How does a top fuel dragster reverse?

[A/Fuel]

From TC's link pro stock uses either 7.00 or 6.25" with 6 fingers and 2 or 3 disks. They appear to be a smaller version of a blown alcohol set up. In those you have to rev the engine up and hold the peddle down, applying pressure to the bearing which keeps the fingers from rotating.

[TC]

If someone could post how a pro stock clutch works then we could discuss the differences.

http://www.ramclutches.com/products/billet%20new909.htm

[A/Fuel]

how does a pro stock clutch differ from a top fuel clutch?

If someone could post how a pro stock clutch works then we could discuss the differences.

[horsepowerfreek]

how does a pro stock clutch differ from a top fuel clutch?

[A/Fuel]

Thats a good question.
There are stall springs that pull the dough-nut to the hat. The fingers, as they rotate try to spread it appart and apply clamping force to the clutch pack. The stall spring tension can be adjusted to counter the fingers to acheive the desired idle. The fingers are what's centrifugal about a centrifugal clutch. As the rpms are raised the fingers will rotate and overcome the stall springs, clamping force increases and the car starts to move. When you let off the clutch peddle the fingers push the bearing back until the stall spring tension is enough to hold it. Now it's starting to heat up and expand taking up the gap between the floaters and disks. You would still have to hold the brake. Thats why it's important to pump the brakes up to about 700psi line pressure before staging.
If you've ever played around with a snowmobile clutch you would find that they work in the same way.

This is an a/fuel clutch but it's similar to a top fuel. In this pic you can see the 6 stall springs and the 12 fingers. The numbers on the fingers tell what radius they are. Or how the lobe is shaped on the underside, .250 long and .265 short is a popular radius for staggered fingers in a/fuel. The nuts and bolts attached to the fingers are the weight, just by looking this clutch appears to have about 516 grams, which would be typical a/fuel starting point.

[Deaf Bob]

Uh, I musta missed something.

If you let off the clutch, doesn't the car start to move? What holds it in place against an idling 8000-hp monster?

I was thinking trans brake? ... Probably not...

[Caveman Tony]

.... Before you get going to fast push the clutch back in. When you pass the starting line, push the clutch back in, pull the brake and stop, reach down with your left hand and pull the lever back. Now, start pumping the brake, and work the peddle until you light the top light. Then pull the fuel lever back, light the bottom bulb, let your foot off the clutch and wait for the flash of yellow.

Uh, I musta missed something.

If you let off the clutch, doesn't the car start to move? What holds it in place against an idling 8000-hp monster?

[A/Fuel]

You just need an input shaft that will engauge the reverser.

[Cart]

So do u need a centrifugal clutch to run a lenco reverse unit with out the rest of the lenco trans or could you use a regular clutch?

[DanStokes]

I have an on-going challenge to get mechanical things to do what I want them to do and not what I told them to do. Sounds like one of THOSE things!

And thanks for the insight. Pretty cool.

Dan

[A/Fuel]

No problem guys. I love thinking and talking about clutches. It's such a simple yet complicated device that does exactly what you tell it to do. Telling it to do what you really want is a different story though! There seems to be an infinite ammount of adjustments and things you can do.

[Cart]

Thanks A/Fuel! That was the best explanation I have gotten from any where. It was also interesting to visualize the staging.

[greenXpress]

ok nothing of value to add here but thanks A/Fuel for your description...it was cool imagining the steps happening

Ditto !!!!!!!

Was picturing it as I was reading. Thanks.

[Bamfster]

And I thought my staging routine was complicated! .... Thanks for the in-sight A/Fuel

[Dignlif]

ok nothing of value to add here but thanks A/Fuel for your description...it was cool imagining the steps happening