I hope this topic is in the correct forum. If not, then please let me know. What is everyone's thoughts on the fact that with the footbraking method, you're loading-up the suspension BEFORE the car is launched which can be detrimental to consistency and/or to traction (on some cars anyway) whereas when a transbrake is used, the suspension does NOT get loaded-up until during the launch when the car is already in motion. So the transbrake can be used to load-up the converter without loading-up the suspension until the tires are being hit. I thought that was the primary benefit of transbrake launches, and the quicker cutting of the light on the tree was merely secondary, or a fringe benefit. Do any of you experienced racers think that there's any truth to this? I'm posing this question, because I'm really not sure, and I'm looking to learn from you guys. I welcome everyone's input on this.
On my T-type (turbo) I can only get about 10 psi of boost before it starts to push. On the the trans brake I can get up to 20 psi. Now saying that, if I leave at 10 psi ,it seems to leave harder, less spin, if I leave off the brake it spins alot more. I'm using MT streets. From my little exprience, my 60 ft. times are better with the foot brake than with the trans brake. I guess it comes down to trial and error. Philo No:
My 67 GS has a transbrake but I usually race it on footbrake. The car is a true 4 link car with an anti-roll bar and 31x10.5W M/Ts. When I first built the car I raced it both ways. It ran exactly the same ETs back to back foot/trans braking. It also ran the same 60' times. Now it did leave with the wheels higher in the air for good photos with the transbrake, but never ran any faster. I did break a ring and pinion after 5 transbrake passes and has run the same one footbraking 250 passes, so from my experience, the only advantage I saw was a possibility of easier lights and more experience setting up gear sets. Jim Netherland
:laugh: :laugh: Said differently, you should see some better reaction times with the trans brake because of "fine motor use" (ie, you are using your finger or thumb to launch the car) as opposed to "major muscle groups" (ie, using your feet and legs). I like the footbrake because the driveline is preloaded, reducing driveline damage (as Jim alludes to). The downside is that a practice tree is not very representative of launching the car, so the only way to practice is to actually do it. K
How about somewhere halfway between? I will be setup to run (when I put the engine in) with a rev limiter and line-locks. It will load the suspension and i will be going at the release of a switch.
Trans-brake launches are fun! If your suspension is set up to be shocked, and you have enough tire under the car, it'll work better. If your car isn't really supposed to be slammed as hard as possible, you'll spin the tires and break stuff. When I've footbraked my car, it left like a slug, when I trans-brake it, it leaves hard and fast with the wheels in the air. I run a Ford 9-inch with 35 spline axles, so there isn't any weak link in the rear and no broken parts for fifteen years running. Driveshaft is a huge aluminum unit with 1350 yokes and u-joints. No problems in ten years of use. Last fall I broke a planetary gear set in the trans after eight years and 300 passes. First tranny hard parts I've ever hurt. Bottom line... If you're set up with a serious driveline to launch hard with a transbrake, you'll be fine. If you're running a setup that's anything close to a street car, you may be in for trouble.
I'm no expert on drag strip racing but looking at what is being said here you are far more likely to suffer damage to the driveline when using a transbrake. The reason is simply that when using the transbrake the driveline is exposed to a very sudden shock loading. When using the footbrake the driveline is already loaded up and if anything you are actually seeing a release of the forces that have built up within the driveline. A similar situation occurs with off-roaders (something I do know about) when they are trying to get over large obstacles. The less experienced ones will build up the revs and suddenly launch at the obstacle in an attempt to bounce over it. They usually shatter something. The more experienced guys let the torque do the pulling and creep over obstacles.
Thanks for everyone's input so far. When I get my A-body car ( a 70 Chevelle) to the track, I'm gonna try T-braking it, because I beefed up the driveline as much as my bank account can afford. Aftermarket TH400, with T-brake, full manual VB,high line pressure (235 PSI in all gears @ 2,000 RPM),34 element sprag, 300M input shaft, Red Eagle clutches and Kolene steels, and a modified front drum. Then I have a chromemoly driveshaft with solid 1350 series U-joints, 1350 slip yoke, 1350 chromemoly pinion yoke, Strange "S-60" nodular iron Dana 60 rear, Detroit Locker, 35 spline axles, Big Ford ends, and 5/8" diameter wheel studs. I have street ring & pinion gears (not the softer race gears) but I'm thinking that the bigger 9.75" diameter ring gear that the Dana 60 rear uses, should handle the hard launches even though they're street gears.o No:
Sounds fine on paper, but you might be disappointed with how slowly many line locks behave once de-energized. May be OK if you don't mind letting off the switch at the first yellow Devon
BTW, do any of the transbrake solenoids out there tend to leak fluid? Is that even possible? I'm not sure exactly how they're mounted. Is there any type of seal or gasket that the solenoid is mounted with that can leak? <!-- / message --><!-- sig -->
Yes, Billy soleniods can leak. Actually the one I took off my car was leaking around the plunger of the soleniod itself, not the o-ring to the case. It was getting old even though it had not been used much. I know of people using the dual line locks and I'm not a real fan of that but it might work in some cases. Doug, I agree there is nothing like leaving on the button if the car is setup for it and you have the good parts and thats what you want to do. Racing NSS I don't want to get too used to using it as it is not allowed. I could get to love it I'm sure. As for parts breakage, I think my ring gear deal was from using a street gear instead of a Pro Gear. Also, at the time I tried it I was using iron heads and a rather mile hydraulic cam that made tons of low end torque. I think that explains why I didn't see an increase in 60' or 1/4 mile et. With the TA Stage 2 heads I have now and the more radical solid cam, I think my car would pick up in 60'. Keith, I have a brake pedal for my practice tree that helps for footbraking. Jim N.
Granted, I just have a street car that I'm dialing in, but it seems like I get better 60' times and ET's just barely being off idle at the light and then just mashing the pedal on the last yellow. The only time out so far, playing with the launch I went form 1.80 to 1.69 60's. (12.38 @ 107 mph) Does this maybe indicate I need to change something in my set up? I run a 10" convertor, 29X10.5 MT's, 3.55 gears, no front sway bar, stock springs and an HRParts swaybar adjustable control arms (pinion angle at 2 degrees down)
I wouldn't think anything's necessarily wrong in particular. I've both heard and read that some folks get better results "flashing" the converter to gain some torque multiplication rather than leaving at stall. Devon
One thing I STRONGLY recommend is hooking up the line-lock in conjunction w/ TB activation. This takes the slack out of the Driveline which is the main cause of broken parts. If you spend the time to get the Converter "right" most cars will be very close in performance with or w/o the TB.
Sounds very common. Although I think that combo could use more gear. Are your tires 28 or 29.5? MT doesn't make 29's
Jim, thanks for your insight on this stuff. What rear were you running when you broke the ring gear using the T-brake?
probably a dumb question but wats is footbrake and trans brake and how do u do both of them ive never ran my car on track but was just wandering
"Just wondering", I hope... ...and you forgot these: ,hayo?'a. Check this out...www.google.com can be an awesome friend: Trans brake: http://www.hotrod.com/techarticles/drivetrain/113_0205_tci_trans_brakes_review_tech/index.html Foot brake: That's the pedal on the left if you have an automatic trans. Same as your daily driving when it comes to the launch. The idea is to hold the car at the line with the brake, and it's up to you to either let off the brake & hit the gas at once on the last yellow, or hold the brake while you open the throttle waiting for the lights to come down. Devon
oh ok thanks i dont race but i like to watch and do burnouts but a guy told me to rev in neutral and when the light it switch to drive but ppl told me thats a good way to tear up a trans
