UEGO and alcohol

[Carl Summers]

Hi all,
    On my UEGO wide band, max power with methanol has been ~4.75:1 on
aspirated engines and ~4.2:1 on Blown Alcohol....this equates to ~11:1
aspirated and ~9.5:1 when looking at gasoline numbers on the meter....hth's
-Carl Summers




-----Original Message-----
From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
Behalf Of Greg Hermann
Sent: Sunday, September 24, 2000 10:41 PM
To: diy_efi at diy-efi.org
Subject: Re: UEGO and alcohol


At 8:29 PM 9/24/00, Jeff Bromberger wrote:
>I'm looking to tune WOT w/nitrous and alcohol, so i need something much
>richer than stoich. My question is basically whether or not the sensor will
>reflect the actual ratios of liquid fuel to air or not. Accel claims that
>you need "a true wideband sensor to tune alcohol because it's out of the
>range of the 5-wire sensors like SpeedPro uses"... this is more or less
what
>i was trying to verify. If the alcohol appeared as 6:1 (vs. 12:1 for gas)
>then this would make sense...

Maybe if I say it again, you will hear what I am trying to tell you. An NTK
UEGO sensor will see stoich as stoich, no matter what fuel you are running,
so long as the fuel doesn't foul the sensor. 14.7:1 is stoich for a typical
GASOLINE. 6: 1 is stoich for methanol. 8:1 is about where stoich is for
ethanol. A UEGO controller, such as EGOR, or the NTK "blue box" will give
exactly the same voltage output at the stoich mixture for any given fuel,
REGARDLESS of whether stoich happens at 14.7 to 1, 6 to 1 or 8 to 1!! The
voltage will vary one way as the mixture goes rich of stoich, and the other
way as the mixture goes lean of stoich.

With methanol fuel, I would bet that a UEGO would work OK down to as rich
as about 4.2 to 1.

BUT--if you have a UEGO METER with a digital output---you will get screwy
numbers out of it unless it (the numbers that correspond to a particular
output voltage) is recalibrated for whatever fuel is being used.

For instance--if you are using a digital UEGO meter which is calibrated for
gasoline on an alky motor, I would bet on it reading 12.0 to 1 when the
mixture was really about 4.9 to 1 !

Greg
>
>
>> It's a matter of calibration, Jeff. The sensor/driver/meter will read
>> stoich wherever the alchohol mixture is stoich, and rich and lean to
>either
>> side of it. The only question is--what number will the meter give you
when
>> you are where???
>>
>> The actual VOLTAGE output from the sensor/driver will be the same at
>stoich
>> for alky as it would be for stoich for gasoline, etc.
>>
>>
>

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