Shaftmasters 1 Piece Aluminum Driveshaft

Piratetip

Far From Maddening Crowds
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Dec 30, 2005
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First I want to thank David and Robert at Shaftmasters.
I was fortunate enough to test the first 1 piece aluminum driveshaft they have made for the MKIII.

Last Saturday, (Nov 17th) I headed down to the Detroit area to meet up with David at a local performance shop/dyno. (Pande's Performance)
The plan was to run some before and after #'s with the new driveshaft, then go for a drive to make sure there were no issues.

We did three pulls on the dyno with the stock driveshaft, results were Max 283Ft/lbs 251HP. The torque curve was interesting, or lack of, you can see it in the pictures.
Then we put her up on the hoist so David could take some measurements. Popped the old clunker 2 piece driveshaft out and David was off to his shop with his measurements.
He arrived back not much longer with the new one piece driveshaft. Driveshaft Impressions: The visual appeal is quite impressive, something you have to see to appreciate. David said the weight came in at 11.5lbs, a 20.5lb drop over stock :) The welds are very nice as you can see in the pictures.
Fitment was right on, had it in, on the ground and back on the dyno in about 15 minutes.

After another 3 pulls on the dyno with the new unit, results were Max 286Ft/lbs 252HP. While not an extraordinary difference, gaining 3ft/lbs is respectable. The pulls were from 2500RPM - 5000RPM in 4th gear. I would expect the low end #'s to see the most difference as the lighter shaft is easier to get spinning initially.

David and I then took a spin to make sure there were no issues with the shaft. The car felt more nimble from a standstill and accelerated smoother. Initially I had doubts about vibrations with a one piece. But after jumping on the freeway for a bit I was happy with the results. Absolutely no vibrations from 0-90MPH. I actually noticed less vibration vs. stock, this is most likely due to the age of the shaft, center bearing and u-joints.
We came back to the dyno and picked up the printouts Pande had for us.

Then I had to head back to MSU to pick up my G.F. from the game. :)

All in all they deliver an excellent product and a pleasure to work with.

Now for the pictures everyone is waiting for.






Technical Specs:
Shaft is made with Alcoa 6061 T-6. 3" OD .125" Wall Thickness
There is a foam insert the entire length of the shaft for sound deadening.
Transmission and Flange Yolks are made by Dana/Spicer.
U-Joints are made by NEAPCO, caps and clips are coated to prevent corrosion.

Critical Speed Information:
87' Turbo Manual Trans
Tube Length: 40in
Material: Alcoa 6061 T-6
OD: 3"
Thickness: 0.125"
Modulus: 10.0mpsi
Density: 0.098lb/in3

Results:
Tube Weight: 4.426lb
Critical Speed: 11,863RPM
1/2 Critical Speed: 5,932RPM
Torsional Yield: 1,990lb/ft
 
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Doward

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Jan 11, 2006
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How is the critical speed different in different gears?

The driveshaft is directly connected to the differential. The differential spins a certain number of rpm per mph. Your driveshaft doesn't give a rat's ass if it's in 4th or 5th gear, it makes no difference to the rpm it spins ;)
 

suprahero

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IJ. said:
Would have expected the Tq numbers to jump a little more from the lower PMoI but pretty much as expected :)
If it's going to raise my torque, I've got to have one..............:biglaugh:
 

suprahero

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What is the turn around time on these? I will be getting one in the next week or so. Thanks, Jay

EDIT: I got the answer in a pm. Shipped out in 24hrs. of purchase.
 
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jdub

Official SM Expert: Motor Oil, Lubricants & Fil
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Feb 10, 2006
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Just got my Shaftmasters aluminum single piece driveshaft installed for the A340E tranny...it is also the first one made for the auto tranny. Shaftmasters does excellent work...it's a very high quality aluminum driveshaft. It weighs 11.5 lbs...much lighter than the stock 32 lbs. As you can see from the pics, the welds are perfect. Here's my review (added to Piratetip's R154 review) in the Parts Review Section.

I was not able to dyno the shaft, but did take it out to give it a good run. Launched from a stop at 2700 rpm (3000 stall torque converter), very rapid acceleration through 60 mph, maintained 16 psi boost (just below FC) through the tranny shifts to 120 mph. Excellent power transfer...barked the tires on the shift to 2nd with no "clunk". No unusual noise or vibration. Highway cruise produced the same results...ZERO harmonic vibration at any speed. Took it to 120 again for a short period...sustained various speeds in the 60-80 mph range. This driveshaft is well balanced with no vibration issues.


Technical Specs:
Identical per above, except tube length is 39"

Critical Speed Results:
Tube Weight: 4.66lb
Critical Speed: 12,480 rpm
1/2 Critical Speed: 6,240 rpm
Torsional Yield: 1990 ft/lbs.

Critical speed should not be a problem on the shaft....it's well above the max an A340E is capable of. The difference in critical speed compared to the R154 shaft above is due to the 1" shorter length of this driveshaft. The complete lack of harmonic vibration due to the perfect balance, makes 1/2 critical speed a non-player as well. This shaft should hold up against the top levels of HP and torque a 7M can produce. A couple of pics of this driveshaft on the Shaftmaster balancer:






The Shaftmasters driveshaft replaced a JawsGear driveshaft I have had on the car for the last 18 months. Comparison pics are below...I am not slamming the Jaws driveshaft; it is also a well made piece. However, there are a couple of differences in construction (Jaws shaft on top, Shaftmasters on bottom). The Jaws driveshaft uses a different rear u-joint and attachment flange to the differential. As you can see the flange is thicker on the Jaws shaft...this required sourcing new Grade 10, longer bolts/nuts (not cheap) to bolt up to the differential. In addition the rear u-joint flange "ears" on the Shaftmasters' driveshaft are thicker...from a strength standpoint, this is what you want to take the torque produced on a built motor (you 1J guys don't have to worry about this...lol). The front u-joints and tranny engagement spline appear to be identical.






As Piratetip said, David and Robert are a pleasure to work with...technical support in answering questions I had was superb. This driveshaft is a great alternative to the stocker. The best part? It's less expensive than other single piece aluminum alternatives out there ;)
 

TurboWarrior

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Apr 1, 2005
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I heard the center bearing in the stock driveshafts is so expensive to replace you might as well buy the one piece. Whats that bearing cost?
 

TurboWarrior

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Even at 200 id still go one piece if it failed. For $350 you are replacing the whole worn assembly its still worth it.