down, the more airflow you will have thru the engine, which will in-turn make it easier to make boost thru the launch.

I make a clutch hit controller called the "Hitmaster", it can temporarily reduce a clutch's holding power just long enough to prevent a bog. Lots of fast turbo cars using it to soften the launch, it can also be configured to be active for short periods of time after the shifts. The more power the engine is making, the more likely it is that the car will also benefit from softening the shifts.

Grant

 

thought i would answer this and leave the solution to the issue I had... anyways turned out the boost control was not correctly set in the BBG tables. she spools up a nice 15 or so psi almost immediately at about 6800rpm and with about 8psi in the slicks she takesoff and avg low 1.7s 60fts everytime.