Flame from exhaust?

[Supra4ever]

Do all NA-Ts shoot out flames from exhaust occassionally?

I nosticed my car miss fire once or twice a day when I make boost and let off immediately with loud bov sound. The miss fire occur when I shift during wot 10~30secs later. I guess too much unburned gas?

[turbo_gts]

i've been told i back-fire a lot when racing. usually when i get into the higher rpms. the only time i noticed it i heard a loud popping sound and a flash came out from behind the car (saw thru the rear view mirror while looking for something to fall off the car) and a short fireball came up. it was cool but i was concerned bcz i thought something broke at first.

[hsspunk]

it happens because your into boost and all of a sudden you let off the gas. when you let off the gas, you drop to like -23~-26 vacuum. and your car most likely isn't tuned from like 6000~8000 rpms under that low of vacuum settings because you are never going to hit that unless you are letting off the gas real quick(-20~-26)

[Bean]

it happens because your into boost and all of a sudden you let off the gas. when you let off the gas, you drop to like -23~-26 vacuum. and your car most likely isn't tuned from like 6000~8000 rpms under that low of vacuum settings because you are never going to hit that unless you are letting off the gas real quick(-20~-26)

It happens because he's probably running an open-vent blow-off valve... all that air is vented out of the system which has already been metered and therefore there is a TON of excess fuel that isnt ignited in the cylinder. The fuel vapor builds in the exhaust chamber and the hot exhaust gases from either cylinders that are firing correctly or the whole motor running correctly whenever more load is applied (as in shifting gears) and then ignites the fuel in the back and it blows out the exhaust.

Toyota didnt leave any stone unturned when tuning the factory ECU. Its tuned literally for all instances of any air pressure and any airflow volume up until the AFM is wide-open at 5v.

I had a open vent bov too and had this happen quite a few times. Once I rerouted it, it didnt happen anymore.

[Supra4ever]

It happens because he's probably running an open-vent blow-off valve... all that air is vented out of the system which has already been metered and therefore there is a TON of excess fuel that isnt ignited in the cylinder. The fuel vapor builds in the exhaust chamber and the hot exhaust gases from either cylinders that are firing correctly or the whole motor running correctly whenever more load is applied (as in shifting gears) and then ignites the fuel in the back and it blows out the exhaust.
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Exactly what you two described.

is this bad the the car?

[Bean]

Exactly what you two described.

is this bad the the car?


Not really, you're not gonna burn a valve with a tubular header like that; its able to flow enough air out of there to be ok. Though your bumper probably HATES you ROFL :thumbup:

RX-7s however do this STOCK... well when cat-less anyways. And it is partially because of the reasoning described by hsspunk and because they just run piss-rich anyways ;) The irons and manifold get so hot on that motor that it just ignites that fuel while in the exhaust and you'll hear a loud POPPING and CRACKLING... sometimes its loud as fawk.

My friend had an FC with a 60-1, big fuel, and running via a Haltech E6K... that bitch BOOOOMED... it wasnt a crackling at all either. And big flames would just "whoomp" out on occaission. Was pretty impressive. Scared the shit out of some people.

[soarerflame]

nice!