IAC Counts

[Bruce Plecan]

-----Original Message-----
From: Walter Sherwin <wsherwin at idirect.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Sunday, October 11, 1998 6:17 PM
Subject: Re: IAC Counts


>Your comments about the interaction of IAC counts, injector positioning,
and
>fuel spray pattern with a TBI were great!  I have also twiddled with these
>parameters and have found the same results.  How many IAC counts do you aim
>for (warm 5-8 ?)?

0,Zero. If when the rad fan kicks on, or some other draw 5-8.

   I have also found that the Rochester TBI injectors
>respond positively to more fuel pressure.

Yep,  in the tune-up notes, I mention using two fuel pressure
regulators.  One being vacuumed referenced to the engine, and
the second one to clip it at a specific psi.  Also, does wonders
for deccleration (clean+responsive).

  The reward is slightly better
>"shattering" of the fuel and a steeper, more regularly defined cone which
>helps to reduce part throttle mixture maldistribution (especially with the
>big 454 blades which tend to "paddle" the fuel towards the rear cylinders).
>Of course, the injector constant has to be changed to match the new flow
>resulting from the increased pressure differential.  Starting in 94, GM
also
>moved in this direction, with a target system pressure of 26-32psig.

That is news to me.  Or is this for the CFI system?.

Cheers
Bruce
>
>