How do you determine the correct DS length..I will be pulling my DS tomorrow since I didnt get it shortened when I installed the Moser12 bolt...What is the correct way to determine this..

Cody

 

ttt

 

I can tell you what I did, which probably has no relationship to what's actually right

I pulled the rear springs and shocks, so I could swing the rear through full travel with my jack. Then I marked a line on the yoke where it enters the tranny, and swung the axle up and down to find the point where the driveshaft was furthest into the tranny. Then I unbolted the DS and determined that I had about 1/2" from bottoming out in the tranny. I decided this should be enough, but I know it's pretty a tight tolerance and usually you want a bit more than that. It's been fine through 1/4-mile launches and plenty of RR, so at this point I don't think I've got an issue with that 1/2"

Dave

 

The stock DS has about 1/2" clearance before it bottoms out in the tranny. That is OK for a stock or moderately modified engine. But if you are going to a power adder, you need to increase the clearance.

I went through this pretty thoroughly after my ACPT carbon fiber DS broke (just moving the car from the engine shop to the body shop - not under load). ACPT claimed the DS was too long, had bottomed out in the trans, and broken the bond of the front yoke to the CF tube. I was able to prove that the clearance of the ACPT DS, as installed, was 1", and that both my stock 1/2" clearance DS, and subsequent 1" clearance Mark Williams 3" chrome moly DS had not bottomed out. Reluctantly, after many months and nasty telephone conversations, ACPT gave me my money back.

Point is, in researching the design standards for driveshafts, the best advice I got was from Steve Spohn (Spohn Performance)... he builds/sells hi po DS's.... and he confirmed the 1/2" for a stocker, and up to 1" clearance for a big power adder application.

 

Well mine prolly has about 1/4" right now so Ill prolly just take 1/2" off. That sound good?

Cody

 

Welll....got under the car today and checked the DS length...

My DS will NOT bottem out no matter how far I push it in the tranny...The output shaft seal on the tranny keeps the DS from going that far..The seal is 1/8" from the yoke on the DS though ; I can only see that much of the shaft going into the tranny..I could see about 3/4" of the shaft going into the tranny on my stocker..In my case I dont think there is a need to shorten it at all What do you guys think? This was with the tires on the ground also..I cant tell how close the DS is from botteming out I just know I cant see as much of the shaft as before which would mean the rear-end is closer than the stocker like you guys said..Point is Im not sure how far it is from botteming out..Ill prolly just cut that 1/2" off that is farther in the tranny..

Cody

 

Took my DS to my local shop and they said they didnt shorten Aluminum shafts..He also said he would build be a steel shaft that would be alot stronger and better for only $150(he runs this in his 9sec camaro) He said my aluminum DS would not hold my motor ecspecially if I plan on spraying it..I know a shop in Dallas that will shorten Aluminum but should I do that or go with the steel?

Anyone running a aluminum DS with alot of power?

Thanks

Cody

 

Come on guys...I need to figure something out tonight...

Will an Aluminum DS hold 500-600hp?

Cody

 

aluminum? no - I pretzeled mine I had.... went back to stock. I do have a 3" chromoly as well.. take it as a spare.


As far as length.. I've got about an inch between the seal and my yoke. never had a problem.... right @ 2 inches from the edge of the tailshaft housing to the round/flat part of the yoke.

HTH

 

do anyone know how many inches it is like what i would tell denny's when i call?

 

I should find out tomorrow..I think my best bet is to get this guy to custom build one and he ensures me it will hold just fine..$150 aint bad at all which includes computer balancing...

Cody