optimus

I was racing last night and believe something is wrong with the tranny. When I hit the gas from a stand still the car takes a very long time to get moving. There seems to be a lot of noise with it as well. Once the car is moving though it seems to go pretty well. I checked the temp after racing and it has not exceeded 90 but it is hot to the touch.

The car is geared at 81-24, I am running 45 boost, no timing advance, 13.5 motor.

Any ideas? Thank you in advance

Dave H

Might be a loose ball diff. Is the noise sorta like a barking sound? If so, at the very least the diff needs tightening, ideally a full rebuild with new diff rings and balls. Setting a ball diff is one of the trickier things to learn at first, suggest seeking out an experienced racer at your track for a little assistance.

Other main possibility is a loose slipper, worn pads, etc. Or perhaps a slipping drive pin on the wheel.

jag5508

iTrader: (15)

Did you check the slipper it might be to loose ?

BuggyKing

iTrader: (17)

That could be why your T4 is slowly accelarating. Youll have to recheck the slipper and tighten it properly. Also I wonder if he is overgeared if he is running real hot.

brickshouse

iTrader: (7)

Cant be overgeared, said it was 90*, either your diff or slipper like everyone else said....might need to take diff apart and rebuild if you were driving it that loose.

optimus

I will try a rebuild. How do you guys tell when the slip is tight enough?

Dave H

There are several methods for setting a slipper, but a good common way: Securely hold both rear wheels. Quickly blip the throttle, the front wheels should just lift a little.

For the diff, hold both rears, then turn the spur gear by hand. Observe the slipper spring and nut, they should not turn. If they are turning it indicates the diff is slipping instead of the slipper. Never allow a ball diff to slip.

Hope this helps, good luck!

optimus

Thanks for the help Dave. Would the same apply for the SC10?

Dave H

I would think so. For the slipper, generally no need to go any tighter than lifting the fronts a little, can’t put down the power anyway. Any looser and you run the risk of burning up the slipper pads and inconsistency as it heats up before burning.

One possible caveat on the diff, not sure are all SC10s are ball diff? Thought some might be a gear diff, I don’t know for sure (for that matter isn’t there a gear diff on some versions of T/B4.1s?).

Ball diff I stand by my comments. If it’s a gear diff it may need some shimming to avoid gear teeth jumping and to reduce backlash (big word for slop).

Oh, and on the ball diff, be sure not to over tighten as well. Be cautious as you tighten it, stop as soon as it starts to bottom out/tighten up, don’t keep cranking like you would with a normal bolted connection. Just takes a little experience to get the hang of it, again a little hands on help from an experienced racer can be very helpful.