[jesus818]

hi guys today im trying to get your opinions on the pros and cons buying a aluminum driveshaft

cause im trying to buy a new one but i dont know if i should buy a original or should i get a aluminum driveshaft?:kooky:

 

[Harmon2011]

there are no con's on getting a aluminum ds. way lighter than the factory 2 piece which means less rotating mass = more power hitting the rear wheels.

 

[cindys_sn95]

same as your other post! why two screen names?

 

[robs91fox]

An aluminum driveshaft isn't really worth buying unless your already in need of a new driveshaft. I only bought mine because my stock one was causing a bad vibration at 65 MPH+

But the performance gains are minimal. I was more excited to not have highway vibration than noticing any gain in performance.

 

[Old man]

hi guys today im trying to get your opinions on the pros and cons buying a aluminum driveshaft

cause im trying to buy a new one but i dont know if i should buy a original or should i get a aluminum driveshaft?:kooky:

The popular notion an aluminum driveshaft frees up some measurable horsepower is a myth. The driveshaft is not large enough diameter, is not heavy enough, nor does it constantly change rotational speed to be any significant advantage for the price.

The return on weight savings is almost the same as shaving twice the weight off the car's mass. So if you dropped from 20 lbs to ten, the effect would be around the same as lightening the car by 2 times 10 = 20 lbs.

I've spent about $45,000 on my current project car, and have yet to consider driveshaft weight. As a matter of fact, I ran an 8 second Mustang and never changed to an aluminum shaft.

Now if I had a light weight road race car that needed instant tire speed control when sliding, I'd use an aluminum shaft in a heartbeat.

 

[Coupelover]

Mine needed to be replaced, so I went with the Ford racing aluminum one....

Comes with U-joint pressed in, for a tad more then the OEM one.

Shaving weight is always good, without destroying the interior or anything else.

 

[Midnight21]

Believe I read something a while back where someone said they had issues with coupling an Aluminum Drive Shaft with Aluminum Flywheel on there DD. They were saying the lighter flywheel doesn't have the centrifugal force weight to help in the DD's normal duties. Such as slow turns, driveway, up a ramp or hill around parking lots, decks and they would have to rev it a lot higher instead of feathering the gas/clutch.

Any other DD's out there that have also done that swap that can give us your experience with that???

 

[jimmy77]

like these guys have said only replace it if you have a problem already or are already in there. since i am just finishing a total rebuilt and beefed it up i decided to go ahead and replace the stock shaft.
getting ready to send in measurements to dennys driveshaft and upgrade to 1350 stuff. the old setup had some vibration which should be gone now that i've rebuilt suspension rear and then driveshaft.

 

[TKC]

The popular notion an aluminum driveshaft frees up some measurable horsepower is a myth. The driveshaft is not large enough diameter, is not heavy enough, nor does it constantly change rotational speed to be any significant advantage for the price.

The return on weight savings is almost the same as shaving twice the weight off the car's mass. So if you dropped from 20 lbs to ten, the effect would be around the same as lightening the car by 2 times 10 = 20 lbs.

I've spent about $45,000 on my current project car, and have yet to consider driveshaft weight. As a matter of fact, I ran an 8 second Mustang and never changed to an aluminum shaft.

Now if I had a light weight road race car that needed instant tire speed control when sliding, I'd use an aluminum shaft in a heartbeat.

If its a 5/10lb ratio or a 20/2000lb ratio...weight is weight whether its measurable by the "seat of the pants" or on a dyno. If you can lose 10-15lbs that's just that much weight of the car in totality, if you wanna talk parasitic centrifugal loss then old man is right. But physics are still the law, if its lighter it will spool up quicker and vice versa. Why do we install aluminum flywheels then? Same principals apply to DS just not on the same magnitude because its not as much of rotating mass(outside perimeter respectively). Lighter is quicker. Bottom line.


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[Old man]

. But physics are still the law, if its lighter it will spool up quicker and vice versa. Why do we install aluminum flywheels then? Same principals apply to DS just not on the same magnitude because its not as much of rotating mass(outside perimeter respectively). Lighter is quicker. Bottom line.


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The drive shaft spins up SLOWLY at the same rate the car accelerates.

The fly wheel spins up much faster, because of the transmission. It also speeds and slows constantly going down the track, because of the transmission.

