Less exhaust popping\backfires with 94 octane ?

[TheDamned]

What would cause this considering that my Stang is bone stock (except o\r h-pipe) ?
I notified a BIG difference in the deccelaration popping\backfiring since I fill her up with 94 octane yesterday.

 

[Daggar]

Start looking into your ignition system. My first thought is that your spark may not be doing the job. What's you timing set at and why are you running 94 octane is a basically stock motor?

 

[srothfuss]

The popping / backfiring in the exhaust is from unburnt gas igniting.

Higher octane gas is harder to ignite. So by increasing the octane you are just making it harder for the exhaust to burn up your unused gasoline...

 

[Daggar]

My other thought on this issue is that perhaps you thought that by running the highest grade gas that you could get your hands on, is that you figured it gave you cart blanch to wind your initial timing into the roof. If that's the case, then you're probably firing off the mixture WAY too soon.

 

[TheDamned]

OH ok

I tough putting 94 octane and having less popping\backfires was better... I guess not. I have no idea if the timing has ever been touched, i bought it like that. Is there any easy way to see what its at ?

 

[Daggar]

OH ok

I tough putting 94 octane and having less popping\backfires was better... I guess not. I have no idea if the timing has ever been touched, i bought it like that. Is there any easy way to see what its at ?

I'm not sure if I would consider "LESS popping\backfire" much of an improvement. hehe NO popping and backfiring would be a good thing though.

Put a timing light on it to see where it's at. If timing is good (12 to 14 would be a good start) then start looking at other portions of the ignition system to see if you can find any faults. The idea (of course) is to discover why it's doing it. Timing too far advanced would be the simplest to look at first. There come a threshold where no amount of increasing octane will cure problems by timing too far advanced. If you're starting the combustion process too early in the cycle then burning of the mixture is taking place at the wrong place in the cycle (like when intake valves are still open, for example). Tuned properly, I would hazard a guess that maximum HP could be obtained running 89 octane fuel on a stock combo.

 

[TheDamned]

I'm not sure if I would consider "LESS popping\backfire" much of an improvement. hehe NO popping and backfiring would be a good thing though.

Well i think backfires and popping are badass lol, you should see the face of the people when im putting the bitch on 2nd gear going downhill haha

 

[crazypete]

Well, if it's bone stock except for h-pipe then I would say you have carbon buidup on the pistons and the carbon gets hot and causes preignition.

Run some seafoam through the motor and see if that improves it. Add some acetone 4oz/10 gals to your gas. It reduces popping/backfiring a bunch.

Check for exhaust leaks. Air gets in through loose flanges and causes the exhaust gases to ignite in your tailpipes.

 

[Daggar]

Are your injectors also stock? Larger injectors without a tune (specifically to fuel ramps and injector brekpoints) can case a significant amount of popping during deceleration. It shouldn't be causing that kind of symptom when on the gas though.