UEGO and alcohol

[Garfield Willis]

On Mon, 25 Sep 2000 13:25:57 -0700, Carl Summers <InTech at writeme.com>
wrote:

>    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

Ahhh, I was hoping someone had the equivalent numbers handy. This
proves my suspicion that a "stoichiometry tutorial" is needed, in
order for people to understand how to re-scale n-tane AFRs to
alternate fuels. And of course I got a good laugh outta this, no fault
of Jeff's, he's just passin on what Accel said over the phone I
gather, but still...

On Sun, 24 Sep 2000 20:29:27 -0500, "Jeff Bromberger"
<blownz at home.com> wrote:

>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"

It might be instructive to give SpeedPro a call and hear what they
have to say about the above. :)

Does seem tho that blown alky is getting WAY down there where the lil
piggies live. Yow, 9.5:1 equivalentAFR. Is that like solid rocket
fuel?

I have some notes for such a "stoic tootorial" :), but the interesting
thing is that the combustion products don't follow the simplest
chemical equations; this is discussed in Heywood, so even with an
understanding of stoich, you still have to rely on testing of the
products of combustion to understand what the ratio of byproducts
actual ends up at when the exhaust gas "freezes". Unfortunately, I
don't have access to either the notes or Heywood, so I can't quote you
chapter & verse. Suffice it to say that a certain percentage of what
you think should end up as H2O vapor, a small part is disassociated,
and since the sensors are sensitive to H+ also, simple stoichiometry
doesn't end up giving you the exact AFR. Sigh, why is that no
surprise, eh?

Gar


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