I currently have a set of poly engine + trans mounts in my Rx7. I really like how firm and direct they make everything feel. They start to get buzzy at 3k rpm or so, which doesn't bother me too much.

But what does bother me is the noise. While reinstalling the stereo I'm realizing just how loud I need to raise the volume to be able to hear it. Not even factoring in road / exhaust noise.

I like the feel of the poly mounts, but not being able to hear the stereo is a deal-breaker unfortunately.

As far as I see it my options for quieter mounts are OEM, OEM convertible, Mazda Competition mounts, and possibly the Banzai "street" isolator kit which looks like it is designed to quiet down poly mounts.

Anyone have recommendations for mounts that are as firm as possible without being unreasonably loud? Thanks, Chris.

 

i like the FB67 convertible mounts they are 10% stiffer than the coupe (not sure how i know that!) and have none of the NVH penalty of the comp mounts (40% stiffer)

 

Interesting, I had been leaning towards the Competition mounts. Would you say the 40% increase in stiffness leads to a significant increase in NVH?

My car came with broken stock mounts, then I went to Delrin (ouch), and now Poly (loud). I have never had a car with healthy stock mounts to even compare to.

 

new stock mounts are really smooth, and its so quiet, you keep that with the FB67 mounts. i've done the comp mounts at the transmission with no complaints too. the comp engine mounts start to have some NVH

 

I have the Mazda comp mounts. I can't say I've noticed the NVH. I wonder if my exhaust is louder than the NVH so I never noticed. RB header presilencer & HKS sport catback. Hearing my current radio isn't a problem. I have 2 way 4&1/2"in the dash and 5 & 1/4" in the door ran off the stereo and 2 x 12" subs run by a 65w RMS amp. Stereo is 50w peak so maybe 25w RMS by an online calculator I found..

 

Just speculating, but i would dare say the comp mounts would barely register on the nvh scale compared to through-bolt poly mounts

 

My current exhaust is stock manifold, no pre-cats, high flow cat, then into a REV TII catback. I have a feeling the HKS is louder but I've never heard one in-person.

The system I'm currently installing is 6.5" door speakers (component) with tweeters on the door triangles, then twin 8" subs in the rear shock towers. Should be fairly comparable to yours albeit maybe louder, but I only ever turn my stereo up high enough to drown out the road noise anyways.

Current plan is to see what it's like after replacing the mounts and then possibly work another silencer into the exhaust somewhere if I want it quieter. Sound deadening will help some, I'm sure.

The other problem is that the vibrations from the poly mounts make all of the interior trim rattle and squeak...

I was actually toying with the idea of casting some poly mounts using the stock metal pieces from the original engine mounts (if I even stil have those parts somewhere), that way they aren't through-bolt designs anymore. I decided I didn't really want to leave my engine mounting up to a set of experimental home-made mounts.

 

I got Banzais Poly Race mounts and its horrible. between 1 and 2k rpm the car vibrates horribly and rattles like a ************. Definitely going Mazda Comp.

 

It's basically the system at the bottom of the page.
https://web.archive.org/web/20040423...m/r-ex86nt.htm
If you've heard the full collected header RB setup think that but less raspy. Since it has a header it's fairly loud. I too most just turn the volume up till it drowns out the road noise. I don't mind hearing a little exhaust noise but I think I could drown it out completely if I wanted. Your setup sound like what I wanted. I wanted to put some 8" subs in the shock towers but I had a box with trashed 12's in it so I took the easy cheap way and got some 12's at Walmart. I may still go to 8's one day to lose the weight of the box.

 

I've read differing reviews over the years...comp. engine mounts ok but comp. trans mounts up the NVH substantially .Then I've seen a few run run one comp. engine mount and a standard mount..I bought a pair of the comp. mounts but am leaning to try using one comp. mount on the compression side of the engine and a vert one on the other . maybe in that case can get away with the comp. trans mounts as well as my trans mounts are done. what are your thoughts on that combination?

 

so i know what i don't like after its done, but i don't have enough seat time with all the different mounts to know what each setup is going to do, so try it and see

 

Yes most of this is subjective .I'll most likely try both first and work from there..if all else fails throw more money/time at it.