msonne

Hi...

I just lost a race!!!
I was racing against a psycho-Cossie in my MY99.
It sounded absolutely wild - with huge bangs at each gearshift.
And a lovely rumbling when downshifting...
My question is - he said that he (among some other stuff!!! had anti-lag) - can I have that peease...
And what excactly is it???

Martin

stevenuk300

Lag is the delay when the turbo spools up. If you want to keep your turbo in pristine condition, don't have anti lag. Turbos with anti lag don't last very long. The lad in the Cossie will most likely require a new turbo every couple of months. There are mods that help to reduce the lag, which is the safer option.

Denmark

iTrader: (2)

Was it red

Skassa

msonne

Hi Skassa...

Are you here!!!

Yes it was did you talk to Steen???

It was Nicolas Kiesa!!!

Denmark

iTrader: (2)

Just get a race on a track,and you will leave it with a huge

Skassa

msonne

Right!

MorayMackenzie

stevenuk300,

ALS systems can be mapped to be very agressive or very mild in operation... some ECU's will support closed loop ALS control strategies that will allow you to reduce ALS aggressiveness as EGTs rise, and then increase ALS again when temps become safer again. Most systems will also have a configurable time limit to allow safer control of ALS.

You wouldn't really want to run antilag on a day to day basis in a road car, however, it is quite possible to setup a mild ALS system that can be used on occasion that will not destroy the turbo and headers.

IIRC, A friend of mine ran ALS at more than one trackday without a problem. I ran occasional ALS on Motec without a turbo failure too. I guess this means it may actually be possible to run ALS in moderation without destroying turbos every couple of months, despite what you state above. I wouldn't suggest it as something to do just for the sake of it on a road car though.

Moray

[Edited by MorayMackenzie - 2/25/2003 5:10:39 PM]

Tino

'Turbos with anti lag don't last very long'

I think I read somewhere that anti lag injects petrol into the exhaust manifold on lift off of throttle,this then promptly explodes,causes a huge pressure increase in the manifold and keeps turbo 'spooled up'
Any conformation of this appreciated!

msonne

Tino - Interesting, but sounds brutal...

...and Moray - no guess I don't want it that bad anymore...
But the sound....mmmmmm...

Is it true that the boxer engine doesn't bang from the exhaust as easily as a normal engine (ie. the Cossie). And I guess you'll need the Cat off too??

Anybody know what the ALS system actually does?

Rally Nutter

The ALS still lets fuel into the cylinder whilst off throttle, then when it is exhausted it hits the red hot manifold and ignites, keeping the turbines spinning and maintaining pressure in the system. So when you hit the gas again everything is there waiting to launch you towards the horizon.

I would of thought the level of agressiveness is the mapping of the 'off-throttle' fueling, although not entirely sure.

MorayMackenzie

The agressiveness, on at least the als systems i have used, is greatly affected by the level of spark retard you use when igniting the overrun mixture.

msonne

Not sure I quite understand - is the overrun mixture ignited by the sparks?? og the hot manifold (In which case I don't see how it is comtrolable??) Or did I get something completely wrong?

And is it possible to control all this from within the car - ie. shut if on/off completely or adjust it somehow?

Pete Croney

ALS works by allowing fuel and air into the manifold, normally by using a separate, steppable air intake (the Idle Speed Control valve on Imprezas) for the air and by mapping fuel in on over run.

The common way of doing it is by cutting the spark to every 5th cycle and running massive amounts of ignition retard. The retarded burn ignites the air fuel mix from the non firing cylinder and the explosion in the manifold keeps the turbo spooled up. By not firing every 5th stroke, no one cylinder gets cold or bore washed.

An anti lag car can pull 50bhp with your foot off the throttle, so can take some getting used to.

As Moray says, you can map the aggression of it by controlling the amount of air and fuel going in. It can significantly reduce the turbo life, as manifold and turbo temps will go to over 1000degC if it runs for long enough and frequently enough.

Not really for road cars and I suspect the Cossie had it because he was using a massive turbo. Without it, he would grow a beard waiting to get onto boost and you would have left him standing.

I have never heard anything as loud as the ALS on the Skoda Octavia WRC cars.

msonne

Thanks a lot guys - that cleared it up..
Don't want it anymore now..

Martin

Fifi

ALS combined with Witches Brew and High Boost makes for the most cool car sounds...