turbo and WOT injector

JShadzi at aol.com JShadzi at aol.com
Thu Aug 24 19:06:28 EDT 2000

   Theoretically, what you say may be true regarding dist. between cylinders-But, BTDT may prove better than theories at this point.  
   Since I do have an injector in each runner (and the car is running very well), untill it blows up (its been over 10k miles including track days at 13+ psi), I will assume that the way I have chosen to execute the solution is a good one...

In a message dated Thu, 24 Aug 2000  5:50:53 PM Eastern Daylight Time, "Buchholz, Steven" <Steven.Buchholz at kla-tencor.com> writes:

<< The one thing that I have not seen discussed here is the relative
distribution of air and fuel to the individual cylinders.  While Audi has
tried to even out the flow to each with the large air reservoir in the
intake manifold, it remains true that at high flow rates on the WX and MC
engines (which have the TB mounted at one end of the reservoir and aimed
rearward) there will be more air flowing to the rear cylinders than the
front ones.  Given that you have a system that provides the same amount of
fuel to each cylinder you will naturally find that the mixture in the
rearmost cylinders is on the lean side, while the mixture in the front
cylinders will be rich.  Adding pulsed injectors into each intake runner
could be used to address this variation, but it would require either
individual measurement and control of the mixture at each cylinder or a
compensating algorithm that would apportion more fuel to the rear and less
to the front.  The thing I've always kinda liked about the sixth injector in
the flow is that it actually would tend to distribute the fuel in a similar
manner to the distribution of the air.  In this case we are not talking
about an injector mounted in the CSI location, but something in the airflow.
I forget the manufacturer, but I've seen this sort of setup installed in an
urquattro that had bumped up boost.  

Steve Buchholz
San Jose, CA (USA)

Quattro mailing list    Quattro at audifans.com
To remove yourself, change to digest mode, or temporarily stop delivery
please visit the web interface at

More information about the quattro mailing list