I keep hearing about torque converter lock up and non lock up and i have no idea what is, what it means to do so, when you want to do, what rpm you want to do it. My last car was a 5spd camaro so i know nothing about automatics and tc's. Any info and any extra info greatly appreciated.
Thanks

 

If you are cruising down the road at 70'ish. You give it a little gas and the rpm's only raise a little as speed goes up. That's the converter locked. Now ... with the accelerator still holding 70, touch the brake enough to turn the brake lights on, that will unlock the converter, notice how the rpm's raise.

The converter has a clutch in it that makes it a 1:1 ratio between the motor and trans. It's only applied some times. When you're idling at a stop light, its obviously unlocked. If you floor it from that light, it will raise up to the 'stall speed'.

Does that help clear things up? What did I leave open?

 

The TC clutch is a clutch that takes the torque converter effective "out of the picture". When it locks, it locked the engines output directly to the input shaft of the tranny - no slippage or fluid coupling from the torque converter.

Stock the earliest mine locks up is at about 36mph in 4th, at light throttle. It unlocks when my speed goes below 34mph. It can lock/unlock in 3rd and 4th at various throttle and speeds. (I didn't realize applying the brakes locks/unlocks the clutch - that's cool).

I think the main reason the clutch is for fuel economy and emissions. It's kind of like running a very effient 5th gear.

As far as using the TCC to your advantage at the track - I'm not familiar with that stuff. All of my TCC lock/unlock points are just about stock.

 

Thanks for the help guys

 

You can see,hear,feel it shift once after fourth. Listen to the engine and look at the tach...it'll drop a hundred or so after it has been in 4th a bit.