QA1 GT350 CF Driveshaft

[Donkey]

I've honestly never associated QA1 with quality due to previous experiences. However, this piece may change my mind.

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[Zombo]

For the record, I didn't disparage the CF drive shaft discussed. I just pointed out some of the mechanical characteristics which may affect performance in both designs and how material and physical properties impact these characteristics. I stated that without having this information, it is not possible to evaluate either design. Of course, empirical data would also help.

After thinking about it further, I now begin to wonder what impact changing to the CF drive shaft will have on the vibration abatement system Ford developed for the drive train. Will the heavier CF drive shaft, with its center of gravity further from the trans mount by roughly double impact the vibration isolation system? You read correctly, I said heavier, because, for the OEM drive shaft, only the weight of the first segment of the drive shaft adjacent to the trans impacts the vibration system; with the CF design, the entire drive shaft and its weight does. Will the change in configuration with the CF shaft affect the long term durability of the vibration isolators? I don't know, but I think these are certainly valid questions to ask, prior to committing to the change.

I recall George from MGW mentioning in one of the videos that Ford was adamant about not changing the vibration isolation components in this system; I would think changing the weight and CG of a major component in the system would also need to be evaluated. No?

I hope the CF shaft performs better than it is anticipated to. Either way, I most likely won't be a buyer - personally, I'm not looking to extract that last bit out of the car and don't really care about bad ass modifications. I only posted to this thread to help those considering this modification understand some of the technical points.

 

[stanglife]

CF shafts, for me....have always been an unknown. For over $1k - I'd expect some measurable aspect, and it's never been seen afaik. If it was tangible, it would be a metric, IMO. For that reason, I always stick with OEM for this specific mod.

Generally, if a manufacturer doesn't include or can't prove a performance metric from their product, I move on.

 

[EF300]

CF shafts, for me....have always been an unknown. For over $1k - I'd expect some measurable aspect, and it's never been seen afaik. If it was tangible, it would be a metric, IMO. For that reason, I always stick with OEM for this specific mod.

Generally, if a manufacturer doesn't include or can't prove a performance metric from their product, I move on.

Agree, the drive shaft thing is so subjective. Of course someone who spends 1+K on a CF shaft will say they notice a difference. Personally, I can think of a bunch of other ways to spend 1K on the GT 350. To each his own as they say.

 

[Tomster]

For the record, I didn't disparage the CF drive shaft discussed. I just pointed out some of the mechanical characteristics which may affect performance in both designs and how material and physical properties impact these characteristics. I stated that without having this information, it is not possible to evaluate either design. Of course, empirical data would also help.

After thinking about it further, I now begin to wonder what impact changing to the CF drive shaft will have on the vibration abatement system Ford developed for the drive train. Will the heavier CF drive shaft, with its center of gravity further from the trans mount by roughly double impact the vibration isolation system? You read correctly, I said heavier, because, for the OEM drive shaft, only the weight of the first segment of the drive shaft adjacent to the trans impacts the vibration system; with the CF design, the entire drive shaft and its weight does. Will the change in configuration with the CF shaft affect the long term durability of the vibration isolators? I don't know, but I think these are certainly valid questions to ask, prior to committing to the change.

I recall George from MGW mentioning in one of the videos that Ford was adamant about not changing the vibration isolation components in this system; I would think changing the weight and CG of a major component in the system would also need to be evaluated. No?

I hope the CF shaft performs better than it is anticipated to. Either way, I most likely won't be a buyer - personally, I'm not looking to extract that last bit out of the car and don't really care about bad ass modifications. I only posted to this thread to help those considering this modification understand some of the technical points.

Exactly.

 

[Greg35]

Agree, the drive shaft thing is so subjective. Of course someone who spends 1+K on a CF shaft will say they notice a difference. Personally, I can think of a bunch of other ways to spend 1K on the GT 350. To each his own as they say.

IF I may......."so subjective" : Yes, true! Much like when asked statements such as "is it more comfortable, "*is the ride more controlled, buttoned-down", "is there more/less NVH",
"Is it more responsive", and a plethora of other questions we as car guys are often asked.
It is our feeling/driving impressions of ANY noticeable differences.
"...will say they notice a difference." : Honestly sir, as stated in my previous post I really didn't know exactly what to expect in terms of possible driveline enhancement. I immediately DID notice differences and tried to relay those in straightforward fashion .
"..bunch of other ways to spend 1K on the Gat350." Absolutely! And many of us have done so....some of us many times over. Personally, to look at this as a top 3 weight- saving mod
would be off base. To approach it as a 1st performance gain purchase, likewise.
However , as you certainly know, when making changes to your ride it is always best to have a plan and follow it in a very careful fashion.its all about maintaining balance. Some here are at the pt. to consider the tangible--subjective as they may be-- benefits of a C.F. drivshaft.

 

[mustang_guy]

C.f. shafts are far superior to absorbing shock loads from the axles or from transferring to the axles or diff vs a steel or an aluminum shaft.

