2fastoyz

has anybody experienced big time back firing on decel at almost every rpm range above 3000 rpm. It's so bad that my buddy following me the other night saw flames popping out of the muffler. FYI i have LT headers no cars and a dynomax muffler that dumps before the axle, any help is appreciated

SURFINUSA

iTrader: (3)

I have some backfire, but nothing too bad. Do you have modifications to the car? If so, did you get it tuned?

SURFINUSA

iTrader: (3)

*modifications other than the exhaust?

2fastoyz

i do have many mods, but the major are 383 stroker, zo6 custom ported heads, mild comp cam, fast 102 which since i got the intake installed and dyno tuned the back firing got worse

strokerrace

iTrader: (8)

What was your AFR at after the tune?

2fastoyz

13 to 1

orangeapeel

iTrader: (18)

hmmm. LS1's do tend to do it a bit. Sounds like yours may be a tad much. What are the cam specs?

2fastoyz

218/224 565

2fastoyz

im going back on the dyno this weekend, im thinking its something with the tune and not the exaust, cause my buddy has the same exaust set up as me and his car don't back fire at all

ls1 1990 VN

Do you know if your fuel over-run on deceleration has been turned off maybe when car was last tuned.

It usually is associated with the tune.

I had my car tuned & it drove me crazy with the constant back firing, took it elsewhere to get it fixed & now it's a pleasure to drive.

2fastoyz

that makes sense, i will ask em on friday when i bring it in for a tune, thanks

a-low

iTrader: (26)

Same thing here lts, sweethunders dumped,frost tune backfiring is not that uncommon especially
when my plugs are going out.

2fastoyz

well my fuel over-run on deceleration is turned off but it still backfires, anybody else have an idea what else it could be? Im ready to switch out my 5" Dynomax muffler to a
4" to create more back pressure, don't know what else to do....HELP!!!!