foot brake racing

[davidthe2]

How do you hold the car on the line with the footbrake if your engine is jammed up against the converter. Can this be done with a 600hp small block at 6000 converter or do you have to hit the gas at the same time.

It seems a lot to ask of the braking system

Any answers

[af2]

How do you hold the car on the line with the footbrake if your engine is jammed up against the converter. Can this be done with a 600hp small block at 6000 converter or do you have to hit the gas at the same time.

It seems a lot to ask of the braking system

Any answers

RED light every time you mashed the throttle!

[davidthe2]

so what do you do.... How do the footbrake racers get the revs up and launch??

How do they get close to a good light each time

[af2]

Most of the ones I know leave between 2500 and 3500 and are great at the first bulb to stab the throttle and go. If you want to launch at the flash you need a trans brake which I feel is wrong. (leaving at flash no reduction/1to1 and major heat. The brake is good though leaving lower before flash and hammer down.)

[Shaffy]

I stage at 1500rpm... on a .500 pro tree, deepstaged, the car will go .011 on the tree...

[davidthe2]

But can you hold thecar againsgt the converter... can you use the mark williams twin calipers per wheel and a good set of fronts to hold the thing until you release the brake or is there no chance of the brakes holding when up on stall?

[af2]

David look at this thread. It might shed some light.

viewtopic.php?t=6697

[automotive breath]

But can you hold the car against the converter... can you use the mark
williams twin calipers per wheel and a good set of fronts to hold the thing
until you release the brake or is there no chance of the brakes holding
when up on stall?

Every car is different, the power of the engine, the torque converter the
quality of the brakes, tires etc.

With one car you may be able to stall the engine up to 2000 RPM and the
car would start to creep forward.

Put better brakes on the same car and you may be able to stall it up to
2500 RPM before it starts to creep forward.

With a strong engine, 5500+ stall and great brakes, you would be able to stall
much higher. But still at some point the converter will begin to lock up and
the brakes will no longer hold.

The key is to find a good comfortable stall RPM where you can hold the
car with ease controlling power with the throttle. At the launch you release
the brake and floor the throttle, the converter stall allows the engine RPM
to instantly rise to launch the car. This is called the flash stall speed of the
converter.

[automotive breath]

How do they get close to a good light each time

The key to a good light is consistency. You do exactly the same thing
every time. This includes engine temperature, burn out, how deep you
stage the car, how high you stall. Everything you do must be consistent
every time.

Thats the easy part, next you must react to exactly the same spot on the
tree. For, instance I will focus on the last yellow light and try to react as
soon as I see the yellow light come on. Once consistent reaction is
accomplished then you can make adjustments.

If I'm leaving on the flash of the last yellow and my lights are consistently
0.040 I will make a small adjustment. I might add air to the front tires to
get the car to leave a little faster, or I could stall the engine a little higher.
If I'm successful at getting the car to leave a little quicker and don't
change my spot on the tree, I should see better reaction times.

[af2]

How do they get close to a good light each time

The key to a good light is consistency. You do exactly the same thing
every time. This includes engine temperature, burn out, how deep you
stage the car, how high you stall. Everything you do must be consistent
every time.

Thats the easy part, next you must react to exactly the same spot on the
tree. For, instance I will focus on the last yellow light and try to react as
soon as I see the yellow light come on. Once consistent reaction is
accomplished then you can make adjustments.

If I'm leaving on the flash of the last yellow and my lights are consistently
0.040 I will make a small adjustment. I might add air to the front tires to
get the car to leave a little faster, or I could stall the engine a little higher.
If I'm successful at getting the car to leave a little quicker and don't
change my spot on the tree, I should see better reaction times.

Thanks for the better advice!
It is hard to right thinking!

[amcamx]

The ramcharges first car had the carb mounted higher than the roof. That is fine if you measure the RT with a sundial.
With the top stage light out on a full tree, a 17sec car may have a .030RT. It is the stage rollout of maybe 8in that is so hard to get right.
Few foot brake cars are setup for RT. If they are they will then be tuned for low and midrange torque and be slower. A flat torque curve in the RPM range used for a pass means that you leave at the same torque, even if the stall is not the same. More consistent RT and 60ft. This can be found out with a Computer Dyno. The RT setup is harder to hook up and if it does it can break parts. It may daylight the tires, and shorten the rollout for quicker RT even if the car is not fast. Only l00lb ballast can be added.
The closer you come to the RT setup you will be at about stock muscle car. Now the car cannot rev enough to destroy itself. So it can be geared to hit the peak power curve 100ft from the finish line. A headwind can't hurt and a tail wind can't help.
Get it right and the mph should come out the same for 2 digits to the right of the decimal point, for 3 time slips for a day of racing.
For a BB the ET and RT should not vary more than .03 for a day of racing. If you are there now you have 540-580 under your hood.
A BB has one third the life but is 3x better than a SB.
Your results may vary.
With a BB you should now be able to run on the dial and have 00RT with 20% chance of redlight or breakout. Size up the other car, don't go for it unless you have to.

[Rick!]

I would run a two step and use the foot pedal brake switch as the input. Chip it to 1000rpm below stall and let it eat. Easily done in any modern MSD box. I've watched many footbrake (no box) cars at the track get on the chip once both cars are staged.

[1980RS]

Just use 2 line locks like we did years ago.