Carbon Fiber Driveshaft coming soon!

[zombiekiller]

Excellent comment. I am saving up for a set of track wheels and tires. The wheels is where you will feel the biggest difference due to the reduction in unsprung weight. Unfortunately, finding a set of light weight track/race wheels with the 350R dimensions is almost impossible.

forgeline!

Give them a holler. the wheels will make you happy, the price may not though.

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[Driveshaft Shop]

Hello Everyone, im Frank from Driveshaft shop and im here to help understand the info that has been given, sort out what what has been said and try to help what were doing will make sense to you. I was going to just start picking posts and answer questions but 1st ill post some info we always use when questions about Carbon come up. Read below and then ask me questions, ill do my best to keep up with you.
some of the info is generic so please ask if you are not sure.

Critical Speed.
There is a certain speed each and every shaft can spin safely,the tube will eventually go into a jump rope shape and break.
we need to make sure the shaft does not reach this and stays with in whats called the safe factor of this number. what i would
need is the following
1. Top MPH of the Vehicle
2. What is the Rear Diff Ratio
3. How tall is the rear tire (not its size but how tall like 27" ?)
with this information i can calculate the correct size for this application.

Harmonics
You see the rubber bushings in a car are there to remove harmonics from the cabin, harmonics are caused by the engine firing in pulses and the firing turns the crank, but not smooth like an electric motor, it speeds up every time the spark plug ignites the fuel, this is why the engine has a harmonic damper on the front to kind of smooth this action. when you change from rubber to solid or poly mounts it will sometimes re-introduce the harmonic back in the cabin (the reason rubber is used is to make it quiet)i have been asking under scrutiny why a stock 2 piece will not do this as much as a single one and its simple. the center of the driveshaft that is supported but a by a real soft rubber hanger. its hiding this,shaft is still moving around but the rubber is soaking it up. put a solid rubber there and it would change this tremendously. its kind of masking but its still there, when you put a single shaft in there is nothing hiding the center moving around so its transferred to the ends (think of a tuning fork, hit one side and the other moves not because its out of balance but because a sound it being transmitted thru it) Hope this make sense

material and Harmonics
you are standing in front of (3) 48" long pieces of tube, all about 3.5" in diameter but one is steel, the next aluminum and the 3rd Carbon Fiber. You then pick up the steel on with your thumb and your index finger and strike the middle of the tube with a long screwdriver. The steel shaft will ring like a bell and continue until the harmonic being produced by the strike exhausts itself. You do the same with the Aluminum next, you will get a bit of ring but not as loud and will not hold for near as long. You then pick up the Carbon Fiber and strike it the same way as the others, it make a clack and stops almost immediately.

This affect is the same thing that happens when the motor if firing and pulsing the power from the explosions in each cylinder(this is what a Harminc damper trys to stop on the engine) This pulse along with the frequency coming out of the trans and the diff all collide in the hollow tube of a driveshaft, the material will either broadcast it or will not allot it to go any further. Think of a Tuning fork, hit one side and the other moves. Its not out of balance its being excited by the frequency being sent to it, the driveshaft does the same thing so balance is not to blame its harmonic, on the 2005+ mustang Ford had such a problem with this on the car they did a 2 piece driveshaft with (1) u-joint, a hanger bearing (2) CV's and a 9lb damper in the back shaft (talk about a
flywheel affect) this shaft weighs 46lbs and was used to stop the issue. other things like solid or poly mounts will make this even worse but thats a story for another day......


Carbon
Carbon is lighter but its not the real prominent thing it does. The carbon shaft would make the car more consistent with the 60ft times. and help lower them you see when the shaft starts to twist the each of the materials will wrap up. Steel/chromoly 5-7 degrees aluminum is about 20 degrees and Carbon 30 degrees, what the difference is the Carbon releases slowly and does not shock the tires, most see between .1 to .3 gain in the 60's.

Guibo/hanger issue with stock shaft
The stock shaft will have to start by putting the torque into the front Guibo and it
gives, then it moves down to the hanger that is very soft and will move up about .750" then back to the
rear guibo and compress that one, so by the time the torque goes thru the shaft its dampened allot to
the point of feeling soft or disconnected, by putting the single shaft in the car will be allot more responsive to
pedal/torque input. It will have a more athletic feel and be quicker due to the lack of the soft parts being
removed.

Dear DSS, I have some questions regarding your drive shafts.

1/ How do carbon fiber drive shafts cope with radiant heat from the exhaust system? Should a product such as this be used on the relevant section of the exhaust pipe?
the bonding of carbon will start to have issues at 300 degrees, if the exhaust is close wrapping it or shielding it will bring the number below this.



2/ How do cf shafts cope with stone chips and abrasions caused by gravel and other road debris?
our Carbon shafts actually have a outer layer of Fiberglass, this is done to ensure the surface of the carbon to be protected, its about .125 thick and
is very good at saving the shaft, if something were do dig thru it the shaft would be bad but also keep in mind if something were to do this to aluminum it would also ruin the shaft.


