parish8

iTrader: (6)

i have a t76 and a 4l80e, i can brake boost to about 2psi, i tried to go higher and just sliped right off the line, is there some way to build more boost out of the hole?

is this where a tranny brake would come in handy? i have never seen or used a tranny brake so i am not sure how it would work. would there be enuff time on the line after i staged to set the brake, build the boost and release the brake?

anyother ways to build boost faster? what could i do tuning wise to get it too spool faster? it doesn't spool real slow or anything but 12psi on the launch would be better than 2.

Crunch

There is no reverse manual valvebody for the 4L60/4L80 transmissions, and therefore no transbrake.
Those transmissions could not even withstand a transbrake even if there was one available. They are not considered racing transmissions.
You'll have to go to a turbo 350/400 to do what you are asking.

Big Rick

iTrader: (1)

You can get a two step and when that's activated you can retard all of the timing and dump a bunch of fuel to spool the turbo faster.

Jammer

iTrader: (1)

Nice idea Rick!
As far as them not being racing transmissions, this may be true, but they can be built to to handle 9's for sure. See Rossler. And Derek (yes , formerlly of TCS) offered the vacuum modulated 4l60's... not sure if others do or if it would help in any way.

sbrown99TA

There is a way to do it that CMotorsports developed. They were pretty hush hush when I asked them about it but on a 101mm turbo they were seeing 77,000rpm on the line.

parish8

iTrader: (6)

hmm, i got my kit from them, they should share with me i would think , if they want their kit to do well and sell more of them that is.

y2khawk

iTrader: (5)

The turbo Buick guys are known for parking brake launches

Short string on the release handle, stage, hit the e-brake and the foot brake, just tug the rope to launch. The force should get your foot off the foot brake. I don't know how much the parking brake in the trucks can hold though.

Worth a shot anyway

sbrown99TA

I think they are in the patent process right now. All he would tell me is that it's nothing like anybody has out right now. All he kept saying was "there's always energy in an engine, you just need to know where to direct it".

Crunch

Explain how to use a 2-step without a transbrake? How are you going to lock up the transmission? Unless you mean footbrake with a 2-step, but is it worth using at such a low RPM?

427

iTrader: (3)

The 2 step would be my choice also. If you retard the timing and add fuel the fire in the pipe will help spool dramaticly. You also may want to loosen up the torque converter a little.
Kurt

smokinHawk

iTrader: (48)

actually there is a trans brake out for the 4l60E
not sure were but nbm00ws6 was telling me about it once.

weather or not it would hold up though is another question.

SS00Blue

I was under the impression that the 4L80E was essentially a TH400 with an additional gear. Am I mistaken? If that's true, then obviously the 80E would handle anything you can throw at it.

SC-

Crunch

I stand corrected, Yank actually has a transbrake for the 4L60E, at least thats whats on their website.
http://www.converter.cc/high_perform...nsmissions.htm
I would actually like to see one pop a nice wheely and last more than 5 nitrous/blower ten-second passes, though.

parish8

iTrader: (6)

the first thing i did on this truck was to swap the 60 for the 80, i blew up too many 60's to even look at one again. i dont exactly know how a transbrake works or if it would be ideal for geting a good launch, if they make one for the 4l80e would that be the hot ticket to get a hard launch? i can build way more than 2psi out of the hole, i just cant hold it back with the brakes and these trucks have prety good brakes.

y2khawk

iTrader: (5)

A transbrake uses an external solenoid on the valvebody to engage 1st and reverse at the same time. It locks the transmission. You are then free to load the motor against the converter without any power transmission to the wheels. It builds ALOT of heat in the trans/converter, so not intended for more than a second or two when staged.

You release the button and the solenoid releases reverse, and WEEEEEEEE

RyanJ

two-step = load. new fuel/timing tune = more load. more load = higher spool rate. with that you should see more than 2psi at the same engine rpm. with that come power though, which means you could be pushing through the lights or trying to spin the tires. w/o a brake, you run that risk. TCI makes a manual vb for an 80, don't know if its reverse, however.

Also, Rons Custom Auto makes this brake deal (with a solenoid) that helps divert braking power to help hold the rear wheels/brakes for turbo buicks. maybe that can help.

parish8

iTrader: (6)

i have a 4wd and with mashing the brakes hard i can't hold it back, not sure how the brake thing would help.

XLR8NSS

iTrader: (4)

Would a two step set to a low rpm build more boost than just footbraking alone? Without a transbrake the two step would have to be set at whatever the highest footbrake rpm was that could be attained. Would it help?

RyanJ

I have no idea on the Ron's brake deal.. But they sell it....must do something. perhaps it puts more fluid pressure/force on the caliper?

XLR8NSS

iTrader: (4)

Parish how about trying a hydraboost brake setup to hold harder? That setup is pretty awesome.