i heard this exhaust sound before when my car was still n/a and now it's turbo it is still there. i initially thought that maybe my exhaust pipe was big(2.5") for my stock motor hence the sound, but when i put in the turbo, i know the pipe is just the right size but the sound is still there. i feel there's something wrong but i'm not sure or maybe it's normal, i just don't know and it's annoying.

this is what it sounded:
instead of the normal steady brooooooooooooooooooooo, mine got a very faint broooooooooooooooooooooo but on top of it there's this bob bob bob bob bob bob sound(close to that, its hard to describe but it's like some tribesman drumming). it's usually more pronouce when i drive the car hard even when it's n/a but if i didn't drive hard it's not as pronounce.

the engine doesn't sound like that only the exhaust. what could be wrong? can it be misfiring? how can you tell if it's misfire? can it be the plugs coz when i took all four out it's a bit damp with oil coz of the seal on the valve cover? i'm confused. please help.

by the way the car is a 99 SiR boosting at 6psi.

 

replace your seals asap. youll know if you have oil on your spark plugs, youll blow out white smoke through your exhaust. get new spark plugs, ngkbkr7e-11s from advanced auto, part number 1283. gap them to .030, then you should be fine.

 

huh? what seals dude?

 

he mentioned the seal on the valve cover as well as oil on the spark plugs, so i assume he means the 4 circular seals that go on the inside of the valve cover.

 

thanks. i know i should replace the seal but i don't think that's the major reason why my exhaust sounds wierd. could the seals be the reason of the wierd exhaust sound? what could be wrong?

 

im going to say its your spark plugs right now. get the plugs i told you about, gap them, replace the seals so you dont soak the new ones with oil and then tell me how it runs. if it runs like *** still, we'll take it from there and figure out whats wrong...