Earlier today I was surfing around youtube and found a couple of videos of skylines and evos, dumping the clutch from like 5000rpm on a dyno. All of which claimed to have some anti-lag system, which might just be a fancy word for a 2-step, I dunno.

So I'm just looking for some insight to this out of curiosity.

My understanding is Anit-lag keeps you engine in it "powerband" while racing and it eats turbos.



Tinkles

2003 Cavalier 1SV
Bagged and Blown

there's two different things I can think of that would be referred to as anti-lag.

the first version is for drag cars.. also referred to as boost-builder. Its basically a fancy 2 step that helps to build boost off the line so instead of launching at atmospheric, you can actually launch with around 2-5psi of boost. Better than nothing.

the second version of anti-lag is for road course cars. Basically what they do is retard ignition timing extremely far so that the combustion actually happens in the manifold. the explosion pushes itself through the turbine housing and out the exhaust (usually with a pretty large flame coming out the rear)

it keeps the turbo spooled, but puts a lot of stress on the manifold and the turbine. Japanese dudes refer to it as "boom-boom turbo"

Anti-lag youtube video
it sounds like backfire on this subaru, but you can hear it clear whenever he comes into the turn or lets off the throttle

http://www.rallycars.com/Cars/bangbang.html]
read that, its a good description of what anti lag is.


horsepower is the force that determines at what speed you hit the wall, torque is the force that determines how far you take the wall with you after you hit it.

http://www.rallycars.com/Cars/bangbang.html (fixed)

fixed that link for ya

for the lazy:

Quote:

When the driver lifts his foot from the gas pedal the ignition timing is altered with sometimes 40° or more of delay (retard) and the intake air and fuel supply mixture is made richer. The inlet butterfly is kept slightly open or an air injector, bypassing the inlet butterfly, is used to maintain air supply to the engine. This results in air/fuel mixture that keeps getting in the combustion chambers when the driver no longer accelerates. The ignition being severely 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 mentioned above. Additionally, the exhaust temperature being extremely high, the unburned fuel explodes at the contact of the exhaust tubes. Luckily the turbo sits right there and the explosion keeps it turning (otherwise it would slow down since its intake, the exhaust gases, is cut-off). The effect is vastly lower response times with some downsides:

* A quick rise of the turbocharger's temperature (which jumps from ~800°C to the 1100°C+ region) whenever the system is activated
* A huge stress on the exhaust manifold and pipes (mounted on a street car a bang-bang system would destroy the exhaust system within 50-100 km)
* The turbo produces significant boost even at engine idle speeds
* The explosions which occur in the exhaust tubes generate important flames which can, sometimes, be seen at the end of the exhaust tube
* Reduced engine brake

The ALS effect is mostly dependent on the quantity of air allowed into the engine, the more air supplied the more the ALS effect will be noticeable. Consequently ALS systems can be more or less aggressive. A mild ALS will maintain a 0 to 0.3 bar pressure in the inlet manifold when activated whereas, when inactive, the pressure in the inlet manifold with the throttle closed would be in the region of -1 bar (absolute vacuum). Racing ALS versions can maintain a pressure of up to 1.5 bar in the inlet manifold with the throttle closed.
While the systems mounted in Toyota and Mitsubishi racing cars are relatively smooth and noiseless those fitted in Ford and Subaru cars are much more noisy and aggressive.
The bang-bang system owns its name to the loud explosion noises one hears whenever the driver lifts off. Most racing implementations have user selectable anti-lag settings depending on the terrain, usually three settings can be selected by the driver going from mild to very aggressive.

i have Anit-lag, it is one of the joys of SDS

There's an Evo at the strip that sounds like a firecracker at launch and between shifts. So now I know.



Listen F***ers. FASTERTHANAHONDA is a joke because I WORK FOR HONDA. I'll talk @!#$ about Fords to, that doesn't mean I can beat a 12 second mustang.

Awesome it all comes together, thanks. I remember in the summer, I was out for a cruise and was following an Sti that just kept on poping SO loud, like I mean I had the stereo blaring and I thought someone was popin' Caps at me.

Seems like a good idea for a drag or rally car if they are just going to be rebuilding the engine turbo after ever couple of races anyway.

Thanks for the info, Skwril

p.s. ur cars dirty!

the only damage your cat, if you have one!!