Thanks a bunch to the NAM community and Yupetc specifically.

Ever since I put a Stage 1 ECU tune on the car I had a mild, intermittent, but still annoying rattle. It wasn't metallic enough for the heat shield, but I still pounded around with my hand to see if I could mimick the sound. No luck. The rattle sounded some-what plastic oriented so I strapped down some charge pipe areas. Not it. Banged around with my hand another two weeks with no luck either.

If I accelerated from anywhere below 50 MPH, I could generate the rattle about half the time. I could never get it to rattle when accelerating, even at full throttle, above 60 MPH, not even a hint. I'm guessing it must have been how the engine twist responded at the higher speeds.

Then I see the posts about the weakness of upper mount and filling it with Window Weld. I actually bought a brand new mount, filled it with Window Weld and let it cure a few days before putting it in. I thought it would be too rigid and I'd feel the vibration, but not at all, and the good news....Viola...no more rattle!

A week later I put in the lower PowerFlex yellow bushing with the black inserts. Too stiff for me. Pulled the inserts and its fine, although no different feeling than when I installed the Window Weld to the top mount.

Also, my original mount wasn't torn at all, but you could see clean creases where the dust constantly rubbed a clean line during maximum twist. (they looked like little slits but they weren't).

Here's a picture. I'll admit I just mashed it in there with a Popsicle stick

 

That's what I did too on mine, I also filled the bottom side up with the 3M rubber weld. I can feel slight vibration upon taking off from a stop (normally it'll vibrate between 900-1300 rpms, other than this range, all are smooth as butter. But it's a real good mod to do though, seeing so many failed engine mount so far.

 

I hope you didn't miss my first sentence. I totally got the idea from you on a different post. Thanks

 

Didn't realize you and I are running around in circles on this. But yea, this is a must-do mod.

I also analyzed the window weld that we apply. It's actually a bit tougher than the factory rubber. Therefore, the amount and the location you put this on will affect the total harshness and vibration in the end.

For whomever is doing this in the future, all you need to apply is enough to cover the top square void like Warren did here. The bottom box don't need it at all, it'll make it a bit rougher if that void's being filled, too.