WORKISSLOW

Its tough to figure out what mod to try next and changing the Driveshaft out is near the top of my list.

The one AM sells is $689 and one of the few aluminum DSs you see for the 3.7 MT.

I called a drive line shop that a friend had an AL DSs made at to see what they offered and they do not currently have an aluminum DS available for the 3.7 MT, the guy said he was having trouble get the correct parts for a continuous diameter drive shaft and he did not like putting hardware with a smaller diameter on the aluminum shaft or something like that.

He did say they have a 1pc steel drive shaft (presumably a larger dia.) that was lighter and stronger. He said the stock DS was about 47lbs and the replacement steel shaft is 26lbs and rated for 4000 RPM (20% Safety margin), $575 + $40 for install. (as savings of 21lbs over stack and $114 over the AM AL DS)

So that is temping, it is hard to say which is a better value, I am not sure if anyone posted an accurate weight on the Aluminum DS yet?

and I have not figured out what 4000 RPM on the DS equates to on mile per hour. I would imagine both shafts will handle similar speeds but it be worth finding out.

hogasswild

So I am going through a similar drill. Based on what you're telling me, I would not recommend going with his steel DS. It's basically rated lower than the stock shaft. I personally called Axle Exchange who makes the shafts AM sells and was told they weigh 21-21.5lbs.

By the way, your stock shaft weighs 29lbs, not 47lbs.

Search for dynotech on the AFM forum. I have a thread there with weights and specs. Just ask if you have any questions.

If your guy says critical speed on his shaft is 4000rpm, then that roughly equates to 96mph with 3.31 gears.

hogasswild

Another thing, a 4" shaft is as big as you can go and doesn't give you much leeway. Most aluminum shafts are 3.5" for our car. The Axle Exchange shaft is 4" in diameter.

freyes

Shaftmasters makes a quality aluminum driveshaft that costs $597.99. This is their 3-1/2" diameter. Their fabrication and raw materials go through rigorous checks, most of the other manufacturers do not perform. This, coupled with a lower cost make this purchase, a no-brainer.They also sell a BMR driveshaft safety loop, a recommended option, for $139.95. Check out driveshaft critical speed on google to learn more about tube length, tube diameter and maximum RPM.

WORKISSLOW

Freyes, the 3.5' Shaftmaster is a no brainer because of the quality and price?

I was kind of under the impression that the 4" dia. was preferable even if it is a tight fit?

AM 4" AL DS is $689 and weighs 21-21.5 lbs (made by Axle Exchange)

From the AFM thread
-Axle Exchange from AM $647 including shipping, 4", 21lbs, spun at 5000rpm (-8lbs, +500 RPM)
-DSS $720 plus shipping from CFM, 3.5", 20lbs, critical speed 7023rpm (-9lbs, +2523 RPM)
-Dynotech $694 including shipping, 3.5", 17lbs, critical speed 6700rpm (-12lbs, +2200 RPM)
-Dynotech $706 including shipping, 4", 19lbs, critical speed 7600rpm (-10lbs, +3100 RPM)
-Shaftmasters $597 including shipping, 3.5", 19.5lbs, critical speed 6850rpm (ok I see the value here)
(-9.5lbs, +2350 RPM)

Shaftmaster is claiming "14HP peak increase, and 16 ft/lb of torque increase with their 3.5" al ds, they don't list a 4" for the 2011+ v6, but their 4" ds for the previous years are under $500,,


http://www.dynotechengineering.com/

http://www.driveshaftshop.com/driveshafts-101

thanks guys, that was a big help

robinsonda1

Why are these drive shafts so weak? 96mph, 4k rpm? really, if that's the case I'm sure the stock DS is better than that.

hogasswild

Read the entire thread. The 4000rpm one was a steel shaft a local shop could fab up. The other shafts can potentially allow you to go as fast as the car is capable of.

hogasswild

A comparably designed 4" shaft will have a higher critical failure speed. The only thing to be concerned with is your tunnel wall and if you made modifications to the exhaust that may have brought the pipes in too close. They will also weigh just a little bit more.

I am leaning toward the DSS shaft but they won't ship to a separate address from your billing address and I'm in the process of moving.

hogasswild

Also not sure where you got the shaft masters hp increase numbers. All I have ever seen was 8whp/wtq. Do you have a link?

WORKISSLOW

It is on this page, I guess the claim is aimed at the Mustang 3.5" driveshafts in general and not nessaraly the DS for the V6.
http://shaftmasters.com/3mualdr1.html

I was kind of thinking the the 3.5" Dynotech just because it is the lightest, even though the numbers seem to fluctuate a little from source to source but for every pound off the drive shaft seems to free up 1 pony and on 1+ft/lbs... that one dynotech seems to be the lightest,, at about 2lbs-2.5lbs less then the other options, it is not a big difference but for say $97 more then the shaftmaster your freeing up 2.5hp and maybe 3ft/lbs for $97,, you only get so many opportunities to buy extra power for that kind of money and that extra $97 will prolly get returned in better fuel economy and then some.

So Hog, what is steering you toward the DSS?