hogasswild

I think the amount of power freed up in that weight range will be very similar, so you're talking 1-2hp differences. I am torn between the dynotech for its weight (very similar to CF), the shaftmasters for its cost and reputation and the DSS for its cv joint and higher critical failure speed.

hogasswild

You don't have to worry about pinion angle with the cv joint.

WORKISSLOW

oh, so some have CV joints and some don't? I didn't realize that.
I guess the CV joint make sense if you are going to play with your suspension down line, I know I will.
If the DSS has a CV and the others don't then the main shaft tube is prolly shorter, so that would make sense that it has a higher critical RPM. Unless some how the other components add up to the same length?
Personally I don't think I would blow up any of these shafts, so I am kind of searching for that secondary criteria to make a choice.

The OEM shaft is rated for 4500 RPM right?

Chromeshadow

Hogasswild, are you a little worried that you'll hit the limit on the stock drive shaft at a lower speed than the 3.31s or the 2.73? I think 123 MPH for you is about the same as 140 MPH for the 3.31....about 5,800 RPM for the drive shaft.

hogasswild

I've put 20,000 miles on the stock shaft since I installed the 3.73 gears, so I'm not overly worried, but it is the next logical mod for me.

hogasswild

I'm not sure what the stock shaft is rated, but most people think its around 4500, so about 100mph with 3.73 gears. No one with 3.73s have snapped a shaft on a drag strip, so it may be higher or won't fail because the speed isn't sustained for more than a second.

Only DSS offers the rear cv joint, all the others offer a standard u-joint. You can still save money going with Shaftmasters, but if you factor in getting an upper control arm, then you could get the DSS shaft and not worry about that purchase. I can get away with any of them since my pinion angle is still in spec. I only have Eibach Pro Kit springs.

And yes the couplers on the DSS do help to shorten the shaft and allow for higher speeds. That's probably why it weighs a little more too, but still a good 9lbs less than stock.

WORKISSLOW

in all fairness when it comes to price I think I should mention that the DS from American Muscle has free shipping and assuming I or anyone else on this forum gets the same discount I got on my last purchase (ask one of the AM guys for a code), then that is about -$41.34, so that is a cost of $648.65 not $689.00

It appears that Hoasswild might have figured this in in his post on the other site that I copied, but figured it was worth mentioning, I don't know what the shipping costs are for the other shafts, but it can't be cheap to shift a driveshaft?

I guess if you want to compare apples to apples the next step is finding out what the shipping costs are on the other products. Of course the the other issue is that the shipping costs are going to be different for different people in different places.

I guess the an additional question is quantifying the CV joint in the DSS model, how much trouble and cost will it be to adjust the pinion angle should you need to vs the additional cost of the DSS DS?

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 (-9.5lbs, +2350 RPM)
(ok I see the value here)

Funster_2011V6

Interesting topic. Did some calculations:

I used 5th gear for my example since its a (1:1) ratio, so then engine rpm = driveshaft rpm.

At engine redline (6850) in 5th gear with 3.31 gears and p235/50r18 tires (about 27.3" diameter) equates to 168mph.

I dont know weather or not a stock motor can pull these cars that fast, or that you'd have enough road, or that your tires would hold together.

BUT this tells me that a driveshaft with a critical speed of 6850 rpm is probably plenty for an otherwise stock car. No reason then, in my opinion, to buy a 4" diameter shaft and risk clearance issues if a 3.5" will do the job. My money goes on the shaftmasters offering.

Figure out your own car using this link :

http://www.dennysdriveshaft.com/pote...alculator.html

Chromeshadow

A new drive shaft is on my list as well. Hog and Work, thanks for the summary and the discussion, you guys have answered all of my questions!
I'm not sure why these are limited to 115 MPH and have a drive shaft that fails above that, when these can probably hit 150 without too much work. I drive mine all year long, so I cannot lower it unless I get airbags, so I'm looking at the shaftmaster.

WORKISSLOW

I see the logic in not bothering with the 4" DSs, so the list gets shorter and the price range is only about $150+/-, this is one of those things you wanna do right, so that is not to bad.

$720+S/H, 20lbs,7023rpm -DSS from CFM, 3.5",
$694 -17lbs, 6700rpm Dynotech 3.5",
$597 -19.5lbs, 6850rpm Shaftmasters 3.5"

So with three strong contenders on the list I think it comes down to figuring out if the DSS shaft with CV joint is worth the extra weight and the $$. I know for me I will probably never see my car a top speed and I don't know that it matters with DS that can turn this fast. If I hit 6700 RPM in 5th gear I would be going 201.6 mph,, so maybe down hill with a strong tail wind,,, but prolly not, even is I go to a shorter tire and new gears I doubt it, so the 17lbs dynotech is still very appealing. I know it is only 2.5-3 lbs lighter then the other 2 shafts on the list, but the way I see it, 3lbs here and there adds up.

So to have a CV joint or not?
From what I understand if you need to correct the pinion angle on the rear end you need an adjustable rear trailing arm, Which I think HOG was pointing out costs more then the price difference between the DDS DS with the CV joint and the other brands.. hmm ,,, So now we have to look into the crystal ball and see what scenarios might require the CV joint or adjustable upper control arm in the future?

I guess the other concern is the compnents in the DS, when you read the other threads you see comments about "adapters" that are used on the after market Drive shafts that cause vibration. So how do you sort that out, do you just go by the customer reviews? or certain brands are just know to do it right?

BTW, thanks for all the input from everyone.

As a side note, the adjustable upper control arms seem to be priced around $250, but I wasn't able to determine if the GT and the V6 use the same part? and you see them listed primarily for the GT. I see Shelby has one for $130