Re: [alfa] Webers and MPG

[bearbvd@xxxxxxxxxxxxxx (Greg Hermann)]

At 1:16 PM 10/2/03, Mark Battley wrote:
>Greg commented:
>-------------------------
>All the carping and sarcasm aside--a SPICA pump with an electronically
>controlled linear positioner on the fuel control rack would make a RATHER
>slick system--- and likely be superior to electromagnetically controlled
>injectors in many respects.
>
>Further-- the advantages of fully programmable ignition timing are probably
>significantly greater than those of modern, programmable electronic fuel
>control !
>-------------------------
>
>I'm not quite sure what you're trying to say Greg -

What I was saying was :

1. A fully programmable ignition combined with good, properly tuned
carbys--such as Weber DCOE's--will give incredibly good performance, and,
quite likely, better highway mileage than virtually any EFI--with the
exception of EFI which uses air shrouded injectors.

2. A SPICA injection pump and injectors give MUCH better atomization of the
fuel --and also a much shorter duration of the injection event,
particularly at full power--thus making it practical to time the injection
event (to a significant degree) with respect to intake valve opening at
full throttle. Typical EFI injectors are at about an 80% duty cycle at WOT,
and thus timing of them becomes irrelevant at WOT. Clearly--full electronic
(and programmable) control over the fuel delivery from a SPICA pump would
be more desireable and accurate than the mechanical alpha/N metering system
which these pumps used in stock form.

As for Motronic ECU's-- any ECU which does not have either open source code
available OR readily available (at a reasonable price) laptop software via
which ALL of the various tuning parameters can be adjusted is virtually
WORTHLESS to any serious tuner. I am afraid that the Motronic ECU's do not
fit into either one of these two categories. So--while a Motronic MAY
function tolerably well on a dead stock engine, I tend to regard it as next
to useless for any sort of tuning effort.

Webers. on the other hand, are readily tunable to suit virtually any engine
combination to a tee, by the competent, using readily available metering
parts.

It is NOT commonly understood that Weber DCOE's do a FAR better job of
atomizing the fuel--and timing its delivery into the air stream into the
intake ports--than ANY typical EFI system does !

Some of the aftermarket ECU's fit these criteria, as do those of the GM
ECM's which have been fully hacked.

I hope this made it all a little more clear to you.

Greg

 Yes, good control over
>the ignition is valuable - My mid 80s technology Uno Turbo has basically
>standard L-Jet injection, but a fairly sophisticated Microplex ign system
>with mapped ign curves, retard under boost, knock detection etc. It works
>well.
>
>However modern factory (not that modern in fact, my 84 Alfetta had Motronic)
>or aftermarket programmable engine management systems normally control BOTH
>the ign and injection. I suppose that there might be something to be gained
>by fitting a programmable ign only system to a SPICA or carbed car, but by
>the time you've got the sensors fitted you might as well fit an EFI
>manifold, fuel system etc and be done with it...
>
>Mark Battley
>Auckland, New Zealand
>
>1973 Alfa Romeo 2000 GT Veloce (best looking, but slowest of the fleet.. for
>now)
>1989 Fiat Uno Turbo (with new clutch.. Yee-hah, shame about the front tyres)
>1999 Fiat Marea Wagon, 2.0 20V
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