Turbo Lag in the WRC

[avsfan733]

Not quite sure if this belongs here or in the tech forum but the mods can always move it.

I have read that the engines in WRC cars the engines have a "anti-lag" system on the turbos. Knowing what i have read and what i know about turbos, I am assuming that these are something more mechanical then a well designed set of impellers. The way i understand the systems used no, they work by severly advancing the ignition timing so that the exhaust valve is open during the power pulse to keep the turbos on boost when shifting.
1) is this correct?
2) why do it like this?
3) couldn't a seperate gas injection system be better and easier on the engine?

[alfasud]

The ignition is retarded (when the driver lifts off the throttle), not advanced.

Here's one explanation:
http://www.rallycars.com/Cars/bangbang.html

When you suggest a seperate gas (petrol?) injection, I guess you mean in the exhaust, just before the turbo? I think this was tried/tested in 1980's F1 (Ferrari?) but possibly banned, because then the turbine could be considered a seperate "engine".

Street driven cars and cars driven in some competition events that don't allow anti-lag (Targa NZ tarmac rally is one that doesn't allow it) have to use other methods such as blow-off/dump valve to help keep the turbo spinning during off throttle conditions.

[avsfan733]

i was actually wondering about somethingless destructive (read flammable) injection like nitrogen gas i should have been more clear but thanx for the information.