djloc79

https://www.dropbox.com/s/u9ico7oot0...220_132330.mp4

Ur thoughts?

usdmholden

Looks to me like the driveshaft broke.

ls1nova71

iTrader: (4)

Not exactly sure what happened, but it looks like you exceded the horse power limit of your driveshaft.

hackster

^^^ What he said....I bet the guy running the dyno had more to say about it though =)

Sean

Project GatTagO

iTrader: (7)

Looks like a classic case of the driveshaft turning into a jump rope. This happens as a result of the driveshaft exceeding it's critical speed. Did this happen on a chassis dyne?

https://www.markwilliams.com/driveshafttech.aspx

Andrew

wavebyby

iTrader: (1)

^^^ hahaha.....time for a new drive shaft , weird how 345 hp bent it like that but i dont know **** lol

Project GatTagO

iTrader: (7)

Power had nothing to do with it.

Andrew

sweetk30

stupid drive shaft . . . . your made to spin round and round . . . NOT make turns

ROCNDAV

iTrader: (100)

When VW was playing commercials talking about torque, my (non car) buddy asked me what torque was and if a car could have too much torque.

That would be a good picture to show him

thunderstruck507

iTrader: (18)

as mentioned above look up critical speed

HP has nothing to do with it; it's the result of material weight, driveshaft length, diameter, and RPM

bczee

iTrader: (12)

Either you exceeded the power limit or ( most likely) it was either damaged or a badly made tube. Was this a new or used shaft? Was there any dents, bumps or fold/seams in the tube?

BC

djloc79

Yeah, he mentioned that maybe the trans sized up or the pinion angle was off.
Not sure what u mean. Chassis dyno?

djloc79

It was a used driveshaft. If there were any dents, or folds, they were to small to notice.

djloc79

I failed to mention, It ripped the tail housing off the trans. My mechanic thinks the driveshaft could've been a little to long. Also, I came across this right up-

http://www.turbobuick.com/forums/thr...y-pics.179024/

Mine was running 138 mph when it broke.

thunderstruck507

iTrader: (18)

Won't hurt to check driveline and pinion angles and all that, but I highly suggest you google "driveshaft critical speed" and do some reading before buying a new driveshaft.

I had this happen and it took out a brand new built 4l60e with it. It busted the case and all.

Every short wide truck I have ever seen try to turn to redline on the dyno has also done the same thing.

Chicago TDP

iTrader: (3)

138MPH....holy shyt!

Pop N Wood

iTrader: (1)

It is an oversimplification to say "power has nothing to do with it". Just because something hit a resonant frequency doesn't mean it is going to blow up. Think guitar string. Hitting a resonant frequency does amplify the forces going through it making less capable of carrying all that energy, especially if other flaws or weak points are present.

At any rate pretty fing cool. Must have been something to see.

1970camaroRS

iTrader: (8)

You can twist a driveshaft with 100hp if you spin it too fast. Like others have said, it's a critical speed issue, not power. Probably bad pinion angles too (did you lower the car?) because that can make it worse. Could also be too long as that would make things worse as well. But you're just spinning a stock shaft at too many RPMs, just that simple.

Old Geezer

iTrader: (3)

What Andrew said^^^^
Used shaft. Any evidence of rust, either on, or inside?
Talked w/ the shop I get my d/s from. They said that near 90% of the F body shafts they spin up, looking for vibration issues, show signs of deflection in the exact same location... The middle.

http://www.wallaceracing.com/driveshaftspeed.htm

djloc79

Ok I'm kinda getting and understanding of critical speed and and what happens when this point is reached. What I'm not getting is a drive shafts critical speed something that stays the same the life of the shaft as long as the length, width, material type...etc, is not altered, Or can an unaltered drive shaft's critical speed rating decrease overtime as it is worn. I've seen old cars with old driveshaft go fast with no problems. It almost sounds like a new drive shaft is a must when hot rodding a older used vehicle.