QA1 GT350 CF Driveshaft

[H6G]

[MENTION=19066]Epiphany[/MENTION], thank you for providing details and outstanding pics. Great driveshaft... It's very apparent that they've selectively used quality components. A driveshaft that looks like a masterpiece.... and yet, it looks like it can take some punishment on the strip. Thank you again.... I'm definitely getting one as well.

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[Tomster]

I don't recall seeing the weighr difference between the CF vs regular steel shaft. Do you have that figure Tob?

 

[mustang_guy]

Thanks so much for that. Totally using these guys. You helped with any questions or hesitation I had. Let's be honest 1700 isn't cheap for a driveshaft.

 

[Epiphany]

@Epiphany , thank you for providing details and outstanding pics. Great driveshaft... It's very apparent that they've selectively used quality components. A driveshaft that looks like a masterpiece.... and yet, it looks like it can take some punishment on the strip. Thank you again.... I'm definitely getting one as well.

That's great to hear. I'm a capitalist at heart and want to see all the players in this game succeed. When Ford Racing put the kibosh on the TracKey I was more than a bit disappointed. Thankfully there are a few other ways to skin this cat and a CF driveshaft, while not inexpensive, will help to increase the performance of an already fantastic car.

I don't recall seeing the weighr difference between the CF vs regular steel shaft. Do you have that figure Tob?

I posted this photo of the QA1 shaft weight on the last page.

Weight savings is ~10lbs, or roughly one third the weight of the stock shaft.

Thanks so much for that. Totally using these guys. You helped with any questions or hesitation I had. Let's be honest 1700 isn't cheap for a driveshaft.

This shaft (sans the SFI sticker) can be had for $1,330 shipped from LMR.

https://lmr.com/item/QA1-JJ21213/shelby-gt350-carbon-fiber-driveshaft-qa1-15-17-jj-21213

 

[H6G]

[MENTION=19066]Epiphany[/MENTION],
I was just thinking about the overall diameter of the CF driveshaft vs. the stock unit.... Although, the CF shaft is lighter and at the same time wider..... how would that affect the moment of inertia? I realize that weight and diameter play a role when it comes to the moment of inertia. I figured that although it's slightly larger in diameter, it's compensated by the drastic reduction in overall mass.

 

[Zombo]

That is an excellent observation and question! The moment of inertia (I) is somewhat related to the weight, but more importantly, to where the weight is located with respect to the center of rotation. In the simplest terms, the moment of inertia is a function of this distance of the weight (to the center of rotation) to the 4th power. For example, if the distance is doubled, the I goes up 16X. Knowing the ID, OD and material densities of both shaft materials, it is quite simple to compare the Is. Or course, a lower I is better for acceleration performance.

Another consideration is the overall weight, which may or may not impact I (depending upon where the weight is located). What weight does impact is the driveshaft fundamental resonant frequency, which is a function of the square root of the (shaft stiffness divided by shaft mass). I believe this frequency for driveshafts is commonly referred to as the critical speed. If the drive shaft is rotated at (or near) that speed, it would start to uncontrollably vibrate and, without sufficient damping, tear itself apart. So, for a given shaft design, it's not just weight but also stiffness which are critical.

Enter the single piece shaft vs. the center supported 2 piece OEM design. The center supported 2 piece design has an inherent advantage because the shaft is divided into two parts, roughly 1/2 the length of the single shaft, which makes each segment, in theory, potentially stiffer and lighter, both of which will raise the fund. res. freq. Each shaft segment, due to the center support can now be evaluated structurally as separate components, whereas the single shaft is one, long component. Analytically, a comparison can be easily made if the dimensional and material properties of both designs are known. However, not knowing this info, it is impossible to know definitively which is a superior design in terms of critical speed, but intuitively, I suspect the OEM design is. That doesn't mean the single piece isn't sufficient, however.

The torsional stiffness is also a consideration. My understanding is that having a lower torsional stiffness will reduce shock loads on drive train components, which makes sense, intuitively. But, like the critical speed, without knowing the specific dimensional and material properties of both designs, it is impossible to know the torsional stiffness of each design.

In conclusion, there are many factors that influence the function and performance of a mechanical system and one has to be aware of the various relationships to make proper design decisions.

 

[Tomster]

I agree with all that, but the deal breaker for me is I would have figured a much more significant weight savings. All of the above would translate to a minor performance change, but the end game is getting the vehicle weight down. I guess if you have done everything else (ie- deleted the seat delete, smaller battery, remove pax seat, and starved yourself to skin and bones, etc) and you still have to get 10 more pounds from somewhere..... I guess this is it.

I applaud [MENTION=19066]Epiphany[/MENTION] 's hard work. Everything from the caliperfexion studs, work with George at MGW, and now this...... exemplary!

You had my interest, but probably not for 10 pounds. By the way, what is the weight difference between the MGW and the OEM shifter?

 

[J_Maher_AMG]

I agree with all that, but the deal breaker for me is I would have figured a much more significant weight savings. All of the above would translate to a minor performance change, but the end game is getting the vehicle weight down. I guess if you have done everything else (ie- deleted the seat delete, smaller battery, remove pax seat, and starved yourself to skin and bones, etc) and you still have to get 10 more pounds from somewhere..... I guess this is it.

I applaud [MENTION=19066]Epiphany[/MENTION] 's hard work. Everything from the caliperfexion studs, work with George at MGW, and now this...... exemplary!

