TCC lockup question for modifyed engines...
Thread Starter
Race Director
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
TCC lockup question for modifyed engines...
why would you want the TCC to unlock at a lower TPS% than the factory settings at a given speed? does an unlocked converter give better throttle responce? I know that a locked converter gives better gas milage.. and at lower speeds aviods chugging.. but is there some gain to be had with an unlocked converter? Why does the factory ECM have the computer unlock the TCC when it senses a rapid opening of the throttle body blades (TPS%) even if the car is above the speed in which it normally engages the TCC.. and then at a high MPH speed (90mph in the case of my vette) does the ECM force the converter to lock no matter what the TPS position..
:confused:
:confused:
Burning Brakes
Joined: Jun 2003
Posts: 1,229
Likes: 1
Re: TCC lockup question for modifyed engines... (BluByU)
the only thing I know is that a TCC is made to multiply the Torque of your engine.
Thats all I know, I don't even know the difference between a lock and unlock TCC.
Can someone explain? :confused:
Thats all I know, I don't even know the difference between a lock and unlock TCC.
Can someone explain? :confused:
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: TCC lockup question for modifyed engines... (BluByU)
Well for sure throttle response would be better if the TC were below the lockup point and the TCC unlocked and I think it would also be the case above lockup. The reasoning is that there is still some torque multiplication above TC lockup.
I've heard that the best 1/4 mile times come with the TCC locked though. This must come from the fact that the slight slippage of the TC is eliminated when the TC is locked and so the engine speed equals drive shaft speed. In this case the vehicle is staying in each lower gear longer before each shift point is hit (or should be). It's possible to force the (700R/4) TCC stay locked in any forward gear above 1st by jumpering ALDL pina A & F. So far I haven't tried this at the strip and so have no time slip comparisons to make.
I believe that the TCC in our A4s is a compromize and so are the lock/unlock algorithms. That clutch is rather light duty and so doesn't hold up well to high torque application. This could be the main reason for the lock/unlock characteristics. Also driver impression would be another consideration of the General; a lot of new Vette owners don't want to "feel" when the tranny is shifting or the TCC is locking/unlocking.
I've heard that the best 1/4 mile times come with the TCC locked though. This must come from the fact that the slight slippage of the TC is eliminated when the TC is locked and so the engine speed equals drive shaft speed. In this case the vehicle is staying in each lower gear longer before each shift point is hit (or should be). It's possible to force the (700R/4) TCC stay locked in any forward gear above 1st by jumpering ALDL pina A & F. So far I haven't tried this at the strip and so have no time slip comparisons to make.
I believe that the TCC in our A4s is a compromize and so are the lock/unlock algorithms. That clutch is rather light duty and so doesn't hold up well to high torque application. This could be the main reason for the lock/unlock characteristics. Also driver impression would be another consideration of the General; a lot of new Vette owners don't want to "feel" when the tranny is shifting or the TCC is locking/unlocking.
