how do you do backfire?

Question

how do you do backfire? you know where fire comes out of the muffler. have you guys seen fast and the furious? when they're behind the line about to race they rep there engines and backfire comes out? i've also seen a video where a supra killed a mustang cobra and they were doing like 160+ and the supra i think before it put the brakes or at the same time, backfire came out. i want to learn how to do that. im not sure if you need a powerful engine to do that.

Answer 1

In the automotive sense, a "backfire" refers to the sudden "boom" accompanying the rapid combustion of excess fuel having been dumped through the engine and ignited typically in the (hot) muffler. They are often mistaken for gunshots.

It is ordinarily an accidental occurrence arising from a momentarily-out-of-tune condition (excessively rich mixture accompanying, most commonly, the shutting of the throttle). Thus, backfires are ordinarily heard during braking or hard deceleration.

The shooting of flames from the exhaust is sometimes accomplished by intentionally running a too-rich state of tune, and using an ignition device (ordinarily a spark plug or glow plug) in the tailpipe (an MSD box and multiple plugs works great).

However, some people use a separate fuel line and either inject the fuel into the tailpipe ahead of the ignition source, or turn the section of tailpipe between the muffler and the ignition source into a carburetor. A flame holder may also be used.

The "cheap and easy" way involves killing spark to one or more of the engine's spark plugs (thus artificially simulating a too-rich state of tune: all you're after is the unburned fuel dumped through the exhaust).

Make sure you don't have one or more catalytic converters, though, as such a device could ignite the raw fuel prematurely -- and, potentially, catastrophically.

Fire coming out the exhaust will create backpressure in the exhaust system, reduce engine efficiency and lower your power. Serious racers try to avoid having it happen, but sometimes the compromises that cause it outweigh the disadvantages of it if it is very temporary and sporadic.

Watch a road race in which Porsche-powered cars compete, and you'll often see flames from the exhaust during hard braking and cornering (and explaining exactly why is basically covered in the foregoing, but a detailed explanation would take up a whole book).

You can make a lawnmower engine do that, but unless you are just totally into the "hey, I can make fire come out my exhaust" crowd (is there one?), once you learn how bad it is, you won't want your car to do that.

Answer 2

Step away from the television... there are a few ways to do it. You need to tap a spark plug into your tailpipe and wire a coil on a switch. You can wire an interupt switch that kills fire to the engines spark plugs while at the same time sends power to the coil that feeds the plug in your tail pipe. When you hit the switch at full throttle it sends raw unburned fuel into the exhaust and burns it as it comes out the tail pipe. I did this one night to an old car I didn't care about one night when I was bored but don't do this to your car.....it's not healthy...kinda like too much TV.

Answer 3

I have done it in the past, and have had to replace exploded mufflers.

By the way, what they have is an igniter at the tailpipe and purposely cause an overly rich condition thru the engine for gasoline vapors to empty out the exhaust unburned, and then light them with the igniter. Which is installed aftermarket.

Answer 4

Backfire is a timing malfunction at worst, or a condition when unspent fuel escapes on the exhaust stroke while still burning at best. It looks cool at night, but you don't want it! It's an error that reduces engine life.

Somebody else chime in and tell me what I'm missing, if anything...

Answer 5

It means unburnt fuel is being dumped into the exhaust and igniting when it hits the muffler. It's a bad thing really - means you lose fuel economy and if you have a 'cat' it can burn it up really quickly.

Answer 6

ITS CALLED A FLAME THROWER DUH LIKE EVERY ONE ELSE SAID BACKFIRE IS A TIMING MALFUNCTION = NOT GOOD.. NOW CARS IN A RUNNING RICH SITUATION IE THE SUPRA YOU SAW SPANK THE MUSTANG WAS RUNNING RICH.. YOU CAN BUY A KIT TO SPIT FLAMES OUT OF YOU EXHUAST.. NOW STEP BACK AND STOP WATCHING FAST AND VER RIDICUOUS 1,2 AND 3. AND WATCH THE ORIGINAL GONE IN 60 SECONDS.. NOT THAT KNOCK OFF WITH ANGLINA AND NICK CAGE. THATS THE REALL SHIZZNIT