Dennis, The vibration characteristic you describe is common with involute spline connections (I've seen this here at work). When splines are loaded, the male spline is centered in the female spline by the tooth loads.
Run the same set unloaded and this natural centering ability goes away. Now, one spline is offset relative to the other which creates a larger mass unbalance and higher vibration. I'm unfamiliar with your vehicle so i have no idea if something like this is applicable. Perhaps there is some type of joint that behaves similarly and maybe has worn a bit to allow extra motion when unloaded. Joe On Mon, Jun 9, 2014 at 12:55 PM, Pestka, Dennis J via EV <email@example.com> wrote: > The shocks are new, but I'll take a look. > > I don't know if this means anything, but let me repeat one thing. > Under acceleration with torque on the motor and drivetrain the vibration > is not too bad. Starts showing up ~ 55 mph. > When you let off the accelerator at that speed, the vibration gets very > bad and gradually goes away as the vehicle slows down to ~ 40 mph. > > Thanks; > Dennis > > > > -----Original Message----- > From: Jay Summet [mailto:j...@summet.com] > Sent: Monday, June 09, 2014 1:02 PM > To: Pestka, Dennis J; Electric Vehicle Discussion List > Subject: Re: [EVDL] Vibration > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > One thing to check is your non-drivetrain elements, although if you get > the vibration without moving in neutral it's probably in the drivetrain. > > The reason I mention it is that our car had developed a vibration at the > 58-60 MPH speed range, and it turned out to be rear shocks that needed > replacing. > > Jay > > > On 06/09/2014 07:49 AM, Pestka, Dennis J via EV wrote: > > Removed the drive shaft, had new u-joints installed, and had it > > balanced. No change. > > > > I’m guessing it’s either the angle on the motor/transmission in > > relation to the rear end, or I may have to pull the > > motor/flywheel/pressure plate/clutch assembly and have it balanced. > > When I sit in neutral and rev to ~ 3000rpm, I’m getting some > > vibration, although it doesn’t seem to be as bad as when I drive. Here > > again I feel it at ~ 50 mph and up, but it is really noticeable when I > > let off the accelerator at those speeds. > > > > Thanks; Dennis Elsberry, MO http://www.evalbum.com/1366 > > http://evalbum.com/3715 > > > > > > > > > > > > From: Daniel Busby [mailto:busby.dan...@gmail.com] Sent: Tuesday, May > > 27, 2014 1:52 PM To: Pestka, Dennis J; Electric Vehicle Discussion > > List Subject: Re: [EVDL] Vibration > > > > I'd try balancing your driveshaft. It's relatively inexpensive once > > you get it out. A local place in LA costs less than $70. > > > > My '64 Spitfire definitely has a wobbly shaft, but I haven't made the > > time to pull it out and get it balanced yet. I stick to surface > > streets in the meantime. > > > > On Tue, May 27, 2014 at 11:29 AM, Pestka, Dennis J via EV > > <firstname.lastname@example.org<mailto:email@example.com>> wrote: Didn't know if > > anyone had any clues to a problem I'm having. > > > > Since I have my new Lithium pack, I've getting my 65 Datsun out on the > > highway and up to ~ 60 mph. Never did much of that before. When > > accelerating, I don't experience it, but when I let off the > > accelerator, I'm getting a pretty good vibration. Step back on the > > accelerator, and it goes away. Don't seem to notice it at 45mph and > > lower, but when going 55 - 60 mph. I just put new tires on it, and > > have had the front end aligned. > > > > Any suggestions ? > > > > > > Thanks; Dennis Elsberry, MO http://www.evalbum.com/1366 > > http://evalbum.com/3715 > > > > > > _______________________________________________ UNSUBSCRIBE: > > http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing > > discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) > > > > -------------- next part -------------- An HTML attachment was > > scrubbed... 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