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Lightweight driveshafts

20K views 38 replies 19 participants last post by  Bad daytona 
#1 ·
Hey, guys.

thedriveshaftshop.com offers a few lightweight driveshafts for our cars. It seems to me that dumping the 85lb. OEM boat anchor for a carbon shaft that weighs only 25 lbs, or an aluminum one that weighs 27lbs, would allow for a reduction in power loss to the diff owing to less rotational mass.

Is this in fact the case? What other benefits would it yield? Is a one-piece carbon or a two piece aluminum shaft preferable on my 6m?

Appreciate your input.

- Rob
 
#2 ·
Weight reduction is one of the best mods you can do. It will not get you as much in the 1/4 mile as say supercharging or nitrous. But you will benefit everywhere. Acceleration, cornering, braking, fuel use, wear and tear. You will feel it all the time not just at WOT.

It scales well with other mods. Shaving 400# is equivalent to 40 horses in the quarter mile for an R/T. But its worth 70 horses to a stock Hell Cat. Maybe worth 100 hp or more when its getting hard to find more engine upgrades.
 
#4 ·
P.S. I would not run carbon fiber on a street car. It does not like sharp impacts. Failure might be unlikely, but the 2#s isn't worth the extra money and potential for catastrophic failure. How many times have you carefully inspected a drive shaft as part of regular maintenance, the shaft itself not wiggling it to check u-joints?
 
#15 · (Edited)
The factory 2-pc 6-speed driveshaft weighs in right at around 25lbs. The lightest 1-pc. replacement driveshafts I've seen are the GForce 3.5 & 4" aluminum ones that weigh 15 to 18 lbs. so there's definitely some misinformation here on the weight of the factory 2-pc ds!!!! You can almost bet that the factory A-5 automatic 2-pc ds weighs just about 25lbs as well.
 
#21 ·
Robocop - do you have personal experience with this regarding those weights or did you glean it off of the web somewhere?


I'd love to find out the actual weight of the OEM driveshaft without having to unbolt mine and weigh it.
 
#17 ·
The whole notion of weight reduction vs rotational mass can be a bit dicey when it comes to stuff like driveshafts (so be careful). Things can be made in a lighter material, and it will likely be lighter on a scale, but rotational mass may not be as improved as you think. It may not even be much different than the stock one. When you see the diameter of the part increase, that is a direct increase in rotational mass (possibly enough to wash out the effect of the lighter material, entirely).

There was another topic on this some time ago, and I did a preliminary analysis on the aluminum and CF options. I think the aluminum was a wash, altogether (due to diameter increase). The CF was a "bit" better, as far as being less rotational mass, but it wasn't as much as you expect. ;)
 
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#22 ·
I agree.. especially if its only 6 lbs. Thats not worth the trouble to me id rather stick with the OEM.. Even with wheels you have to be careful. Like the light weight performance 20" wheels that came from the factory on my Scat Pack are like 27lbs not to bad for stock and there probably a very strong wheel. Then there are aftermarket wheels that are very close to the same design as my stock wheels but they weight 21lbs and 6 pounds per wheels of reduction rotational mass would be great but the cost of the aftermarket wheels and then they might be weaker then stock and not worth it. I remember i got a nice set of aftermarket 17" wheels for my 67 Camaro years ago. Loved those wheels on that car well until a hit a small pot hole and bent the dam rim.. And it was a pot hole that ive hit before and had no problems.. Especially at night those pot holes are a b$#%h.. Same thing with an aftermarket drive shaft.. unless you have a lift to inspect it all the time i dont know if id trust it not to mention the money you have to put out for 6 little pounds.. now if it was 40lbs of rotational mass id say that might be worth it especially if its known to be a good shaft..
 
#18 ·
I'm almost thinking maybe the better direction to go is smaller diameter and stronger metallic material (i.e., titanium). That's only if you stay reasonable with the hp/torque rating. Once you are building to handle heavy-duty output, then you just need a stronger part, altogether (which means more diameter and more material mass).
 
#19 ·
There was a one piece aluminum drive shaft for sale a few months back in the classifieds. I contacted the seller after it sold and asked him his honest opinion of it. He said the one piece DS transmitted more noise into the cabin over the OEM two piece, enough so that the additional noise was always noticeable.
 
