I'm going to ty to set up our race car so that I can stall it :on the flooor: so that the car's reaction when I release the brahe will always be the same. If you have to modulate the throttle from a partial stall, then you run the rick of an inconssistent leave. At least, that's the plan.

I do not want to have to resort to a trans-brake (also called a "trans-break") because they are so hard on drivetrain parts.

I am considering putting pickup truck rear drums on in place of the stock, B-body brakes to hold the car at stall, on the line. The pickup truck brakes are, I believe, 1" larger in diameter, and maybe, with somewhat wider shoes, but I am not sure about that. I was told that if you use all the truck backing plates, drums, and all the brake hardware, it will all bolt it. This is on an 8.75" housing.

Anyone done that? If that's a mistake, I'd like to know before I buy all that stuff...

Any comments/information willl be appreciated.

Bill
'64 Valiant, turbocharged slant-six powered

As far as I know, a 1/2 ton pickup has the same size brakes as your B Body. Also I don't see how increasing the size of the rear brakes is going to make any difference with holding the car on the line.

If you want to raise your starting line rpm you need to up your stall on the torque converter.

You can put 11" brakes on, but if your motor has any nuts it will not hold at WOT no matter what brakes you have.

I can stage my Dakota at WOT, but it is computer controlled, all wheel drive, and gutless to start with.

Don't fear a trans brake. I've used one for years both normally aspirated and spraying and never so much as nicked a u-joint.

People that break a lot of stuff with a brake are either staging incorrectly or using weak parts.

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Official Cookie and Mater Tormentor.

It is not necessarily my desire to raise the starting line RPM. What I do want, is to be able to floorboard the throttle with the brakes on and have the car remain motionless until I pop the brakes off. If that raises the rpm, great. If it doesn't, then I'll get my converter modified to allow for more slippage, but the main thing is to allow a wide-opan throttle at stall. It's possible to do this with a 2-step, of course, but I don't think all that unburned gas going through the turbo during a 2-step stall is going to be of much help spooling it, which is the whole idea.

Hopefully, whoever told me the truck brakes were larger-diameter was right... I still am not sure.

RE: " I don't see how increasing the size of the rear brakes is going to make any difference with holding the car on the line."

Have you driven an automatic car that wants to drive thru the brakes when the throttle is applied during a stall start, and you applied too much throrttle and it pushed through the staging light, giving you a red light?? If you have, then you can understand how that if the back brakes had been more effective (like, BIGGER,) maybe they could have held the engine's power and kept thje car motionless, no matter how much throttle had been applied.

That is why I want more braking power for the rear wheels. Bigger drums would seem to be just one way to get it.

Thanks for your comments!

Bill

Were you spraying while at stall?

Though not trans-brake related, Steve Nitti recently twisted the input shaft clean off his 904 with a supercharged slant six. I'm pretty sure that was the result of a full-throttle stall.

These turbocharged /6 motors make egregious amounts of torque at stall, if they are sufficiently spooled. I haven't experienced it yet, but hope to, soon. I probably should wait until I have done it, to talk about it, but Ryan Peterson's and Tom Wolfe's engines have that capability; I can only HOPE that ours will, too.

With larger-diameter truck brakes on the back (drums) and a small-bore primary-cup master cylinder, I feel like we have a fighting chance to hold this thing...

Talk's cheap! We'll see...

Thanks for you interest!!!

Bill

Trans brake is the way to go. A chip in the low side of a 2 step rev limiter will help with consistent launches also if you have one.

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There's no such thing as too much cam....only not enough engine!

Bill you will have to have either a starting line throttle controller or a 2 step. 2 step will be easiest, you can even wire it up to the brake lights if you want.

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Official Cookie and Mater Tormentor.

I am not familiar with a "starting line throttle controller" beyond my right foot...

Seriously, what sre you referring to????? I know about 2-steps...

Thanks for any information.

Bill

It usually an air cylinder hooked into the throttle linkage that will hold the RPM at a set point until you release it. It is normally used with a trans brake but can also be wired to a switch on the brake pedal, brake light switch, etc.

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Official Cookie and Mater Tormentor.

Is the Starting Line Throttle Controller the same device referred to as a "Throttle Stop"?


I have heard that bit of terminology tossed around a bit but was not sure.


Thanks,


Greg

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http://www.youtube.com/hyperpack

Sounds handy if you don't need the whole nine yards (full throttle) to spool the turbo to the max, but I think I'm going to have to do that (full-throttle stall.) The idea is to maximize breakaway torque to get the best 60-foot time possible. Lots of questions, here...

What do you think of a 75-shot of Nitrous for one second, just as the brake is released???

Bill, in Conway, Arkansas

I think if you don't have the suspension, set up right, you'll blow the tires off the car. The turbo should spool in less then a second, without nitrous, and the nitrous builds a ton of torque. My 170 stock short block, makes 358 lb/ft at 2900 rpm, on the bottle.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

No, a throttle stop is something completely different.

A throttle controller will hold the throttle partway open even though the pedal is on the floor. The purpose is to allow you to stage wide open and not have to move your foot when the tree comes down. It's like a mechanical 2 step.

A throttle stop is usually an air or electric plate that has butterflys in it just like the carb. They normally are set to close downtrack for a specific time, and then open again. Purpose is to slow down a car that is way too fast for the class. This is why you see Super Class cars launch and then lay down. Most of the cars in S/Comp (8.90 index) will run mid 7's with ease. They will run 8.90 on the stop and go 160-170 MPH.

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Official Cookie and Mater Tormentor.

Thanks Dennis!


I dont think any slant cars will be needing a throttle stop anytime soon unless we all start running a 15 second index for some reason..


I like the Idea of the 2 Step for launches .... Might have to investigate that for ruster..




Greg

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http://www.youtube.com/hyperpack

I have a throttle stop on my car already Greg. I smash my right foot to the floor and my throttle stops.!

I am amazed by the amount of "stuff" that can be put on a car to make it run better. Sometimes it works Ok, but I sure see a lot of people with problems keeping all their "techno Gizmos" working.

My technology is an Edelbrock Carb and an HEI module. That's about it and I like it that way. I am not all that happy about adding relays to my car to power stuff, although I know they are needed. I like it simple, and I like it to start and run immediately every time. Time will tell if I have achieved my goal.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6