Re: Turbo Theories

[steveb@newkla.kla.com (Steven Buchholz)]

> 
>      ".....the report created by raw fuel exploding as it reach the red-hot
> vanes of the turbocharger. You see, some years ago Audi discovered that you
> could overcome turbo lag by squirting gasoline into the air intake system
> just upstream of the turbocharger. When the gas ignites, the ensuing series
> of backfires keeps the turbine spinning after the driver has backed off the
> throttle. This makes the engine more responsive and life a lot easier for a
> rally driver who uses mostly the throttle to position the car."  R&T Mar '95
> pg124
> 
>      The article addressed rallying in general but not Audi's specifically.
> Do you think the gasoline injected was misted by a version of a cold-start
> injector? If so, was it cycled on and off or was there always fuel ignited in
> the intake. It makes one wonder what effect this had on the rest of the
> system, how many parts did they replace on a regular basis because of damage
> caused by this technique? It certainly doesn't seem like an acceptable
> solution for the street, but an interesting historical item though. I'd never
> heard it before!
> 
> -Chris
> 
This might actually be the source of the flames that someone spoke about.  
The fuel was probably injected into the exhaust.  I don't think that the 
compressor wheel gets red hot, but I've seen a dull red glow from the tur-
bine housing on my car (YEEE HAAAAAAAAAA!), so you can bet the blades are 
getting quite hot.  The injector would be mounted somewhere on the *exhaust* 
manifold upstream of the turbo.  If things weren't hot enough or you wanted 
to be sure, you could have some type of spark plug that ran with the injec-
tor.  Actually seems like a simple way to increase the volume of exhaust 
gasses going into the turbine.  I wonder how much oxygen is in there ... 
maybe since the FI controller shuts off the fuel under decel there is still 
a sufficient amount of oxygen for combustion.  If you were thinking of try-
ing this out you might want to consider getting rid of your catalytic con-
verter and mufflers though.  

Steve Buchholz