The fibers actually twist a little to asborb it, similar to bias ply slicks

 

[Epiphany]

7/

After thinking about it further, I now begin to wonder what impact changing to the CF drive shaft will have on the vibration abatement system Ford developed for the drive train. Will the heavier CF drive shaft, with its center of gravity further from the trans mount by roughly double impact the vibration isolation system? You read correctly, I said heavier, because, for the OEM drive shaft, only the weight of the first segment of the drive shaft adjacent to the trans impacts the vibration system; with the CF design, the entire drive shaft and its weight does. Will the change in configuration with the CF shaft affect the long term durability of the vibration isolators? I don't know, but I think these are certainly valid questions to ask, prior to committing to the change.

I recall George from MGW mentioning in one of the videos that Ford was adamant about not changing the vibration isolation components in this system; I would think changing the weight and CG of a major component in the system would also need to be evaluated. No?

Two damping systems you are discussing. First one is two weights, totalling 12lbs, bolted to the underside of the transmission. Nothing short of a major accident or catastrophic transmission failure will damage them. The second, the ones George discussed with some at Ford, were the dampers attached to the exhaust system.

 

[Zombo]

Two damping systems you are discussing. First one is two weights, totalling 12lbs, bolted to the underside of the transmission. Nothing short of a major accident or catastrophic transmission failure will damage them. The second, the ones George discussed with some at Ford, were the dampers attached to the exhaust system.

I'm afraid this is not correct. What I was referring to is at 3:15 into this video and is not related to the exhaust:

[ame]

I understand what George was saying on this point and it makes sense with any vibration isolation system; on the OEM system, the first part of the drive shaft is an integral component of this isolation system. It's weight and CG were included in any analysis and testing. Changing these properties possibly impacts functionality. I don't know this for sure, but I'm informed enough on the subject to know this is a valid question/concern.

Again, I hope there are no such issues and best of luck with those who choose to go this route!

 

[Epiphany]

I'm afraid this is not correct. What I was referring to is at 3:15 into this video and is not related to the exhaust.

I'm afraid it is correct.

Not only did I build the stand for that transmission but I incorporated the dampers into it as well so as to emulate the stock drivetrain configuration. And I was standing there as that video was filmed.

George didn't mention there about the exhaust but that's what he was told. What he was intimating in this one was to not remove or modify the 12lb worth of mass dampers bolted to the transmission. Nothing was said to him about the driveshaft or how it relates to the drivetrain system as a whole.

 

[zzrat]

Guys, I have really enjoyed reading &most of all learning on a list of topics that are mentioned here on this site. The day will come when one of these machines will sit in our garage.

Would like to hear your thoughts on a two piece CF driveshaft. Thanks,Rex

 

[Epiphany]

Zombo, there's quite a bit I'd love to share but can't. Something I can.

From the day of the video. The first shifter produced (which had gone through numerous iterations to that point and was changed after as well) went into my car on that day. A 14 hour drive home and a great way to add to the test data already captured.

George considered a few different shifter designs. Of importance, the reverse rotation of the transmission shifter linkage output shaft which constrained choice somewhat with respect to architecture. One thing was clear - any design had to work with the dampers bolted to the transmission/crossmember and not interfere with their function. So the stand for the transmission had to be able to emulate stock driveline angles, etc. I made the elevation adjustable to dial everything in.

I modeled the transmission support system in Solidworks to compare it to data I had for the Coyote/MT-82 to weed out the differences in design.

I unearthed everything I could as Ford never shared anything about the transmission related mass dampers. An effective method but somewhat lazy from an engineering perspective. Works well for production. These are what George was getting at in the clip linked above - don't remove them, as ugly/heavy as they may be.

The exhaust dampers that I mentioned earlier. These were suggested to never be removed either.

Here's one to chew on Zombo. Ford tested CF shafts but ultimately chose to not use one for production, just like the CC brakes. I have a good friend that was present for a TR3160 teardown in Michigan at Tremec. He shared/posted and did a writeup on everything. The post was pulled from the SVT Performance (dot com) due to a request from Ford. You can still find it if you look. Something I noticed right away, I saw a photo that clearly showed a '13/'14 GT500 fixed flange on the TR3160 output shaft. It is a cup style, meaning they tested with a CV joint up front. This coincided with a development photo at the axle end which showed the aft half of a CF shaft. All of which confirmed to me that Ford was testing a CF shaft. Yet in those same photos from that day with Tremec, I saw a different TR3160 flange, the one that ended up going into production. The flange on the transmission is the GT500 style, the one you see being held is production.

What I learned was that Ford wanted to shorten the flange as much as possible. They were seeing a "tail wagging the dog" effect as was said to me. They reduced the moment, shortening the overall length of the transmission (and lengthening the OAL length of the driveshaft).

More importantly - there isn't anything "special" about the GT350 factory two-piece steel driveshaft. It is near identical to the S550 shafts Ford has used on the Ecoboost 4cyl, the V6, and the Coyote V8 cars. All of which are near identical to every S197 shaft(s), save for the CF unit used behind the '13/'14 GT500. In essence, Ford went with the lower cost production oriented two-piece. Except for one thing. S550 cars utilize a Guibo joint between the transmission flange and the u-joint at the front of the driveshaft. It is there to improve NVH, as much as it does not enhance performance "feel." After seeing that Ford was now using these I was a bit shocked that the vibration happy Voodoo S550 cars, the GT350, did not. The driveshaft is bolted directly to the transmission just as God intended.

