aluminum drive shaft - anyone?

[Xinshadow]

Originally Posted by Boofneenee

http://www.axle-exchange.com/inc/sdetail/365

I came across this on my Facebook account
TAX MONEY BACK - SPECIAL] - FREE SHIPPING - $389

DRIVE SHAFT - Aluminum light weight from Axle Exchange

BRZ/FRS Manual: http://www.axle-exchange.com/inc/sdetail/365

BRZ/FRS Automatic: http://www.axle-exchange.com/inc/sdetail/399

Apply code at the checkout: OVR2015 for special discount

Price: $389.75 US (including shipping within USA)

• 3" o.d. Alcoa 6061 aircraft aluminum
• Spicer HD u-joints.
• HD slip yoke and flange all straightened and hi speed balanced.
• These shafts run very true and are rated to 600hp+.
• NEW - Sound deadening insides

Few people have these installed on their cars and are very happy with it. The quality is unrivaled! The acceleration is immediate, the cars feels eager to just jump when push the throttle. The best bang for the buck…like all the other mods wink emoticon.
Subaru BRZ MT
The Axle Exchange in Fairfield NJ is your source for in house driveshaft fabrication, brake parts, clutch kits and flywheels, c-v axles, rack and pinions, pto shafts and more.
axle-exchange.com

I hardly see much talk these days about lightweight driveshafts but I understand they can really shed unsprung weight. Any thoughts on driveshafts all together or this particular product?

I understand the stock shaft is a two piece. Most after market are one piece to save weight. Anyone care to share their experience as to what negative consequences of going from 2 to 1 would have? I mean it must be 2 piece for a reason.

I've had the DSS aluminum unit on my car for about 14 months now. Without getting into any maths, does it make a difference is acceleration feel? Yes, but slight. However in terms of total weight reduction its pretty significant for not a lot of money, and I plan to go with a lightweight flywheel down the road so it made sense.

The biggest change you will see, and I'm surprised no one mentioned this yet, is that it makes heel-toe shifting SIGNIFICANTLY easier, saving some wear and tear on your gearbox over time.

That said you will notice an increase in NVH, with the rubbing noise some others have described, and you may also feel a pulse through the gas pedal when the diff kicks in that the stock shaft kept muted.

Interestingly after going through some winters with both units, the factory one was developing small surface rust spots in a few areas, whereas the aluminum one for obvious reasons still looks fresh as a daisy. I'd be more worried about a factory one becoming unbalanced and damaging the gearbox over time in harsher climates than I would be about the aluminum one doing any harm.

Overall I'd say its a pretty effective cheap mod, if you're willing to work on your driving technique enough to take advantage of it.

[FirestormFRS]

Reducing the weight of engine driven parts is always going to benefit straight line acceleration. Will it always be noticeable? No.

I don't want the NVH and driveline wear that comes with longer driveshafts. You kids have at it though!

[Koa]

Originally Posted by stugray

Try this.

If a cyclist were to do the following two experiments, what would the results be:

Test A - Remove 10 grams from the perimeter of the tire and compare that to removing 10 grams from the seat.

Test B - Remove 10 grams from the wheel HUB and compare that to removing 10 grams from the seat.

What do you think?

The analogy applies this way for our cars:
Remove weight from the perimeter of the flywheel vs same weight removed from the spare tire: Noticeable difference! (removing from flywheel made a significant difference to rotational inertia)

Remove weight from the driveshaft (or the engine pulley) vs same weight removed from the spare tire: NO Noticeable difference!

Stu continually making haters out by being one of the realest people here.. straight up let 'em have it

[Sypher]

Originally Posted by stugray

Try this.

If a cyclist were to do the following two experiments, what would the results be:

Test A - Remove 10 grams from the perimeter of the tire and compare that to removing 10 grams from the seat.

Test B - Remove 10 grams from the wheel HUB and compare that to removing 10 grams from the seat.

What do you think?

The analogy applies this way for our cars:
Remove weight from the perimeter of the flywheel vs same weight removed from the spare tire: Noticeable difference! (removing from flywheel made a significant difference to rotational inertia)

Remove weight from the driveshaft (or the engine pulley) vs same weight removed from the spare tire: NO Noticeable difference!

i believe you are wrong. see references below

http://www.stangnet.com/mustang-foru...weight.789990/

http://www.hpwizard.com/rotational-inertia.html

[stugray]

Originally Posted by Sypher

i believe you are wrong. see references below

http://www.stangnet.com/mustang-foru...weight.789990/

http://www.hpwizard.com/rotational-inertia.html

Notice in the first post the OP talks about "equations" but does he show any? - No. so that makes it hearsay.

