For you "real" racers,

I have a '71 Cutlass convertible, 350/350, EBrock Performer RPM cam and intake, stock compression, ported heads, HEI, reworked QJet, Dynomax headers and 2 1/2" duals, 3.42 posi, stock converter, trans cooler.

I haven't been on a track in 20 years and we are having BOP drags at a local track in early December. One of my buds is loaning me his BFG drag radials.

I've heard brake torquing tears up a tranny and it certainly makes my street radials go up in smoke, but I need better RPMs to get into the torque band of the cam (2500-5500). I know the cam is kinda agressive for the street, but it was installed by the previous owner. Really scares the hell outa the ricers!

What are your recommendations for lauching? Just punch it and let it "wind up"? Would a short brake torque (when the lights start down) hurt the tranny?

This ain't for money...just for fun. But I don't want to embarress myself and I know the more you win and the less you break, the more fun you have!

Thanks in advance.
C.J.

if you are talking a rolling start, I would down shift to a lower gear to help it wind up. If it is a standing start, bringing the converter to stall wont hurt anything, but that isnt gonna help much because your cam is pretty agressive, and a stock converter will stall at like 1500... So I am not sure what advice to give except put it in low, stall the converter, and let er rip!

Andrew

HI texasred, hello everyone,

Not a racer. I've always been on a budget, and mine have all been "drive anywhere" cruisers.

Since traction problems have to be resolved first, my statements normally assume a car does have traction.



Never had any experience with a "tranny". Not that kinky.

As I stated in a different thread on the same subject:
Heat is a trans worst enemy. Powerbraking builds large amounts of heat, very quickly. It's the quickest way to kill a trans.

It also unloads the suspension and lifts the right rear tire which causes it to hop, then spin when the brakes are released. Great for burnouts. Not good for a quick leave.

Bottom line: the life of the trans is shortened for no reason.


The three ways to get the RPM quicker, are to break the tires loose, use more stall, or add more gear. How much help is that torque without traction? If you have traction, more stall will cause it to go away.

You'll get more RPM by flashing it, than you will by braking it. I've seen a 300 RPM difference.

Combine the flash with an unloaded suspension (as with a transbrake) for a better leave. Traction and off idle response have to be right, but that's a given.


Depends on the state of tune. With advance curve and carb settings at optimum for your particular setup, yes.

Guessing that the reworked carb is matched to your combo, and the advance curve is close enough. If you mash the gas in neutral, from a 700 RPM idle, do you get a "crisp" response? If not you might need to let it go a little higher or so, but load the suspension as little as possible.

With the mismatched TC and cam, and no idea what traction you'll get, it's impossible to tell. I would take it (and the drag tires) to your local T&T, play with it, and let the car tell you what to do. At that time you can powerbrake it a couple of times and let the timeslips tell you if it helps.

With treaded tires, always drive around the water. If you can do a dry burnout, do a short one. If not you have enough traction.

But what do I know?

Regards, Norm

That's what I'm trying to figure out!

From your advise, I'll try a little late-night T&T tomorrow night. See which gives a "faster" launch. I won't have the drag radials until the day of the race, though.


What do you mean by "let it go a little higher"? Idle speed? My HEI is tuned for my current driving (14 initial, 38 all in by 3500) with an adjustable vaccum advance hooked to ported vac and limited to 10 degrees with no ping under accelleration. I've had it to 20 initial, but had hot start problems.

Thanks again for your time.
C.J.

Rolling start? At the strip?

I've had a rolling start when I was "racing" the cops in my MUCH younger, MUCH wilder days!

C.J.

Hi texasred, All,

Looks like I missed this one.


On the strip with different tires, its going to be a different car in a different world.


A little higher RPM against the converter, but only if the throttle response is not there.


It'll work.

Regards, Norm