Backfire Misfire

[1mic]

Whats the difference?
Show pics and is this a backfire:

 

[Goomba]

I think, and I stress the think part of it, but anyway, a backfire is where unburned fuel makes it way into the exhaust manifold/piping, and is then ignited by the temperature, making it shoot out in flames. Again, I think a misfire is when the spark in the engine doesn't occur at the appropiate time.

 

[vat_man]

Goomba - I think you about nailed it.

 

[rollazn]

Originally posted by Goomba
I think, and I stress the think part of it, but anyway, a backfire is where unburned fuel makes it way into the exhaust manifold/piping, and is then ignited by the temperature, making it shoot out in flames. Again, I think a misfire is when the spark in the engine doesn't occur at the appropiate time.

The ignition being delayed, the air/fuel mixture reaches the exhaust tubes mostly unburned. When the spark plug fires, the exhaust valve is starting to open due to the ignition delay. Additionally, the exhaust temperature being extremely high, the unburned fuel explodes at the contact of the exhaust tubes. That is what happen in a Misfiring system or Anti Lag system. Im guessing since its called Misfiring system then that is a misfire?

Im not sure about this. I always thought it was the same thing, that the unburned fuel make it to exhaust tube so it misfire or backfires.

Im still not sure what is what.

Goomba is probably right.

 

[Goomba]

I thought the valves would be controlled by the cams and that would be a whole different beast than the spark plugs. Maybe the computer compensates, I'm not sure.

I wouldn't say I'm right though. I'm rarely right.

 

[Cap'n Jack]

Originally posted by Goomba
I think, and I stress the think part of it, but anyway, a backfire is where unburned fuel makes it way into the exhaust manifold/piping, and is then ignited by the temperature, making it shoot out in flames. Again, I think a misfire is when the spark in the engine doesn't occur at the appropiate time.

I think your about right Goomba!

 

[slimer90210]

Originally posted by Goomba
I think, and I stress the think part of it, but anyway, a backfire is where unburned fuel makes it way into the exhaust manifold/piping, and is then ignited by the temperature, making it shoot out in flames. Again, I think a misfire is when the spark in the engine doesn't occur at the appropiate time.

this ones right on.

 

[skip0110]

Does a backfire have to include unburned fuel? When you drop the revs on a highly tuned engine quicky you sometimes hear a little -rumble-blat-crackle-blat-blat- in the exhaust, but no flames. Whats that called?

 

[TS1AWD]

Originally posted by skip0110
Does a backfire have to include unburned fuel? When you drop the revs on a highly tuned engine quicky you sometimes hear a little -rumble-blat-crackle-blat-blat- in the exhaust, but no flames. Whats that called?

I believe that is still a backfire. Unburned fuel is still igniting in the exaust system, but alot less of it as the engine isnt under full throttle. Not having a catalytic converter on your exaust system will cause alot of this as to the cats mostly muffle or filter out the unburnt fuel.

 

[Takumi Fujiwara]

Do misfires cause fire coming out the exhaust as well? In games (like BG2), Rally-spec cars with Misfiring systems are often portrayed with fre coming out the pipe. But does that really happen?

 

[rollazn]

Originally posted by Takumi Fujiwara
Do misfires cause fire coming out the exhaust as well? In games (like BG2), Rally-spec cars with Misfiring systems are often portrayed with fre coming out the pipe. But does that really happen?

The ignition being delayed, the air/fuel mixture reaches the exhaust tubes mostly unburned. When the spark plug fires, the exhaust valve is starting to open due to the ignition delay. Additionally, the exhaust temperature being extremely high, the unburned fuel explodes at the contact of the exhaust tubes. That is what happen in a Misfiring system or Anti Lag system.

In rally cars it uses an Anti Lag Systme or some kind of misfiring system... as you will see very often in a rally car the car make a big bang noise and fire usually come out of the exhaust pipe.

 

[drifter7]

Originally posted by Takumi Fujiwara
Do misfires cause fire coming out the exhaust as well? In games (like BG2), Rally-spec cars with Misfiring systems are often portrayed with fre coming out the pipe. But does that really happen?

yeah im pretty sure it does i saw a 180 drifting and i think he had a misfire system cuz when he took one corner you heard a big pop and flames came out his exhaust but he was goin at real high rpms too the engine was whinin so much. it was like eeeeeeeeeee POW!

