[Diy_efi] A/F mixture, EGT and engine damage

gary gas-
Mon May 16 22:55:14 UTC 2005


Stoichiometric AFR (for gasoline) of 14.7 (appr.) will give the best 
compromise, in regard to emissions, or a lack thereof.  In regards 
to fuel economy, 15.5-16.0 will give the better economy.  Of note, 
are the AFRs as commanded by GM ECMs in 'lean cruise' mode.  

GAS 

----- Original Message ----- 
From: "David Cooley" <n5xmt at bellsouth.net>
To: <diy_efi at diy-efi.org>
Sent: Monday, May 16, 2005 5:32 PM
Subject: RE: [Diy_efi] A/F mixture, EGT and engine damage


> WOT you want to be 12.0-12.5:1 for peak power... Part throttle as 
> close to 14.7:1 will give the best economy. 
> 
> > -----Original Message-----
> > From: diy_efi-bounces at diy-efi.org 
> > [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Tim Marsteiner
> > Sent: Monday, May 16, 2005 4:26 PM
> > To: diy_efi at diy-efi.org
> > Subject: Re: [Diy_efi] A/F mixture, EGT and engine damage
> > 
> > Both EGT probes are exactly 3" from the cylinder heads.
> > 
> > http://www.superxtune.com/images/EGT.JPG
> > 
> > I have heard that going too rich can damage the engine by 
> > "washing" the oil film off the cylinder walls. Is there a 
> > safe lower limit on A/F or EGT ? 
> > 
> > Thanks,
> > Tim






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