Hi stall converters without a trans brake. How to launch?

[wiso]

hmmm, i face the exact opposite of most of you, with a standard torque converter, Mine can hold 2400rpm to launch off the line effectivly, if i hold the brake and just mash the trottle (anywhere over 2400) however my car will never wheel spin, it will begine to creep forward but it feels like the tranny is bogging down.

very strange situation to me as i would have expected it to simply light the rears

I don't understand it myself

[Bored?]

id imagine that would be a well smart way of killing your transmission quickly.

How is it different to any other transbrake?

[1JZ-Rolla]

How is it different to any other transbrake?

True, this is how a normal transbrake on a C4, powerglide etc would work, however although the Toyota A340 is "electronically controlled", this only applies to forward gears, and even then there are still manual valve body events that take place along with the solenoids diverting fluid flow through the valve body. Reverse is physically selected with the shifter only, no solenoids are used, so simply activating particular solenoids will never engage both reverse and first together.

[BMWTurbo]

I was looking inside a 2jzgte auto yesterday ( I muched 2nd gear) and from what I could see the only mechanical part of the auto was to engage park. The rest was literally jsut flicking the switch on the side fo the gearbox.

[TA-022]

reed switch on revese gear that triggers 1st gear solenoid? have the reed switch activate by a dash switch and at the drags the dash switch is effectively your trans brake switch.

shift 1st ...reverse disengages ... 1st gear solenoid is already going so VROOM.


although i doubt this would work in real life?

[-==L=a=N=c=E==-]

im surprised he hasn't posted yet, but Shane aka 1JZ747 uses a A304 rebuilt to hi hell with no trans brake, and he gets off the line a-ok...?

[chris davey]

Trans brake could be possible I think via electronics if what bmwturbo is saying is correct. I don't think it would like it very much though as was also said.

I already have a manualised auto and I know where the reverse 12v signal wire comes from and goes to the ecu. But I am unsure which wire it goes back to. I could check with the multi to find out and then if you wired 12v to a switch which spliced into this wire I think you could then activate the reverse solenoid while the car is in 1st gear.

Anybody think this is a terrible idea?

no transbrakes in street rwd anyway but I would like to see if it is possible.

Shane has monster brakes on the front and sticky tyres on the back so that would help.

I don't really understand how you can get the nitrous to bring boost on without a transbrake though. It is only activated at 100% throttle and from what I have found anywhere near 100% throttle would either try to light em up (even with no boost) or push it through the beams. I was planning on activating at 3000rpm and I should get 2800rpm on the stall so that would mean boost at takeoff not launch.

[jampac]

Isn't transbrake but when both reverse and 1st is engaged at the same time, causes the gearbox to not go forward or backwards, but still loads the shit out of the engine and of course causes massive gearbox temperatures and pressures to occur.

I can't see how you can electronically engaged 1st and reverse at the same time in an a340e.

[chris davey]

yes that is correct. Just checked an old thread and the 3 wire plug I was thinking of that goes to the solenoids are Sol A & B for shifting and the lockup one. So I got no idea how reverse works

[-==L=a=N=c=E==-]

actually a little while back i had the opposite problem when trying to do a static burnout at the drags, my rear brakes were grabbing too much.

I have a load sesning valve in the ute, similar to a p roportioning valve, which i backed off, and now can rip hectik skids bru....

Perhaps crank up the line pressure going to the rear brakes in a hope of holding them for longer...?

[Ribfeast]

Is there upgraded/better brake pads/shoes available for the handbrake? On the cressy it has a separate drum for the handbrake I think.

[Sam_Q]

would a hyraulic handbrake help with getting extra pressure to the rear?

[1JZ.747]

a transbrake is being developed at present, its only in early stages, its works but its too slow.

once its complete we will be testing it for when i want to run slicks. at this stage it wont be available to every one. it is going to be given to a couple of us to use and thats it, until we see whether the box can handle it.

there are some other suprises on the way with the a340 but im not letting the lid off that.

[MR 1JZ]

will I need to go bigger than a 3200 stally with the T78 that im going to put on my motor?

[2JZR31]

So Shane, how are you holding boost of the line?