Vibration @ 2250rpm

[elwesso]

The 'node' is just aft of the front seat rear track fastener--and where the rear cross member attaches. You CAN weld a reinforcing plate where the rear cross-member mounts (+/- 12" wide, across the body to at least 6" outboard of the crossmember mounts)--which will 'stiffen' this area of the frame/body enough so the engine/exhaust will not excite the body resonance node any more.

Your referring to the transmission mount, and not the rear subframe, correct??? So it sounds like you weld a plate between the area right behind the rear subframe??? im interested to hear how this would work.

[elwesso]

Keith - you omitted the 96 and I definately have this resonance. I'm reluctant to remove the premufflers, as Wes suggested, because I like a very quiet cabin - one of the things I appreciate most about the Q, and I use it mostly for long trips on freeways. So I can pop for the expensive TSB fix, or I can fiddle with the existing hangers.

Do you have a recommendation?

96... I really dont think youll be disappointed.. My exhaust is LOUD by most peoples standards, yet its JUST as quiet as a stock Q on the freeway....

PLease trust us...

[goody90q45]

This thread prompted me to change out the transmission mount on my 94Q45. I have the same vibration in the same rpm range. The job so far has been very easy. It's more work getting the car jacked up on 4 wheels than removing the mount. I called the dealership to make sure they had a mount in stock before I started but wasn't planning on both cat hangers being shot also. I'm waiting on the second cat hanger to arrive today to put everything back together.

I've included a pic of the old mount next to the new and one of the broken cat hangers is placed on top. (Sorry I don't have the patience to figure out how to get it to appear in this post. Maybe one of the moderators will want to insert it.) The old mount has compressed over 1/3" and is close to bottoming out. What you can't see is the rubber is almost competely separated from its metal frame. Same with the cat hanger, a pair of which bolt the cats to the aft end of the mount bracket. This is a square block of rubber bonded to a bracket and both are about 75% separated. (In the pic I've stuck a golf tee in the opening to show the extent of the unbond.)Both hangers looked OK until I jacked up the transmission and took the weight of them.

Hopefully this will solve a majority of my vibration. Cost for the 3 parts was $130 plus shipping thru Wes, and $175 at the dealer. I didn't plan ahead and use Wes but I had the day off yesterday and decided to get it done. I struck up a conversation with the parts tech, Patrick, mentioned NICO, and got 10% off plus free overnite shipping on the back-ordered cat mount. Came to $170 with tax.

I

[goody90q45]

Sorry. I meant to say through Joe, not Wes. It looks like I'm not as computer challenged as I thought since I got the pic to show up in the post.

One Question. What is the purpose of the black steel block mounted on the crossmember below the transmission mount? It weighs about 5 pounds.

[maxnix]

Nice picture, and yes it was past its time.

Are you asking about the bracket?

[goody90q45]

No. There's a black-painted steel block bolted to the main crossmember covering the transmission mount. It's about 3" X 6" X 5/8" thick, weighs at least 5 pounds, and is the first piece to remove (closest to the ground) when starting the mount removal.

[goody90q45]

Just finished the transmission mount and cat bracket installation. All vibration is gone. I was only noticing it in the 2200 rpm range but the mounts have smoothed out the ride at all rpm's and the Q is driving very smooth. What a great car.

Thanks NICO.

[elwesso]

Could you post a picture of the transmission mount?

[goody90q45]

It's there, about 5 messages up.

[elwesso]

I had a brain fart... I meant the part number......

[elwesso]

Looks to be11320-60U01-

Could you verify?

[goody90q45]

Correct. transmission mount is P/N 11320-60U02Exhaust hangers (insulators) attached to transmission mount are P/N 20610-60U00

[elwesso]

Did you have to remove the driveshaft to do this?

[goody90q45]

The driveshaft does not have to be removed. Only had to loosen one bolt to move a cluster of connectors to get started.

[3Q Jay]

Sorry. I meant to say through Joe, not Wes. It looks like I'm not as computer challenged as I thought since I got the pic to show up in the post.

One Question. What is the purpose of the black steel block mounted on the crossmember below the transmission mount? It weighs about 5 pounds.

i have one of those also on my 94. i *think* it is there to dampen vibration.

btw nice avatar. i recognise the D-II with the 9.5 ft fairing.

[goody90q45]

We make the 2nd stage engine.

[elwesso]

Hmm... SPL offers a poly transmission mount for the z32, may consider buying it...

Since the transmission is the same as the Q (auto) it will work.

[DrewQ45]

I Have a 94 q45t with a vibration @ 2250rpm. The tires are new and have been checked for balance. All the injectors are working properly and test @ the correct ohms. The driveshaft is original . The u- joints are good. The carrier bearing is good. The motor mounts are new. The transmission mount is 60%. The engine is timed properly. The plugs are not and have never been fouled. The transmission filter and fluid is new with 1 bottle of lubegard red. The vibration occurs in any gear at any speed provided the rpm's are 2250+/- 50. The vibration also occurs in nuetral and in park @ 2250+/-50 rpm's .

Can anyone help?

Has the vibration always been present, or can you recall when it started. If so, were there any changes made just prior?