OK, what has been the experience of the drivers that have a footbrake and a T-brake.
Is there a difference in the 60' of at least a tenth?
What about top end ET/MPH, any change?

Really trying to decide if I want a T-brake in the trans or not.

Car will be 3100 or less. I hope to stay on a 26" tire with 4.11s but if I NEED to go to the 28" I will and run 4.33s probably.

 

On the motor I have had better 60ft's using the T-brake but on the NOS I got better 60ft's off of the foot brake.

 

Foot brake only allows you to come up on the converter so much before the tires break free. Transbrake allows you to come up to the full stall speed of the converter. Using a transbrake also allows you to use a 2 step and launch at the same rpm every time.

The more consistant you can be, the more consistant a run will be and will win races in a bracket race.

If you can launch at the same rpm every time by footbraking, you won't notice any difference in 60' or top end times if you use a transbrake and launch at the same rpm.

The real advantage to a transbrake is being able to launch at or near the converters true stall speed. If the engine is already at that rpm when you launch, it doesn't eat up time building in rpm. Transbrake launches are also violent. It's like doing a high rpm clutch drop with a manual transmission. Don't expect the small factory u-joints or tiny 7-5/8" ring gear to survive for very long.

http://tinyurl.com/f9b8r

Here's a video of my car launching at 4500 rpm off the transbrake. My converter stalls at 6100 rpm with this new engine which is higher than I want to launch at. You can hear the engine banging off the 2 step when the tree is coming down. Just ignore all that tire smoke.

 

We are now launching at 6000+ on the 12bolt/4.33 combo and nearly dead hooking each pass, 1.53-1.55, 1.55 being the avg, not happy to see a 1.57-1.59.
So I got to think that a T-brake launch would be comparable to what we are doing now. I will have to go to a 28" tire or go to the 4.10 gear/26" tire to get the top end out of the A3. I really want to stay with the 26" tire.
1st gear gearing will be close with a 2.75/4.10 as it is now with the M6/26/4.33 combo so I hope not to loose anything there either.

I am leaning towards no T-brake and still a 2 step. And in the past (other 4th gens) the best launches I have had are from off idle launches.

 

An off idle launch allows the converter to flash and can be a softer hit on the tires if you have traction problems.

 

I know noone can say you will 60' 1.49 with a T-brake and off the footbrake it will be 1.52 but knowing what other cars have done would be helpful.

I get all the TC will stall to the true stall of the TC and i can launch at the same RPM everytime with the T-brake but is there a way to know based on other combos how much I might be giving up without the Tbrake....

 

You need a transbrake. Impossible to say for sure what the gain in ET will be, but potentially in the .1-.2 second range. And if you are bracket racing, you will be MUCH more consistent with a brake.

Your sig says M6, what tranny will you be using?

Rich

 

I am going to a TH350/2.75 1st gear/Vig 4000ish stall, possibly with a transbrake.

Not really into the bracket racing, more heads up if anything but truthfully most of my racing is done TnT nights or track rentals.

 

Don't forget that this new combo will SUCK on the street. Get a brake, I assume this will have a manual VB.

Rich

 

IF this car sees 500 miles in 12months of street use I will be
I bought an old grandpa buick lesabre to drive daily and to haul the kids in.
I dont even have tags/ins on it and doubt I will, the cruise in scene is not much around here and if it does bloom then I can put up with alot for a little drive, you know?!!?
I am the type that wants the car to be 100% at the track and I will give up a ton for street stuff.

And VB I have not thought about that but either way I will be shifting it via a shift light manually.....

 

First of all why would that combination suck on the street? I know we all have different ideas on a "street" car but mine was every bit as docile on the road as my work trucks, sure I had to manually shift it, but WFT it's a toy

As for the comparisions, once I got my car tuned right I wanted to see first hand what the difference would be between T-brake and foot brake since everybody I asked gave me a deer in the headlight look and no real answer one way or another-and for practical purposes every car will react differently per combination so my results might not be what you may find.

T-brake staging I always stage at 3000-3200 for killer R/T's, 60's were typicall 1.52-1.55 depending on air and track conditions and I'd run 11.20's at 120mph for all practical purposes with my racing tune in the carb.

I went up and "power braked" to 3000 rpm the next pass, and 60 was 1.55 (from preivous run of 1.52) so the 60' dropped but by the finish line I ran identical ET but with a touch higher mph so it all came out in the mix. No matter which way I tried it with higher foot braked launches or dead idle the final time was always the same and only 60' and mph changed.

