My car is an 02 WRX with a catless up/dp and cobb AP. I've noticed that at around 3k rpm, i hear a fast rattling, buzzing or tapping sound. It sort of sounds like preignition, but it disappears at lower or higher RPM's. Is anybody familiar with this problem? I've tried a few different maps including the economy map, but the problem seems to remain.

For those with Cobb AP's without problems, did you have to have the car custom tuned or did you reflash and drive off? Thanks in advance for your advice.

possibly a loose heat shield.... check em out.

thanks blu. would a loose heat shield rattle at 3k only?

thanks blu. would a loose heat shield rattle at 3k only?


yeah most times its the frequency of THAT rpm that it will rattle and only then.

I'm crawling under the car tomorrow to install cartboy bushings, so i'll look for a loose heatshield too. Thanks again...

I'm crawling under the car tomorrow to install cartboy bushings, so i'll look for a loose heatshield too. Thanks again...


no prob. be sure to check everywhere. any idea of a location of the rattle specifically pass side, driv side?

Is the AP your only mod or somthing?

Is the AP your only mod or somthing?


why???

Revert to stock (unmarry) and see if the problem goes away. If it does, you know where your problem is... if it doesn't start looking elsewhere. Yes, it's really that simple.

Revert to stock (unmarry) and see if the problem goes away. If it does, you know where your problem is... if it doesn't start looking elsewhere. Yes, it's really that simple.


your saying the ap is causing a heat shield to rattle? :confused:

your saying the ap is causing a heat shield to rattle? :confused:

Don't be stupid. Can you be absolutely sure it's a loose heatshield without hearing it in person and from what the OP has stated here. No, you can't. From the OP I gathered that he started experiencing this after marrying the AP (based on the wording of his post) so taking it off would take 5 minutes and pinpoint the issue as being (det, wastegate flutter, or simpley some rattling not related to the engine internally). There have been several people in the past that have experienced either wastegate flutter or det arround that RPM level and thought it was some kind of rattle... I never stated it was the AP most definatly... I stated that it would be easier to try this then track some rattle down if in fact it wasn't a rattle. In either case, if he unmarries the AP and it goes away then it wasn't nessaceraly the AP, but rather the POS OTS Cobb map that's on it. Those maps don't work for everyone. But hey, it could also be a rattle... who knows... no one does because you haven't heard it in person.

I have the exact same problem on my 02 wagon, I tried everything to find it, but was unable to pin point it.. it was not pinging in my case, but the noise is always there under decent boost.. I've tried to unmarry the AP and it was still there..

I have the same problem, but it sounds like the dash is vibrating due to the resonating frequency of the exhaust. Is this similar to your problem?

hey all, sorry for the late reply. my notification doesn't seem to be working. I think I will unmarry the AP and see what happens. I've gotten enough advice from long time AP users and tuners to be plenty worried about what i'm hearing, so i'll let you guys know what i find out after I unmarry the AP and drive it around. Thanks for the advice and i'll let you guys know what happens in a day or two.

ok, so i went ahead and unmarried the ap this morning before going to work. here's what i found out. First, the sounds are still there. Second, it's not exactly at 3k. it starts somewhere around 2500 rpm, but is the loudest at 3k. it's also not in every gear. It seems to be worse in higher gears. Under very slow acceleration in first, i don't hear it at all. Do you guys still think it's a heat shield? I actually feel better knowing it's not the AP since i now fully realize just how much power i got from using the AP after unmarrying and driving this morning . Thanks again.

Is it related to the temp of your car in any way?

Louder when cold but quiet when warm?

i'm guessing that it doesn't have to do with temp b/c i heard it this am on a completely cold engine, and hear it all the time when doing 2+ hr drive to/from LA from south OC. Can i figure out if it's a heat shield with the car not running? I've got to take this car to the Wednesday meet's and let some of you guys hear it.

yes im pretty sure its a heatshield of some sort.... have you even looked yet? check the manifold and turbo heatshields.

What DP.....I swear I have heard that some peope have thier after market DP rub on a crossmember...maybe the tranny crossmember?

i've got a cobb catless dp. i'm not exactly sure what i'm looking for since the only time i can crawl under my car is when it's cool and not running / moving, but i'll poke around and see what i can. thanks again for the advice.

that's the wastegate.

could be wastegate flutter. what's your boost at? is it happening between .05 and 0? if so its wastegate flutter.

i'll head out to a local meet and see what the guys there think of the funny sounds.

I had the same issue. Not to freak you out but mine was rod knock. It would start at 3k loudest around 3.6K gone by 4K. Take a screwdriver and listen to the cylinders on the drivers side as see if you can pinpoint the noise. I could hear a light click/clack at idle on the rear cylinder.

i have a friend with an sti listen too and he thinks it's a heat shield. here are my reasons. first, it doesn't happen in first gear, or when i am accelerating under a light load (first gear, downhill). Second, i unmarried the ap and it makes no difference. the sound is identical. i can also change maps and the sound stays the same. third, temperature makes no difference. whether the engine's cold or hot, the sound is there.

so i'm kinda sorta deciding it's some kind of buzz from a heat shield and turning the radio up. i don't think i can open the hood and listen since it only happens in 2nd gear and above and i don't know anybody willing to be strapped to the hood of my car while i spool it up. :)

The heat shields on WRX's are well known for a rattle between 2500-3000 rpm. This goes back to GC WRX's as well. Especially in 1st and 2nd gears.

Let your car decel. from around 4000rpm without throttle and listen if it starts rattling from 3000rpm and under. If it makes a metal rattle noise, it is most likely your heatshield.

doesn't seem to happen under no load or deceleration. i can mainly hear it in 2nd - 5th gears under a medium load. if i floor it, it doesn't seem too bad. if i'm really lightly accelerating, it's not too bad either. seems the worst under medium load.

I am guessing it is the turbo heatshield. If you hacked the stocker to fit over the cobb dp, then it is definitely the turbo heatshield. It is a two layer piece and when you cut off the bottom half to fit over the bigger dp, the two pieces begin to delaminate and rattle. Same thing happened on mine.

I used some liquid weld to seal the seam, then applied exhaust wrap to the whole piece on the outside of the shield. This cured the rattle and significantly reduced the heat radiating off the shield.

Thank you for the advice. i'll check out the heatshield and see if that does the trick and let you all know.