Anti-lag for turbocharged cars..., just thought everybody should know what it is.. Options

[RUNNIN-LOW]

ANTI-LAG
Anti-lag, (often incorrectly called a Misfiring System), is a system used on WRC rally cars to completely eliminate turbo lag. It is a feature of the engine management system. WRC cars are fitted with a class mandated restrictor on the turbocharger inlet and this increases turbo lag significantly. Because of the pressure drop across the restriction, the pressure ratio for a given boost level is much higher and the turbocharger must spin a lot faster to produce the same boost as before.

Anti-lag effectively increases the mass of exhaust fed to the turbocharger. This is typically done by retarding spark timing to a point where most of the combustion happens in the exhaust manifold, typically around 40° ATDC. At the same time more air must be added, this can either be done by the use of a throttle bypass valve or a throttle stop solenoid. When anti-lag is switched on it is typically active when the throttle is closed, and when the throttle is opened the spark timing is resumed to normal.

Exhaust temperatures produced by this system are phenomenal but they can be controlled by varying the amount of fuel injected while anti lag is active; a richer mixture lowers the temperature. Anti-lag is typically only used on race cars because it can shorten the turbocharger service life down to impractical periods for street use. The turbine blade life is drastically reduced, and the entire exhaust system is put into shock, which can lead to explosion or fire. Rally cars generally change turbochargers every chance they get to do so.

As a note, all Subaru Impreza WRX STi (and STI) and Misubishi Lancer Evolutions are equipped with a Anti Lag System because FIA rules require complete homogulation with street cars ( only until 1998, newer "WRC" class cars do not have true street going versions. By way of example the roadgoing STI has 2.5L engine which is 25% larger then the engine used by Subaru to rally). These cars, however, do not carry the computer or software necessary to activate the system, ( the computer software is the chief component of any anti-lag system).


This was in the gt4 meet video that driveby posted in general discussion it sweet if you watch the video...
just thought everybody wanted to know what it was...

[97sccelica]

ST205 WRC's came with anti-lag, but its not hooked up. It basically cuts ur engine life by 75%.

You ment turbo life? I just do not see how retarding the timing and soaking exhaust in gas can reduce engine life by 75%

But the coolest thing about antilag is those tailpipe fireballs

i dont know about 75% reduction, but it will reduce engine life

the car is always in boost and very high EGT's, so its like the driver is beating the crap out of the car non stop

i have a type of anti-lag system on my wrx(launch control)

[CilverSeliST205]

ST205 WRC's came with anti-lag, but its not hooked up. It basically cuts ur engine life by 75%.

You ment turbo life? I just do not see how retarding the timing and soaking exhaust in gas can reduce engine life by 75%

But the coolest thing about antilag is those tailpipe fireballs

i dont know about 75% reduction, but it will reduce engine life

the car is always in boost and very high EGT's, so its like the driver is beating the crap out of the car non stop

i have a type of anti-lag system on my wrx(launch control)

First of all car is not always in boost like you said because it does not need to be for ALS to work (different principle), second of all launch controll and ALS are two different things (also a different principle).

High EGT in use of ALS occurs mostly past exhaust ports of the engine damaging mostly turbocharger, manifold, cats, and the rest of exhaust system

It might reduce engine life but i doubt that it would be anywhere past 10%

Something to read: http://www.rallycars.com/Cars/bangbang.html - how does ALS work

This post has been edited by CilverSeliST205: Mar 21, 2006 - 12:13 PM