 

[Zombo]

Guys, I have really enjoyed reading &most of all learning on a list of topics that are mentioned here on this site. The day will come when one of these machines will sit in our garage.

Would like to hear your thoughts on a two piece CF driveshaft. Thanks,Rex

A 2 piece CF shaft may have some advantage, depending upon why the current single piece is designed the way it is. For example, is the current CF shaft sized (ID, OD, material selection, end fitting interface, etc.) to meet a minimum torque transmission requirement, or critical speed requirement? It's possible that it just so happens to do both with the same design, but more probably, it's sized to meet one requirement and exceeds the other.

If it exceeds the torque transmission requirement in order to meet the critical speed requirement, a 2 piece design could most likely be reduced in diameter (weight & I), because the 2 piece design is inherently stiffer, due to the center support. Critical speed would no longer be the dominant factor, torque transmission would.

If the current shaft is designed to meet a minimum torque transmission requirement and meets/exceeds the critical speed requirement, there probably isn't any advantage to going to a 2 piece design as the shaft(s) is already optimized for torque and wouldn't be reduced in size (weight & I).

 

[Zombo]

Zombo, there's quite a bit I'd love to share but can't. Something I can.

From the day of the video. The first shifter produced (which had gone through numerous iterations to that point and was changed after as well) went into my car on that day. A 14 hour drive home and a great way to add to the test data already captured.

George considered a few different shifter designs. Of importance, the reverse rotation of the transmission shifter linkage output shaft which constrained choice somewhat with respect to architecture. One thing was clear - any design had to work with the dampers bolted to the transmission/crossmember and not interfere with their function. So the stand for the transmission had to be able to emulate stock driveline angles, etc. I made the elevation adjustable to dial everything in.

I modeled the transmission support system in Solidworks to compare it to data I had for the Coyote/MT-82 to weed out the differences in design.

I unearthed everything I could as Ford never shared anything about the transmission related mass dampers. An effective method but somewhat lazy from an engineering perspective. Works well for production. These are what George was getting at in the clip linked above - don't remove them, as ugly/heavy as they may be.

The exhaust dampers that I mentioned earlier. These were suggested to never be removed either.

Here's one to chew on Zombo. Ford tested CF shafts but ultimately chose to not use one for production, just like the CC brakes. I have a good friend that was present for a TR3160 teardown in Michigan at Tremec. He shared/posted and did a writeup on everything. The post was pulled from the SVT Performance (dot com) due to a request from Ford. You can still find it if you look. Something I noticed right away, I saw a photo that clearly showed a '13/'14 GT500 fixed flange on the TR3160 output shaft. It is a cup style, meaning they tested with a CV joint up front. This coincided with a development photo at the axle end which showed the aft half of a CF shaft. All of which confirmed to me that Ford was testing a CF shaft. Yet in those same photos from that day with Tremec, I saw a different TR3160 flange, the one that ended up going into production. The flange on the transmission is the GT500 style, the one you see being held is production.

What I learned was that Ford wanted to shorten the flange as much as possible. They were seeing a "tail wagging the dog" effect as was said to me. They reduced the moment, shortening the overall length of the transmission (and lengthening the OAL length of the driveshaft).

More importantly - there isn't anything "special" about the GT350 factory two-piece steel driveshaft. It is near identical to the S550 shafts Ford has used on the Ecoboost 4cyl, the V6, and the Coyote V8 cars. All of which are near identical to every S197 shaft(s), save for the CF unit used behind the '13/'14 GT500. In essence, Ford went with the lower cost production oriented two-piece. Except for one thing. S550 cars utilize a Guibo joint between the transmission flange and the u-joint at the front of the driveshaft. It is there to improve NVH, as much as it does not enhance performance "feel." After seeing that Ford was now using these I was a bit shocked that the vibration happy Voodoo S550 cars, the GT350, did not. The driveshaft is bolted directly to the transmission just as God intended.

Thanks for the information and for putting in the time getting it together. It is very informative.

The point I am trying to make is that this vibration isolator system between the trans and chassis is specifically designed to do a job with specific components in place, one of which is the OEM drive shaft. I suspect Ford worked with an isolator company (maybe Lord or one of the other outfits) to develop this solution. Changing out a somewhat substantial component in the system, in terms of weight, CG, etc. may impact how the system operates. Although I'm not a powertrain engineer with Ford, but have worked these types of problems often in my career. They are quite complex and, based on my experience, worthy of questioning. That's all I am doing here, questioning whether this aspect of the CF drive shaft was considered, analyzed or tested.

On a side note, I find it interesting that the Ford vibration isolator system, like the drive shaft itself is marked "scrap if dropped". It must be pretty critical.

Best of luck with your CF drive shaft - I suspect you will provide a comprehensive review, as always.

 

[H6G]

[MENTION=19066]Epiphany[/MENTION].... any updates on the driveshaft? I was just curious to see if you had a chance to test it. Thank you!

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