Fuel tuning...

[Bruce Plecan]

-----Original Message-----
From: David A. Cooley <n5xmt at bellsouth.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Sunday, March 14, 1999 3:54 PM
Subject: Re: Fuel tuning...


>>The brown area, is the fire band,
>
>Ideally, where should the fire band be?

Ideally at the top of the cone.  But, that takes more timing CR, and racing
fuel to do.  You have to learn you engines sweet spot.  It will tell ya when
your there, in max HP, and greatest fuel economy,  hence accurate testing.
>
>>your descriptions of the black might be carbon deposits flaking off.
>>Might try seeing where the timing is during cruise, might be having a
trace
>>detonation problem.
>
>Depending on speed, at 70MPH I see between 35 and 40 degrees advance at
>cruise... lower speeds around town, 23-30 degrees seems to be "normal"

This got an AL head?.  cruise might be a tad high (40), and cruise (low) of
23
low..     The 23 being low is for a cruise rpm of no less than about 1400,
if you have one of the applications that can do a low cruise of say 1100
then 23 might be fine, just I usually don't deal with anything that can do
that low of cruise rpm.
>
>I normally run 93 octane in the car, and have minimal knock counts picked
>up by the sensor...

IMHO, any sensed knock  is to much
>