DONT expect a t-brrake alone to make you faster, even when I chipped it at 46-5000rpm for wheelies the ET was always right back where it always runs, actually slowed a bit ET wise when chipping that high. ALOT of times you can 60' better leaving at a dead idle since your "getting a run at the convertor" and forcing it to flash so that inital hit vaguely mimicks a t-brake launch (but at the same time not even close Often when your power braking your pre loading the suspension/chasis so some of your inital "power" is already absorbed thus resulting in less to propell you when the light turns green since that power is already tied up so to speak. This is also another reason to really push a t-brake since the chasis is essentially neutral when your staged, so all those suspenions parts you've just installed are now given a chance to work the right way as all the shock from the hit will force the chasis to do it's thing instead of being all out of sorts from foot brak pre-loading. Also remember the combination for a foot brake car converter/gearing will be different than for a t-braked car since foot braking you need the car to react as quickly as possbile to WOT you'll either gear it a lil higher and/or run a tighter convertor so once you give it WOT, the car reacts with little to no lag what so ever.

Either way, do yourself a favor if going T-brake, get a TH400. TH350's that have survived a t-brake are few and far between and require extensive parts upgrading and a builder that knows exactly what he's doing and even then most wont guaruntee it will last due to internal design-your money ahead by going TH400 since your done once, instead of constantly finding wek links and rebuilding replacing parts.

There is no need, and I've met very few sucessful bracket racers that have stuff that work/last that have to ever chip a t brake any higher than 34-3500 rpm unless they're reactions are just soo slow they're required to wear a helmet even outside of the car or the car is just not set-up right...10,000 rpm shift points and 6000rpm launches are just cover up's for set-ups' that are'nt right...or they're doing it for show. Personally never seen a bracket car so poorly set-up you have to be beyond typical peak tq numbers to make the thing work right, but I guess anything's possible.

1350 solid joints and a 3" driveshaft should be mandatory if you dont want any issues, driveshaft loops at both ends is a really good idea too, seen some ugly stuff when u-joints let go with the shafts coming up through the rear floor boards and tearing alot of things up.

 

I have a TH400 with a brake and my stall is 3500. My 60's before the brake were in the 1.60s, now I am in the 1.50s. Before barely any front tire lift, now my front tires come about a foot in the air..








Make sure you have a really good cooler cause the transbrake makes the temp flash to around 220 degrees. As for the manual VB, I think you have to have a manual VB with a brake.

 

Your coming up on the 2 step waaay too soon if this is your deal, you should at most see 220 at the finish line if your staging around 150-160* trans temps. Both my car with the 10" convertor and the truck with the 8" convertor RARELY EVER see anything higher than 200* and that's going round robin in later rounds.

But you bring up a good lesson to anybody racing, NEVER EVER get on your convertor be it T-brake or foot brake until you see both stage lights get lit, otherwise if the other guy is smart and sees you do that....he'll burn you down and cost you money all the time laughing cuz he knows exactly what your tranny temps are doing...been on that side of the coin once until I learned and now use it against others since the hot tranny temps will always affect the number's they thought they'd run-make the other guy give you the win due to lack of experience, and if he's like most it will take a few years before they finally "get it"

 

The guy that built my tranny warned me about that. He told me to always let the other guy stage first, once all four stage lights are on then get on the brake.. I would say I go into the stage with my tranny temps around 180 - 190 depending on how hot of a day it is. I have a little inline cooler though and I am planning on moving to a cooler with it's own fan.

Another sugestion, do AN lines. You don't want to be the guy that blew a tranny line..

 

Another reason not to come up on the convertor to quickly is the fact the tree activator guy is'nt always on the ball and just cuz you've lit the 4 bulbs does not mean the treet will automatically come down, I've been in this situation more times than I care to remember and it really plays with your brain wondering wtf is happening and when are the bulbs going to start...seems you relax that split second they start falling and then your brain froze for a split second

In the car I bought the largest cooler BTE has to offer and thus far it's been working very good. Street driving it never exceeds 120* unless I'm really playing hard: often, then it'll creep upto 180*, but quickly return to 150*

The truck has a B&M cooler with fan and I'm not at all impressed with it, with the 8" convertor it get hot quickly and the turn around time to cool it off is no where near that of my standard set-up in the car. We gave up trying to figure out why it does'nt work, but have no plans to change anything since it's just burps down the 1/4 with that one anyways...just noway in the world that truck could ever be streeet driven given the tranny temp issue and lack of proper cooling.

I will say THE BEST thing I ever did to me junker is install AN fittings on everything possible from drivetrain components to brakes. easy to take apart and even easier to put back together for guarunteed leak proof connections