I'm running a track event this weekend and the car is running good, tires wearing well, no brake issues. The track is Gateway Intl., in St. Louis, a Oval/infield road course.

I put about 200 miles on the car in about 10 20 minutes session during Friday testing day and Saturday. Today I run the 1st session and everythin is great, then in the 2nd session things went south.

I had run about 4-5 laps and had all the stuff up to temp. As I go into the "esses" I felt a sligth vibration and again in T5 (a slight left) and a little more pronounced in T6a & T6b (a double apex carrosel). By T7 (a tight left hand 180 putting you up on the NASCAR oval) I think I've got a flat so I take pit entrance.

Pit staff says no flats...I go down pit land and feel a big vibration in the shifter, so I go into the paddock and make some slow turns. No vibration. I go to about 30 ,ph and vibration.

Go to the garage and remove the wheels and nothing is worng there. I drive the car around some and get a big scrapping noise from the shifter (like a screw driver on a lathe against metal).

I go back and get someone to ride with to help evaluate and we hear a noise like someone is hitting the exhause with a wrench.

I go back to the garage and look at stuff again and then go for another test ride. This time just the vibration from the shifter @ about 3500-4000 rpm. and also an occasional noise like metal bouncing around against metal, heard forward of the shifter, under the hood/dash.

I have an idea but don't want to influence opinons.

Your help is appreciated.

:smash: :smash: :smash: :smash: :smash:

 

? torque tube maybe?
The older C5s had a smaller driveshaft and bolts in each end that could only take so many downshifts and didn't like when we spun the rpms over 7200.
The newer tubes seem to hold up much better but still get worn out from all the extreem track use.

 

Torque Tube? We have damaged a few with to fast of a down shift. It leaves the car with a "VERY" noticeable vibration. :sad:

 

(Always blame it on the driver!)

 

Even though I have my rev limit @ 7200, I tend to short shift @ Gateway.

I've also found that hanging out in the extreme high r's tends to foam up the oil and creates low oil pressure.

I tend to agree with the torque tube theory though.

I initially thought a bolt could have worked it's way loose on the clutch and sheared off or come out, causing the vibration and the sound of the bolt head boucing around in the bell housing.

Any other possibilities? (expecially ones that involves less work and cash :lol: )

 

Ok. New guy question....what is a torque tube?

:confused:

 

Engine in front of car Transmission in back...connected by the torque tube.

It's like a drive shaft only it's inside of a tube, thus the term torque tube.

GM refers to it as the driveline, with the shaft referred to as the propeller shaft. (although it has "torque tube" printed on it)

 

If you find the issue to be the torque tube. before installing the new one you might consider doing what we have done on McClures C5-R and put an aluminum joint at one end of the prop shaft in the tube, replacing the rubber stock one. Doing this seems to have helped the durability and did not create any harmonic noise we could notice in the race car. (Not sure about street driving?) :thumbs:

 

Thanks, I remember the discussion on that, a while back, when it was posted.

I think my BasicGaurd warranty should cover this though.

It there any TSB on the upgraded part?