anyone's exhaust spit flames?

Sh0velMan · 06-05-2013, 09:17 PM

Lean won't cause flame. Rich will. (Within reason, you can be so rich that your EGTs are really low and thus external combustion won't happen) The hot fuel vapors meeting cool oxygen = burny burn.

That said, you usually see it in turbo applications where there's a spike in exhaust fuel content on up-shift due to boost fall off and the exhaust is really hot due to being turbo (naturally higher EGT, turbine heating exhaust gasses a little immediately off boost).

forza370z · 06-05-2013, 09:32 PM

Quote:

Originally Posted by Sh0velMan

Lean won't cause flame. Rich will. (Within reason, you can be so rich that your EGTs are really low and thus external combustion won't happen) The hot fuel vapors meeting cool oxygen = burny burn.

That said, you usually see it in turbo applications where there's a spike in exhaust fuel content on up-shift due to boost fall off and the exhaust is really hot due to being turbo (naturally higher EGT, turbine heating exhaust gasses a little immediately off boost).

Well, after some research the anwser is both lean or rich will cause the backfire which leads to shotting flames out of the exhaust...

Quote:

Backfiring in internal combustion engines occur outside of the combustion chamber, and are typically the result of an improper air to fuel ratio. An overly lean air-fuel mixture (i.e. an overabundance of air) can lead to a failure to ignite in the combustion chamber, also called a "misfire". The unburnt fuel then enters the exhaust system, where hot components can cause the fuel to ignite unpredictably. Alternatively, rich air-fuel mixtures (i.e. an overabundance of fuel) can result in incomplete combustion, again causing unburnt fuel to enter the exhaust system.

Back-fire - Wikipedia, the free encyclopedia

Sh0velMan · 06-05-2013, 09:40 PM

Quote:

Originally Posted by forza370z

Well, after some research the anwser is both lean or rich will cause the backfire which leads to shotting flames out of the exhaust...

Back-fire - Wikipedia, the free encyclopedia

That's true as well! I guess the afterburner looking flames like the video had can be a lean condition and the crazy flame thrower style flames could be rich... Meh.

forza370z · 06-05-2013, 09:48 PM

Quote:

Originally Posted by Sh0velMan

That's true as well! I guess the afterburner looking flames like the video had can be a lean condition and the crazy flame thrower style flames could be rich... Meh.

The conclusion is we were both correct.

SouthArk370Z · 06-05-2013, 10:13 PM

Quote:

Originally Posted by Sh0velMan

That's true as well! I guess the afterburner looking flames like the video had can be a lean condition and the crazy flame thrower style flames could be rich... Meh.

I'd say your guess is right. Most (if not all) hydrocarbons burn with a bluish-whiteish flame when in normal to lean conditions and burn yellowish-orangeish when rich.

06-05-2013, 09:17 PM	#1 (permalink)
Sh0velMan A True Z Fanatic Join Date: Jan 2012 Location: Dallas/Ft.Worth Posts: 3,349 Drives: Noisily. Rep Power: 22	Lean won't cause flame. Rich will. (Within reason, you can be so rich that your EGTs are really low and thus external combustion won't happen) The hot fuel vapors meeting cool oxygen = burny burn. That said, you usually see it in turbo applications where there's a spike in exhaust fuel content on up-shift due to boost fall off and the exhaust is really hot due to being turbo (naturally higher EGT, turbine heating exhaust gasses a little immediately off boost). luigi90210 likes this. __________________ Buy My Car! \| Build Thread Last edited by Sh0velMan; 06-05-2013 at 09:20 PM.

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