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-   -   your take on driveshaft (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/your-take-driveshaft-548479/)

RX7Junkman 06-09-06 09:00 AM

your take on driveshaft
 
i'm thinking about what type of driveshaft I shoul get carbon fiber, aluminum, or stay stock, u guy who may have them what are the advantages if any? please share your experiences

RX7Junkman 06-09-06 09:01 AM

never went with carbon or aluminum so I dont know if there up to it or there durability

cewrx7r1 06-09-06 09:10 AM

Depends on what you are using your car for.

Street - stock
Drag Racing - the strongest
Track Racing - the lightest

adictd2b00st 06-09-06 10:17 AM

yea my u-joints are bad on mine, i was thinking of getting the stock replacement that mazdatrix sells, with the serviceable joints. anything else i should be considering?

RX7Junkman 06-09-06 10:34 AM

gonna be an every other day driver, street/strip car Only got a t60-1 with stg 2 act clutch/ pressure plate racing beat flywheel. has anyone really felt or notice the difference is my real question?

RX7Junkman 06-09-06 10:36 AM

with a microtech lt-10s and all the other goodies

rynberg 06-09-06 11:09 AM

No, you're not going to feel a difference. It's an incredible waste of money, IMO.

DaleClark 06-09-06 04:55 PM

The whole "upgrade the driveshaft" is from too many hours of playing Gran Turismo :).

The stock driveshaft is actually INCREDIBLY reliable, is very light, and works just fine. If you truly have bad U-joints (which I've NEVER seen or heard of) a good used driveshaft is a much better idea.

There's tons better ways to spend money on the car. I don't believe I've even heard of high HP drag guys breaking driveshafts - it's normally half shafts or differentials.

Our cars don't put a lot of load on the driveshaft U-joints, due to the PPF keeping the driveshaft from flexing enough to put wear on the U-joints.

Dale

GoodfellaFD3S 06-09-06 05:13 PM

I agree with dale and tyler.

I have modded my FD out the ass, and the driveshaft shall remain forever stock.

rajeevx7 06-09-06 05:43 PM

Does someone know the weight of the stock DS and what it is made of? Chuck RE used to offer an all aluminum one that was advertised as supporting up to 800HP, and it was only $500. The 'all aluminum' part of it made it so tempting, as I remember the HUGE difference in rev speed my 9.5lb fly made.

Julian 06-09-06 06:35 PM

Have not weighed mine but it is light for a steel shaft. I almost wasted money on a CF shaft for no apparent reason other than that I am a weight freak who is now personally overweight, Glad I did not, my race car can always use the money out of need for a part not like the FD's want of a part.


As far as weight and flywheels, the benefit of liteweight flywheels is that they have a much larger polar moment of interia [since it is a big round thing i.e. the weight is farther away from the spinning axis] thus requiring more energy to spin up to speed. This is also a big reason wheel/tire/brake disc weight is important.

Julian 06-09-06 07:14 PM

read that as a much lager reduction in polar moment of inertia with a light weight flywheel

DaleClark 06-09-06 07:50 PM

I can easily lift a stock driveshaft over my head with one hand, and I'm not that strong :). I'd say it's maybe 10-12 pounds, max.

Making an aluminum one, you'd likely need thicker aluminum to take the same torque, so you may lose out on weight reduction - using more aluminum to do the job of less steel.

Dale

cptpain 06-09-06 10:03 PM

one thing with carbon fiber driveshafts is that they ar not reliable....not many cars run a carbon shaft because they are subject to a lot of sudden shock...resulting in the carbon weave "brooming" or breaking. ever took a handful spaghetti noodles when theyre not cooked and twisted them? what happens? thats whats going to happen with a carbon shaft after a while. plus it very expensive...ive heard they go for like at least $500 or more even more like $1200..plus a stock steel shaft can handle a lot of abuse..correct me if im wrong

dgeesaman 06-09-06 10:11 PM

As for driveshafts, it's kinda like FD trannys - it's cheaper to break and replace a couple of stockers before it's worth worrying about an upgrade. The stockers are so cheap, generally plenty strong, and the upgrade is so expensive that it's a component that shouldn't (IMO) be upgraded unless it's really necessary.

BTW Julian, lightweight flywheels work because they have a *smaller* polar moment of inertia, not larger. Mathemetically, the diameter of the rotating component is the most dominant element in polar inertia, so a 3" driveshaft is a much less effective place to remove inertia compared to the 14" at the rim of a flywheel. But anyway the concept has been made very clear.

Dave

Julian 06-09-06 11:19 PM

Dave, That is exactly what I was trying to say: A greater reduction in inertia can be gained by playing with the flywheel .. because the stock heavy one has so much inertia to begin with. I would have entered the equation but for what point, we are trying to present realistic images here not the absolute.

dgeesaman 06-10-06 06:19 AM

Actually I mis-read your statement because I was skimming too fast. No clarification required. Sorry

Tim Benton 06-10-06 04:13 PM

Stock driveshaft - 14lbs
ACPT CF driveshaft - 11lbs

I got the CF driveshaft and even though it saves 3 lbs on rotational weight, since it has such a small diameter, can't feel it on the butt dyno like you can a lighter flywheel.

Tim


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