Help wiring pressure switch,line lock and 2-step

[201250]

I did a search and found a lot of good info on using the brake pressure switch/2-step/line lock, but not much on wiring everything together. Sorry for the long post. I have a 2012 Mustang and plan on using 2 line locks (one for left front one for right front) using the anti lock brake distribution block as the junction. Seems like the cleanest install. I also understand the disadvantage if one line lock goes bad you are screwed. Have the rules changed allowing line locks on the rear wheels? If so is that how you are holding the car instead of the fronts?

Will it work to put the pressure switch at the Master cylinder into the line feeding the front brakes into the distribution block? I assume you are using the pressure switch to activate the 2-step using a 40psi switch.

The line lock would be activated by a momentary switch (steering wheel cc button). then what you bump the car in at about 2000rpm,
set the 2-step to about 3000-3500, stage, go WOT and leave on your bulb. If so will the front brakes only hold the car on the line without creeping forward. I know it;s not that simple but in theory?
I could also see adding a pressure gauge to help with consistency

I've got Baer SS4 11" dual calipers for the rears and 11" SS4's for the front.

Hope someone can clear this up for me Thanks in advance for the help.

TC

[Lew Silverman]

TC -

I "think" I understand what you're trying to do, but it sounds like you're complicating things a bit. Is this a street car you're racing or a race car you drive on the street? It matters!

The idea of using two line-locks, one on each front wheel, is, as you've mentioned, very dangerous. You should be able to plumb both front wheel brakes to a line-lock after the anti-lock manifold and not have to worry.

You can install your pressure switch to activate the two-step just down-stream of the master cylinder. I would think you'd want to tap into the rear brakes to isolate it from the line-lock, and you'll need a momentary-on switch installed on your shifter to prevent the two-step from activating at the end of the run.

One other observation - it's my understanding that 4-wheel line-locks are not allowed and that the brakes must be released by the action of the foot pedal, not a finger-operated switch. You might want to look under the hood of a Cobra-Jet to get an idea of how the brakes are set-up.

Good luck!

[Tgreen3724]

Ive posted very similiar questions here on classracer. What I ended up trying was using a two step button with no transbrake. Basically I stage with engine rev'd 500 or so short of 2 step limiter. Once the stage is on i go WOT then just let go of the button when you want to leave. The foot comes off the break on its own. I really wasnt sure if this would work or not before i tried it and let me say it works great. First shot out i was .050, adjusted my button went .036, then .019, then .039, over the course of three time runs and four rounds my lights were all green and between 0.019-0.056. I plan to raise the two step up about 400 rpm next time that should take about 0.014 out of the Vehicle Reaction time and put me 0.005 - 0.042. Of course im no expert and different things work for different people. Just my thoughts.

I wouldnt tie it into the line loc but thats me

[201250]

First off THANK-YOU both for the informative responses. This what I was looking for.

Lew......What I am trying to do is undo 35 years of superstock racing using a trans brake and trying to understand the "tuning" process of the new Mustang. Computers instead of timing, jet changes and 4-link adjustments. Originally I was building a Cobra Jet 5.0 N/A car. However it became crystal clear I could never stay with the big boys based on resources they have available which outsiders don't have.
With that let me say I know these CJ guys work there ***** off getting every bit of HP out of them and I admire them for there dedication. Sometimes getting answers is like pulling teeth. It hurts and you finally give up. The car will be street driven/limited racing mostly testing for about a year; then converted to a full race car when I retire.

My hang-up has been the rear line-lock issue. When I raced it was illegal. Now it seems everybody has there own opinion on the subject. I suspect it depends on if you have it or not.

Upon further investigation I see the front brake line out of the Master cylinder runs to a factory proportioning valve. I can put the line-lock in that line along with the pressure switch. I am also going to install a pressure gauge. I had a pressure gauge back in the 70's with my B/SA car to help with consistency and it worked well. Are there guys still doing that?

So the line lock is only used for the burn out and foot brake using both front and rear brakes to hold the car.

Tgreen....... Great information. So the button only controls the 2-step and the line-lock is only used for the burn out. With the button releases there is no worry about the 2-step engaging on the other end? With the consistency you have, I can't wait to try it.

[Hans Olsson]

Originally Posted by 201250

So the line lock is only used for the burn out and foot brake using both front and rear brakes to hold the car.

Yes.

[201250]

Got it !!!!!!!!!!!