hmm... could be a leak then.

Check the bellmouth of the dp for any soot(black spots). It maybe just a leak. You could also wait till the dp is cool to the touch. Next turn the car on and put your hand around the area where the dp and the turbo meet. Try to feel for any exhaust leaks. You may have a friend tap the gas and check if you still hear the noise.

Hope that helped.
Keep us updated.

 

hey guys! thanks again. I will take a look underneath the car later today... if it's a leak i'll be very happy. Also, do you think it could be a leak between the midpipe and the catpipe?

Mcdrama, if it's not a leak i'll try the colder plugs, and if that doesn't solve anything then maybe i'll drive down to SJ sometime

i'll keep you guys updated!

 

what's up guys.
I took a look under the car, dont see any soot or signs of any other leaks... however i did notice that my exhaust system is pretty close to the chassis and i'm wondering if the sound is coming from my pipe banging against something... i think it might be a possibility since i can feel the vibrations from under me and i can recreate the sound everytime i lurch the car in reverse... makes sense right? (again, why would i be detonating in reverse? haha) I tried to wiggle the downpipe and exhaust up and down and it would play just a little bit too.

 

Check for signs of scuffing on the DP.

 

afterfire possibly? is your car catless now or only has one high-flow cat?

 

d'oh it's raining now but once i get a chance i'll check for bumps and scrapes.

Right now i only have one cat left, it's in the uppipe... i've heard of afterfire before but i'm not exactly sure what that's about...

 

afterfire is excess gas being burned off in the exhaust system. it usually happens when you lift off the gas abruptly or downshift.

 

so can someone explain to me what denotation means, i have no idea. i read the thread on nasioc on denotation and it seems that it only happen mainly with 04 models. so if i go catless on a 02 wrx i should be fine right?

TIA

 

im not 110% sure, but I think on an 02 you should be fine.

The detonation problem with the 04/05 models happens because of (correct me if I am wrong) a delay in fueling. It is the switch from closed loop(stoich) to open loop(rich) fueling where on the 04/05 models there is a greater delay that will cause you to run lean(stoich) while the turbo is producing boost when it should be running rich.

edit: here is an interesting PDF on OL/CL fueling:
http://www.autoshop101.com/forms/h58.pdf