buick_lsx

I know this goes with auto transmissios but since this is primarily for as turbo car I posted in here.... Anyways I fragged my stock 4l80 and picked up a built unit with a trans brake. Before I was just foot braking the car and getting 6-7 lbs on launch....

When using the TB do I need to keep the 2-step on to keep my boost up, or will letting off of it lose the boost? Or will it keep the boost/ make more since the motor will be loaded even harder against the converter?

WS6HUMMER

iTrader: (19)

I wired my T-brake & 2 step together, mine pretty much makes max boost (12-14 psi) that way. I like using the 2-step mainly as a limiter to help with the consistency of the launch and I can just floor it and not worry about keeping a certain RPM.

Did you Jake's 4l80 brake or Rossler's?

buick_lsx

Neither, it's a non sponsor so I don't think I can say.

And I'll have my 2-step and TB wired separately since most the time I'll just be foot braking....guess I should just add a toggle for the TB ground wire and just use one button, thatll make things easier on launch lol

MUSTANGBRKR02

iTrader: (91)

You can say who's it is. Just don't post links.

WS6HUMMER

iTrader: (19)

A lot of guys wire it the way you mentioned, I dont bracket race so I always use mine.

About the brake, I asked because from what I heard they are the only 2 shops that make a TB valve body for a 4l80. I got my 400 brake from Jake, he doesn't make it CK Performance does, but he does make one for a 4L80.

buick_lsx

I got mine from c k performance.

Does loading the car againt the converter usually make the car launch any harder vs. a lower setting on the 2-step? And is that a better way if you can launch like that and keep traction?

Just trying to get my 60's down to help my et's...i got them down to 6.91 and 1.61 last race of the year, im sure i can get 1.5's or better

WS6HUMMER

iTrader: (19)

I'm still learning how to launch mine, just swapped gears. I can tell you though the harder I can hit the tires and hook the better my 60' is.

buick_lsx

foot braking i launch at 3k, but have gotten it to 3300-3400 before but it is hard to keep from pushing, so with the TB i assume ill be around 3500-4000 if i dont use the 2-step and just load the converter, rear is a S60 so i went with the 3.54 which is the lowest gear they have.

Im hoping to take a tenth or more off the 60 when using the TB and get my 3900lb pig to pull the tires off the ground finally. Only 550 rwhp now so dont know if thats enough to get it done in this heavy of a car.

MIGHTYMOUSE

iTrader: (59)

you will def want to use the t/b vs foot braking if you have any sort of tire on the car

the two step will let you fine tune the launch instead of chasing the converter stall as boost comes in.

buick_lsx

Can you explain?
Right now I just run MT 275 60's and I hope to be able to use and hook them with the TB, If not I'll just buy some 28 x 10.5's and that should hook easy

WS6HUMMER

iTrader: (19)

You can hook on a 275 radial tire, just gotta tune the suspension. I run a 275 60 15 too.

buick_lsx

Right now I'm not spinning at all with the 275's and 9lbs of boost, ran 6.91 @ 102 and a 1.61 60. Just have a set of comp 90/10 and 50/50's for now, might have to upgrade to done double adj. Coil overs but hope not... Whatever I gotta do to pull the front tires though lol

buick_lsx

BUMP for a mighty mouse answer

also, how much 60' et do you guys pick up foot braking vs. TB launch?

my take off's are lazy right now lol, 1.61 60' but the motor also makes peak torque at 5k rpm's, takes a sec to get my pig moving

03supercobra

iTrader: (38)

As the boost increases it'll makes more power on the footbrake, and cause the RPM to change or push through the footbrake. If you put a 2-step on the car it will set at your set RPM and you can play with how hard the converter will flashes (varying RPM) when you let off the brake, and you can also play with your timing to increase boost level on the TB.

The 60ft will change from foot to TB depending on converter, suspension, power ect. It will differ for every car.

1fast bird

iTrader: (22)

You need the two step to help build boost on the line. Like Mightymouse said you can fine tune the two step for wherever the sweet spot is. My picture i have in my avatar was the result of 4300 rpm's off the trans brake. When I had the two step set at 4200 it was barely lifting the wheels. The car has had a best of 1.31 60'.

As far as only making 550hp, don't worry about that. That is plenty of power to cut decent 60' times with the right setup.

MIGHTYMOUSE

iTrader: (59)

my car footbraking hard as i can has a best of 1.52 short

the brake its gone a 1.29 and could leave harder if i rased it.. if it would hook.

buick_lsx

i already have a 2 step on the car, foot braking the car i can get 6psi at 2800 rpm....i have foot braked it up to 3500 before but its really hard to keep the car from pushing, anything past 3k is hard to hold.

Now with the TB ill know that i can atleast rasie launch to 3500, but dont know how much more stall is left, but a 3500 launch has to be better than a 2800 lol

Only running 9psi so atleast ill be able to launch at max boost

even just a tenth better 60' on a TB launch will be nice, anything better is bonus to me...trying to get a 6.50 and 10.50 et on this lq9 and 9 psi before i add anymore power

Fbodyjunkie06

iTrader: (10)

Are you using the 12 volt activation wire for your 2 step or the ground activation wire? You said your brake uses ground for activation, mine does too. The problem I had was my brake uses 2-3 shift solenoid for activation and when I tied the t brake wire and 2 step wire together it worked perfect until I shifted into 3rd gear and the 2step came on at 3600rpm not allowing me rev past the 2 step limit. I know why it came on because the t brake wire became grounded in 3rd gear and activated the 2 step like it does on launch. I had to wire the 2 step to a seperate button on my shifter. It's still easy to get to, but it would be so much easier for me if it was on one button.

I had the 2 step wire just tied into the t brake wire that went to one side of the button and then the other side of the button has a wire going to a ground point.

I wonder if I were to have the t brake wire going to one side of the button and the 2 step wire going to the other side of the button and used two seperate grounds for each function but the same shared button if it would work without coming on in 3rd gear that way.

slow67

iTrader: (2)

http://en.wikipedia.org/wiki/Diode
A diode is your friend.....

Fbodyjunkie06

iTrader: (10)

I know I have been told this is what I need but where in the circuit would I put it?