Anti Lag+ Classic = ?

[scottishtaffy]

what is the benifit of anti lag and is is hard on the engine? was wondering about it when i finally get round too mapping the ra wether to get it mapped in along with maffless. but dont know if i would be asking for trouble on a older engine or would this be better on a new rebuild engine?

[oj 89]

afaik, you'll notice it more in your fuel tank than the engine, and the benefits aren't usually worth the outlay - either up-front or over-time. There is more stress put on the engine, and this might play a factor depending on how well it's been maintained etc.

Could be talking out of my backside though, and it'd probably be better to wait for the more experienced users to wake up, but that was my understanding of it...

[davey l wrx]

shortens the life of the engine, turbo and exhust.

I'm sure i read somewhere it's best if you have no CATS fitted or it trashes them.

[scottishtaffy]

thats not an issue dave as you should know by the sound of mine that i have straight thru exhaust but the stress on the engine is my concern so dont think i will bother. mine spits lame now anyway just being silly

[ccrien]

See march 7th last year under general subaru topics, was covered well there. Not sure how to cut/ paste the info into here though:

Mark Harris posted this in the thread:

I won't comment on the basics of turbochargers in case you don't know how to suck eggs, but the compressor pull air through and if you get a blockage, you get back pressure developing which stalls the compresor increasing the drag just at the point where the drive force of exhaust gas decreases rapidly.

As you lift off the throttle the turbo can go from 50,000rpm or more to 10,000rpm in an instant due to this, and for this reason dump valves are fitted to relieve the back pressure and the turbo then slows much more slowly. It doesn't matter if they are the standard re-circulating type or the noisy Chav variety, both work the same.

The drive from the exhaust has still ceased and the turbo still slows a lot. Once you go back on the gas the flow to the turbine comes back and it will accelerate.

The purpose of the anti-lag is simple. By over fuelling on the overrun, the neat fuel is injected very late in the cycle as the exhaust valve is open and it will ignite and burn out of the engine increasing pressure on the turbine inlet.

Hence the flame and baap! sounds. It doesn't do the fuel economy much good, neither does it lend itself to long life exhaust valves and seats either.

Let's just assume you've de-catted already, because Anti-lag will do it for you in quick order if you haven't!

Fine on a Rally engine, just a bit silly for a road car...

0

Mark

Isle of Man

Edited December 3, 2013 by ccrien

[scottishtaffy]

cheers for that