One Piece Drive Shaft? experiences?

[carl johansson]

I'm not sure what would be the issue causing this vibration many of you speak of. Most vehicles have one piece drive shafts, and do not suffer from excessive vibration, so I am wondering what is it specifically that makes the Supra more prone to vibratioin, so much so that engineers went to a 2 piece drive shaft to reduce the vibration - which in actuality would not eliminate the source of the vibration, just mask it.

So I guess I am, looking for more than -" well it vibrates more!"

We have no problem with the 2 piece, other than excessive maintanence costs, and more "complexity" which typically ends up being less reliable.

We never plan on changing a drive shaft or U joints at a race, but you never know - and seeing as how you spend alot of money to prep a car, and alot more money to get to the race, once you are there, you want to maximize your racing dollar. Our primary goal is always to finish the 15 - 18 hours of racing - still running! (even though this is "cheap racing" a weekend of racing costs us about 2500 bucks, entry, tires 75 - 100 gallons of fuel , hotels etc, not including transportation to and from the track, and not including the car prep, which typically is 2 - 3 K after all of the safety stuff you have to have, and all of the systems you have to repair)
So we figure if we went with a 1 piece, it would change out easier in an emergency, the Ujoints could be changed in 15 minutes at the track, instead of finding someone to press those things out and screw with the carrier bearing!

I plan on having the one piece professionally built, and balanced, Don't know if that would eliminate some of the "vibrations" many of you speak of.

Anyone know or have an idea why the one piece is creating the reported vibrations (other than a misfit drive shaft, bad ujoints, or incorrect installation?

Rana, Google up 24 hours of LeMons to see the kind of racing we do!
in our opinion the supra is pretty well suited for this race series!

87 hilux, just saw your response - most is accurate, but the races are on road tracks, so 2 - 3.5 miles long, left, right, up down, we run on some of the best tracks in the country. We will be running at Infineon in 2 weeks, same course as the NasCar boys, with some added pieces those nascar guys whine about (so no carousel for them - cause they wear ballerina tutus!)
we often hit speeds of 120 - 130 at the end of the longest straights, followed by panic breaking down to 35 mph to make the next corner. We shift 20 - 35 times per lap, so you better know how to heal and toe!

Good place to learn to become a road racer, great place to have fun!

Carl Johansson

[Ranma]

Well Carl,

When I first bought my Supra brought him down to the toyota dealer. The U joints in him were bad, so sent the drive shaft down to the shop. So the U joints were changed in a professional shop and it was balanced. Well that did not eliminate the vibrations. Sent it back to the shop while replacing an axle and rebuilding the differential and the other axle. Put it back tougher and still had the vibration. At this time "genius" realized it was the drive shaft when I saw Ford on it. Got a replacement 2 piece, sent it to the shop. Put him back tougher and the drive is as smooth as smooth itself.
What you do does sound like fun, but not sure if I could take the g forces on the sharp turns. Do be careful Carl and enjoy your racing time You are right a sitting car is so much decoration.

[El Supracabras]

The excessive vibrations are probably from a poorly executed conversion. If you plan on using a professional service to build a driveshaft I would think (hope) you wouldn't have any problems. In Ranmas case, it sounds like the kid she bought the car from didn't care about or more likely didn't know what he was doing. The 2 piece is pretty stout, but ripping the rubber out of the center bearing in the middle of a good race would suck. Race cars are supposed to rattle, right?

[87hilux7mge]

Originally Posted by El Supracabras

The excessive vibrations are probably from a poorly executed conversion. If you plan on using a professional service to build a driveshaft I would think (hope) you wouldn't have any problems. In Ranmas case, it sounds like the kid she bought the car from didn't care about or more likely didn't know what he was doing. The 2 piece is pretty stout, but ripping the rubber out of the center bearing in the middle of a good race would suck. Race cars are supposed to rattle, right?

agreed. +1

[carl johansson]

Originally Posted by El Supracabras

The excessive vibrations are probably from a poorly executed conversion. If you plan on using a professional service to build a driveshaft I would think (hope) you wouldn't have any problems. In Ranmas case, it sounds like the kid she bought the car from didn't care about or more likely didn't know what he was doing. The 2 piece is pretty stout, but ripping the rubber out of the center bearing in the middle of a good race would suck. Race cars are supposed to rattle, right?

Thanks, thats kind of what i thought. someone here made a good point about length leading to excessive vibrations - but a one piece in this application is not real long!

As for the vibrations in a race car, the car is loud, jumpy vibrates all over the place from all sorts of things, but you would be amazed at how in tune you are to it. You can easily pick up a loose exhaust, and ID that, you can pick up a drive shaft, and ID that as either drive shaft or tires. The biggest difficulty is sorting out if the tire just picked up some melted rubber from another tire - it will vibrate and bounce like crazy till it wears off, or if you have a real tire problem. Plus everything is hard mounted, so you feel every vibration!