Anti Lag

[jc052685]

Ok, this is stemming from BigPhil's thread. It was stated that AntiLag will cause the turbo to fail prematurely. I dont really see any reason why it would be any more harmful to the turbo than 7500rpm and 20psi boost. I doubt that it is any hotter anyway. Only thing I could think is that there is a shock load on the turbine shaft.

 

 

That's not quite what anti-lag is. Anti-lag systems typically retard spark timing and dump in more fuel in drop-throttle conditions (shifts). The much higher gas pressure and temperature caused by this are then used to keep the turbine spinning faster than it otherwise would be. It is true that anti-lag decreases engine and turbine life.

 

 

Also, is this the true method.

Edited September 22, 2010 by jc052685

[ktm]

Here you go: http://www.rallycars.com/Cars/bangbang.html

 

It looks like it increases exhaust gas temperatures rather significantly which would have an effect on the turbine.

[jc052685]

Great find. Yeah I did not think that temp would be nearly that high.

[goodoldjam]

Antilag isn't actually launch control or "sparkcut".

Antilag is non stop between shifts and has nothing to do with limiting. It continues to ignite fuel even off throttle.

Launch control is a limiter or "2 Step". Basically you cut spark at intervals and let unburnt fuel enter the manifold. It ignites and causes a load on the turbo, enough that the turbo will creative pressure. It's not good for the turbo, I would imagine it not only adds alot of heat. Also it causes basically what are shockwaves. I would imagine true antilag will destroy the turbo much faster than sparkcut.

Your igniting fuel meant to drive a piston in front of a turbine.

Edited September 22, 2010 by goodoldjam

[jc052685]

Antilag isn't actually launch control or "sparkcut".

Antilag is non stop between shifts and has nothing to do with limiting. It continues to ignite fuel even off throttle.

Launch control is a limiter or "2 Step". Basically you cut spark at intervals and let unburnt fuel enter the manifold. It ignites and causes a load on the turbo, enough that the turbo will creative pressure. It's not good for the turbo, I would imagine it not only adds alot of heat. Also it causes basically what are shockwaves. I would imagine true antilag will destroy the turbo much faster than sparkcut.

Your igniting fuel meant to drive a piston in front of a turbine.

 

 

We were not talking about any of those things

[Leon]

When anti-lag is used, what you're getting is combustion inside the turbine! With retarded ignition timing and a rich mixture, the exhaust temperature is highly elevated and essentially the flame continues out of the cylinder and into the exhaust/turbine. Yes, burning fuel inside your turbo will make it wear quicker.

[Leon]

Here it is, explained in more detail from the posted link:

 

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

[goodoldjam]

We were not talking about any of those things

My mistake you said stemming from Big Phils thread, so I assumed you were actually referring to sparkcut.

[FlatBlack]

When anti-lag is used, what you're getting is combustion inside the turbine! With retarded ignition timing and a rich mixture, the exhaust temperature is highly elevated and essentially the flame continues out of the cylinder and into the exhaust/turbine. Yes, burning fuel inside your turbo will make it wear quicker.

 

This is what I was trying to say in BP's thread

[Pzary3233]

But it sounds soo friggin cool!

 

I had anti lag on my WRX for a total of about 20 minutes, It was great for Rally X but that's about it. Tuned it right out. Gotta love the open source nature of the Subaru tuning world.

 

For a street driven car it would not be a smart idea.

 

Basically you are able to keep the turbo spooled up when off the throttle due to the combustion of the fuel in the turbine housing.

 

I do not suggest you ever run this on your car. You will be sorry unless you like replacing turbos frequently as well as any semblance of an exhaust system.

[B00STDZ]

the newest gymkhana being an example of true antilag? With the ford focus?

[510six]

http://www.youtube.com/watch?v=RkSunzu24J0&feature=related

 

AEM two step anti lag , I prefer nitrous to spool the turbo .

[m4xwellmurd3r]

the newest gymkhana being an example of true antilag? With the ford focus?

Yeah. I'd be willing to bet every car in the WRC runs anti lag. instead of firing on the combustion stroke, it fires on the exhaust stroke, with tons of fuel. big BANG into the turbocharger. burns them out real quick. glowing hot i'll bet even.