XFI Aux 2 output and transbrake control?

Blazer406

Mechanical Engineer
Joined
May 2, 2002
Got an idea....

1st... the transbrake control must be hooked up thru the XFI.... then in the circuit going to the trans brake solenoid.... with a little wiring..... and another relay....you could hook the Aux 2 output (which is ground) that would open the transbrake circuit....and release the transbrake.

Here is why I would want to do that:

If I were testing... not in an actual race.... and I wanted to leave at a certain boost..... once the light goes green....I would have to release the transbrake myself... at the desired boost... with everything else going on....it is difficult to leave at the correct boost (unless you have a CO2 boost controller).....you could do this wiring.... and the transbrake would function normally... you get up to the line.... and start building boost as the lights go green.... and at whatever boost setting you set the aux 2 output to (example 12 psi)..... it will trigger the circuit... which with some creative wiring... will interrupt the transbrake circuit.... and the car will launch....at the exact and repeatable boost level you set in the aux 2 output parameters....as soon as the car leaves... you would turn loose of the transbrake switch like normal....

Anybody done that?

One of the challenges on tuning a car... watching the slips...and trying to "tune" is to get the car to leave on as much boost as possible. This is always hard to do with no fancy boost controller.... however... it seems the launch boost could be tuneable using the above creative wiring. Obvoiusly this wouldn't work so well... if you were actually racing someone... and needed to leave the instant the light goes green..... but it should work great for T&T.
 
The relay could kill your reaction time, but it should work.

Try pins 30 & 86 from transbrake button, 85 to Aux 2 and transbrake to pin 87A.

Hopefully everything else went ok today. Call again if you have more questions.
 
The relay could kill your reaction time, but it should work.

Try pins 30 & 86 from transbrake button, 85 to Aux 2 and transbrake to pin 87A.

Hopefully everything else went ok today. Call again if you have more questions.

I was only talking test-n-tune..... racing against someone else... it would never work..... that is where the AMS1000 would be a "must-have" IMHO.

Y'all stay with me on my twisted thinking......

Well.....if you took the ground output from the aux out2 .... pin B2 ...... and ran it to a SPDT relay.... pin 85 on the relay.... then took pin 86 on the relay and went to 12V switched.... then pin 30 on the relay to 12V + .....then pin 87A to the positive side of the transbrake solenoid...... then you set the Aux output 2 to say 170 kPa (10 psi) ...... you stage....hit the TB button.....transbrake activates......you mat the gas..... boost starts to build.... at 170 kPA (10 psi) .... the XFI grounds the Aux Output #2... which makes the solenoid activate.... breaking the circuit going to the transbrake solenoid... therfore releasing the transbrake. As soon as the car moves.... then you turn loose of the transbrake button..... and the car launched at the desired boost level.

I realize the mechanical relay is "slow" ... but for test and tune.... .001 second reaction accuracy is not necessary.

It would allow one to launch on the same boost every time... eliminating one of the many inconsistencies of launching..... and if you wanted to leave on more boost... just go into the aux 2 output settings... and dial up a little more boost.

Sound crazy?
 
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