Velox Motorsports Carbon Driveshaft Thread
 

Happy New Year! We’ve been holding off on starting this thread for far too long and I’m finally forcing myself to put the time towards starting this thread that it deserves.

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Around April/May last year we started testing a carbon driveshaft we heard about from a friend. It touted some pretty cool features that we thought would warrant trying it out and potentially offering for the community. After 50 or so dyno pulls (at 350-400whp), 6k miles, and a dozen or so passes down the ½ mile event, we feel it’s time to start a thread and show what it has to offer.

First, we’ll start with the testing the manufacturer does:
-It is rated for 5000 n-m of torque (a little over 3600 ft-lbs)
-It has been fatigue tested at 2000n-m (fully reversed, so +2000, -2000) per cycle, for 100,000 cycles
-It is balance tested between 8,000 to 10,000 RPM
-Similar BMW models have passed over 10,000 RPM @ over 200 MPH without vibration failures

Carbon Tube Construction:
-Strictly kept 76% carbon to 24% epoxy ratio, ensuring high strength and low weight
-Dual filament windings based on Formula One class manufacturing technology
-Raw carbon fiber material is from Toray in Japan, who is the same carbon supplier as Nissan’s GT-R carbon driveshaft unit
-Military Grade T700 24k Carbon Fiber, which is used on missile bodies and high pressure fuel tanks
-The tubes are cured in an autoclave mold to closely control temperature and pressure bonding, improving performance without increasing weight.
-Weave pattern is designed for high torque loads

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Other Neat Features:
-Weight savings of approximately 55%
-With a failure rating of 5000n-m, this will pass SFI certification if that becomes what multiple people are interested in. We will go through these motions if enough people ask, but it isn’t cheap to do so unless there is a demand, we aren’t going to do it.
-The ends are 7075-T6 cold forged, then heat treated, and have an anti-oxidation treatment
-High quality joints are used featuring low stiction


Carbon to Aluminum? How does that work and is that even safe?
-The manufacturer will not divulge in entirety how they bond aluminum to carbon, as each company has their own “proprietary” means of doing so. Without getting into too much technical jargon, it’s basically a very strong glue with specific surface finishes on each to ensure they withstand what is deemed a reasonable service life. 100,000 cyclic loads to nearly 1500 ft-lbs seems reasonable to us to consider this component to have a life cycle to that of the entire car.

Short Video we created with some of the manufacturing videos that we asked for:
[ame="https://www.youtube.com/watch?v=ND-y2YBTNeI&t=1s"]Velox Motorsports Carbon driveshaft - YouTube[/ame]

Below are some pictures of the products, let us know if you have any questions, comments, concerns and we’ll do our best to address each .

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@Drakiv has tested the driveshaft, as have a few others. Hoping they will chime in as well :).

Thanks for your time,
Eric

Very nice piece, I like how you included the small shield on the transmission side. Hope to purchase one of these in the future.

One question I always had about these pieces - does this compromise safety at head-on crash? Our car has 2-piece shaft with a joint, and IIRC this joint is designed as a point of failure during crash, so the engine can slide "under the cabin".
My concerns are about road-use since this will be super strong piece.
Thanks.

Any confirmed fitment with short shifter kits? DSS shafts have issues clearing them, looks like this one has a little more room.

I can confirm that after running a DSS Carbon fiber shaft first and now having the opportunity to test the Velox Carbon Fiber Shaft out, that the DSS did have issues (even though it was minimal) with clearance for a kartboy short shifter and the Velox doesn't have the same issues. Plus the rating for the Velox is 4 times the rating for the DSS which is only rated for 900+ ft/lbs of torque for informational purposes.

Thats a good question since the engine dropping down is one of the major safety points. Never would have thought about if that is a a crumple zone sort of speak

How would the joint (which is supported and bolted to the body) be a point of failure that would allow the engine to drop?

One other thing to keep in mind is that a carbon driveshaft probably isn't as strong to longitudinal force as you might think. They're designed to take rotational force, not force along the length.

I don't believe this to be relevant. How many people are producing 900 lbs/ft.

Ok, here is my not quite sober reply. I have to preface this by saying this is an un-informed opinion.
My impression of cf is that it is incredibly strong for the loads it is designed for and quite fragile otherwise. When cf driveshafts gets over torqued they tend to disintegrate (which is a good thing). As for end on compression , well, given the sample size of reported car accidents where a carbon fiber drive shaft has impaled the moose crossing the road I am suggesting that one can't say with much certainty the ramifications of having a cf driveshaft fitted.

