Hi guys, I have 07 RX8 auto, it jas 115000 miles. I had an issue, where the car would vibrate at the stop when I'm in gear. I replaced spark plugs and wires, didn't replace coils yet, I'm saving for the BHR ones. Car also has BHR Midpipe with no cat. So to fix the issue of vibration on the redlight I decided to replace the motor mounts and replaced them with the RX8Performance ones. The car now doesn't vibrate when I'm stopped at all, but when I start to accelerate, it vibrates enormously bad between 1000 and 1300 rmp and vibration dissapears above 1300 and below 1000. Vibration is so bad that the whole interior is shaking. I don't know what to do now. By the way, the original mounts I replaced were not broken. Should I keep the new mounts and replace coils or should I put the old mounts back? I know many people have issue with vibration at the stop but I couldn't find anyone with problem like mine. Thank you!

 

Does the vibration stop when you turn the AC off?

 

With an auto trans you might want to check is compression first before dumping any more $$$.

 

It vibrates even without AC on

 

Well, my concern is that it fixed vibration at idle but now there is vibration at 1000-1300 RPM, I'm wondering if it is due to new mounts or what caused it. Maybe the new mounts have to be broken in and it will dissapear with time.

 

Was about to post and say engine mounts then read this haha. Did the vibration only start when these were installed?

 

2nd sentence in first post

the RX8P mounts will vibrate more, but you should feel it at idle too. Are you sure it’s bolted together properly?

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Yes, I just installed them today and the problem started right after I started the car and began driving.

 

Yes, I can feel they are more stiff than the factory ones, but this vibration at those rpms is really bad and loud. I actually texted RX8P to send me pictures of mount's assembly since there is a lot of washers and parts and maybe I messed up and assembled them in a wrong order, but it poped on perfectly and I didn't have issues installing them.

 

You got the automatic engine mounts and not the ones for the manual? They are different.

 

At the RX8P Website there is only one choice of mounts so I'm actually not sure.

 

They only offer one type. You should probably ask Scott there about it.

 

So the vibration went from idle to 1000-1300 rpm when you changed the mounts.

The vibration was there before...the same? just moved to a different RPM? Or its worse after the mounts?

Kinda hard to tell whether the issue is from the mounts, got worse after the mounts? or just moved up the RPM band a bit?

 

Yeah, I already emailed him, however I'm not sure if he's going to anwer me tommorow since it is Saturday. I will try to clean MAF sensor and throttle body, and change air filter tommorow and see what happens. Thanks a lot for your all replies.

 

Yes, it feels like the vibration just changed on the RPM band, it is now not at idle but on 1000 to 1300 and it is actually worse than it was on idle. However everywhere else on the RPM band it's much smoother than before.

 

Sorry for my English, It's not my native language, but I hope you all understand me clearly. Thank you all for replies!

 

Russia, Ukraine, possibly Belarus? The reason I suggested compression because auto trans rotary engines seem to have more of this issue. If you have a rotor face or two with substantially different compression it can result in a harmonic frequency imbalance under certain conditions. But it might be a coil too. Need to spark-load test them.

 

Hey, I saw you also installed these mounts. Did you have some similar issue? I was looking at your post on how to install it and noticed that I actually assembled the mount wrong. There was a thick washer which I put between the rubber and the nut and I think it doesn't belong there.

 

Ukraine I don't know anyone in New York who is really good at rotary and could do a compression test. I only have a rotary car for a month.