After Fire

[Rallyforshizzle2222]

I looking to get/make a After fire system any helpful info about where to get parts, what good setups are ect....

[jamal]

a what system?

[Rallyforshizzle2222]

An after Fire system....

It is when u have fuel injectors and spark plugs in the exhaust manifold and when you shift the engine fires into the manifold to keep the turbo's boost up. They use it in rally all the time. Its the same concept of running without a bov.

[DLC]

It's called "anti-lag".

I think someone here has done it, might search for that term and see what comes up.

[jamal]

Oh I thought you meant something like a spark plug in the exhaust tip to shoot flames.

A lot of standalone management systems have the capability for it. For it to work well I think you'd need that, for the rotational idle and whatnot to get enough fuel and air into the exhaust.

Prodrive and wrc cars have a cooler way of doing it, with a bypass from the intake to the up-pipe with a butterfly valve. Then they can just use that and dump extra fuel into the motor.

Is there some particular reason you're doing it? Is this a rally car? It's not something you'd want to drive around with on the street. A few people on nasioc have done it. Searching there would probably get you more results.

[evolutionmovement]

You're better off saving bleed air to a compressor tank. Ford and Subaru tried this out a few years ago and had it banned by the FIA. It's clean, reliable, gentle on things, and apparently works. The details of the system they used I'm unsure of, but I came up with this idea myself a couple years before it was used in rallying. With my version, I routed blow-off valve air to a compressor tank (which can also be easily topped up with an air compressor if necessary) and would have liked to incoprorate a valve that would open at a predetermined manifold pressure (more or less the same as max boost), taking some of the extra pressure and routing it to the compressor tank (which would have an over-pressure dump valve when it reached max safe pressure) for more convenience in keeping the tank pressure topped up. The wastegate would be set to open at a higher pressure than intended for the engine to allow for the additional volume of the anti-lag system. After all that, a manifold pressure sensor would be used to discharge air from the compressor tank into the manifold when it fell below a certain value. The system could be disabled by switch for when it wasn't needed. Tuning would take some time, but once set, should be pretty damn reliable. IIRC, the WRC teams used 3" tube or so and kept the compressed air tank in the trunk. I read about it in Racecar Engineering and I think there's a thread on here somewhere about it from around that time. Search for something with 'antilag' or 'another stolen idea' in the title.

[555BCTurbo]

An after Fire system....

It is when u have fuel injectors and spark plugs in the exhaust manifold and when you shift the engine fires into the manifold to keep the turbo's boost up. They use it in rally all the time. Its the same concept of running without a bov.

That's not how antilag works...


Basically, antilag retards the timing somewhere around 40 degrees, which therefore dumps fuel into the header, and it is combusted by the intense temperature of the exhaust system pre-turbo...also, the throttle butterfly is opened a slight amount to allow a small amount of air in the exhaust to combust the gasses...


The WRC cars don't have injectors and spark plugs in their exhaust...


And running without a BOV is nothing like antilag...as that just stacks the compressor..

[HellBinder]

the initial D cartoon called it a "back firing system"
Ive also heard it called a "batch firing system"
im also curious about how it works, the only thing ive been able to find at all is the BeeRacing system thats used as an adjustable revlimiter that bounces the timing around instead of cutting fuel or spark causing lots of back firing and some flames out the exhaust.
Cant be the same thing though cause its only $250

[555BCTurbo]

im also curious about how it works

Basically, antilag retards the timing somewhere around 40 degrees, which therefore dumps fuel into the header, and it is combusted by the intense temperature of the exhaust system pre-turbo...also, the throttle butterfly is opened a slight amount to allow a small amount of air in the exhaust to combust the gasses...