Audio clip of rattle...

Link: http://www.eviltwinkie.com/RX8/RX-RATL.WAV

Background:

Just finished a 20 minute drive to get it warmed up. Pulled into the driveway and deployed recorder. The rattle is slightly apparent.

I then press clutch in (should hear me say "IN") and then release the clutch (should hear me say "OUT"). Notice no change in rattle.

I then lightly apply throttle and the rattle disappears. I release throttle, and the rattle reappears. I do this a second time just to be sure.

I then proceed to flog it a little bit. Afterwards, as soon as the engine returns to idle, the rattle reappears, however this time much louder than before. The increase in rattle always happens immediately afterwards.

No loss in power or anything else. Simply noise for now.

I'm going to get under the car and see if I can find anything later today.

 

Yup that is the same thing I have. Some guys said it sounds like a motor mount. I can feel the car rock when going into any gear (yest i know how to drive stick), over bumps i feel rocking.

Here is my thread:

https://www.rx8club.com/series-i-trouble-shooting-95/worried-about-my-05-a-121629/

 

Got pics to post in a few...

Looks like the welds on the heat shield of the exhaust manifold have come off...

It's just kinda hanging around all floppy...

 

Pics from below...

The arrows and letters on the corners are for orientation.

R= Rear
F = Front
D = Driver
P = Passenger

The circled red areas appear to be the heat shield which lost some of its welds and is now kinda of floppy. I figured that after the manifold heats up the shield gets to rattling. I'm not sure I found the problem, but after a short chat with the pry bar the rattle has diminished.

Is that what the shield is supposed to look like?

 

The "welds" on your CAT heat shield are fine. That is the way they are supposed to look.

When my car developed a similar rattle, it was the driver's side motor mount.

It could also be any one of a number of things that are run along that same side of the motor, like the starter motor harness or the fuel lines.

Best bet is to get under the car with a short length of 3/4" heater hose up to your ear and point it around like a stethoscope.
Only problem is that changing the attitude of the vehicle might abate the noise.

 

Um, that is the exhaust manifold. The CAT was replaced by a midpipe. The pic is where the manifold and cat pipe meet.

Does that change your opinion? Or still thinking its the mount?

 

I meant ex-man. My fingers are faster than my brain tonight. I've been in the garage welding for the past 48 hours.

Is it louder on one side of the car than the other when you put your ear just behind the tire?
I still think its the mount, but use a hose like I suggested.

 

Heh...no worries I'm on day 3 of no sleep...I know what you mean...

Its seemingly louder drivers side...

I'll check the mount manana in the afternoon...

 

OK, so after taking the pry bar to the shield last night, I could not get the rattle to reproduce as severely as I used to be able to. Did the same 20 min warm up.

After I check out the motor mount, I'll take it out for a proper flogging to try to get the rattle.

If its not the mount, its got to be something related to my blind pry bar fury...

 

There are some 10mm bolts that are supposed to hold that shield to the manifold. Did you check to see if they were still present?

 

Yep all bolts present and accounted for. All of them are tight too...

 

Didn't get a chance to check the motor mount...but after a good amount of flogging...

Rattle appears to have definitely decreased due to my pry bar antics...

I'll update after I check the mount...

 

the same thing happened to me, i took into mazda and they replaced the motor mounts and it stopped the rattling noise, that might be it, hope everything works out with you

 

eviltwinkie: did you find where that rattle is? an update would be great. thanks.

 

Nice...actually I'm glad someone poked at me about this...I HAVE FOUND MY SOLUTION!!

I discovered it when I replaced the OEM exhaust...

It was a loose bolt located above the pipe where the midpipe meets the back at the joint near the hanger...

I was missing a bolt and the one left looked like it had almost rattled itself out. As soon as I tightened it all up...rattle is gone...

I want to say it was on the transmission brace...but I do not remember...however if you look in that area...you'll see it...