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Old 06-19-2008, 07:06 PM   #13 (permalink)
metromizer
Master EcoModder
 
Join Date: Jun 2008
Location: NorCal
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Holy cow! The wealth of information here <on this forum> is nothing short of incredible! Thanks to those who have welcomed me, and a huge thanks to everyone who spent the time putting together very informative and understandable replies.

As I said, I don't know much about EFI systems (I appreciate your patience), all of my past tuning has been with carburators and mechanical fuel injection (MFI) systems, but those were WOT drag race applications, that have little in common with with what I'm doing.

let me see if I have this right; Narrow band O2 sensors used in OEM's help the computer learn what fuel map to employ the 'next time', but that could vary from ECU brand to ECU. I fully understand that pulling fuel away and burning a little lean isn't going to change the basic design (limitions) of my 3 cylinder Suzuki, but employing a few complimenatry changes might get me to my goal 50mpg at 65mph.

I have a head and cam change in the works, used stuff I will have reconditioned (taken off a Metro XFi) I'm contracting out for a little port match, bowl, and valve work by a proffesional head porter I know, I might bump the compression ratio up a little and file in some Singh grooves while I'm at it, for those who fiddle with Suzuki's.

From my race tuning I know that typically most race cars are running way too rich, safe, but rich and lower on power than they otherwise could be. I am wondering if my little Metro isn't also running a little on the rich (safe) side by design, to accomodate poor/uneducated driving technique, hot weather and marginal fuel, as to keep warrenty repairs at a minimum. I wonder if I could manually trim back the amount of fuel the engine gets under ceratin conditions, which BTW is where this commuter spends most of it's operating time, 65mph for about 1 hour per day. If I could reduce fuel consumption by 10% by trimming fuel, the excersize would be a success.

Catalitic converted overheat? noted... those things aren't cheap to replace.

Carlos: Was your O2 circuit 'voltage adder' ever successful on your car?
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