Steel vs Aluminum driveshaft

Geerhead55 · 11-23-2010, 01:21 AM

Tom,,,if you're feeling a little "slutty" and need a shower,,just step outside,,theres a hell of a storm going on tonight. Just make it brief,,,with wind chills in the teens, you wouldn't want anything to freeze or fall off!! Happy Thanksgiving ( Dang,, we're not even in Minnesnowta!)
Danny Durham

Jeff Lee · 11-23-2010, 01:36 AM

Remember Robert Turner's F/SA Duster 360? He ran a junkyard RAMBLER driveshaft in it for record runs! Seems like it was only 2" OD. I can't understand why it didn't twist in half. I can't remember what ET he found but it was worth something.

Tom, you'll be OK. I have found myself agreeing with you before. Well at least once...

Jeff Kitchen · 11-23-2010, 10:10 AM

Setting aside any performance gain, I think aluminum drive shafts increase the life of the ring and pinion, axles, etc., by absorbing some of the shock load on launch. Any experiences to that effect? BTW - I even heard Warren Johnson make a statement to that effect, for whatever that's worth. I'm just a hack, but I thought I would bring up the subject. Thanks.

FED 387 · 11-23-2010, 12:22 PM

maybe no performance advantage but ya are taking WEIGHT outa the car--Comp 387

Ed Carpenter · 11-23-2010, 01:32 PM

Quote:

Originally Posted by FED 387

maybe no performance advantage but ya are taking WEIGHT outa the car--Comp 387

My car is 65lbs heavy for H. Maybe more if I get some HP off. LOL

Jim Caughlin · 11-23-2010, 08:07 PM

In case anyone is wondering about weights, my 3" steel driveshaft weighs 13#, the duplicate 3" alum with the same size yoke and ujoints weighs 10#. I didn't do back to back runs so don't have any data on performance differences.

Jim Caughlin
SS 6019

FED 387 · 11-23-2010, 09:08 PM

OK guys not sure what if any performance advantage if there is one but the BIG 3 have been installing aluminum driveshafts in rear wheel drive vehicles from Camaros to Lincolns to full size pick ups/vans etc for about 20 years---there must be a reason they are doing it--anybody wanna guess why a multi billion dollar company would do it?? It aint the color of silver vs. black or rust so why do ya think they are doing it????? comp 387

KingReptile · 11-24-2010, 02:25 AM

Quote:

Originally Posted by Jeff Kitchen

Setting aside any performance gain, I think aluminum drive shafts increase the life of the ring and pinion, axles, etc., by absorbing some of the shock load on launch. Any experiences to that effect? BTW - I even heard Warren Johnson make a statement to that effect, for whatever that's worth. I'm just a hack, but I thought I would bring up the subject. Thanks.

Its Safer too what would you rather lose a big chunk of steel or alumium??? Arent steel driveshafts illegal in stock in cars that didnt have them from the factory in NHRA still?!?!?

Run to Rund · 11-24-2010, 12:18 PM

Aluminum shafts are illegal in most stockers, not steel. Some at yellow bullet swear aluminum gives them a few hundredths. My guess is that if you run a thick wall, long 4" steel shaft, there could be some gain with aluminum.

Bill Edgeworth · 11-24-2010, 01:32 PM

I don’t think you can really make a blanket comparison between steel and aluminum drive shafts. Beneficial to some not to others, there is a lot of things to consider when swapping them out and seldom are the new and old physically comparable. One would first think that if its lighter it will take less energy to accelerate… well not necessarily if you take a small diameter steel shaft and replace it with a lighter large diameter shaft.
Here is an example
7000 rpm a 3” shaft will have a surface speed of 5498 feet per minute
7000 rpm a 4” shaft will have a surface speed of 7330 feet per minute a 33% higher speed
Using basic physics equations like Ke=1/2mv^2 if they weigh the same and most of the mass is in the tube not the end yokes the 4 inch shaft will take roughly 78% more energy to accelerate to 7000 rpm.
If you do all the math the 4” shaft would have to be about 40% lighter to take the same amount of energy to accelerate as the 3” shaft.
What this exercise shows is that most comparisons are apples to oranges you probably won’t see any gains unless you are replacing your current shaft with something lighter and the same or smaller diameter.
And this is without taking into consideration what’s going on in the rest of the car.

For something as simple as a drive shaft there is no simple answer.

