j87w

I have a 95 LS Teg. My exhaust like backfires or pops sometimes when its revving down. I have a dc sports header 4-1, aem cold air, and a trust cat back exhaust with no resonator or cat. Anyone have any idea why it does that?
Thanks

trex_tegra

a little pop is normal like does it do it when u put the clutch in when u get exhuast it nothing to worry about unless its really loud and messed up u should def get a cat tho if u get pulled over u can get in some serioius trouble chances are its a lot louder becuase u dont have either cat or resonator u should get a high flow cat or throw the stock back on and step up to a good cat-back with resonator ive got a greddy evo2 and i love it

ADRONICUS

I know exactly what it is cause I just had the same problem. The exhaust is too free flowing. The trust exhaust itself is not a backfiring candidate, but with no cat the air is moving out so quickly that when you slow down an air pocket develops at your tail pipe and then POP!!! I recently removed my muffler from the axle back and put my stock one on and it went away. I still have the piping but not from the axle back. The muffler on the end was just too free flowing and made the pops, and it just became annoying.

acuratxracer

thats exactly what mine is doing right now, and some times when im haulin ass down a fun road and it pops every now and again its kool, but ya it gets annoying and it doesnt do it when i have my silencer in so its jsut cuz the exhaust is to free flowing? it coudnt be that it is in need of a tune up?

XSrcing

when you release that throttle, your engine is getting little to no air into the cylinders, but you ECU is still sending a little fuel into the cylinders. there isnt enough air in the cylinders to ignite the fuel, so the unburnt fuel enters into the extremely hot exhaust manifold, which does have enough air for ignition. so small amount of fuel ignites in the exhaust creating a popping noise. you cant hear it with the stock muffler on because it does just that, it muffles the sound to the point that you cant hear it.

in other words, unless it starts getting very loud and you are shooting fireballs, dont worry about it.

acuratxracer

lmfao its still very annoying and i even start looking around to make every one think it wasnt me, like when you accidently fart in public.. but ya so it means that the exhaust is to free flowing ? if so do you or any one else know of a bad ass cat back system for a 91 ls that is quit but yet when you stomp it, it screams, and not the damn pissed off bee in a can sound like a nice deep bassy tone both at lower and upper rpm's

Provocateur

If you are shooting fireballs, it is most likely due to blowdown. It is when the exhaust valve opens before the compression stroke is done and it sends some of the explosion down the exhaust pipe.

ADRONICUS

So are you suggesting that the backfiring is always happening? We just don"t hear it when we're running stock exhaust? I find truth to your stmt. as well as mine. It may be a combo of both. A stock muffler can still pop, the pressure develops in the muffler and exits your tailpipe, like the muzzle of a rifle.

TheOtherDave™

Run a catalytic convertor. Please.
The modern high-flow cats flow very well and they keep the air breathable for everyone else. Please run one.

Adding a resonator will go a long way toward muffling the minor pops and gurgles on a trailing throttle. If you start belching fire out your muffler, then you've got a bigger problem, like leaking injectors or blowdown.

:chuckles:
I think you may find this helpful. h: