Switchable torque converter lockup. What's involved?

[whatthe?]

Hi all, Since autos are a reasonably new thing to me I've been reading up on them and now understand how most things work. I'm not really able to find anything on converter lockup setups though, so I'm hoping someone (maybe Sean) can explain exactly what's involved in setting one up

Cheers

[mrshin]

I'm assuming you're thinking of using it to tighten things up a bit at the deep end of the track? If you just want a big button to hit yourself, then you just have to put power to SL on the auto. Connect it also so it can't work if your foot is on the brake, and also only in the appropriate gears (you'd be probably wanting it in third?)

[whatthe?]

Yeah, I noticed in Sean's crown thread the power gains he saw on the dyno with the converter lockup engaged. I wonder if an autronic output could be used instead of a manual button? Bit tricky I'm guessing, as the SM4 wouldnt know what gear the car was in

[MS-75]

If you have the SM4 I reckon you'll be okay as you can use the road speed input to control the solenoid application. If you want some more info I can check with a mate who has an SM4 with the speed sensor set up. (we had some chopper discs lasered up to go on the tailshaft yolk)

HOWEVER-a standard lock-up is not designed to hold full torque of a stock motor-let alone a modified one. The converter I have in my car is significantly modified to significantly increase (like 2-3 times) the clamping area of the clutch face along with upgraded clutch material. (Mike at MV obviously)

In addition, I have only used the lock-up on the dyno so far. Locking the converter and then applying power is far less stressful on the clutch than trying to lock it under load. I know shane (1JZ-747) has done it, but he's had the converter re-done during last year and I'm not sure how long it would last when locking under power-and neither is Mike as no-one has been doing it enough to work out the durability of an upgraded converter. All that would ultimately happen is that the lock willl just fail to grab.

It will depend of course how much power the motor has. I'm of the opinion that in my case it's not worth using it as I'll be amazed if it holds the HP, but on the dyno where the clutch can be locked with no load ito begin with it works fine.

On the dyno it should deliver anywhere from 10-25rwkw depending on haw big the stall is.

Sean

[whatthe?]

Thanks for the reply Sean. All my gear has been built by MV autos, the box has extra clutches and upgraded friction material and is rated at 600bhp (apparently). The converter itself is a 3500rpm job made by MV, I belive they use a pajero/a340e hybrid setup.

The engine is certainly modified (although I dont expect the type of power you were making!). I'm not too concerned about dyno figures, so I might just run it as is and wait to see how long it takes Shane to break his

Cheers

[mrshin]

You could get the ECU to do it, and have it also switched by gear - say you wanted it to work in 3rd and 4th, you could make it so that when S1 had power, no power could go to SL. Then again, surely a nice big red button would look the goods next to your Bogan Shifter?

[2JZR31]

I made a thread on this a while ago. I just use it for economy. All you need to do is hook a switch to ground the pinout for the converter lock up. Just try not to floor it or change gears with it locked.

[brett_celicacoupe]

to make the TC lockup only possible in 3rd and 4th you should find a relay that is closed with no power and open when there is power. ie. normally-on relay

for 3rd and 4th gear, solenoid 1 is off.

its possible the ecu will have a sad if it sees the solenoid is open while it wants it closed. O/D light may flash etc.

this should work for wiring it up. relay would be a couple bucks from jaycar

[2JZR31]

My Aristo auto doesn't seem to lock it in 1st or 2nd anyway. I can just leave it locked and shift to 1st and 2nd when I slow down to prevent the engine stalling. When I shift down it unlocks.

What gearbox are you running Brett?

[brett_celicacoupe]

errrr.... w58 in the GA40
w50 in the ra40
a340e in the mx83 that i just sold
and another a340e in the MZ12 i bought but havent picked up yet.

i plan to have a bit of a play with the a340e in the soarer

[2JZR31]

ahh OK Because going by your diagram the converter wants 12V+ instead of a ground like in my car. Are you sure it locks in 1st and second? Which one of your cars did you hook the switch up to?

[chris davey]

I have the most simple setup possible.

Lockup solenoid wire goes to power switch (not used as manualised) and on the other side of the power switch is accessory powered 12v. I have only used it for general cruising, not on dyno or track as my box is stock.

So mine definitely needs 12v not ground.

[brett_celicacoupe]

ahh OK Because going by your diagram the converter wants 12V+ instead of a ground like in my car. Are you sure it locks in 1st and second? Which one of your cars did you hook the switch up to?

im only assuming the solenoids are switched on with +12v. i say this because i pulled apart a a340e and they only have 1 wire coming out. ie the case of the solenoid is grounded. though i cant remember if the TC lockup solenoid is the same

Are you sure it locks in 1st and second?

not sure what you mean by this as i didnt say anything about the TC locking in 1st or second.


the diagram i posted would only allow locking of the TC in 3rd gear and Over Drive.

[2JZR31]

Not my box. Toyota has no consistency with things like this. Some solenoids are grounded some need 12V+.

Re 1st and 2nd lock up. If the box automatically does not allow lock-up in first and second there would be no need to rig a circuit like you describe. Just see if it will actually lock in 1st and 2nd before you bother making the circuit. Like I said as soon as I shift to 1st or 2nd it automatically unlocks even though I have the solenoid grounded still. I think its a hydraulic circuit in the box which won't allow lockup in 1st and 2nd despite activation of the solenoid.