 

[rollazn]

Originally posted by drifter7
yeah im pretty sure it does i saw a 180 drifting and i think he had a misfire system cuz when he took one corner you heard a big pop and flames came out his exhaust but he was goin at real high rpms too the engine was whinin so much. it was like eeeeeeeeeee POW!

Just because the car had a big pop noise and flame coming out doesnt mean it has a misfiring system. In Best Motoring i saw one of their stock skyline which had a flame from its exhaust doesnt mean it has an Anti lag system (misfiring system).

 

[drifter7]

sorry i guess it was unclear i also said he was goin at high rpms and i should have said that might have been why

 

[I6-4-eva]

damn i want flames coming out of my exhaust that way when some jerk is tailgating me i can burn his ass!

 

[Fenrir51]

On the internet somewhere a guy with his Chevy pickup did that, not surehow though but it was cool.

 

[Darin]

1mic. I find it funny, that you picked a race car. They braking continously and of course they are gonna spit fire out of the exhoust. Go a ALMS race, look for the Corvette C5-R's go under heavy braking, thats no back fire.

 

[Goomba]

Originally posted by Darin
1mic. I find it funny, that you picked a race car. They braking continously and of course they are gonna spit fire out of the exhoust. Go a ALMS race, look for the Corvette C5-R's go under heavy braking, thats no back fire.

What does breaking have to do with backfiring?

And since we're talking about things that don't relate to backfires/misfires, check this out:

A nice and toasty 300ZX turbo. Looking more at it, It almost seems that it isn't a 300ZX. They had V6s, and this looks to be coming from either a V8 or an I4 because of the shape of the exhaust manifold. I'm not really keen on the inside of a turbocharged engine though, so again, I could be wrong.

 

[Fenrir51]

That looks no way like a V8 manifold

 

[1mic]

Originally posted by Darin
1mic. I find it funny, that you picked a race car. They braking continously and of course they are gonna spit fire out of the exhoust. Go a ALMS race, look for the Corvette C5-R's go under heavy braking, thats no back fire.

what the *uck does braking have to do with spitting fire out of the exhaust? unless the driver is braking/gasing at the sametime...??? what a pro
anyways ive seen these cars spit fire when they shift, it was back in 2001 at infineon raceway. ive seen these in particular spit out more fire than any car, (maybe becuase there was like 6 of them 1 right after the other).
btw i think it was the s7s first year in the GTS class

 

[Goomba]

Originally posted by Fenrir51
That looks no way like a V8 manifold

Looking at it some more, and thinking about it, I'm totally with you on that one. But doesn't it look like an inline four or something because of the four ports?

 

[Jay]

you guys are talking about it being a V8 or IL4, but how many plug leads do you count. i only count 3 and i doubt theres one behind the intake pipe. looks to me the exhaust ports arnt even along the head

 

[extreme car]

I've got a question how do you create back fire? can you create back fire by using stock car? eg. Honda civic, Jazz
do you need Turbo to create back fire? or just a Natural Aspirated car?

 

[Takumi Fujiwara]

Just about any car can back fire. Just run rich. Even my car backfires sometimes, although the Catylitic Converter blocks the fire from coming out.

You can also get a rev limiter that will cause the car to backfire everytime you hit redline.

 

[JNasty4G63]

Any car can "back fire" as you guys call it. My car will spit a flame out the back about 3 feet long sometimes. If I run up through the gears, and then coast out in gear, it will blow a flame out the back for a couple seconds. Its just because my car runs a little rich (little, HA ), and I have no cats what so ever. I have the Apexi GT down pipe and GT exhaust, both of which are 3.75" with no cats. If the car is warmed up and the exhaust is hot, it will do this just about on command.

Its basically the same thing you see in most race cars. They have so much fuel going through them, that when they go from full to no throttle to brake for a turn, some fuel will undoubtedly flow out and burn in the exhaust and blow a flame. The anti-lag systems that rally cars have is very similar. The engine techs realized a few years ago, that if they let a little fuel go through the engine on purpose when the throttle closes, it would explode in the exhaust manifold, and keep the turbo spinning and spooled up. Sounds crackly and loud, but works.

Hilg

 

[Jay]

Try and start the engine with the timing way way off, that will create some backfire .

Another easy way to get most cars backfiring (although I dont recomemd doing this) is when driving at speed in gear turn of your ignition for a second or too (pumping the throttle helps to in carby cars) and then turn it back on (all while still in gear), then BOOM

I dont recommend you trying this at all, actually dont try it.

Most turbocharged cars with and large exhausts and Catylitic Converters removed can do it quite easily. Most factory set ECU's are rich so that helps.