ok boys, how big around is your shaft?

tomslik · January 06, 2007, 05:01:25 PM

figguring out the driveshaft situation and i'm gonna have to have one shortend. well, i've got a pretty good selection but if i gots to have one cut and you wanna go fast, is bigger or smaller diameter better?

Dave · January 06, 2007, 05:08:58 PM

Quote from: "tomslik"figguring out the driveshaft situation and i'm gonna have to have one shortend. well, i've got a pretty good selection but if i gots to have one cut and you wanna go fast, is bigger or smaller diameter better?

Depends on the girl :?:

Its got a lot to do with wall thickness. Bigger isnt always better if the smaller shaft has a thicker wall. Since you would have to cut em all and measure it though id go with the bigger diamater.
I cut mine my self. I cut it short with room to go shorter then i worked down thru the weld with my sawzall till i got thru into the land of the yoke all the way around then i got the bfh and knocked it out. I finished the shortening then put it in the car and ran it around and indicated it till i got it to look good then i took it out and welded it... in all honesty ive had very few that ive had to have balanced that ive cut. So it can be done at home.
Dave

tomslik · January 06, 2007, 05:19:47 PM

Quote from: "jusjunk"
Quote from: "tomslik"figguring out the driveshaft situation and i'm gonna have to have one shortend. well, i've got a pretty good selection but if i gots to have one cut and you wanna go fast, is bigger or smaller diameter better?

Depends on the girl :?: Its got a lot to do with wall thickness. Bigger isnt always better if the smaller shaft has a thicker wall. Since you would have to cut em all and measure it though id go with the bigger diamater.
I cut mine my self. I cut it short with room to go shorter then i worked down thru the weld with my sawzall till i got thru into the land of the yoke all the way around then i got the bfh and knocked it out. I finished the shortening then put it in the car and ran it around and indicated it till i got it to look good then i took it out and welded it... in all honesty ive had very few that ive had to have balanced that ive cut. So it can be done at home.
Dave

i use a wizzer to cut the yoke out but at 7000rpm, i think i'll have it balanced;)

Dave · January 06, 2007, 05:59:18 PM

Ok im not gonna argue that.
Dave

kb426 · January 06, 2007, 09:22:32 PM

The rest of the answer is"how much horsepower?" I used a 3" shaft in my truck with an auto. With a manual I don't think it would have lasted long. I ended up with a steel mustang gt unit. It's heavy. That's why Ford sells alum. units. But the rest of the answer is a drive shaft is one more flywheel to turn. The lighter the better. IN theory, I believe a thicker smaller diameter unit may take less drag than a thinner larger diameter unit. I like the larger ones myself. I feel more comfortable with larger diameter tubes.

enjenjo · January 06, 2007, 11:15:07 PM

Length enters into the equation too. The longer the driveshaft, the larger diameter it has to be. It becomes a function of leverage. A 2"shaft 2 ft long will be as strong as a 3"shaft 4 ft long.

tomslik · January 07, 2007, 09:36:35 AM

well, it needs to be 46 1/2 long but i'll be running 28.5 or 29.5 9" slicks with a sbc of undetermined size with a 4 speed in a 48 chevy coupe...
i'm shooting for something in the 10's...

enjenjo · January 07, 2007, 10:58:37 AM

With that length, a 3" shaft should be enough. but 3 1/2" would be better.

sirstude · January 07, 2007, 12:10:15 PM

You guys all shure have short shafts!! Time to move up to big iron. I have none less than 5 foot.

Doug

kb426 · January 07, 2007, 01:11:34 PM

Mark Williams super shaft after that description.