General tuning question - fuel economy

[Romans, Mark]

I have 87 Vet, 89 code, man trans.  I have done extensive tuning with hwy
fuel and spark.  I have ended up running zero hwy spark.  I suffered from
trace detonation with any hwy spark.  I have 11.1 to 1 compression though so
your experience may vary.  89 code supports hwy fuel. I tried command as
lean as 16.0 to 1 and suffered from lean misfire, I am currently running
15.5 to 1 at light load areas.  3.45 gears, 30% od in 4th, 23 mpg (US GAL)
at 70 -75 mph.  AC on.  HOT LT4 cam, headers supperram.
I just installed  a ZF 6 speed with 50% od in 6th and expect fuel econ to
improve slightly in 6th once I get a few bugs worked out.
Mark
----- Original Message -----
From: <JTesta1966 at aol.com>
To: <gmecm at diy-efi.org>
Sent: Tuesday, June 13, 2000 12:15 PM
Subject: Re: General tuning question - fuel economy


> In a message dated 6/13/00 3:10:46 PM Eastern Daylight Time,
> smarteney at xlvision.com writes:
>
> << e the O2 sensor, hence gas mileage goes down.  How do I compensate, or
>  can I?  I noticed there are some Hiway mode parameters, such as Hiway
spark
>  add (?), in the 165 ECM that I could take advantage of.  Or, is the only
way
>  to get better mileage mean changing the target AFR? >>
>
> In my GN, I run 16.2:1 Hiway mode AF ratio and in the lower load sections
of
> hiwat Mode Spark Advance, I added 4* timing. Added 3-5mpg on the highway,
> depending who of my friends you ask
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Jim Testa                                                         TType86
on
> #BuickGN
> ASE Master Technician
> buick.fiendish.net:6667
> L1 Advanced Engine Performance                          NJ Lic MV
Inspector
> jtesta1966 at aol.com                                  NJ Lic Emission Repair
> Tech
> http://members.aol.com/jtesta1966/buick.htm
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