RX8_Buckeye

That's a curious void in the Mazda6 roll restrictor. My guess is that they needed those holes to achieve a desired stiffness along a certain axis while keeping uniform stiffness in other directions. In any case, it goes to show that there is more to mount design than stuffing some rubber of a certain durometer in a metal shell.

I'm not sure I completely understand your statement about NVH differences not being as noticeable with the stock suspension. The powertrain mounts, while they do influence the natural frequency of certain combined vibration modes of the powertrain and suspension, are primarily to isolate vibration from the powertrain itself, not the suspension inputs. Generally, shock and vibration from road inputs is trasmitted through the springs/shocks and control arm bushings into the body. If anything I'd say that you'd be less likely to notice NVH differences on a vehicle that has a modified suspension--because the driver is probably somewhat adjusted to a very rough ride! The degradation I'm talking about will be most noticeable at idle and during smooth-road acceleration where the main noise and vibration sources are from the powertrain.

JoeMamma

This sounds interesting, with my temp gauge has been "spazzing out" since I dumped and loaded a different map in my system...Hmmmm...need to give Benny a call...

ttt

scott is the man

crossbow

Buckeye,

Forgive my ignorance. I noticed that after the mount was installed, my suspension seemed to float more...as if now that the engine was tightened down, the suspension had to take up the slack instead of the engine mounts. I figured if you then stiffened up the suspension to take up the slack, you'd then notice more vibration transfered to the chassis itself, and thus more noticable to ones self.

RX8_Buckeye

Okay, now I understand what you're saying. It's true--the engine on its mounts acts like a "vibration absorber" for road force inputs to the suspension. When you stiffen up the engine mounts, the engine and mounting system lose the ability to "absorb" some of the energy associated with low-frequency road inputs, thus you will notice more suspension activity. However, for powertrain vibration transmitted to the PPF and body, the suspension characteristics have very little influence.