[bragggf]

Working on a setup on car with a Pro-Ratchet/THM400 electronically shifted trans and Gear Vendors overdrive. The gear vendors is used to split the shifts between gears to optimate engine RPM down the track, as well as allow the car to cruise on the freeway. Currently we have an MSD RPM Window switch (P/N 8969) that handles the trans shifting for now.

However, when racing we really want the car to automatcially shift 1-1over, 2-2over, 3-3over and do this automatically. Has anyone worked on a similar setup? Both the OD unit and the trans will be set to shift at a designated RPM point (it is possible that the RPM point needs to be independent for each device since one enduce more or less delay than the other, altering the programmed PRM point). We need to 'alternate' the responsibility of which device is going ot handle the next shift. Logically I could see how this could be done with 2 independent relays but don't know how to get a signal to a relay to either active/inactive it. This relay would need to sit between the RPM switch (which simply completes a ground circuit) and the solenoid(s) controlling the Pro Ratchet/THM400 and Gear Vendors OD.

Can a deadenbar box do this? Any RPM based device needs to handle a 5 volt square wave coming off of a waste spark ignition. The MSD #8969 can handle it but doesn''t provide the other functionality.

Appreciate any comments, suggestions. Thanks!

PS. Anyone needing an RPM switch should look at the MSD 8969. It can handle just about any type of ignition and is programmable in 100RPM increments. All for +- $90.
Much cheaper than having to go with a full blow DIS-2/4 ignition.

-Gerry Bragg
Brighton, MI
bragggf@sbclgobal.net