You had my interest, but probably not for 10 pounds. By the way, what is the weight difference between the MGW and the OEM shifter?

Agreed on your points concerning overall weight, but I think this is one of those matters where feel becomes more important than pure weight loss. Just like reducing wheel weight, the effects are often far more significant (as we surely know by know with the R wheels) than the raw weight loss data would suggest.

If you're looking for pure weight loss, other items certainly take priority. But I'm interested in hearing Epiphany's thoughts concerning how it changes the feel of the car in terms of response, acceleration pick up, and rev-ability so to say. Would also like to thank [MENTION=19066]Epiphany[/MENTION] for these write ups, and personally hope you continue to mod the hell out of your car so that I can geek out and continue enjoying these threads of yours :cheers:

I imagine the MGW is probably 4-5lbs heavier or more, but well worth it! Hell, don't wear your steel toes or just take a poop before you go on a drive to make up the difference if you got to

 

[Tomster]

I get all that and I agree, however as zombo mentioned, without further testing and documentation of an increase in performance, then it is just a weight reduction excercise (IMHO).

Again, I feel we will get an unbiased review of the possible benefits of this modification from [MENTION=19066]Epiphany[/MENTION] when he is complete. 2pc vs 1 pc vs small weight reduction will only have significance when the rubber hits the road.

I'm looking forward to the review.

 

[JN66]

This is one of those things you could also just do because it is awesome. We don't always need to justify things with weight or performance necessarily. A carbon fiber driveshaft is just a badass piece.

If I keep this car then I'll be adding one as well.

 

[Greg35]

Lol! "A bad ass piece". True! However, this is one "bad ass piece" with benefits;
what's not to like? (Other than the not so insignificant cash outlay of course)

 

[Epiphany]

@Epiphany ,
I was just thinking about the overall diameter of the CF driveshaft vs. the stock unit.... Although, the CF shaft is lighter and at the same time wider..... how would that affect the moment of inertia? I realize that weight and diameter play a role when it comes to the moment of inertia. I figured that although it's slightly larger in diameter, it's compensated by the drastic reduction in overall mass.

Yes.

Two concerns for moment of inertia - diameter and weight. The question becomes whether or not the increase in diameter offsets any weight reduction. From what I've seen in print the tradeoff from the increased diameter is minimized due to the significant reduction in overall mass. Another consideration beyond the CF tube vs steel tube argument is that of the yokes at the end of the driveshaft. The stock GT350 uses steel yokes whereas the QA1 uses aluminum. Hence the mass moment of inertia is reduced there from a material change alone.

You had my interest, but probably not for 10 pounds. By the way, what is the weight difference between the MGW and the OEM shifter?

A 1/3 weight reduction in a major driveline component is significant. How that translates into "feel" or a measurable performance gain is something I hope to see soon enough.

I'm fairly certain that the MGW shifter is indeed heavier than the stock shifter. How much? I'm headed down to see my good friend George at MGW this Tuesday for a week or so. If you're at Mustang Week you might see me at MGW's booth. We can take a good look at the GT350 shifter there if you'd like.:cheers:

Agreed on your points concerning overall weight, but I think this is one of those matters where feel becomes more important than pure weight loss. Just like reducing wheel weight, the effects are often far more significant (as we surely know by know with the R wheels) than the raw weight loss data would suggest.

I imagine the MGW is probably 4-5lbs heavier or more, but well worth it! Hell, don't wear your steel toes or just take a poop before you go on a drive to make up the difference if you got to

Feel, however subjective, is one of those things that sometimes trumps the math or science involved. When I removed the two-piece steel shaft and replaced it with a one-piece CF shaft, the transmission of power became seamless, almost like there was no driveshaft and the engine was connected directly to the rear axle. It absolutely felt smoother and that was as important to me as any measured performance gain.

And I agree about the poop analogy. Some are full of more of it than others and a reduction in that category can be beneficial to everyone.

I'm looking forward to the review.

Me too my friend!

This is one of those things you could also just do because it is awesome. We don't always need to justify things with weight or performance necessarily. A carbon fiber driveshaft is just a badass piece.

Amen.

 

[xXANCHORMONXx]

On my 15 EB with Borg Warner turbo kit and laundry list of upgrades I got the DSS CF shaft.

I did it for two reasons
1 I was installing the MGW so it was a "while your in there" sort of thing
2 To help with NVH, CF is suppose to help a bit with absorbing some of that which it did

It's definetly not something I recommend to be on the top of your list. I think money can be better spent on suspension components, lighter wheels or even the DSC controller.

If I was to buy one I really like this QA1 unit, the weave looks great as well as fit and finish.

Thank you as always for the in depth posts.

 

[Tomster]

I'm fairly certain that the MGW shifter is indeed heavier than the stock shifter. How much? I'm headed down to see my good friend George at MGW this Tuesday for a week or so. If you're at Mustang Week you might see me at MGW's booth. We can take a good look at the GT350 shifter there if you'd like.:cheers:

Lets see what hurricane Irma does. I would like nothing more than to rent a pickup with a car transporter and come up there and enjoy, but right around that time frame will be crunch time for us SE folks living under the threat.

 

[Epiphany]

I wouldn't recommend the hassle of bringing a car there. Fly in, spend some time with any vendors you choose (there is a plethora of Mustang market heavy hitters there), see a couple sights/eat good, and get the hell out.

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