3/ Do cf drive shafts have a shelf life? That is, should they be replaced after a certain amount of time?
Heat is the only thing that will shorten the life, all shafts will have a fatigue cycle, Carbon is as high if not higher then Steel/Aluminum


4/ What is the advantage of a carbon fiber shaft over an aluminum shaft?
The biggest this is its ability to absorb harmonics and its torsion properties. you see all shafts will twist before a vehicle moves, steel about 7 degrees aluminum about 20 and carbon about 30. the difference is the others will come back like a spring and put reverse torque or time compounded stress on the shaft and the rest of the drivetrain. Carbon releases its energy over time and will help with either 60ft times in a drag car, coming out of a corner with a Drift,road race/rally or time attack car and it will also protect the drive train from harmful shock. The harmonic advantage is the fact that it will not amplify drivetrain drone or motor/trans harmonics like the other materials.

 

[Voodooo]

I had the opportunity to talk to Jamal Hameedi about why the factory didn't pick up where the last GT500 left off and include a CF shaft on the GT350 as well. He was clear that fiber shafts weren't stiff enough, hence the two piece. So I'd love to hear DSS' point of view and what they are doing differently with this specific application to make it work - properly.

Why do people assume engineers and designers know what's best. When Jay Leno had Jamal on his show about the GT350, Jay asked Jamal how many cubic inches the 5.2L was and he didn't even know! A one piece driveshaft isn't going to cause any problems at all. Just like how everyone thought not having flex pipe and dampers on the Aftermarket long tube headers and X pipes would vibrate. I can tell you first hand their is absolutely no more vibrations then stock. A lighter driveshaft will only increase life in the drivetrain. Anytime weight is reduced it helps remove wear and tear.

 

[Driveshaft Shop]

I will say the S550 cars did seem to have some sort of harmonic in them, when we 1st started making shafts for them we saw some Harmonic inconsistent issues and changed the aluminum from 3.5" to 4" and the carbon from 3.25" to 3.8" and this has cured the issue. We do balance the shafts at real/high speed in a custom balancer we had made to ensure the shaft is smooth.

We really need to update this video but it shows the work.
[ame]

 

[krt22]

Why do people assume engineers and designers know what's best.

I really don't know why either, but hey it pays the bills. :cheers:

 

[Voodooo]

Lol

 

[chopsui]

Why do people assume engineers and designers know what's best. When Jay Leno had Jamal on his show about the GT350, Jay asked Jamal how many cubic inches the 5.2L was and he didn't even know! A one piece driveshaft isn't going to cause any problems at all. Just like how everyone thought not having flex pipe and dampers on the Aftermarket long tube headers and X pipes would vibrate. I can tell you first hand their is absolutely no more vibrations then stock. A lighter driveshaft will only increase life in the drivetrain. Anytime weight is reduced it helps remove wear and tear.

You may not feel any additional vibration from the driver's seat, but that doesn't mean it's not there. Maybe you'll be fine, or maybe after a while, nuts/bolts will start working loose or cracks might start appearing in welds, etc.

I can believe that the real reason they didn't go with a CF driveshaft boils down to cost but believing the dampers on the exhaust are there for no reason is asking too much. They cost money and they add weight, both things that the Ford guys would be loath to add if they didn't think it was necessary.

 

[SpursFan]

You may not feel any additional vibration from the driver's seat, but that doesn't mean it's not there. Maybe you'll be fine, or maybe after a while, nuts/bolts will start working loose or cracks might start appearing in welds, etc.

I can believe that the real reason they didn't go with a CF driveshaft boils down to cost but believing the dampers on the exhaust are there for no reason is asking too much. They cost money and they add weight, both things that the Ford guys would be loath to add if they didn't think it was necessary.

Exactly. Just because you don't feel it doesn't mean serious harmonic issues are not at work.

 

[stanglife]

Why do people assume engineers and designers know what's best. When Jay Leno had Jamal on his show about the GT350, Jay asked Jamal how many cubic inches the 5.2L was and he didn't even know! A one piece driveshaft isn't going to cause any problems at all. Just like how everyone thought not having flex pipe and dampers on the Aftermarket long tube headers and X pipes would vibrate. I can tell you first hand their is absolutely no more vibrations then stock. A lighter driveshaft will only increase life in the drivetrain. Anytime weight is reduced it helps remove wear and tear.

Because they usually do. They need to design and test these things for higher mileage. There's a good chance that some of the issues that might pop up would not show up until later in life - which might not make a difference to some of us because we might not hit those miles...It doesn't make it right to completely discount real engineering.

RE: Jamal vs Leno on engine size. I'm confident that he was being polite by not correcting Jay. He knows what size the engine is and overly correcting him at that point would be a complete douche bag move, ya know?