Sorry, but I will not accept - "You are wrong go read some stuff that proves it"
Cant you answer the "what do you think?" as it applies to the question?

Point out where I am wrong and then explain where I can find an explanation where I am wrong.
Physics is on my side (something I excel at).

I am not saying that reducing rotational mass does nothing, just that reducing the mass of certain items is below the threshold of detection of our "butt dynos".

EDIT - OK I read the second link.
THANK YOU for making my point for me.

In the example for driveshaft & half shafts, the author and the calculator explain that the "mass ratio" (equivalent vehicle mass compared to rotational mass) is.... wait for it..... wait for it....

1.01 = which in my book is approximately ONE.

So as I said - removing 1 pound from the driveshaft is the SAME as removing one pound from anywhere else on the car.

[Poodles]

And everyone ignores the elephant in the room, driveshaft critical speed.

Look it up, the math is easy.

[D K]

I have the axle exch alum ne because it was faster than the drive shaft shop.
No other reason.
Im pretty sure they are both almost identical.

I personally stay away from carbon stuff because they are more fragile, etc..

If you have an exhaust leak, you are much more likely to damage a carbon one than an alum one.
For a race car, I will take reliability over outright performance.
To a point, of course

D

[Sypher]

Originally Posted by stugray

Notice in the first post the OP talks about "equations" but does he show any? - No. so that makes it hearsay.

Sorry, but I will not accept - "You are wrong go read some stuff that proves it"
Cant you answer the "what do you think?" as it applies to the question?

Point out where I am wrong and then explain where I can find an explanation where I am wrong.
Physics is on my side (something I excel at).

I am not saying that reducing rotational mass does nothing, just that reducing the mass of certain items is below the threshold of detection of our "butt dynos".

EDIT - OK I read the second link.
THANK YOU for making my point for me.

In the example for driveshaft & half shafts, the author and the calculator explain that the "mass ratio" (equivalent vehicle mass compared to rotational mass) is.... wait for it..... wait for it....

1.01 = which in my book is approximately ONE.

So as I said - removing 1 pound from the driveshaft is the SAME as removing one pound from anywhere else on the car.

if you read the whole paragraph he states that the 1:1 ratio is for axles and half shafts. yet for drive shafts use the ratio of the differential. I believe that if you put in the correct dimensions for the drive shaft it gains quite a bit.... when i use the calculator the stock drive shaft should be roughly 30lbs of equivalent mass. I'm no physics major so i could be wrong.

[Captain Insano]

That might be the lowest price yet I have seen for a DS.

[zdr93523]

The biggest difference with the 1 piece driveshaft is the way the car reacts to throttle input. Once you drive one with a 1 piece, you will realize that you can no longer feel the delay when the center joint is loaded/unloaded. There is an immediacy to throttle inputs that is absent in the OEM 2 piece.

[Wyattkb]

So no input on whether the one piece drive shafts causes any premature wear on any parts?

[Poodles]

Originally Posted by zdr93523

The biggest difference with the 1 piece driveshaft is the way the car reacts to throttle input. Once you drive one with a 1 piece, you will realize that you can no longer feel the delay when the center joint is loaded/unloaded. There is an immediacy to throttle inputs that is absent in the OEM 2 piece.

The center joint has nothing to do with this... The driveshaft more likely has a bonded section in one of the shaft pieces. Eliminating that would achieve the same feel.


I'm waiting for someone to make a light weight 2-piece...

[Hawk77FT]

Seen the dss one before: wrong position of the counter weights, bad weldings . Looks cheap Chinese made!
Removing weight off the driveshaft will reduce the rotational mass= engine will get to high rpm quicker. Same as the crankshaft pulley. Look up the Grimmspeed research on lightweight weight pulley!

[Xinshadow]

Originally Posted by Wyattkb

So no input on whether the one piece drive shafts causes any premature wear on any parts?

It seems unlikely. People have been running (and various trim levels of cars come with as stock) one piece CF or aluminum shafts for years with no issues. I think your ability to row the box smoothly up and down at speed is going to be a far more significant factor in driveline longevity than the shaft itself.

The only reason steel was used in the first place is its cheap and does a good job dampening nvh in a car that already has a pretty thin interior sound wise.