My 04 Cobra backfiring?

[SL0BRA650]

Hello SVTP, I have a stock internal motor 04 cobra. Ive been dealing with a small back fire and I cant figure out whats the reason for the backfire to occur whenever I let off the gas.

Current Mods:
2.8h kb
60# injectors
kb bap
afco h/e
ngk plugs #3334 at .028 gap
accufab tb
jlt cai
Exhaust:
stock manifold with custom welded (previous owner) bassani o/r x pipe with borla stinger catback. (the car use to have magnaflow race cb with flowmaster tailpipes and that use to backfire like crazy)

Ever since I put on the borla cb, the backfire isnt too bad compared to the old magnaflow race cb.

Car was tuned by AED in NORCAL. Car has stock 2.8h kb upper pulley, so I think its only at around 15psi of boost.

Im just looking to see what other reasons why the car is still backfiring a bit.

Thanks.

 

[BMR Tech]

I never really figured out why mine does it.

I've gotten to like it, actually. lol

 

[SL0BRA650]

I never really figured out why mine does it.

I've gotten to like it, actually. lol

lol How long have you been riding around with the backfire?

 

[gnatsumarboc03]

If you referring to when the car is slowing down then I think that backfire is awesome and is normal :shrug:....but if its just backfiring at random times could be exhaust leak.

 

[SL0BRA650]

If you referring to when the car is slowing down then I think that backfire is awesome and is normal :shrug:....but if its just backfiring at random times could be exhaust leak.

Hmmm, yeah backfires while slowing down while being in gear. Use to be horrible with the old magnaflow catback. My old 03 cobra never experienced backfire to the point where it was really noticeable as my 04. My 03's exhaust set up was: bassani o/r x pipe (no modded weldings) with the same borla stingers on my 04.

 

[JuStAkId]

Mine does it as well. Search and youll find its quite common

http://www.svtperformance.com/forums/terminator-talk-229/393983-exhaust-popping-deceleration.html
http://www.svtperformance.com/forum...und-come-out-exhaust-during-deceleration.html
http://www.svtperformance.com/forums/exhaust-215/435460-popping-decel.html

 

[Mystic03]

i had same thing with my car. now when i went return it went away my blue 03 cobra does it too though. so i guess its just the nature of the returnless? :shrug:

 

[SL0BRA650]

Mine does it as well. Search and youll find its quite common

http://www.svtperformance.com/forums/terminator-talk-229/393983-exhaust-popping-deceleration.html
http://www.svtperformance.com/forum...und-come-out-exhaust-during-deceleration.html
http://www.svtperformance.com/forums/exhaust-215/435460-popping-decel.html

Thanks, I apperciate the Link.

 

[SL0BRA650]

i had same thing with my car. now when i went return it went away my blue 03 cobra does it too though. so i guess its just the nature of the returnless? :shrug:

Im thinking that, that could be possible as well. I know that backfiring while deacceleration is normal to a certain level imo. But idk, I think ill have to get a vid of my case.:dw:

 

[03TopDown]

Mine pops pretty good when slowing down because it runs a little rich

 

[03Steve]

It isn't normal. It is very tunable. Spark source goes to 18 during decel. This indicates that the Spark Under Deceleration table is being used. Modifying this table will eliminate the popping/backfiring. It is very common on modified stick cars.

 

[BayAreaTech]

Mine pops on deceleration aswell but I think it does it more because a lil rich.

 

[03Steve]

Here are my notes on it:

How To Get Rid of Exhaust Popping Under Engine Deceleration - Tuning and Tweaking Talk - STLMustangs Forums

 

[Zemedici]

^^ bingo

 

[svtshadow]

I love it when it pops like that especially when downshifting. Its screams badass lol

 

[MalcolmV8]

It isn't normal. It is very tunable. Spark source goes to 18 during decel. This indicates that the Spark Under Deceleration table is being used. Modifying this table will eliminate the popping/backfiring. It is very common on modified stick cars.

This is correct. I go through phases where I love my car to cackle and pop like mad on decel and then I go through phases where I like it to be a smooth more refinded exhaust rumble. The joys of tinkering

 

[04DeadShort]

Here are my notes on it:

How To Get Rid of Exhaust Popping Under Engine Deceleration - Tuning and Tweaking Talk - STLMustangs Forums

I agree

 

[unlgrad2002]

Anyone get the popping/backfire when shifting under moderate acceleration?

 

[40mpgH8r]

Yeah, I didn't think this was normal. Mine doesn't backfire at any time.