Tom M'Guinn

The combination of rear seat delete and the Xschop semi-solid tranny mount has made my car louder than I want. The rear seat area is like a megaphone for every whine, tick, whir, and groan from the tranny.

Has anyone tried/compared the noise from a semi-solid mount and a urethane-filled factory mount? Can I expect the urethane-filled mount to be quieter and/or close to stock in terms of transmitting noise? Don't want to go to the trouble if it's not going to help quiet things down... Thanks all!

gruhsy

It's still noisy on mine with this. Slab of Mil-spec rubber

944crazy

I have a urethane filled factory mount, and I didn't notice any increase in sound. But I still have the full interior.

Tom M'Guinn

Thanks, that's encouraging. I noticed the increase in noise before the rear seat delete with the semi-solid, though it was a bit more tolerable with the rear seat installed. I could add sound deadening material, but it will still be louder than a factory mount and I'm hoping I can add urethane without adding this kind of noise back.

Grushy -- I'm not surprised that is a loud set-up you have there. The semi-solid mount has much thicker rubber busing on both top and bottom, but is still loud. Your solid mount on a rubber sheet is less isolating for sure...

V2Rocket

Urethane-filled adds no noticeable NVH to the cabin.
Done tons of them.

Tom, stripping the leather off the rear seat cushion and re-covering it with carpet is easy to do...looks good, BTDT too.

Tom M'Guinn

Thanks, I'll give it a try and report back as to how it sounds compared to the semi-solid mount. I did the rear seat delete a few months ago using the Deutsche 9 shell...very happy with it...

E-man930

URG8RB8

If I ever get the car back together I can give you a ride to see what crazy expensive sound deadening will do for you. I had ever square inch of the car covered. The road noise nearly went to zero compared to without it, but I had the stock tranny mount installed then. Is it just the mount or the new CV joints? The guy at the Dune Buggy Shop in Arizona asked me about putting them on a street car. He said they are VERY noisy. I was like how noisy, he said 4X.

Tom M'Guinn

That's interesting. Did you use the same joints I did? Mine seems RPM related, not MPH, so assume its not the joints. But I'll keep that in mind as I hunt it down!

I removed all of the sound deadening from the rear seat area to help isolate the sounds and -- wow -- does that area act like a megaphone! I can literally hear the shifter forks move the gears. With some sound deadening I can live with the extra whine, etc., from this mount, but on the freeway at moderate loads (not light cruise, not heavy throttle) I get a harmonic sound (think rolling your R's in Spanish class), that I can't stand. It's faint with the sound deadening, and louder without it. Never heard it before, so assuming/hoping it's just a noise that's always been there but wasn't transmitted through the stock mount.

URG8RB8

We have the same CV joints. The sound deadening I used will help with the drone noise. I hope the CV joints are not as loud as he told me.

Jay Wellwood

Reading though this, I'm curious as to the sound deadening material you used?

Tom M'Guinn

Well I can confirm these CV joints are no louder than stock. I started by putting DynaMat in the rear seat area and that helped to dampen all the gear and linkage noise I was getting, but it was still there, just quieter. The car also had more vibration at idle than I liked, which can't be cured with sound deadening. So I swapped out the Xschop semi-solid tranny mount and installed a bone stock mount this morning. The difference is night and day -- all the vibration and mechanical noises are completely gone. It's a civil street car once again. The Xschop mount is well made and has it's place for sure, but it just changed the character of my civil street car too much for me.

Next up I'm going to try a urethane-filled mount to see if I can firm up the mount without all the noise and vibration. Planning to try the softer 60A urethane, since reports seem to differ as to how harsh the 80A-filled mounts become. I had ordered a can of both last year before opting for the Xschop mount, but it turns out they have a short shelf live and were both past their expiration date. So, in the interest of science, I tested both in plastic containers. After 2 days, the 60A is noticeably softer than the 80A. The 60A feels about as firm as a pencil eraser, whereas the 80A just feels like hard plastic. Will report back after trying the 60A...

944crazy

I used 65A, so I think you will be fine with the 60A.

E-man930

Tom I used 60A in my version 2 mount I posted pics of above, no regrets. ����

Tom M'Guinn

Version 2? Did you try 80A in version 1?