Dealing with a vibration over 100mph. Need some help.

[n_123]

Running into an issue with a vibration above 100 mph. It’s a low buzz that kind of sounds like you’re going over rumble strips really quickly. It intensifies with speed. This started after I installed the Steeda stop the hop kit and my dealer replaced my rear axel/wheel bearing under warranty (happened within a week of eachother). Since this has started I’ve done the following:

-Alignment
-Rechecked torque on subframe and diff bolts
-New set of tires (makes exact same vibration so I don’t think it’s a balance issue)

I’m sort of at a loss. The only thing I feel like it could possibly be at this point is a fuck up on the dealers part with the install. Maybe left a bolt loose. Any ideas?

Sponsored

 

[MAT1955]

@n_123 ...... I'm sure you have checked the lug nuts on the wheels. At 100 mph any degree of off-torque can quickly cause a vibration. As well, if you will be going over 100 mph I would have my wheels balance checked - by a professional shop (not the dealer). Afterwards they can be torqued, then you can drive 50 miles and re-torque them yourself or have the shop re-torque them - most will do so no charge. Before I got into any exotic examinations or "take aparts" I'd check wheel balance and lug nut torque. BTW at 100mph you start to get into ground effects. The Steeda anti wheel hop kit is I assume primarily for launches - is it aerodynamic at 100 mph?

 

[n_123]

@n_123 ...... I'm sure you have checked the lug nuts on the wheels. At 100 mph any degree of off-torque can quickly cause a vibration. As well, if you will be going over 100 mph I would have my wheels balance checked - by a professional shop (not the dealer). Afterwards they can be torqued, then you can drive 50 miles and re-torque them yourself or have the shop re-torque them - most will do so no charge. Before I got into any exotic examinations or "take aparts" I'd check wheel balance and lug nut torque. BTW at 100mph you start to get into ground effects. The Steeda anti wheel hop kit is I assume primarily for launches - is it aerodynamic at 100 mph?

I have verified lug torque. I just feel like it would be odd if it was a balance issue or a bent wheel given the fact that the same vibration was present before and after I got new tires.

 

[smurfslayer]

This started after I installed the Steeda stop the hop kit and my dealer replaced my rear axel/wheel bearing under warranty (happened within a week of eachother).

I’d start with the Steeda kit and pull it; RTS - return to stock. That rules in or out 1 of the 2 variables.
if the vibration goes away - there’s your issue. If it doesn’t, return to the dealer.

Since this has started I’ve done the following:

-Alignment
-Rechecked torque on subframe and diff bolts
-New set of tires (makes exact same vibration so I don’t think it’s a balance issue)

Alignment won’t cause a vibration like you describe. It may cause drift, weave, wear the ever living cr@p out of your tires, but not make it vibrate.

Agree on verifying wheel lug torque, it’s basically free, and rules out that possible variable- which you introduced with new tires.

Don’t stack on any more mods until you have this under control.

 

[n_123]

I’d start with the Steeda kit and pull it; RTS - return to stock. That rules in or out 1 of the 2 variables.
if the vibration goes away - there’s your issue. If it doesn’t, return to the dealer.




Alignment won’t cause a vibration like you describe. It may cause drift, weave, wear the ever living cr@p out of your tires, but not make it vibrate.

Agree on verifying wheel lug torque, it’s basically free, and rules out that possible variable- which you introduced with new tires.

Don’t stack on any more mods until you have this under control.

The only part of the kit that I think could possibly cause an issue are the differential bushing inserts. Everything else just keeps the subframe in place and aligns it which I don’t think would affect anything besides the alignment, which isn’t an issue. I’m gonna put the stock bolts back in and remove the inserts and see what happens.

 

[smurfslayer]

That is called out right in the description so it does sound like a good place to start. Good luck !

 

[Alan Applegate]

Find a shop in your area that has a Hunter Elite balance. You pay more to get a race (fine) tune, but when all else fails...

The first place I'd look is the wheel the dealer worked on. I also agree with the torque of the nuts. One would assume an imbalance in torque couldn't cause a rotor to warp, but it can happen. If possible, once balanced and reinstalled, start the car on the lift and run up the speed just to check.

 

[LoneRanger57]

Slow down..........

 

[n_123]

Update: Diff bushing inserts are removed and the vibration is completely gone.

 

[smurfslayer]

Slow down..........

You’re in the wrong place. You should probably register over at PriusChatPriusChathttps://priuschat.com › forum

Update: Diff bushing inserts are removed and the vibration is completely gone.

Well done!

But this raises some other questions to me.
The more solid bushing inset is only transferring the NVH already present and isolated, I wonder if yours is abnormal?

Maybe anyone else running the Stop the Hop kit could chime in.

 

[LoneRanger57]

I'm glad my GT doesn't have that kind of "problem" and sorry you were butt hurt by a simple joke
Best of luck figuring out why your car is doing that

 

[steveo1960]

That makes sense. I installed poly urethane bushings in my 2003 GT in the rear control arms, also upgraded, and it was a huge mistake. NVH and vibrations notched up to 10+. Might be great for the track but not for a daily driver. Live and learn. Glad you figured it out.

 

[smurfslayer]

That makes sense. I installed poly urethane bushings in my 2003 GT in the rear control arms, also upgraded, and it was a huge mistake. NVH and vibrations notched up to 10+. Might be great for the track but not for a daily driver. Live and learn. Glad you figured it out.

Is it really _that_ bad? My ’97 had Ford motorsport rear UCA’s and lowers with the spherical bearings. It was definitely a bit more NVH but nothing like y’all are describing.

I have my eyes on stop the hop... I don’t want to compromise streatability too much.

 

[steveo1960]

Is it really _that_ bad? My ’97 had Ford motorsport rear UCA’s and lowers with the spherical bearings. It was definitely a bit more NVH but nothing like y’all are describing.

I have my eyes on stop the hop... I don’t want to compromise streatability too much.

It was more the wife complaining. Also my car was a vert so that may have been why.
It was definitely streetable though. The s650 is a different beast altogether so it's not really an accurate comparison.

 

[Adamrx11]

So did you put the Stop The Hop kit on a convertible? Is it still on? I have a convertible myself and was looking at that exact same kit. Worth it?

Sponsored