Competition boosted launch?

[AMcCormick]

Maybe a dumb question but what is the proper technique for a controlled boosted launch? Hold the service brakes or just drop the thing in gear? This would be with an auto

 

[JJPage]

Engage the transmission, make sure you are in 4x4, go from drive to reverse and back to drive.



With moderate pressure on the brake pedal, start applying throttle, my truck starts to break loose around 15#, LET-R-RIP...



2wd, just hit it, or you will just roast your tires.

 

[AMcCormick]

drive, reverse, drive. under throttle? or apply throttle when back into drive?

 

[JJPage]

No, not under throttle, I do this to make sure my transfer case is engaged and I am in fact, all the way in 4x4.

 

[AMcCormick]

easily smoke the rears in 2wd and for a long ways if I stay on it. I'll wait a bit until a 4wd launch. Are the big hp trucks at the race track doing this same technique? Thats got to be a load of load either on the torque converter and or brakes. If they are using transmission brakes how do they work?
Thanks

 

[2Rowdy]

You can try it in your drive way. Just put into 4x4 and hold the breaks and feather the throttle, just watch your boost gauge start to come alive. You can stop it 5 psi, 10 psi, and take outta 4x4 and go to bed.

 

[fest3er]

easily smoke the rears in 2wd and for a long ways if I stay on it. I'll wait a bit until a 4wd launch. Are the big hp trucks at the race track doing this same technique? Thats got to be a load of load either on the torque converter and or brakes. If they are using transmission brakes how do they work?

Thanks

Using the foot brake is fine until you have too much power to hold. The foot brake works quite well with 4WD launches. Unless you have tremendous power, you won't break 4 tires loose.



The only drawback to boosted launches is that tremendous heat is be generated in the TC/trans if you have to wait a while before launch. Cool-down is important.



A trans brake essentially engages 1st and reverse simultaneously (locks the 'drum' and planetaries so nothing can turn). Be aware that certain classes of racing prohibit trans brakes.



In bracket racing, it doesn't matter what you do, as long as you do the same thing every time, such as launching at 1500 RPM every time, or launching at 15# of boost every time. In bracket racing, consistency wins.