Torque convertor lockup, how does it work?

[NicT]

So im messing around with the crown gearbox wiring and i have a solenoid i can control to lockup the torque convertor.

What is lockup good for? I imagine its direct engagement between the engine and the gbox like a manual flywheel with no slip.

I was considering setting up a PWM reading circuit to engage the lockup after a certain rev, and momentarily disengage between gear changes.

Or i could use a voltage detecting circuit and connect this to my TPS and show when i hoof it it locks it up for instant v8 action.

I was also thinking of waterfalling them both, so the lockup would happen only after a certain rev and above a certain TPS threshold, meaning when i change gear i can get it to engage smoother between shifts.

Whats going to work for me? and does the torque convertor lock up mechanically after a certain range anyways? (hence why people change for higher stall torque convertors)

And what does the stall rating on a torque convertor actually mean?

Chur,

Nic

[Spencer]

are you shifting this manually? should just wire up the ECU to do it, its all of 10 wires

From a a340 service manual, cant find the page that outlines the engagement rules

basically your box is designed to only have lock up engaged in 3rd and 4th gear and it should not be engaged while shifting. So your basic inputs for a torque converter lock up are a RPM signal and a connection to the shift indicator (thats for BASIC operation ^ as above you want the brake switch, TPS, Coolant etc to make it work like factory). And your output would only turn it on in 3rd or 4th above a certain optimum rpm and would disengage for shifting. It saves allot of gas if your cruising to have it working

Also if your shifting manually without solenoid control there is a brake and one way clutch that doesn't get selected, I have heard from some trans guys this is not a good thing for your gearbox. If your using the solenoids carry on

[phr34kr]

viewtopic.php?f=1&t=23622&start=80

scroll down

KK-Kolonel explains in in depth (this is for what the ratings mean and the effect they have)

[cletus]

they are not designed for large power loads, they only work at light throttle. the clutch in the converter isnt very big

[NicT]

Cheers guys, pretty much put everything into perspective for me.

I intended to manually shift the gearbox, with the selectors waterfalling a relay board to engage the correct solenoids for the correct gears.

I was hoping to have lockup in maybe 2nd for more skid action as well.

Long term id like to manual the car, i can afford to do it now but would prefer to get it on the road, certed, legitamised then see how much cash i have left over.

[Spencer]

Later model boxes that have PWM pressure control have lock up in 2nd, no way you should be thinking about the lockup as a skid thing.

You dont need a relay box to engage the solenoids, go find the solenoid shift sequence. You can engage them off the gear indicator switch

[NicT]

Later model boxes that have PWM pressure control have lock up in 2nd, no way you should be thinking about the lockup as a skid thing.

You dont need a relay box to engage the solenoids, go find the solenoid shift sequence. You can engage them off the gear indicator switch

I have the shift sequence, have made relays so that power to one solenoid doesnt backfeed into the other when selecting gears.

Also selection for D has no output which means a switch needs to close to engage a solenoid when there is no output from the selector. 2 way relay fixes this problem.