crazyhouse2011

My 1995 Civic EX has (what I recently discovered to be) a catback exhaust and a 4.5 inch fart can. It is the original D16Z6 and is unmodified. It is a five speed. Now. Sometimes when I'm shifting gears and the revs drop down while the clutch is in I will hear a faint but distinctive POP coming from the exhaust pipe, like a miniature backfire. Boy, it sure is pleasing to hear that noise, but I am still unsure what it is. Also, sometimes if I am driving and I let the revs get to about 3 grand, then back off the gas and coast (engine brake) I will hear a bunch of these pops in succession and overlapping. It will sound like a throaty gargling noise, and it is very satisfying to hear. I cream every time it happens. What exactly is this noise? (note, it usually only happens in 2nd and 3rd gear, but I don't try it in first because I slow down too quickly and there really is no reason to.)

In about a half hour I'm going to a friend's to pick up a power drill for a little home improvement, so I'm gonna put my laptop in the trunk and record the trip, then take it home and listen to the soundtrack and see if I can isolate some of these phenomena described above, and then convert it to video format and upload it in this thread.

Once again, thanks H-T

pityocamptes

Three possible things:

1) Running Rich
2) Running lean
3) Exhaust leak and sucking in O2

crazyhouse2011

Aww man that blows. I think it is running a little rich though. My grandpa said so because of the black residue above my exhaust pipe. It does smell good though! I dont think there is an exhaust leak though. Unfortunately I was unable to record a decent track, because putting it in the trunk put it right above the fart can and all i heard was fuzzy crackling when I played the track back afterwards.

pityocamptes

You usually can tell, assuming your can doesn't have a flame arrester. I know on an older truck I got, when it was running way rich and popping like you describe you could see a pretty blue flame at the tailpipe at night...

I would make sure you do not have a cracked exhaust or running lean, you can burn the valves out...

B_Swapped93

100% runing rich my bumper had lots of soot on it before i got it tuned. but insted of slight poping it would just snap/crackle/bang but i've got a GSR with with a full straight pipe. You like that smell ? i chocked evey time exhasut leaked into the cabin !

crazyhouse2011

Something tells me the last owner straight piped the catalytic converter because it doesn't have that shitty smell that new cars do. It smells more like an old muscle car, and kinda has that throaty sound too. Whoever did the exhaust did it right, because the fart can doesn't sound like your typical BUZZZZZZZ BAH BUZZZZZZZZZZZZZZZZZ.