Injector cooling fan

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <000701bd5994$36023c70$aafd8ac0@flanders.avs.com> "Rob Winchell" writes:

> Silly question: do I have an injector cooling fan on my '91 200Q?

It's a 'turbo' feature, relevant to the 10V engines.
 
On the 10Vs, the inlet and exhaust are on the same side of the engine block.  
On the turbos, our hot little friend is down that side too.  The problem arises 
when the vehicle stops - the flow of air into the front of the engine 
compartment stops, and the heat remaining in the turbo subsystem (lot of cast 
iron down there) rises up to just under the bonnet/hood.  The German is 
"Hitzestau" - heat jam.
 
The trick is to keep the heat in this area below the point at which fuel under 
residual pressure (around 3 bar) will boil.  There's a thermoswitch on the end 
of the heat shield.
 
This is a non-issue on a non-turbo (there's no source of heat big enough to 
be a problem) and on a 20V (inlet and exhaust are on opposite sides of the 
block.
 
The main feature of the injector cooling fan is a plastic shroud draped over 
the cam cover.

-- 
 Phil Payne
 UK Audi [ur-]quattro Owners Club