2916jr

are yall using the hpi centax clutch and the hpi 2 speed or some other combination ,and would a 1/10 scale centax clutch fit a .21 motor?

lanerbrainer205

good question heh heh heh I know ur set-up now! haha

2916jr

[:@]

griz11

I tried a 1:10 clutch and went back to the 1/8 scale one myself. Both mugen. The .21 needs a bit heavier flywheel. Some mill out the backside of the flywheel on the 1/8 clutchset but you have to be careful with them. Clearing them out on the line can cause them to overrev with too light of a flywheel. Mugen finger type tranny's are hard to come by now. I switched my cars over to the shoe type. They offer more adjustment and it takes more time to figure them out but they work just as good IMHO. Get the lightened gear carriers alloy clutchbell and pressure plate. Anything to make it lighter so it doesn't have rotational mass. Drill out the flyweights so it will engage quicker. To set up a clutch properly when using a boat pipe you need to learn how the motor sounds when its 'on the pipe' A properly slzed boat pipe will cause the motor to accelerate rapidly at a certain point. That point is where the motor 'gets up on the pipe' and that is where you want the clutch to hit. Its the position you start from to tune a clutch. It will sound like its never going to hit but once it does bang you are gone. The idea is to make sure the motor is developing enough power so dumping the clutch won't cause it to bog down. It might take you a bit of playing around to determine this point. But if you advance the throttle slow enough you will hear it sooner or later. Put a finger lightly on the slick and be ready to pull it off quick to feel when it actually hits. You want it to hit just after the motor gets on the pipe. When you are tuning the clutch pay attention to the timeslip 6 ft time. Use that to tune up the clutch you want that value as low as you can get it. .230 or so for a top fuel car lower is better. I've been told by more than one top fueler the race is won in the first 6 ft. Get a clutch lapper from Walbern to make sure the clutch shoe is ready to go. And have plenty of them on hand. You don't want them to wear much before you change them out. Get a flanged bearing for the front of the clutchbell too. Keeps the clutchbell from vibrating as it hits. Ensures more shoe is in contact with enough force to make it go. Even better is a flanged on both sides but on the rear you have to modify the clutch nut to accomodate it. You might try messing around with an 'air gap' clutch set-up as well. By air gap I mean a clutch bell that has no play. Set it to the correct gap with shims so it doesn't move back when the shoe hits it. And get rid of the thrust bearing before you even start messing with it. You don't need a thrust bearing in a drag car only for turning. Tuning a clutch is probably the biggest skill you need to master to run a nitro car. Engine tuning is about the same level but you can have a perfectly tuned motor and have the clutch off and the car isn't going to run the numbers.

Griz