Sensing 2nd gear pressure

[hgerhardt]

Anyone have any ideas on where to tap into to install a 2nd gear pressure switch (200-4R, of course)? I could put a boss on the servo cover and put it there, or on the 1-2 accumulator housing. What would be nicest is to tap into one of the crossfeed passages on the valvebody, but I can't figure out where.

Here's my idea: I'm running a Motec in my 66 GTO and would like to set up an input telling the ECU when the trans shifts so that it can take out, say, 30 degrees of ignition timing for a couple hundredths of a second to minimize shock loading to the trans. This is essentially what every modern driveline does. This should increase clutch life and hard part reliability substantially while sacrificing only a couple hundredths in performance.

The way I'm thinking this will work is, as the clutch starts to engage, it trips the switch, and completes engagement under reduced engine power. Granted, this will all happen in a few hundredths of a second and may not work at all with the ECU in a "passive" role. Seems like a good idea, though.


Heinrich Gerhardt
66 GTO
428 EFI Pontiac, ~550HP
200-4R, Continental 10"
11.8's 117mph 4100LBS w/driver

 

[WE4]

Great idea but..

2nd gear is a band in a 2004r , if that is the trans we are discussing, which you need the pressure to stop that drum turning backwards at 15,000 rpm in 1/100th of a sec. If a different trans , then there might be another way.
The best way however to sense 2nd gear oil is at the servo. We have a test cover that just has a 90 degree an #4 fitting and hook the gauge to that. You could just 90 it and run an 1/8th pipe switch to it and walla, you are set to go. Just be very careful NOT to run it in too far that it hits or obstructs the pin to the cover. Do it off center so you do not risk hitting the piston or the pin. That would not be good....

Bruce
WE4
www.PTSXTREME.com

 

[hgerhardt]

Thanks, that was what I was thinking too. I figure each switch opens at 30psi or so at the beginning of each shift, the computer will retard timing for a 100th of a sec, and the band and 3rd clutch will see slightly less load during shifting than they would otherwise. Might work. Then again, the shift might complete before the engine torque reduction has any effect. Only way to find out is to try it.