Actually it is relevant to the quality of the unit and the type of material used, but yes you are correct in the fact that there is no one running that much torque that I know of yet on a BRZ, FRS, or GT86. Or will even get close to needing something of that nature in regards to torque requirements. But again, it was to point out the obvious quality of materials used to make this unit compared to one of the most popular units out there. It's also a justification for the slight price increase IMO. No one said you have to buy one or the other, that's what having options is all about. And I never said that the DSS shaft was terrible, I actually had zero issues with it aside from the kartboy short shifter clearance and it was a great unit. I was just stating my experiences with both of them. Sorry if you don't like the information that I included in my statement, which I even put down was for informational purposes.

Love it Eric!

Yeah, umm, as you may have noted above I have had a little to drink with lunch. Your post had raised my pedant mode in my heightened state of awareness. :)

We are talking torque at the shaft, not torque at the engine.
My NA car can produce 770N.m at the shaft in first gear. (far from the 5000N.m maximum load of that Velox shaft).

I bet my wife can produce more talk.

Like this:
https://www.subaru.ca/Content/7907/M..._Engine%20.jpg

In longitudinal direction, in case of o tube or similar - now allow me to simplify - almost everything is relatively strong. Even a piece of paper rolled into a tube is quite strong like that.

Yep, sure (and I am quite sober now thanks!) but I am going to invoke the low risk/ high impact won't happen to me clause.

Yes, there is the chance that in an incident the cf tail shaft is going to cause increased injury because it is not going to fold like the 2 piece tail shaft.

But [1] I am going to ignore the the risk because it won't happen to me.[2]



1. Yes, I have started a sentence with a conjunction.
2. That is, knowing full well that incidents happen all the time but I/we are excellent creatures at dismissing data that doesn't suit our reality. "Pfffft... Head-on collisions? Who cares! I have a cf tail-shaft!"

Pitty that adding extra joint for CF shaft will further rise it's price and weight, making it even harder decision to buy, so probably will not be done by any aftermarket shaft maker.

Hey Eric!

What about high RPM Vibrations?

I would really like a lightweight driveshaft, but how good will it be going more than 200kp/h on the german Autobahns for al longer time?

Im mean round 125mph for more than 15min.

Nice work! I heard a rumor about this a while back...glad to see it out!

Now, for the topic of crashing, (although @VeloxEric should this be its own thread to prevent further derailment of this thread?)
what makes you guys think the stock two piece is (1) going to bend down in an accident and not up? (2) Where is the info specifying that the stock driveshaft is a two-piece because of accidents and not NVH? Or simply cost?


fwiw, I have an aluminum driveshaft, so I guess if I get in an accident and become a human kabob I'll report back.
*knocks on wood lol

@Falcon since the driveshaft is balanced properly, it won't matter if you hit 125mph for 1 minute or 100

continuecrushing: even if it will bend up or to sides, not much difference, as it's where center console is, i guess main point is that it will bend & won't act as extra support keeping engine in place. Also direction of bending might depend on things like if it already is at slight angle and what/how are it's supports made and where/how engine will start to move initially by front & body crumple zones & mounts design.

I was always under the assumption this was for NVH and costs but it could be for safety as well? I honestly have no idea.

No manufacturer of a one piece driveshaft will be testing a driveshaft in a head-on collision fashion, it's far too expensive. So I cannot comment beyond my speculation, which is below. But being a speculation, it is an opinion and from past experiences... not data.

The carbon tube would likely break in a compression loading scenario. I don't see a carbon tube surviving a crash if the engine gets pushed backward in the chassis. Carbon has great strength to weight but it does not buckle and remain intact like steel does when loaded past its yield strength.

Personally, what I see happening if this were to happen, would be the carbon tube disintegrating. Honestly, this would be much safer than a steel or aluminum shaft going downward into the concrete or upward into the cabin. Regardless, I believe the engine would be pushed backward "as designed" from the manufacturer. That's to say the manufacturers even design an engine to move rearward in a head-on collision... I have no idea what failure modes they assume, account for, and try to improve upon...

Regardless, do whatever you feel comfortable with and feel safe doing. I don't have the exact answer for you, beyond what I state above from my experiences with carbon and failure modes.

Thanks,
Eric

You should be fine :).

Thanks,
Eric

Thanks, thats a fair and honest answer.

This isn't exactly the same scenario as an automobile accident, but is interesting nonetheless.

[ame="https://www.youtube.com/watch?v=KZnUp62cN4s"]carbon tube compression test[/ame]

Your link showed up weird on my end.... but I copied the link and watched it. Edit: Forum fixed itself or you did :).

THAT IS COOL!

I wish they gave more information like wall thickness, composition, weight... not really informative but super cool to watch.

Thanks,
Eric

Touched on in the OP.

The direction of deformation is predicted and even dictated but the fixed angle the joint is set at.

