Weird Noise after 5k RPM at WOT (Video Included)
 

*This is a copy of the other thread i posted in the trouble shooting forum but im posting it here so more people see


Ive driven other rx8s and i know the difference between valves opening and what i have. When i go WOT above 5k my car "screams". I have an aem intake and im suspecting the screens got caught in the throttle body but im wondering why it didnt throw a CEL. Im going to take it apart at some point this week and see.

The power above 5k feels very laggy. i will get a video for you guys. Its hard to describe. The pitch changes and almost sounds like dare i say vtech (not trolling)

Any thoughts of what it could be ??

* Coils are brand new jsut changed
* Spark plugs and wires changed about 10,000 km ago

IMG0075 - YouTube clicky

sounds like missfire.
plugs? coils?
are you running a cat?

Drop the cat and look inside.

- Brand new coils were just installed a week ago
- Plugs and wires were changed 10,000 km ago

No CEL is thrown at high rpms (not sure if thats a sign of misfire or not)

Yes i am running a cat Im thinking thats the problem and it could be clogged. WHat exactly causes a clogged cat and what am i looking for when i drop it and look inside ??

Im debating whether to just get a midpipe to fix this if it is the CAT thats the issue.

Year with how many miles on the engine? My Cat went out at ~55k miles so definitely check it.

What you want to see is something like this.. nice and intact.

http://0.tqn.com/d/autorepair/1/0/X/...tic-inside.jpg

What you DON'T want to see is sometihng like this OR worse:

http://www.2carpros.com/images/artic...t_material.jpg

HOWEVER, our Cat as described in MANY posts on this forum before this is designed in two parts and the second section which we can't see could be the problem and the first section could look fine. Not likely, but possible.

car is a 2006 with 105,000 km (not sure how many miles that is)

sounds like broken cat pieces are just rattling inside the cat

I might just get a midpipe to fix it then. thanks

bump any other ideas

gut your cat

Will do thanks !!!

or go claim the cat under emissions warranty (if such thing exists up in the small piece of land above good ol' murikka, and just save it for a rainy day (or sell it for some $$$) and get a midpipe.

Ya at this point. I think i will just wait till someone local sells me a midpipe. I was going to get one anyway and i think its time. That way if the CAT ISNT the problem, i wouldnt have taken it off for nothing .. ill just swap it with the midpipe right then and there.

Also any harm in driving the car with a Shot Cat until i find a midpipe ?? A buddy might sell me his BHR cause hes selling his car so im hoping its soon.

Definitely avoid driving the car if the cat is starting to fail. If you really need to drive the car with the cat on, I'd definitely inspect it to see if it really is starting to fail; if you notice the cat is going bad, I'd say just gut it out and install it back on so you can drive your car safely until you get your hands on a mid-pipe.

Thanks I have no choice to drive it until Tuesday when I have time to gut he cat. Hopefully I find mid pipe by then

update: so got a BHR midpipe installed today. I inspected my cat and the honeycomb material is intact. THe car does pull more but not sure if its in my mind but the car lags right at 5500 - 5000 rpm still then pulls through after.

Mine is doing the same thing it's making a weird noise after 5k or 6k and I have a AEM cold air intake in mine I have no clue what it would be did you end up finding out what the problem was sure would be helpful thanks

Ive been trying to fix a similar problem on my 2007. I have an AEM intake as well, however i don't think its related. If you install the intake poorly and don't line up the sections well it can make a slight noise but this is different. After doing some research i decided to flush the coolant and install a new water pump (i got the re-medy billet one) because the stock water pump is very cheap and inefficient and air bubbles/caviation in the coolant can cause raspiness, especially under WOT. This made things noticeably better, however under wot at high rpm a little raspiness is still noticeable, and a seriously doubt its the cat because I had mine replaced about 10,000 miles ago. As for the dip in power at 5,500, I'm pretty sure if you look at dyne charts for a stock rx8 torque dips a little at around 5 grand, so thats probably what your feeling. I don't know if whatever is causing your problem compounds the torque drop off but theres a chance its unrelated. I also have new coils, plugs and wires as well as an engine which was compression tested 4 months back with stellar numbers.... although i have 104k on the clock. Any help would be appreciated, and I would encourage anyone with this problem to burp their coolant at the very least to remove it as a variable.