 

[Driveshaft Shop]

I will say this, A driveshaft as a spinning mass is prone to outside forces. In the Mustang the force would be harmonics from the motor/trans ect. If the force was strong enough to break a weld or have long term damage it would be felt, no question about it. So what im saying is this, the shaft will be balanced to about 1.0 grams per plane @ about 8000Rpm (way above a standard balance), this would be good for over 12000rpm and not hurt anything in the drive train, if the harmonic did affect the shaft it WOULD be felt as a vibration as it would have to excite the shaft/tube (think of the tuning fork and how it works). The S197 and the S550 both have harmonic dampers in the back of the 2 piece shaft, This was done to try to eliminate the issue. It really should come as no surprise to anyone that allot of manufacturers have made aftermarket shafts for the S197 (eliminating the damper) with out issue. It should really come as no surprise that it can be done in this car also, changing the modulus of the tube, the diameter and even design will effect the resonant signature of the shaft and altering the transfer from part to part.The spline we use is 300m, the modulus of elasticity is way above what GKN's standard stub used on the GT500 would be, is that what was causing a problem ? or maybe Think of how a poly trans mount or motor mount, this would be more violent to the Drive train as it allows the transfer from part to part easily with out being stabilized (do not use poly mount on this or any car people unless you want the harmonic in the cabin)

 

[Epiphany]

Why do people assume engineers and designers know what's best. When Jay Leno had Jamal on his show about the GT350, Jay asked Jamal how many cubic inches the 5.2L was and he didn't even know! A one piece driveshaft isn't going to cause any problems at all. Just like how everyone thought not having flex pipe and dampers on the Aftermarket long tube headers and X pipes would vibrate. I can tell you first hand their is absolutely no more vibrations then stock. A lighter driveshaft will only increase life in the drivetrain. Anytime weight is reduced it helps remove wear and tear.

Why do people assume that people assume that only engineers best? Maybe they are just sharing what was said to them.

It isn't about "a one piece driveshaft isn't going to cause any problems at all." It's about designing to certain standards or meeting/not exceeding specific thresholds.

"A lighter driveshaft will only increase life in the drivetrain. Anytime weight is reduced it helps remove wear and tear." All encompassing statements like this are rarely true. Ford added weight in a number of areas to increase durability whether you believe it or not.

You may not feel any additional vibration from the driver's seat, but that doesn't mean it's not there. Maybe you'll be fine, or maybe after a while, nuts/bolts will start working loose or cracks might start appearing in welds, etc.

Exactly.

Because they usually do. They need to design and test these things for higher mileage. There's a good chance that some of the issues that might pop up would not show up until later in life - which might not make a difference to some of us because we might not hit those miles...It doesn't make it right to completely discount real engineering.

RE: Jamal vs Leno on engine size. I'm confident that he was being polite by not correcting Jay. He knows what size the engine is and overly correcting him at that point would be a complete douche bag move, ya know?

Agree with everything you said.

It really should come as no surprise to anyone that allot of manufacturers have made aftermarket shafts for the S197 (eliminating the damper) with out issue.

As you know Frank even Ford eliminated the heavy damper ring from '11-'12 GT500 TR6060's that were pressed onto the fixed flanges of the '07-'10 GT500 TR6060. I removed mine when adding the '13/'14 factory CF shaft and it was very smooth. That combination worked perfect.

Frank, if I'm correct, you bond your 300M ends to each end of the fiber tube. Out of curiosity, what is the typical cure time for the epoxy?

 

[Spacebird]

Why do people assume engineers and designers know what's best.

Because 1) education 2) experience 3) science. The practical matters of budget, warranty, liability, etc. can and do result in deviations from optimal design, but engineers really do know what's best.

 

[65Terdlingua]

I would be impressed with Driveshaft Shops R&D if the actually put accelerometers on drivetrain components of the GT350/S550 with a stock DS and CF and compared under identical conditions to see how the drivetrain harmonics actually change in the car. Your removing parts and weight, and also changing DS geometry from stock which all will impact vibration and harmonics.

 

[Trackaholic]

Critical Speed.
There is a certain speed each and every shaft can spin safely,the tube will eventually go into a jump rope shape and break.
we need to make sure the shaft does not reach this and stays with in whats called the safe factor of this number. what i would
need is the following
1. Top MPH of the Vehicle
2. What is the Rear Diff Ratio
3. How tall is the rear tire (not its size but how tall like 27" ?)
with this information i can calculate the correct size for this application.

Not sure if you are actually asking, or if this was rhetorical, but my understanding is as follows:

Top speed is reached at redline in 5th, the 1:1 ratio.

Therefore, max rotational speed of the driveshaft will be equal to engine RPM in that gear, or 8250 RPM.

-T

 

[TexasTodd]

I'll make this much less simple. Put CF driveshaft on 1998 Trans Am WS6 and experience severely reduced drivetrain vibration at hyper speeds. Putting CF driveshaft in my Z06 in the next few weeks and, if this product becomes available, I will put one in my late 2016/early 2017 GT350 as well. Well beyond the capability of the stock motor and beyond the capability of the supercharged VooDoo motor as well. My 98WS6 shaft was 1200HP capable.

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