Too much power!??!

[Muzzy]

ok..he goes the story. i was at the track last nite to make some passes to get my time. ok...i get to the line rev to 4k drop the clutch and *rumble rumble shake shake* and continues to shake rumble and thump down the track. and i cross the line and let off the gas..and *THUMP THUMP metal scrape scrape spark spark* until i come to a complete stop at the end of the track. i open the door and look under my car to my drive shaft snapped to of the u-joints places..and i fall out of my car.....yea thas all im tellin u dont need to hear the rest.

but...the thing is that the shaft isnt the stock one. its one my dad had made. its had grease fittings on the yolks....so they werent solid exactally. so i dont think it was up to O.E. specs

anyway....i have 3 questions basically.....the first one is did the shaft snap because of all the power and teh weak shaft?? and when i say "all of the power" i was runnin 12psi from a S14 T-28 on 101 octane, fmic, full exhaust, aftermarket air filter, hollow cat, no clutch fan, exedy stage one clutch with a 1/3 of a tank. i only made 14.1....with a broken shaft so i know i was in the 13s range.

the 2nd question is....when u guys race...does your body shake on launch(car body and chassi) from the engagement of the clutch?? mine has alwasy done this in the past...and yea it stops 3/4 through first...and its not at all a lite shake...its fairly harsh

the 3rd question is....my diff has always made a weird friction/grinding sound for like 1' when backing up and stops after about 6' when in reverse. it doesnt happen all the time but it does happen though. and im am wondering if my VLSD is bad..and is it the cause of my car shaking at launch?? if it is bad could it have contributed to my shaft breaking?? ...to me at launch it seems like it isnt holding both wheels..it seems like it keeps switching between left and right real fast til the torque lightens up and then both hook up....i say this because the rear end seems to hop and shake from side to side as i launch....of course this is a butt diagnosis..i really dont know....idk if that is correct but it popped in my head as i typed this.


i'll show u pics in a few

[Muzzy]

http://www.imagestation.com/album/?id=2131773346

take a look at the damage

[sr240mike]

Wheel hop could have helped it snap. The stock rear subframe bushings can get pretty sloppy. What kind of suspension upgrades are you running in the rear. Stock rear suspension, subframe bushings?

[Muzzy]

lol well i had planed to get some subframe collars yesterday but SPL(bout 100 mile away) is out so i went the track to play(50 miles). so no..no subframe collars. i have GR-2s on Stechs and new strut bushings and donuts....thats it

[drift into a curb]

I'd say it's the shaft. I don't imagine you're making that much power, but my friends run similar set ups with the stock shaft and dump the clutch, kick it multiple times to disrupt the driveline and no problems. Stick in the OEM one or get a aluminum one.

As for the second question, could be a couple things. Anywhere from bushings to the drivetrain. I'd put my money on the flywheel. Get that checked out, could need a resurfacing, so it causes alot of vibrations.

Third, the reverse.. you have an s13 right? I'm willing to bet it's the right rear brake caliper. I've had a few friends with the exact same grinding/crunching.. After they've change the rear caliper (with new pads/rotors, no more grindage. This has happened more than one time.

[Muzzy]

yea i picked up the OE shaft from the yard today...its.....running....in the process of breaking it..the collar for the shaft bent the .....part where it connect to the bottom of the car....and...i dont have an ABS shaft i jus used a regualr shaft...seems to be ok but in 5th it makes a weird noise and starts to vibrate at 80. i think this is because of the collar/retainer.

i jus had my flywheel resurfaced 1k miles and 750 of it was break in time so its not that.

hhmmm..could be right..i'll have to check that rear brake...thanks!

[Muzzy]

anymore ideas or suggestions??

[the head]

i would guess the shudder is from wheel hop meaning that you did not slip the clutch enough on the launch
wheel hop can be the cause of broken drive shafts due to the shock of constantly loading and unloading as the wheels skip across the pavement

get yourself some subframe spacers that will help be slower with your clutch engauge that will help as well. the greatest parts in the world will still break if you mistreat them long enough. One of the guys around has broken two shepard trannys on his eclips GSX in one summer his car is not terribly fast (mid to high 12) and the same trans lasts two seasons in Shepard's car (eights) so remember kiddies just cuz you are breakin parts doesnt mean you are making power.

[Muzzy]

lol i see your point sir....i'll take it easy at the track next time...and less of it.