11-23-2010, 01:21 AM	#1
Geerhead55 VIP Member Join Date: Sep 2002 Location: Tacoma, Washington Posts: 1,632 Likes: 0 Liked 5 Times in 5 Posts	Re: Steel vs Aluminum driveshaft Tom,,,if you're feeling a little "slutty" and need a shower,,just step outside,,theres a hell of a storm going on tonight. Just make it brief,,,with wind chills in the teens, you wouldn't want anything to freeze or fall off!! Happy Thanksgiving ( Dang,, we're not even in Minnesnowta!) Danny Durham

11-23-2010, 01:36 AM	#2
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: Steel vs Aluminum driveshaft Remember Robert Turner's F/SA Duster 360? He ran a junkyard RAMBLER driveshaft in it for record runs! Seems like it was only 2" OD. I can't understand why it didn't twist in half. I can't remember what ET he found but it was worth something. Tom, you'll be OK. I have found myself agreeing with you before. Well at least once... __________________ Jeff Lee 7494 D/S '70 AMX

11-23-2010, 10:10 AM	#3
Jeff Kitchen Junior Member Join Date: Nov 2001 Location: Dover, FL Posts: 5 Likes: 0 Liked 0 Times in 0 Posts	Re: Steel vs Aluminum driveshaft Setting aside any performance gain, I think aluminum drive shafts increase the life of the ring and pinion, axles, etc., by absorbing some of the shock load on launch. Any experiences to that effect? BTW - I even heard Warren Johnson make a statement to that effect, for whatever that's worth. I'm just a hack, but I thought I would bring up the subject. Thanks. __________________ Jeff Kitchen 1972 Buick GS - Stock Susp, 462 Buick Stg 2, 3500 lbs 9.93@131

11-23-2010, 12:22 PM	#4
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,422 Likes: 529 Liked 333 Times in 180 Posts	Re: Steel vs Aluminum driveshaft maybe no performance advantage but ya are taking WEIGHT outa the car--Comp 387

11-23-2010, 08:07 PM	#6
Jim Caughlin Senior Member Join Date: Mar 2002 Location: Woodburn, Or Posts: 685 Likes: 82 Liked 805 Times in 245 Posts	Re: Steel vs Aluminum driveshaft In case anyone is wondering about weights, my 3" steel driveshaft weighs 13#, the duplicate 3" alum with the same size yoke and ujoints weighs 10#. I didn't do back to back runs so don't have any data on performance differences. Jim Caughlin SS 6019

11-23-2010, 09:08 PM	#7
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,422 Likes: 529 Liked 333 Times in 180 Posts	Re: Steel vs Aluminum driveshaft OK guys not sure what if any performance advantage if there is one but the BIG 3 have been installing aluminum driveshafts in rear wheel drive vehicles from Camaros to Lincolns to full size pick ups/vans etc for about 20 years---there must be a reason they are doing it--anybody wanna guess why a multi billion dollar company would do it?? It aint the color of silver vs. black or rust so why do ya think they are doing it????? comp 387

11-24-2010, 12:18 PM	#9
Run to Rund Senior Member Join Date: Sep 2007 Location: Henderson, NV Posts: 583 Likes: 8 Liked 54 Times in 27 Posts	Re: Steel vs Aluminum driveshaft Aluminum shafts are illegal in most stockers, not steel. Some at yellow bullet swear aluminum gives them a few hundredths. My guess is that if you run a thick wall, long 4" steel shaft, there could be some gain with aluminum.

11-24-2010, 01:32 PM	#10
Bill Edgeworth Member Join Date: Oct 2006 Location: Tacoma, WA Posts: 258 Likes: 0 Liked 0 Times in 0 Posts	Re: Steel vs Aluminum driveshaft I don’t think you can really make a blanket comparison between steel and aluminum drive shafts. Beneficial to some not to others, there is a lot of things to consider when swapping them out and seldom are the new and old physically comparable. One would first think that if its lighter it will take less energy to accelerate… well not necessarily if you take a small diameter steel shaft and replace it with a lighter large diameter shaft. Here is an example 7000 rpm a 3” shaft will have a surface speed of 5498 feet per minute 7000 rpm a 4” shaft will have a surface speed of 7330 feet per minute a 33% higher speed Using basic physics equations like Ke=1/2mv^2 if they weigh the same and most of the mass is in the tube not the end yokes the 4 inch shaft will take roughly 78% more energy to accelerate to 7000 rpm. If you do all the math the 4” shaft would have to be about 40% lighter to take the same amount of energy to accelerate as the 3” shaft. What this exercise shows is that most comparisons are apples to oranges you probably won’t see any gains unless you are replacing your current shaft with something lighter and the same or smaller diameter. And this is without taking into consideration what’s going on in the rest of the car. For something as simple as a drive shaft there is no simple answer. __________________ Bill Edgeworth 6471 STK