Loud roaring and vibrating noise at high rpm HELP
 

Hello all, new to the site!

Ive owned my rx8 for just over a year now. Love the car! Brilliant. Just recently ive been getting this loud noise at high rpm which sounds really really bad. Almost sounds like its going to explode. No large noticeable power loss :-/ Sounds like it may be the manifold? It starts to occur around 7000 rpm then gets worse. Drives fine and sounds fine until i hit 7000.

Just taken it to a mazda dealer this morning and he says he has never heard the noise on an 8. He said my engine mounts are a bit worn but they shouldnt be making it make the noise. Dont know what to do? He said he could mess around for ages and never find whats wrong with it.

Things ive replaced on car since ive owned it.

Coils, leads, plugs, catalytic converter plus o2 sensors, Air filter, Oil filter, Oil.

PLEASE PLEASE, ANY HELP WOULD BE GREAT. Tearing my hair out.

Josh

Anyone shed any light?

Could it be preignition? Are you using the highest octane premium fuel?

if you can, maybe take a video of what you're experiencing and post it here.

I wonder if it has anything to do with the ssv...

Im using premium 95 octane fuel. Occasionally i use the 97/98 octane but its a fair bit expensive. Only if im feeling rich. lol
Ill try and upload a video. Whats the ssv?

Secondary Shutter Valve

Use advanced search and search for that in titles.


Here's a link that might get you started.......even though you have no codes for it, it could be your issue.

https://www.rx8club.com/series-i-do-yourself-forum-73/diy-remove-ssv-beta-teaser-video-184663/

Where are you? Is 95-the lowest octane in your area?

Im from the UK. Round where i live thats the lowest octane.

Hmmm did some reading on the ssv. The car runs smoothly at idle and smoothly till it reaches high rpms. Would it not affect it all the time if it was that? :-/ Not very familiar with rotary engines so its been interesting learning about it. Love them though!

Ill do some more research. Thanks all for your help so far.

Your 95 octane may be to low. Try the 97-98 and see if the problem goes away.

Maybe double check to see if the airbox lid is shut tight. Sounds like the noise the Rx makes with a cold air intake.

95 octane is absolutely fine in the UK. But some supermarket fuel may be inferior quality.

Same problem here, it started to happen after I change the secundary air injectio solenoid.

I would almost say the engine mounts. They're fluid filled. and can cause that problem when they deflate. easy way to see is watch the motor and have someone rev it up. if the engine rocks a lot or wobbles at high RPM, then that is most likely your issue.

I would try turning the SSV by hand and see if it moves freely and doesn't feel like it's getting stuck. If it wasn't activating at all, the car would feel slow and dead through the mid range, and you would throw an engine code for sure.

But what I hear is the intake more than the engine it self.

Good info