Brake Pressure Switch for launch control ???

Doug Hoven · 08-21-2024, 08:30 AM

Quote:

Originally Posted by JP1738

Slightly off topic here, but is it legal to use a momentary switch that's not mounted directly to the brake pedal that you hit with your foot? Like a WOT switch on the back side of the pedal that makes contact when the pedal is depressed a certain amount? I could go through the rule book and check myself but I'm lazy and I don't want to. TIA

I believe something like that would be legal. That?s how a lot of clutch guys activate the 2 step, with a momentary switch, sometimes mounted to the pedal, other times activated by the Z bar, or back of the pedal. What I don?t think is legal, is having a button to activate your circuit for your 2 step. Not that tech is really a thing anymore, but NHRA didn?t like that in theory, you could also deactivate the 2 step with the same button, and in Stock you aren?t allowed to launch off of a switch or button activated by hand.
Now, I?m not sure if I?m just ignorant, oblivious, etc, but I don?t understand the issue of having a brake pressure switch active during the run. My 2 step is activated at 600psi. More than likely, if you?re using more than 5-600psi on a run, you are probably not going to be under power, and probably close to locking up the front brakes. To the best of my knowledge, if engine rpm is above the 2 step rpm, ignition will be cut completely.

Rich Biebel · 08-21-2024, 10:24 AM

Makes sense about the brake pressure switch being active down track and not triggering the 2 step because you're not applying enough pressure to trigger it....

The info I've gathered here has helped Thanks...

Adger Smith · 08-21-2024, 09:51 PM

If you don't have some way to deactivate the brake pressure switch down track in theory it could activate the 2 step when you do any hard braking.( dumping, hard backing into, ect) Depending on when, where, and how you hit the brakes that activated the 2 step it could be said you were activating a down track stutter device. I would hate to have that discussion with NHRA Tech. Some sort of deactivation switch is the route that might be all around the best and safest.
.02 for free

08-21-2024, 10:24 AM	#2
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,320 Likes: 25 Liked 557 Times in 217 Posts	Re: Brake Pressure Switch for launch control ??? Makes sense about the brake pressure switch being active down track and not triggering the 2 step because you're not applying enough pressure to trigger it.... The info I've gathered here has helped Thanks... __________________ Rich Biebel S/C 1479 Stock 147R

08-21-2024, 09:51 PM	#3
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Brake Pressure Switch for launch control ??? If you don't have some way to deactivate the brake pressure switch down track in theory it could activate the 2 step when you do any hard braking.( dumping, hard backing into, ect) Depending on when, where, and how you hit the brakes that activated the 2 step it could be said you were activating a down track stutter device. I would hate to have that discussion with NHRA Tech. Some sort of deactivation switch is the route that might be all around the best and safest. .02 for free __________________ Adger Smith (Former SS)