Originally Posted by wparsons (Post 2833231)

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

Originally Posted by Captain Snooze (Post 2833244)

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

Originally Posted by JDM4E (Post 2833377)

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

Originally Posted by JDM4E (Post 2832782)

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.

Originally Posted by Falcon (Post 2833475)

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.

Originally Posted by Pat (Post 2833712)

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

Originally Posted by Falcon (Post 2833475)

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.

Originally Posted by continuecrushing (Post 2833509)

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

Originally Posted by VeloxEric (Post 2833646)

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

Originally Posted by laextreme5 (Post 2833739)

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.