Dynotech Engineering -vs- Shaftmasters one piece driveshaft

[Jmeo]

How difficult is it to change out a drive shaft?

Not difficult actually. Can do with basic tools rather easily.


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[Chameleon]

Picture the DS constantly spinning. And the weights below.

OEM 2-Piece Driveshaft / Manual: 36.2lbs
Shaftmasters 1-Piece Aluminum DS - 19lbs

 

[EXP Jawa]

The mass reduction for a rotating part - where intertia to accelerate and decelerate it comes into play - is pretty significant. Also, keep in mind that the prop shaft is upstream of the final drive. That means it is rotating at roughly 3.5X the speed of the wheels, depending axle ratio. Prop shaft speeds are a lot higher than a lot of folks realize.

Its probably also fair to say the parasitic losses to drag torque are also multiplied by the final drive, in terms of torque at the wheels, so a couple of lb-ft of drag at the shaft could turn into 10-15 at the wheels, if the measurement was accurate and consistent enough. However, most people also don't realize how much torque is actually developed at the wheels, because they don't look past dyno pull numbers. Wheel torque can often be in the 1000s, depending on what transmission gear you're in - even over 10,000 lb-ft in a high torque car (like GT350), so a difference of 10-15 is peanuts...

 

[Schu]

Not difficult actually. Can do with basic tools rather easily.


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Thanks... this might be my next upgrade.

 

[shaftmasters]

And I have to wonder how they arrive at those numbers. First, they should specify RWHP, secondly, I wish some of these companies would publish the process they used to arrive at these numbers.

All claims posted on our website of improved performance, HP gains, reduced times, better fuel economy etc. are reported to us by actual customers.

Thanks,
Shaftmasters Inc.

 

[phunk]

Any there any perceivable disadvantages to switching out the driveshaft's rear CV Joint to a U-Joint?

 

[yellowragtop]

AFTER you installed the one-piece driveshaft, did you experience any kind of THUD or clunk at any time when placing car into 1st or 2nd or reverse, or just driving around?

(If there is no thud or clunk anymore....)---> Does the one-piece driveshaft car use aftermarket half-shafts? and If so, which aftermarket half-shafts does it have?

When your car was on a lift, did you rotate the half shafts by hand to see if the differential had some "slop" ? (curious if you noticed any slop)

Thanks for your help with this !

 

[Jmeo]

Haven't installed it yet. Going to do headers, clutch, shifter and driveshaft all at once. Gonna be a little bit waiting for parts and time.


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[phunk]

Nobody has a comment on the rear joint?

I ask because from what I can see it appears the DSS uses a rear CV like stock, and ShaftMasters uses a U-Joint in the back. I need to order a DS in the next couple weeks and trying to make up my mind on that.

 

[EXP Jawa]

Conceivably, the CV joint ought to offer better NVH characteristics - less lash, lower clunk or chucking, and will probably be more stable at the point of wear-out compared to a universal joint. IIRC, the companion flange on the S550's Super 8.8 assembly has reliefs in it for the CV joint tulip and a 6-bolt flange. A conventional U-joint would probably require replacing the flange to allow it to be fitted.

Frankly, though, since the axle is now fixed to the chassis and doesn't move in relation to the transmission, all it really needs is a joint that will allow a little forgiveness of misalignment and part-to-part variation. The Cadillac CTS test car we have at work just uses a molded rubber flex joint.

 

[lugz]

Dusting off this old thread... replaced my shaftmasters with a dynotech today. The shaftmaster just did not want to run smoothly.

Motivated by the vibration thread and the recommendation of BMR and others, while I had the shaft out I took some angle measurements - the stock pinion angle was +3.5 degrees while the transmission output was only -1.5 degrees. By adding 1/4" shims to the transmission mount I was able to get another degree down. Ideally they would match, but I wasn't comfortable adding even more shim, and didn't want to shim the subframe (at this time.)

The dynotech has yellow paint splats to mark the heavy side, so I lined it up with the yellow splat on the pinion yoke where the factory weight has been removed. Immediately it was 200% better than the shaftmasters shaft. I monkeyed around with a hose clamp trying to get it glass "perfect" but couldn't beat having no clamp added at all.

As far as differences between the shafts:
stock 34lbs, dynotech and shaftmasters were both 18. (all +- .5lbs)
The shaftmasters uses a steel pinion yoke mount, while the dynotech uses a billet mount. The front mount on the shaftmasters uses 3 locating pilot bolt nubs where the dynotech is simply flat on the front face. Both mount snugly on the pilot from the output shaft.

The shaftmasters shaft came with 12pt 10mm bolts, a tap and a useless 10mm socket. The dynotech uses female hex head hardware which is much easier to work with, but does use two pilot bolts to locate the rear mount, making it the more difficult of the two to try clocking (if needed.) Someone recommended 8mm and 10mm long reach ball head allen/hex sockets - those worked great.

Both shafts are nice pieces with great craftsmanship. Is the dynotech really worth a couple hundred over the shaftmasters? Ehhhhh... not so sure.

 

[Schu]

Awesome... what's current pricing on the dynotech?

 

[lugz]

Awesome... what's current pricing on the dynotech?

For the manual transmission version, $920ish-1000ish, depending on where you're looking. Not cheap.

 

[BDMACH1]

So...when you adjusted the trans mount, did you put the Shaftmasters back in??? Or just installed the Dynotech???

 

[lugz]

So...when you adjusted the trans mount, did you put the Shaftmasters back in??? Or just installed the Dynotech???

Just installed the Dynotech. I didn't realize how easy it would be to just shim the trans mount, and I also didn't want to just shim the mount without taking angle measurements first. If I had to do it over again, I would have just tried shimming before taking out the shaftmasters. You don't need to drop the exhaust or anything- probably a 20 minute job to try it.

You do need to note that the trans mount has a metric ton of left-right adjustment to it, maybe even .5", so keep an eye on that if you loosen it up to install shims.

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