Driving home from work tonight and as I pulled in the drive the car backfired and my dad happened to be outside and said it sounded about like a 20 gauge firing off and a bit of flame came out the exhaust. I've searched the forums and haven't seen anything on a 2.4 NA backfiring so figured I'd start this thread in hopes of some possible answer. Mods are Bad-Mab header (which I've been fighting on and off with an exhaust leak), ZZP catted 2.5 inch downpipe, Borla catback exhaust, and a tune from Trifecta that isn't quite dialed in. Any ideas would be greatly appreciated. Thanks

 

probably just unburnt fuel hitting the exhaust

 

An exhaust leak will make an exhaust pop. The exhaust on my Nova would pop violently when it got loose. I probably should've had it welded instead of bolted though. I set off a lot of car alarms with that leak.

 

Get the tune dialed in before you start messing with everything. How old are your plugs

 

haha, when ever i take the nova out, im the dick who drives with the cut outs open >____< open headers FTW!

serious note, def get the tune dialed in first.

 

Looks like a few of us have Novas.... I have a 79

 

sweet deal lol. you, me, and supernovanator lol. and i think one more guy. we all have balts and novas! FTW! i have a 72 nova though and 09 SS/TC.

 

I bumped my nova thread titles my other toy, throw some pics up man!

 

i will have to when i get back to the dorms. military computers dont allow us to hook up USBs lol. ill go check out the thread so i can post some later.

 

My 2.4 popped and spit a decent amount unturned with the high flow catted downpipe every header and the slp catback. With the factory downpipe back on it just pops some on decel now. It's pretty normal.


Now my camaro definitely backfires haha but its currently running pretty much header only lol

 

popping and backfiring are two different things. the popping is normal, backfiring is not.

the popping is just turbulance in the exhaust pipes. an H or X pipe on non-inline motor will balance out the exhaust and eliminate the popping.

if youre backfiring, then you need to check the tune. thats where i would start, esp where you said its not dialed in right yet.

 

Partially correct. But a v8 with an H or x pipe can still pop just depends on muffler choice (some chokebastard and of course SLP will pop probably some others as well). Untuned they can backfire and pop still (have had 7 fox body mustangs).

Im untuned on the cobalt currently and it only pops with the factory downpipe. The high flow catted downpipe I had it would backfire and shot sparks/small flames on high rpm decel. A tune would solve the latter. But the popping would still be there. You can actually tune out the popping but it would most likely hurt performance. (just going on what Ive seen from local cars and from talking to local tuners).

Now if the op didnt change anything and one day it just decided to backfire then he needs to start looking into things.

But if he's just talking about pops and small backfires then I would just look into a good tune.