Peer81
Well-known member
Hello everybody,
As I'm trying to get the 700r4 lockup right in my 81 I think overhere is the best place to ask as the 700 is from a 90 corvette.
The problem I have is that on my original transmission TH350C the lockup was controlled by the transmission and a little by the ECM (ecm controlled minimum mph lockup activation and brake de-lockup.) The 700r4 from a 90 corvette I now have the lockup was almost compleetly controlled by the ECM. So I almost have the lockup wiring right with some extra switches the only thing I need is a vacuumswitch that connects the lockup above ...Hg intake vacuum. (sorry no I'm not interested in the standard lockup wiring kits)
The question I have. Can somebody tell me for how long the lockup will stay active in a c4. For example, at a steady speed it's normal the lockup to work, but at 1/4 throttle will the lockup be on or off, and at 1/2 throttle?
I test drove the vette today with a vacuum gauge next to me. Steady driving at different speeds and rpm in 3rd and 4th vacuum was about 12 to 15 Hg. With 1/4 throttle the vacuum never dropped under 10 Hg. Going more throttle then 1/4 the vacuum will drop below 10 Hg (example taking over a car on the highway). So I'm thinking getting a switch which closes above 10 Hg. Any opinions on this one?
As the C4 lockup is ECM controlled it's maybe in relation to the TPS position?
Greetings Peter
As I'm trying to get the 700r4 lockup right in my 81 I think overhere is the best place to ask as the 700 is from a 90 corvette.
The problem I have is that on my original transmission TH350C the lockup was controlled by the transmission and a little by the ECM (ecm controlled minimum mph lockup activation and brake de-lockup.) The 700r4 from a 90 corvette I now have the lockup was almost compleetly controlled by the ECM. So I almost have the lockup wiring right with some extra switches the only thing I need is a vacuumswitch that connects the lockup above ...Hg intake vacuum. (sorry no I'm not interested in the standard lockup wiring kits)
The question I have. Can somebody tell me for how long the lockup will stay active in a c4. For example, at a steady speed it's normal the lockup to work, but at 1/4 throttle will the lockup be on or off, and at 1/2 throttle?
I test drove the vette today with a vacuum gauge next to me. Steady driving at different speeds and rpm in 3rd and 4th vacuum was about 12 to 15 Hg. With 1/4 throttle the vacuum never dropped under 10 Hg. Going more throttle then 1/4 the vacuum will drop below 10 Hg (example taking over a car on the highway). So I'm thinking getting a switch which closes above 10 Hg. Any opinions on this one?
As the C4 lockup is ECM controlled it's maybe in relation to the TPS position?
Greetings Peter