Re: Tailpipe Probing of EGO

["alexpeper" <alexpeper@email.msn.com>]

You could set up sample pipes at each exhaust port, and run
into sample valve and a port in collector for average. We
did this on the Subaru in 79 for A/F measurement, we used
the Bailey H2 meter (vintage 1950),  or 5 gas analysis
(Horiba meters) or one of the first Horiba A/F machines
(seemed to use some type of high temp catalyst).
Distribution ok until start opening throttle more than 1/2,
then would see spreads of 4 A/F this with carburetor.
Reducing this spread did wonders for power. Also did alot of
O2 sensor(rare and expensive) response times would push the
rich button on electronic carb controller and start stop
watch.
Alex
----- Original Message -----
From: Garfield Willis <garwillis@msn.com>
To: <gmecm@diy-efi.org>
Sent: Thursday, June 29, 2000 12:41 PM
Subject: Re: Tailpipe Probing of EGO


> On Thu, 29 Jun 2000 08:26:12 -0400, Mike Rolica
> <mrolica@meridian-mag.com> wrote:
>
> >>We had occasion to tune an opposed 4-cyl experimental
> >>aircraft engine (water-cooled) that was mounted in an
auto for testing, and
> >>were able to see a mixture imbalance from side-to-side
at the conjunction of
> >>the Y-pipe just prior to CAT, from the way the AFR
jittered backNforth at
> >>ALL rpms (it was worse under load; ick :).
> >
> > Me thinks it may be a subaru engine No??... buit quite a
few of
> >them.....the induction system kinda sucks, as ds cyliners
at front seem to
> >run leaner than the rest......
>
> Bingo, dood. It was indeed a Fuji engine, but this wasn't
the fabled
> Confucius saying,  "siamesed intakes and adjacent firing
order cause
> first cylinder to rob mixture from second". What was
happening here is
> that one SIDE was running leaner than the other. We use
these engines a
> LOT in XA, and I've never seen EVER any plugs that pointed
to the fabled
> "intake robbery". I've heard it's a problem on the Mini's
with siamesed
> intakes, but we don't see it much on the Fuji's. Course,
we rarely use
> the stock induction, but the heads on the smallest of the
family do
> indeed have siamesed intakes. The larger & later OHC
engines from '90
> on, the so-called EJ-22 & EG-33, aren't siamesed, and have
very nice
> induction and FI systems with absolutely no problems of
mixture
> imbalance. An all around nice family of boxers. There were
some early
> turkeys, but we just ignore em. :)
>
> Gar
>
>
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