[RocktimusPryme]

I dont think there is a high chance this is your problem given the tests you have done, but to give everyone food for thought. Im fighting a similar issue with vibration. I read a review the other day for the M/T drag radials that I have on my car that says "They balance poorly and rattle your teeth out"

Then it occurred to me that I have only had those drag radials on the back since I started messing with my pinion angle. Before I lowered the car I mostly had the Rally II wheels with generic street tires on it. So Im going to swap back to street tires on the rear and see if it changes or eliminates my shake. Maybe my 60 MPH shake has been tire balance the whole time.

[JLMounce]

Originally Posted by RocktimusPryme

I dont think there is a high chance this is your problem given the tests you have done, but to give everyone food for thought. Im fighting a similar issue with vibration. I read a review the other day for the M/T drag radials that I have on my car that says "They balance poorly and rattle your teeth out"

Then it occurred to me that I have only had those drag radials on the back since I started messing with my pinion angle. Before I lowered the car I mostly had the Rally II wheels with generic street tires on it. So Im going to swap back to street tires on the rear and see if it changes or eliminates my shake. Maybe my 60 MPH shake has been tire balance the whole time.

Good information for sure. I have actually heard this about drag radials in general.

I can create my vibration sitting on the driveway in park, so it's definitely not the tires.

[Keith Seymore]

Originally Posted by JLMounce

Good information for sure. I have actually heard this about drag radials in general.

I can create my vibration sitting on the driveway in park, so it's definitely not the tires.

This is good. Divide and conquer is what it is all about.

If you can separate "RPM dependent" from "Vehicle speed dependent" from "Load dependent" then it creates a whole long list of things you don't have to worry about.

K

[JLMounce]

Originally Posted by Keith Seymore

This is good. Divide and conquer is what it is all about.

If you can separate "RPM dependent" from "Vehicle speed dependent" from "Load dependent" then it creates a whole long list of things you don't have to worry about.

K

It's definitely rpm dependent, but load effects the severity. In park you can feel the vibration grow between 2800-3000 rpm and it's at its worst from 3000-3500rpm. It is still there, but subsides after 3500 rpm.

While driving the car, the vibration is worse during moderate acceleration. At full throttle the vibration is present but not as severe.

Motor mounts perhaps? Those have been in the car since I purchased it in 98.

[johnta1]

I would say to check the converter to flexplate mounting.
If this is a new converter (to you?) it could be bolted up crooked.
Unbolt converter from flexplate and push converter away from flexplate.
Start engine and see if it still vibrates?

Check the flexplate while under there to see if there is any noticeable problems. (bent/crooked, holes wallowed out, etc)

When bolting back up, make sure the converter is pulled against flexplate evenly and tighten bolts without cocking the converter as it is rotated.

[JLMounce]

Originally Posted by johnta1

I would say to check the converter to flexplate mounting.
If this is a new converter (to you?) it could be bolted up crooked.
Unbolt converter from flexplate and push converter away from flexplate.
Start engine and see if it still vibrates?

Check the flexplate while under there to see if there is any noticeable problems. (bent/crooked, holes wallowed out, etc)

When bolting back up, make sure the converter is pulled against flexplate evenly and tighten bolts without cocking the converter as it is rotated.

This is definitely on my agenda to check. The flexplate was a new SFI unit that was installed about a year and a half ago. Doesn't necessarily mean anything however.

The converter is a new TSP unit. One of their billet faced triple clutch deals.

One thing I just realized is that the vibration range tends to be in the range where the converter starts to couple. It flashes to about 3100 rpm under load.

[Keith Seymore]

Originally Posted by RocktimusPryme

I dont think there is a high chance this is your problem given the tests you have done, but to give everyone food for thought. Im fighting a similar issue with vibration. I read a review the other day for the M/T drag radials that I have on my car that says "They balance poorly and rattle your teeth out"

Then it occurred to me that I have only had those drag radials on the back since I started messing with my pinion angle. Before I lowered the car I mostly had the Rally II wheels with generic street tires on it. So Im going to swap back to street tires on the rear and see if it changes or eliminates my shake. Maybe my 60 MPH shake has been tire balance the whole time.

Happens to the best of us.

I chased a vibration for about half a season; had my new Hoosiers balanced at least twice.

Turns out I had flat spotted the front tires at some point. New front tires fixed it.

K