bypassing the T-brake button for reverse

First of all I really love my CRT billet probrake, what I am having trouble getting used to holding the button and trying to back up and negotiate the car, if I remember correctly some one had a wiring diagram showing how to wire up the trans reverse light/neutral safety switch to activate the t-brake when in reverse mode, all the while not back feeding into the delay box, anyone still have this diagram handy??

I just wired in a toggle switch with an indicator light to let me know when it was rev.

I use the back up light wire to trigger a relay that engages the brake so the car can back up. It also has a trans brake switch that activates the brake, the feed for it is on a toggle switch. My brake will work in first or second and I didn't want to take a chance accidentally bumping the switch when driving it on the street. My two step engages anytime the brake is engaged but it's no problem.

You may have to run the feed wire for the delay box through a toggle switch to keep it from coming on while backing up.

I vaguely remember seeing that.

If I wanted to do that I would use a 1pole double throw relay (spdt) with the reverse lights activating it.

relay common - brake solenoid
n.c. term - power from delay box brake connection
n.o. term - hot 12volt (line side of delay box)

This would isolate the box when the relay is applied and work normally the rest of the time

Read the rulebook though, about transbrake and 2step connections. Some tech guy could have a problem because you are adding a device into the circuit

I ran a separate button off the wheel by my switch panel. In a pinch if the steering wheel button fails I can use it in a race also.

Use the reverse light micro switch in your shifter to trigger a relay

You can isolate the two circuits by using relays to trigger your transbrake instead of feeding your trans brake directly from the delay box - use the delay box to trigger the 2nd relay

The Bosch/TYCO - Relay, SPST 12Volt/30AMP with diode works good for this purpose

By doing this both circuits are not connected and work independently of each other

I had 2 buttons hooked up 1 on the steering wheel the other was on a cord under my seat so when I was backing up I can grab that and still be able to steer

I don't see the need for a relay. The BU light circuit of the 3-prong NSS acts a Normally Open switch so, hooking it from battery power directly to the solenoid would only power the solenoid from that circuit when the shifter is in Reverse.

Having the button and the NSS connected to the solenoid in parallel won't cause any feedback problems unless the button is pressed when in Reverse.

True - but the delay box will get back fed and will activate the lock out on the box - so you have to waite to use the trans brake - plus the NSS is not rated for 30 amps - which is what a trans brake can draw

I was thinking somewhere in the diagram I was talking about there was a diode involved to prevent that, with my T-brake the button will activate reverse in neutral also so you would just have to remember to put it in neutral and use the T-brake button if you needed to back up on the starting line area, in the pit area it wouldn't matter you just wait for the delay to drop out.

My car had a toggle switch mounted on the shifter down low and up front on the opposite side of the shifter for operating reverse when backing up and or having to turn while backing up when I bought the car, it works great Almost fool proof, I have forgotten to push it off when I'm in a hurry to get in the staging lanes backing out of my pit spot, it won't go forward with the switch on and the shifter in low gear
My trans brake button is on the steering wheel for hands free from the shifter launches

Yes you can put a diode between your box and the the transbrake solenoid - that will do the same thing - but your going to need a 30 amp diode - The diode will stop the back feed to the box when you use your back-up switch

Hi,
my delay box has 2 delays, 2 buttons on wheel left and right side, second button delay is set for 9999 sec. plenty of time to back up
gary

really? because A typical transbrake solenoid draws 1.4 ohms resistance. 12 volts divided by 1.4 ohms = 8.57 amps! Now check this out... 16 volts divided by the same 1.4 ohms = 11.4 amps!

The formula is one of three "Ohm's Law": V/R=I (the other's are V/I=R & IxR=V) and this simple check will help you decide what size fuse and what gauge wire should be used when wiring your race car or you can ask people on the internet. LOL

Joe

I think I said “can” - as most boxes are rated up to up to 30 amps - also a solenoid is actually an inductive circuit - a little different calculation - but hey I am only an electrical engineer

I try to keep my electrical systems free of unneeded complexity and "stuff". We have a button on the wheel. Push the button and back up. It's a race car. I'm not parallel parking on a busy city street.

no but sometimes the pit's can get pretty clogged up with car's and trailers and the ocasional dip stick that don't know how to park.

Really what is this different calculation?
you might consider telling TCI about your different calculation, because they are doing it wrong.
www.tciauto.com/media/custom/upload/221300-01.pdf
and dedenbear!
http://www.dedenbear.com/TECH_tipTXT1.htm

I have a 15 amp slow blow fuse on mine and have never had a problem.

Joe

Yes - and that is why you should put a freewheeling diode across the solenoid..........

to much brain power for me !! I just push the button.

Even the button is too much for me. Release the foot brake and mash the gas!!!!! Easy peasy...............

I just spit out my gum.

I'm just tired of my arm's getting tied up in knots trying to turn the steering wheel and hold the button at the same time.