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#20 · (Edited)
The benefit of a 1 piece over the 2 piece besides some weight savings is you eliminate the center carrier bearing, and supports that can get loose and flap around not to mention the losses through the center carrier bearing(s)

If you're building HP with power adders or somewhat aggressive with the clutch I'd seriously look into a 1 piece shaft.
 
#27 ·
I think one of the downsides of a lightweight driveshaft is driveability, in the same way that a lightweight flywheel can affect it. Makes the drivetrain more responsive, but a lot more sensitive, too. Or am I off-base?
 
#30 ·
In the last four years I owned a 2011 GT and 2014 GT Mustangs as well as a 2014 Chevy SS w/ the LS3 engine.All w ere automatics and I installed aluminum DSs in all three and ran many hard runs with no ill effects. They are costly running about $900.00 each and add another $100. for DS loop. I don't know the weight in my SP stock shaft but in the three above the stock 2 Pc. DSs were way more than six pounds difference. I think the stock one could have failure at the carrier bearing which would be ugly if it is used hard enough at strip. The main benefit is not the weight savings but the quicker revving/acceleration. Basically doing what we did in 60s by installing an aluminum flywheel.
 
#33 ·
found this thread to enquire about the stock drive shaft weight and thank you

after cancelling an order w/ G force (Great people there by the way!!), speaking with DSS (I got "Sir!"...so low eyebrow), Gforce owners, and known road racers and designers of trans am cars, 1 piece drive shafts are for the strip and they will create vibrations through harmonics because of the high speed rev and the high speed of the car, even at with a 4" inch design in aluminum

aluminum is used because steel is even a lesser compliance with high speed rotation;

when reaching 160 mph and not staying there because you are on a quarter mile strip the 1 piece shaft will be fine;

for road racing the 2 piece shaft must remain to avoid vibrations that will destroy the rear diff and trans and cause a major failure

carbon fiber in general suffers from its glue weakening when close to the exhaust pipes; DSS tech told me that a bit of exhaust wrap would prevent the CF shaft yokes and couplings from getting too hot......

at 1600 bucks a CF drive shaft i am not convinced; if I was tracking with side exhausts straight from the headers then I would consider CF and if I was rich enough

at the end this whole driveshaft thing is for the 60 ft time freak. the strip guy and the wealthy road racer tuning the crap out of his car with a fat wallet

i'd rather spend money on race brake pads and top notch tires

i got quoted for 1250 for a 2 piece alu drive shaft from DSS for a 6M as a custom piece but since the weight saving is almost null, why bother;

i am sticking solid engine mounts in the bay I am doing right by my 60 ft time anyway and I am not even a drag racer

jmo

ODP
 
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#34 ·
I have a 1pc Driveshaft Shop Carbon Fiber Driveshaft.


It seems as though as there are quite a bit of people that have allot of neutral or negative input on them without actually owning them.


I have ZERO issues. There could be an issue with something impacting the shaft but not really going to happen. Most of the shaft is shielded by the exhaust system down the length of the car. They are well made and in my opinion allot nicer then OEM driveshafts. Just picking up the OEM driveshaft and also the Carbon Fiber shaft, you can feel the weight difference. These carbon fiber shafts are strong.
 
#37 ·
I cant really say if I see gains from just the driveshaft installation. I swapped out my NAG1 to a Southern Hot Rod Stage 4 NAG1 with a Pro Torque 2800 stall convertor as far as driveline goes. I redline pretty much instantly, I can tell you that much. I have too much wheel spin but I am using BfGoodrich Sport Comp 2 tires... no drag radials or slicks yet.


I do feel more confident with my driveshaft as of now. I guess that could change at anytime if I see damage. It's only been on since March with daily driving, 0-60 and full throttle runs. Time will tell.


If I had to do it again I would go with a steel/moly or a carbon fiber.
 
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#39 ·
I have no experience with them,but I was considering it at one point.What I found out through talking with persons more knowledgeable than myself.
Is that for rotational mass reduction the aluminum shaft is larger in diameter which puts the weight out farther.Anyway what it comes down to is any weight savings is lost and comes out about the same.So any benefits of weight reduction would be going with a carbon fiber which is smaller in diameter.But with the cost of those and the small amount of gain I just S-canned that idea.

Of course if strength is what one is going for that's another matter.
 
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