Thx, let you know the outcome tonight.

 

None.

 

Doesn't anybody have an old lower half of the airbox we can send this guy......just to try it out? Bueller? Bueller?

I know we are all leaning various directions as we get more input.........but that is the very first thing that really need to be eliminated. I know we all know this, but Jeez!

 

Or maybe a local member can temporarily swap with him just to rule it out?

 

Spigot52 is down the street from me, I'm going to try that next.

I installed plugs, wires, and coils now. It runs well. Maybe a little better than before.. But the noise is still there!

To the airbox I go.

 

Met up with Brian last night, and tried out his stock airbox/ filter assembly.

Obviously it was almost completely silent in comparison. We could'nt hear the sound at all, but this could be because there was no intake noise what-so-ever now. The next step is to try putting on an aftermarket intake.

My only guess is that because the sound is so loud, it's causing the intake/ tubing to rattle and make the noise. You boys COULD be right, I won't know until an aftermarket intake goes on the car.

 

Sounded almost like the filter element itself flapping/vibrating.?

 

I'd say that is likely the case. I looked at the piece last night in the light when I got home, and it looks like it may need replacement. It has a rather large crack in it.

She still wants some sound, so I guess i'm looking into an intake for the car now.

 

Thats too bad.

 

So, I drove Brians RX8 last night.. And it sounded great, thanks once again.. I like those cars in MT alot.

I know he has had good experience with his MSCAI.. However, are there some other reccomended intakes that provide a performance gain without breaking the bank. Remember the reason we did what we did, was because she just wanted some sound out of it.

 

The long elephant **** going to the VFAD is there primarily to eliminate noise . Try removing it and see what that sounds like .

seems like the hole you cut created a resonance effect with something in the intake .

 

Well it definately did! I did not believe that was the case, but the car makes SO MUCH induction noise that all the plastic in and around the airbox vibrates making our noise.

I took the lower part of the airbox out and fooled with it last night... Removing anything that could cause the vibrations and resonance. We got it down to the point where it sounds normal 92% of the time.

Relieved to know that it is not the engine. And I'm happy we did the ignition work, it feels much better to drive. Smoother, peppier and more rev-happy.

We're on the lookout for a new intake now.

 

With aftermarket intakes for the RX-8 "lookout" is right; the best ones are the AEM 21-485 and the Racing Beat systems. The rest always seem to have some sort of problem with MAF sensor accuracy.

 

Jon, Charles, Brettus, Spigot and those who else helped.

I confirmed tonight that it is NOT the cut factory intake afterall, and is something else that is STILL wrong. The reason we could not hear the noise with Spigot (Brian)'s factory intake, is that suddenly all induction noise whatsoever has ceased.

Still skeptical that it was indeed the intake, I had a new K&N typhoon complete intake system at my finger tips. I KNOW it is generally a poor design, but I needed to see before ordering a non-returnable item out of the states.

After a brief install tonight, it is making the same garbling, gargling rattling sound. It happens at the same point it did before; 5000 rpm and up. It is still definately heat related, the hotter it gets the worse it gets. And for the once by luck you can get it to stop, the car seems to move a little better.

Now the car has the following parts NEW: Coils/ Plugs/ Wires/ Intake/

My last suspected cause is this catalytic convertor. We drove applying the brakes to maintain 5500 rpm at WOT in 2nd gear to make the noise happen, opened the door, and could not hear anything from under the car. It was all induction noise. I have not had time to pull it off yet and check it's condition.

There has been no CEL's with the car in a LONG time. We had one a few months ago. It came on for a couple days and went away on it's own. We're averaging 13 mpg in city. She has a heavy foot however, and often takes the car to it's last beep before limiter. Could this poor economy be a sign of a broken/ plugged cat?

There is also a small sensor with a 3 wire plug on it on the passenger side of the car.. It is bolted with a single 10mm head to, or near the air pump (?). It has a single hose coming out of the bottom, but this hose looks as though it has been cut. There is no sign of a hose anywhere that would connect to it. I plugged the hose, and there was no change noticeable.

We purchased this CDN 06 6AT used. It was previously a lease vehicle in Vancouver BC, and had 33,000 km on it when we bought it in Jan 2010. This is not an issue i'll take up with the dealer until I know it is the engine, as we'd be in for $1500.00 in diagnosing fees already. The car does fall into the extended warranty category, but if it is not a warrantable failure they'll stick us with however many hours they have into it.

I'm seeking your help once again..

 

Do you want to stick my box back on and leave it there for awhile? I'm around mostly all day today, but racing with Corvette Club tomorrow.

 

Thanks Brian, thats a nice gesture.. We should however get this figured out, as something is obviously wrong. Putting a stock intake on the car is only muffling the issue.

We're going to Revelstoke to do some climbing today, so I won't be able to pick up with this issue until monday. If I need to borrow it again, i'll call you come monday.

Is it possible that it could be a stuck port/valve within the engine?

 

Don't do that . That is the atmos. pressure sensor . You will stuff up the tune by plugging it .

I'm confused as to whether the noise changed in any way with a different intake on ?

 

Duely noted, it is un plugged.

With the different intake it is making the same noise, just a different tone. Different tone, obviously because it is a different intake.

Could it be a catalytic convertor rattling??

 

Bad phone video, but it gives you an idea.

Listen to it just as the car sweeps past 5000 rpm in 2nd, and shifts from 2nd to 3rd.

http://www.youtube.com/watch?v=x365mqcr470

 

The last video it was hard to hear anything.

Did you still have issues with your car with the stock intake you borrowed? You said the problem seems to be heat related. If you are still having issues with the borrowed stock intake. And coils, spark plugs and spark plug wires are all good? When my first engine went the car would run great while cold but when warm i was having issues, found out the apex seals were not sealing correctly. Mazda gave me a new engine under warranty.

 

With the stock intake it did not sound like there were any issues... But I think that was because the stock intake emits so little noise that we could not hear it at all.

We tried the modified stock intake, and the K&N intake. Both produced the same results. We tried an OE intake, right down to the OE filter.. And simply could not hear any sounds at all, mainly because it was so muted. I thought I may have heard something from the OE intake, but was not sure simply because of the lack of sound.

Did you have any odd sounds when your apex seals were not sealing correctly? In my opinion, our car runs well. A little slow overall maybe, but it is also an Automatic Full Option car.

The only thing left is ruling out the catalytic convertor, before sending it back to Mazda to have them look at the engine.

 

If all you are changing is the intake and by doing that it changes the sound then , logically, the sound is somehow to do with the intake .

Not the cat .......

 

I would describe it as a flapping/fluttering/stuttering sound...organic/rubbery..not metallic in any way..almost like the engine is misfiring, but it doesnt seem to affect the cars performance. Very pronounced when you hear it in person.
It's the ambient temperature thing that baffles me.

 

It is definately not metallic sounding. And it is definately not something to do with the intake that is attached to the throttle body itself.

The piece making the noise is somthing either in the engine, or bolted on the engine. We have only explored the intake and ignition side of things so far. We havent touched any of the valves yet: SSV/ VFAD/ etc. or the exhaust (catalytic convertor).

It is not so much ambient temp as it is engine temp. It did it for us back in Feb/March too, only when it gets hot. The hotter the engine gets, the louder and more pronounced the sound.

Tonight I'm going to remove the stock midpipe and see if I can see anything wrong with the cat.

I'M FKing FRUSTRATED.