Id like to put a little insight into the crash scenario and factory driveshaft design. I work in the collision industry. My dad and i run a body shop, and frankly put, if you are in a hard enough collision to worry about the driveshaft puncturing the occupant area, thats going to be the least of your worries. The other damage caused by that violent of an impact would have either long since killed you, ejected you, or if your lucky survived but in critical condition.

The front structure of our cars and other modern cars are designed to deflect an impact outward and around the occupant area. For the engine/transmission to have moved far back enough for the driveshaft to deflect from its mount point, puncture the occupant area and cause bodily damage is a substantial amount and would be measured in feet, not inches. My guess is the engine would come through the firewall before the driveshaft would reach a point to cause harm to the occupants.



Now with all that being said im genuinely excited about this. I fully intend to stay NA with my car and any and all reductions in rotating mass tickle my fancy. I love the attention to detail and clarity you provide about your products.

I enjoy learning things! Thanks for your insight.

Thanks,
Eric

Meanwhile i hope Eric doesn't take those joint existence mentions as possible extra crash safety point as any bashing of product. Even if it is so, he has no financial/technical means to do crash testing himself, and his CF shaft product is no less safer then that of other one-piece alternatives on market. If many buyers of those decide for themselves that "it's safe enough for them"/"not a serious issue to care about", things are at very least not worse in any way with his product. So if anyone wishes to start witchhunt on of single-peace shafts unsafety, it would be very wrong to single out just one most recently made alternative on market and bash it. Personally i won't buy it, but not because of some safety concerns, but rather due high price, having other mods of higher priority in purchase & install queue prior that, but see it as good product for those that want to do complete as possible car lightening or for those that want more reliable shaft that is stronger for transfering more torque (eg. for forced-induction-ed twins). After all, if people start looking for stronger gearboxes, upgraded gear sets .. shaft might be failure point too.

Some info

5.5 SAFETY
-
Safety is greatly enhanced with composite
shafts. Composites absorb energy upon impact. They can be
designed to, and will normally, break apart during an accident
rather than entering the passenger compartment catapulting the
vehicle, or whipping a broken end through a tank or valuable cargo.


2 shows a broken composite driveshaft. Note
the broken pieces rather than the bent and twisted club that is
usually left with metal. Impact with hard objects like frame
rails will cause a composite shaft to disintegrate and quickly
dissipate energy. A failure in a bond joint would simply result
in a loss of power. The shaft would probably stay in place
with the loose end spinning inside of it.


Above 128 mph the driveshaft gets into a bending
and vibration frequency that would eventually tear it apart.”
They continue that,to eliminate this problem most high
speed European cars usually have a two piece shaft connected through a center bearing.” Carbon fiber driveshafts can alleviate this problem


http://www.acpt.com/resources/documents/sae_1966.pdf

Thanks. That is fine piece of info, that fends off crash-safety concerns, at least for me. So if someone ever wants to think that uni-piece aftermarket shafts are less crash-safe, that should be attributed only to metallic (IIRC aluminium) ones at most.

You're welcome, Church. Science & Engineering...

That drawing assumes that the joint attachment to the body is the weakest link. The joint isn't floating or free to bend without the bearing block separating from the body.

As for the tube, that assumes the material is strong in that direction. Carbon driveshafts have the fibers oriented to be strong with rotational forces at the sacrifice of longitudinal forces since they'll never see any force like that in a useful scenario.

To which RPM will you test/balance your CF-Driveshaft?

If i do not have miscalculated, it will spin with nearly 9250RPM when i would be going 155mph.

Vibrations are a real concern for me.

Touched on in the OP.

For Velox, are there any distinct advantages of this carbon shaft over the existing solutions on the market, aside from your published testing info that is?

From the manufacturer, they are guaranteed to 9,000 RPM. However, they say users should have no issues up to 11,000 RPM, but they can't guarantee it.

The major takeaways:

-Doesn't interfere with short shifters
-Extremely high-end materials and manufacturing techniques
-Frequency balanced, which results in a superior balanced shaft
-I believe these may be the lightest on the market
-7075 cold forged ends vs 6061-T6 which is more standard

Thanks,
Eric

Thank you very much for the Information.:thumbsup:

So the cf ds is 55% lighter than OEM but what is the diameter compared to OEM? Seems higher wich may in fact negate the weight savings.

Sent from my SM-G920P using Tapatalk

On the whole crash safety issue, this video show's you what happens with the stock driveshaft during a head on collision, watch from 6:52.

[ame="https://www.youtube.com/watch?v=6LQKqs_IvgQ"]2014 Scion FR-S / Subaru BRZ / Toyota GT86 | Frontal Crash Test | CrashNet1 - YouTube[/ame]

Any feedback on fitment with shifters like the CAE Ultra shifter or the IRP shifter? If fitment is okay with short shifters like the Kartboy it should be okay with these shifters as well right?