The energy STORED and returned by a rotating mass is squared in proportion to the distance out from center where the weight is. It is directly proportional to the weight change if the diameter and distribution is the same.

So a 12 inch flywheel has 16 times the stored energy as a 3 inch driveshaft (it is 4 times larger), if the weight and distribution of weight is the same. It's silly to compare a 30 pound 12 inch flywheel that speeds up and slows through every gear to a slowly changing 3 inch driveshaft.

Anyone thinking a few pounds drive shaft change makes a noticeable difference in acceleration is really far off track. Because it accelerates so slow and has such small diameter, it isn't much different than just taking the same weight off the car. It has maybe twice the value of the weight removal, if we are lucky.

 

[Bullitt95]

hi guys today im trying to get your opinions on the pros and cons buying a aluminum driveshaft

Pros:

9lb weight saving
Higher critical driveshaft speed
Raises critical road speed before vibes occur
Compensates for lowering of critical road speed caused by higher ratio axle gears
Stronger than stock shaft and can handle more torque

Cons:

Purchase cost
Shipping cost (oversize item)

 

[ALMOST STK]

I've always found this to be a very good read when it comes to the a aluminum driveshaft. The site says this was written by a Ford driveline engineer.
TCCoA Transmission Article - Page 17

 

[TexasMustang]

I've always found this to be a very good read when it comes to the a aluminum driveshaft. The site says this was written by a Ford driveline engineer.
TCCoA Transmission Article - Page 17

Link isn't working?

 

[Smurf stang]

Very interesting read.

 

[TKC]

Pros:

9lb weight saving
Higher critical driveshaft speed
Raises critical road speed before vibes occur
Compensates for lowering of critical road speed caused by higher ratio axle gears
Stronger than stock shaft and can handle more torque

Cons:

Purchase cost
Shipping cost (oversize item)

Good way to sum it up Bullitt. Weight is weight, whether it be stationary or centrifugal...it takes force(power)to move regardless. Lighter means less force(power) to move any particular mass. Idk how to simplify it anymore. Now, if you're speaking of is it worth it or not that is determined on whether or not that increase is(regardless of how minimal that may be)worth it to the particular user/individual. I think this discussion has to turned into a debate about "is this one better than the other" to just "simple physics."


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[Bullitt95]

You won't be swapping in an aluminum driveshaft for a RWHP/RWTQ gain. The weight saving of 9lb rotates through a radius of 1-3/4" so that's only 1.3lbft extra going to the rear wheels.

 

[86967]

get a carbon fiber unit...metal is so 1980s...the fibers actually allow more "twist"...gotta love modern technology

 

[TKC]

get a carbon fiber unit...metal is so 1980s...the fibers actually allow more "twist"...gotta love modern technology

Interested...share any info/links you have about that if you wouldn't mind.


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[Old man]

You won't be swapping in an aluminum driveshaft for a RWHP/RWTQ gain. The weight saving of 9lb rotates through a radius of 1-3/4" so that's only 1.3lbft extra going to the rear wheels.

That's not how it works. It depends on the acceleration time.

Use this calculator:

Flywheel Energy Storage Calculator - Kinetic Energy, Inertia, Centrifugal Force, Surface Speed

There are 16oz in a pound. Using 9 lbs (144 oz) as a ring 3.5 inches diameter, at 6000 RPM ultimate speed from zero start, the stored energy is 1593 joules. 1593 joules created over 10 seconds linear spin up time (this assumes the car runs ten flats with linear acceleration) 1593/10 = 159.3 joule seconds converts to a drain of 0.2135 horsepower as stored energy. If it is over 20 seconds, the drain is half that because there is more time to spin it up (159.3/20 = 7.965 joules). If it is over 5 seconds, the drain is twice that because there is less time to spin it up.

That's pretty expensive horsepower.

The slower the car acceleration, the less important it is because there is more time available and less force required to spin it up. It's always 1593 joules for zero to 6000 RPM with that weight and diameter, but the time is a factor to covert to horsepower. It takes a lot of horsepower to spin it up to 6000 from zero in 100 milliseconds, so it can be a big power drain when running faster than 1/10th second ET.

 

[Midnight21]

Soooooo, ....it revs faster.