Billybix76

Shaftmasters 3.5 Install & Dyno Its in. The 3.5 DS arrived Friday. I set up a dyno and R&R appointment at a local shop with a Dynojet 630 and good reputation with the speed shop crowd. I went in on Saturday at 1:00 PM to do a baseline dyno, remove the old stock DS on a lift, replace with new 3.5 aluminum, then immediately roll it back on the dyno for a comparison run. Same car, same day, same dyno, same driver, same tune, 3.31 stock open diff. For those who will ask, I ran on both runs with Brenspeed's 91 tune with stock settings. Both were 3rd gear pulls, as the goal was not "my Hp is higher than yours" but to compare apples to apples with a DS change. (of course I did not want my stock DS blowing out on me at 6300 RPM on a 1 to1 gear either...)

First objective = to asses the build quality, install, fit and clearance of the new DS vs Stock. My car is lowered by 1.0 inches front and 1.25 in back with Roush springs. I have installed the new MGW shifter set at 6 out of 10 full turns out.

The fit was perfect. It is same or smaller diameter than stock and I had avsolutely no clearance problems with stock placement of parking brake bracket or MGW shifter (see pics). At ride height I can easily put a couple of fingers between all close objects and the DS.

Second objective = To asses any actual un-biased HP or toque differences on just the DS change out.

The numbers are dissapointing ( we were all hoping for more) for those who are looking at another guaranteed HP mod. My dyno results (see pic) are 190 rwhp / 220 rwtq on the baseline pull, and 191 rwhp / 218 rwtq on the second pull with new DS. Almost identical runs. within the + or - error factor on the physical limitaion of the dyno.

As to why the torque actually dropped, I happen to think that since my measured pinion angle before the swap with stock DS was -1.5 degrees (pushing the edge of reason) and the articulation of the center spline joint in the stock shaft kept it on safer ground and compensated for the low pinion angle somewhat. the swap to the one piece actually lowered the angle to near 0 and at WOT actually drove it past 0 degrees into positive numbers. needless to say I am in the hunt for an adj. UCA next to match my fixed J&M LCA's.

Overall driving inpressions = I saved the best news for last!

The car is tons more driveable now. The rolling take off is twice as manageable. The acceleration feel is smooth and top end rpm's seem stronger, My peg-leg burnout test was more impressive. As for high speed that is still on the test list, but I am confident now that I can easily (on a track with a helmet), exceed 125 with no problems.

I highly reccomend the 3.5" Shaftmasters DS for many reasons, but the best and brightest is that Robert will use his 25 years experience building driveshafts to make yours personally. And he actually cares how it turned out like it was his own. If you have a lowered 4.0, and want the best powertrain you can get this is the real deal.

LEO_06GT

Question, since your pinion angle is off are you getting any vibration??

Billybix76

Not that I could tell. i think with the fixed LCA's I am staying inbounds of tolerance on pinion bearings. I have not measured pinion angle with new driveshaft yet. I will wait for adj uca before I get to much farther.

King Taco

how come u lose torque

Billybix76

Dyno's can vary as much as 5 rwhp and torque as well with same equipment on back to back runs. There is no way to positively identify why HP went up and torque went down by only a little.

shaftmasters

[quote=Billybix76;1063425]Not that I could tell. i think with the fixed LCA's I am staying inbounds of tolerance on pinion bearings. I have not measured pinion angle with new driveshaft yet. I will wait for adj uca before I get to much farther.[/quote
Leo,
Just thought I'd mention that you should noticed more of a high-end improvement than billybix 76 did. There has been some misinformation circulating about the actual weight of the factory original V-6 shaft. We believe that the V-6 OEM shaft weighs around 20 lbs. were as many think it weighs double this. We haven't weighed a V-8 OEM ourselves but it has to weigh considerably more than the V-6 OEM.
Robert

Billybix76

Robert, i will weigh my stock DS on the same scale i weighed the 3.5 on and report back with pic of the scale. if that will help solve the riddles.

shaftmasters

[quote=Billybix76;1063514]Robert, i will weigh my stock DS on the same scale i weighed the 3.5 on and report back with pic of the scale. if that will help solve the riddles.[/quote
The OEM V-6 shaft is identical to some model year Explorer shafts except for the length. We have experience the same complaints from these customers as we have from the V-6 mustang customers and the Explorer's don't rev as high.
Robert

Billybix76

There has been some discussion about the exact weight difference between the Shaftmaster and other aluminum drive shaft's of nearly identical design and weight and the stock driveshaft for the 4.0 V6 Manual. Since I just put on the Shaftmaster 3.5, I snapped a pic of the actual weight of both on the same scale. here they are.....



As you can see, the aluminum is 13.5 lbs lighter....

There has been a misinformation urban legend that 2005+ mustang DS's all weigh over 40lbs. The GT may weigh that, but the v6 is 30lbs...

LEO_06GT

I'll be sure to weigh the oem and shaftmaster shaft when I do the install. I'll post results here and in the thread I started.

shaftmasters

We believed that the V-6 OEM shaft weighed around 20 lbs. based on weighing a similar looking Explorer shaft that we have in our scrap pile. Obviously there is a 10 lb. difference between the two. I am glad that this is cleared up and look forward to hearing what weight you get on the V-8 OEM shaft.
Robert