Anti-turbo lag systems

[Bill Jenkins]

>Not strictly DIY_EFI but sorta related.  This thread on the Saab APC system
>has got me thinking.  I have seen several references in Racecar Engineering
>to anti-lag systems used on current FIA rally cars like the ford, subaru and
>mitsubishi.  In particular I was wondering how the system worked?
>
>I know that early eighties ferrari F1 cars used a system that bypassed air
>from the turbo compressor straight into the exhaust system when the throttle
>was closed and ran a rich mixture to create combustion in the exhaust.  I
>also read somewhere that peugeot used to inject propane into the exhaust to
>acheive the same effect before it was banned in the group B rally cars.
>
>Depending on how these current systems work, I would like to adapt it to my
>current project.
>
>Any info would be appreciated.
>
>Max

   I will say that I saw quite an interesting thing of the sort one time.  A
Mitsubishi Eclipse Turbo came in with a fried plug wire; therefore it was
firing on three cylinders, running rather roughly.  However, all of that
fuel was dumping into the exhaust manifold.  Therefore, you could rev the
thing in neutral, and the turbo would start whining (we had the intake hose
off) and the boost would come up.  It was the only car I have ever seen that
could get full boost without moving.  Really neat.  The extra fuel and air
in the exhaust manifold was burning, and propelling the turbo.