additional injector

[DemonTSi at aol.com]

In a message dated 97-08-12 21:31:26 EDT, you write:

<<      The big problem in doing this with EFI is that in general the O2
      sensor will "see" the fuel mix go richer then the ecu will lean off
      the other injectors to compensate and try to keep the mix at 14.7 to
      1....thats why you need to either re tune the ecu or get a
      replacement that you can tune. The good thing about an aftermarket
      ecu is that you can tune it how you want not how the factory set it.
      >>>
      
      Well actually the car will not be under closed loop control (at least 
      the current ones that I know of) at wot so this correction you refer 
      to won't happen at wot. The enrichment should work fine; we (v6) refer 
      to these devices as "seventh injectors" and see them alot. And most 
      cars go to (or try to) around 12.5:1 or so at wot too. >>

The o2 sensor would not see a rich condition if you set the additional
injector to come on when needed...i.e. when the car is starting to run lean.
In turbocharged applications, this is usually at high boost and high
rpms...when the existing fuel injectors can't supply enough fuel for the
increased air flow. That's when the additiona inj comes in and saves the
day....!  :)

Van