Observation and question about high speed (85-180mph) really tight vibration.

[Jack B]

That is the basis of road force balancing, you match the tire to the wheel.

Did they break the bead loose and rotate the tire 180 degrees on the rim? Thats what I have seen Tire Rack do when they encounter a problem trying to perform a roadforce balance.

[Nine Ball]

Any Gen 3/4 wheels will bolt right on to that car, for simple tests.

My last '13 developed a minor high speed (130+) vibration in the hatch, after I added the TA style aero. It was more like a humming noise, due to wind buffeting.

[triblk6spd]

Bolted on a set of Gen IV ACR wheels/tires today. Zero change. Definitely not the tires. I'm gonna strap it to the dyno next week and decide weather we need to chase down a drivetrain / suspension problem or start looking at an aero ptoblem. Even the Viper tech was perplexed.
I'll keep yall in the loop.
For now this thing is glass smooth until 85mph so I'll keep it under.

[TQMonster]

Area to consider is the engine mounts since they are hydraulic and suppose to reduce vibration but maybe you have a defective one

[triblk6spd]

Dyno tomorrow hopefully.
One might think that if it was motor mounts it wouldn't be sheer speed related but more rpm related and mostly high rpm at that.
I guess the dealership has some type of electronic gizmo that helps pinpoint the source of a vibration. We will see!

[TQMonster]

Any update on your vibration?

[triblk6spd]

Funny you should ask. Dropping her off at the then dealer in the am. I'll definitely keep ya'll posted!

[TQMonster]

Cool good luck and hopefully they don't see this as an opportunity to race your car. i have a habit now of staying with the car or leaving strict guidance they are not to test drive until i am there so i can go with. These cars are just to tempting for anyone that gets the chance to sit in them!

[triblk6spd]

Yup. Agreed. The tech asked me to come back to go on the drive with him. I also told him nobody drives the car but him. I'm in good hands...
They are gonna order a driveshaft is how it looks.

[TQMonster]

Good starting point hopefully that fixes it.

[Russ Oasis]

If it's not the wheels / tires, it's ALMOST certainly the drive shaft.

[triblk6spd]

Well...NOT the driveshaft. Shit! Dealer is gonna try to get in some sort of electronic contraption that measures vibration and frequency.
Halfshafts are 3-5 days out. TX2K15 isn't looking too good.

[FLATOUT]

Well...NOT the driveshaft. Shit! Dealer is gonna try to get in some sort of electronic contraption that measures vibration and frequency.
Halfshafts are 3-5 days out. TX2K15 isn't looking too good.

Damn, sorry you're not going to make it down.

[triblk6spd]

Nono man...hell...I'm definitely gonna make it down. The stupid thing is smooth as glass under 90mph. I just won't be doing any 180 mph passes.

[TrackAire]

Nono man...hell...I'm definitely gonna make it down. The stupid thing is smooth as glass under 90mph. I just won't be doing any 180 mph passes.

Maybe it is an aero issue?.....high speed vibration from the car due to the aerodynamics? Here is something you can try to break up the aerodynamic flow of the vehicle and move them to multiple parts of the car.

Take a few strips of cardboard (18" x 4") and bend it into a "V" so it looks like an 18" long piece of angle iron. Then tape a couple across the leading edge of the roof just behind the windshield with a bunch of painters tape and go for a run. Then move them to the back of the roof before the hatch and go for a run. Then move them to the middle of the hatch between the rear window and the spoiler and go for a run.

These can be cut to whatever length you want and affixed to multiple locations on the car, even the sides of the car and door windows.

When taping them to the car, they should look like a capital "A" sitting on the cars surface. You are trying to make mini spoilers to change the air flow.

It would be interesting to see if you got more or less vibration at speeds over 90 mph. It would be a cheap way to rule out a possible aero issue.

Also, I can't remember in this thread if your rear brake ducts were looked at....IIRC, the 2013's had a funky set up where Dodge just didn't attach them correctly. You might be getting some weird vibration from them fluttering, etc.

Good luck.

[Victxv10]

What shock mode are you running at 90?

[triblk6spd]

Iv always wondered if it's an aero issue as well. I might try that! Thanks!
Same issue in either shock mode.
I pulled both wheels and even screwed down the only portion of the wheel well that seemed loose to me. Brake duct hoses seemed ok.
Speaking of that...I am absolutely gonna stuff a towel in the brake ducts and go for a run. See if that helps.
Thanks again all!

[TQMonster]

maybe just take it out on the freeway on a windy day and run it both directions to see if there is any change in the vibration

[Martin]

I think it's an aerodynamic buffet issue, too. It'll be hard to figure out, though - you'll have to go through the whole car and try to find something that's loose or flexible enough to vibrate when the right amount of air goes over it. Brake ducts would be my first guess, and then other pieces in the undercarriage should be looked at. It could even be the rear hatch - if it isn't adjusted perfectly, there might be just enough slack to allow it to start vibrating when air starts to buffet.

I wonder if anyone else has noticed the problem. Something tells me that not many people get their cars up to those kinds of speeds, so maybe it's just the nature of the beast and most people don't get into the right situation to make it happen - and the rest are scared shirtless just to keep the car pointed straight

[FLATOUT]

Nono man...hell...I'm definitely gonna make it down. The stupid thing is smooth as glass under 90mph. I just won't be doing any 180 mph passes.

Ha that would be perfect for autocross with me on Saturday for the Roundup

[triblk6spd]

Ok well I know it's not the driveshaft. Dealer should have a halfshaft by mid next week. Hope, hope!
In the meantime...today I threw her on the dyno and made a smooth easy pull to 95mph and shit! ....damn vibration is STILL there. Sooooo I can rule out wind and areo as causes. If it's not the halfshafts....maybe the whole diff? We checked motor mounts and trans mount. This shit is really pissing me off and getting the parts has been a pain in the ass too. Looks like my TX2K15 weekend might be under 90mph.
On a brighter note my new wheels shoukd be here in time!

[Jack B]

Did you check the wheel bearings. Unless you pull the bearings, the onset (beginning) of a vibration pattern is physically hard to detect. The nature of a ball bearing/race vibration is that it is cross spectrum and high frequency compared to the fundamental. It is also low magnitude until the bearing gets really bad. Basically, without a $10K vibration analyzer it is hard to pinpoint. If you were to graph a bearing going into failure, you would not see large resonant peaks, but, a series of smaller high frequency peaks that create a plateau effect. The peaks/anomalies are measured in either velocity or acceleration above and beyond the base shaft speed.

[triblk6spd]

I havnt. But I will! That's a lot of info. The dealer has threatened to get one of those vibration analyzers in. We will see!

[triblk6spd]

Update:
New halfshafts installed. No change. I'm pretty much at my witts end. Other than installing a whole new diff...I'm at a loss. I guess they are gonna get a specialist involved.



And back at my shop patiently waiting for Chrysler / SRT to fill me in on the marching orders for next week.

[TQMonster]

Not good news this is definitely time to get some assistance from SRT to help pin point the problem without continuing to throw parts at it.