Anyone use a launch light when footbraking?

I found that at times after I stage and I am focused on the tree, I was letting the launch rpm drop a bit.

The feature is already in my MSD box, just have to wire it up.

Any tips, like it/don't like it?

not same animal but we used one in TA/FC for while. Driver liked it he would get to where it was just on or flickering and thats where he staged. Then your rpm maybe be more critical we where good if+/- 250.+ was better.

Yes. I seldom footbrake though. My track of choice is no-box so that's how I race. I keep the light on the car just in case.

You say it's already in your MSD, which MSD? Is it like a window switch that has an adjustable RPM setting on and then off if you vary? I know autometer made a small digital tach like that. Have a few friends that footbrake and use it successfully. Most tracks around here went no-box so I just use a 3 step on a brake pressure switch.

I have a 7530T,

its an actual feature, you set a staging rpm and a high rpm. When you hit the staging, the shift light lights solid, if you go above the high, it flashes, below it turns off.

I used it this weekend and I definitely like it.

I had to add a relay to the wiring. The wire that activates this feature is the same wire that activates the launch rev control. I set it up where when I hit the brake, the relay activates its for only the launch light. By default, it is connected to the transbrake wire so when I and racing box, I can use the launch rev limitor. Then I failed to realize that every time I hit the brake it would engage the launch rev limitor. So after the burnout when I would hit the brake, or make a pass and hit the brake, it would activate the launch rpm.

I added a switch that I turn on right before I stage and turn off after I leave. Getting to the point of over complicating things. If I am just doing footbrake all I have to do is raise the launch rev limitor way up. I was thinking of maybe a button on the steering wheel that I just push when I launch, again, just may be over complicating things and leaving room to make mistakes. I will have to think on how I want to do it as I definitely like the features because I get a visual cue that I am were I need to be rpm wise.

Eman what do you use for a brake pressure switch? and how is it wired?

I use the brake light switch.

I used a 5 wire relay. The launch wire that runs to the msd box goes to the terminal that switches. I hooked the transbrake wire to the terminal that is normally closed with no power. I hooked the brake switch wire to the other terminal and the terminal that triggers the relay. Then grounded the other side.

I couldn't wire it directly because the 12 volts from the brake switch would engage the t-brake.

I will probably look at a separate shift light to simplify things.

quote:

Originally posted by B Williams:
Eman what do you use for a brake pressure switch? and how is it wired?

I use a simple brake light switch that works on pressure, I can't remember the part # but I can look if you need it. It's a simple 2 terminal with 1/8" pipe threads. I know Jegs sells them but I bought it at the local parts store. Use bullet connectors that just push on the 2 terminals. I run 12v to it which activates the 3 step when I'm on the brake. If you use the brake at the finish line you have to figure a way to shut it off or it will stutter at the finish if you scrub the brake.

Bill, There is an easy way to use one toggle switch, one relay and Digital 7 programming to disable the Launch input and turn off the Launch light for 25 seconds after foot brake release. I can draw the wiring diagram and list the programming needed if you’d like.

Definitely would be curious,

What would the operation be?

If your talking about using the rpm/time switch, I currently use that to activate the air shifter.

quote:

Originally posted by banjo:
If your talking about using the rpm/time switch, I currently use that to activate the air shifter.

Yes, I was using that Output in the Time mode to disable the Brake / Launch input through a relay.

Are you using the Output Switch in Time or RPM mode to shift ?? If RPM I can offer you another wiring method in Dig 7 to do all of this for FB and TB .

I am shifting off of RPM.

I would definitely like to see what you have in mind.

One toggle switch and 2 relays will allow you to run FB or TB class. Dig 7 programming remains the same for both FB and TB modes.

Toggle switch is moved to the ON position with foot on brake at pre-stage.

#86 terminals both relays to +12v ignition ON.

In Dig 7, Set the Launch Light Lo / Hi to a value less than normal TB Rev Launch setting. Example… Launch Light Lo 2500, Launch Light Hi 3000, Rev Launch 4000.

Set the Shift Light 1 to desired 1-2 shift RPM.

Set the RpmTimeSw to Time. Set the OnDelay to a time value .25 seconds less than normal shift time. Example.. if 1-2 shift occurs at approximately 2.00 seconds, set the OnDelay to 1.75. Set the OnTime to value 15 seconds longer than your ET.

The reason you want the relays to energize as late as possible, is to be able to restart the timer in Dig7 if intermittently turning Off / On the Launch input while bumping into the stage beams. Once the timer reaches the OnDelay time value, the relay that provides the launch signal is ON and Launch cannot be reset without cycling the ignition Off / On.

For TB mode, toggle switch remains in the Off position.

To test my theory without purchasing relays or wiring do this. Program as I have written. With your meter set to ohms attach one lead to B/W and other to ground. With engine running at more than 1000 rpm push and release brake pedal. Meter should indicate 0 ohms at OnDelay time out for the OnTime period. If this works, then same test, but push and release brake and then push and hold prior to OnDelay time value timeout. This should rest and hold timer off not energizing relays until released.

this is how you control launch rpm, prevent creep, when footbraking, not with a light

no surprise you don't have a clue.

Where does the toggle switch wire in?

you tell me genius.

launch light to control rpm creep

Ed, Maybe when you go some rounds, win some races and actually be somewhat successful in bracket racing, I may see you as something more than the internet loudmouth that you are. Until then, just keep checkbook racing and regurgitating what others have told you.

Another CLUELESS club racer^^^ with a POS playing in a duck pond that thinks he knows.

Meanwhile, I go rounds every week and would easily trailer your a s s.

If you say so ed....