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Re: 747 & 4cyls



> I see; I'd forgotten that 747 was TBI only. I thot it had a TPI mode,
> and that in TPI mode, you had one driver driving a gang of SATs; score
> one more for altzheimer's I guess. At least I think there are SOME GM
> ecms like that, ain't there?

The 730 and 165 have been used in single injector TBIs, but no hacs

> >Other thing is MAP is going to be all important on this. (MAF is way too
> >unreliable for aero use, IMO)
> Oh yes, we're definitely going MAP, so no need to worry or factor in a
> possible MAF into the equation; idn't gonna happen. Besides the
> restriction and reliability issues, it's also a no-go if we wanted a
> redundant pair of MAF sensors. Ick.
> >Forgot to ask, DIS or Distributor?
> DIS generally. The smallest engine in the family has a dizzy hole &
> gear, and there's a retrofit to run an Escort dizzy (which would be
> dual'd; pickups, modules & coils--for IGN redundancy) off one of the
> OH cams, on the next engine up in size (which is what Andy's working
> on), but for generality across the whole family, just assume we're
> goin crank-fired.

For the 4 cylinder distributor set up the syclone code, might be a good one
to look at.
The 4 DIS is another matter, that applications does exist, just I don't know
of a hac for it.
On thing that has been tossed around here is using the sy code DIS, but it's
not working yet.

> Hey, no problem; when yer hot, yer hot. :)  And when yer busy, yer
> usually buzzie, too. That's life in the GN fast lane, I guess. :)
> How's black beauty doin, BTW. Are you finished with the main organ
> transplants?

Ya, things are all bolted in, and she drives, just got bugs to work out,
just need to put some time in on her.

> >Injector sizing may be an issue to.
> >Have you taken a gm MAP sensor aloft and recorded the output with a 5v
> >source / ground, might need to know rather early how this looks.
> No need, they've been used in aircraft apps before. They be fine.
> Geez, Bruce, we're not going into space with this stuff, just up to
> 12k ft. max (for VFR flight, anyway)!

Ohhh, I was thinking like 2-3s that high, like approaching needing O2

> >While a stock engine might idle at 40 K/Pa at sealevel, and reach 96 out
of
> >98 K/Pa at WOT, what is ambient K/Pa at altitude
> >This is something where you might just want to get a full time baro
input,
> >and that would have to be with Johns 730 stuff.
> >   The more I think about it the Baro is probably gonna be a mandatory
item,
> >or you'll be futzin with the AFR all the time.

> Eat yer hearts out, you land-lubbers. This is one of the niceties of
> the aircraft engine playground. Except for the VE errors caused by the
> exhaust dumping into a different ambient than MSL, the MAP is good
> enough for first-order alt. compensation inherently. At 10k ft. we're
> used to making a max of 70% power at WOT. The OL fueling tables will
> be close enough, AND your error is on the rich side also, so no
> problemo. Since without an O2 sensor, we just about HAVE to have some
> kind of manual mix control, and that with wide enough AFR authority to
> cover cold-start enrichment levels too, those same manual controls are
> more than able to be used to compensate for altitude effects, given
> the inherent compensation from MAP-based fueling to begin with. This
> is already/currently soup de jour in XA engines, sotaspeak.

Just having trouble unthinking what you need.  The auto application is like
totally different, in execution.

> Until unleaded Avgas comes to the fore, just assume we'll be using the
> normal/everyday EGT and a manual tweak of AFR at cruise anyway. And
> also no2worry re the "futzin"; remember an airplane's normal regime is
> to climb to cruise altitude under 75-100% power (which assumes PE/OL),
> level off, and then throttle back and tweak AFR for economy via EGT.
> That's why I said "eat yer heart out"; with NO rapid or frequent
> throttle excursions, the minimal "futzin" you mention is already a
> normal part of a pilot's climb2cruise scenario, since the carb's in
> use all have manual mix control anyway.
> Point being it's already a demonstrated fact via carbs and other
> custom manual-mix EFI systems out there, that OL in the ecm, along
> with a manual AFR tweak, is perfectly workable and more than
> acceptable to current pilots. But it's good to bring up all these
> issues just in case we missed something on the way to the forum.

Forum, just don't tell me committees meet there
Bruce
>
> Gar
>
>
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