[Diy_efi] alpha-n

[Perry Harrington]

On Thu, Jul 03, 2003 at 03:11:41PM -0700, Adam Wade wrote:
> --- Perry Harrington <pedward at apsoft.com> wrote:
> 
> > Actually, Honda still does that.  On their i bikes
> > the MAP sample tube from each runner is attached to
> > a brass tube that has rougly a .030 inner diameter.
> 
> Far out.  I will have to look into that some more (I
> have not yet gathered much research material on the
> Hondas).  Now you have me wondering about other makes.
> 
> Does Honda do that on their big twins (RC51) as well
> as their inline-4s?  I can see I4s as being very
> practical, but I am not sure you could get enough
> damping without slowing response greatly when dealing
> with a 1000cc v-twin.

Not sure, but I assume so.  Consider the situation:

With a Hawk twin, you have a 232/488 ignition.

You can really treat them as 2 single cylinder engines rather
than a twin.  Honda actually did that.  My Hawk has a twin
pickup ignition with dual waste spark.  It has 2 plugs per
cylinder and 2 pickups.  Essentially the ignition module is just
2 single cylinder modules paired up.  MAP sampling is best done
in sync with the cylinders.  If you sample your MAP at the tach
event, then it's consistent.

The 4 cyl has a unique issue too.  Honda uses a flat crank, which
makes the CBR motor more like 2 vertical twins.  It's firing
order is 1-2-4-3, with a 150 degree rather than 180 degree crank.

If you can reliably sample a 4 cyl with such an odd layout, a
90 degree twin shouldn't be difficult.

--Perry

-- 
Perry Harrington			Data Acquisition & Instrumentation, Inc	
perry at dainst dot com					 http://www.dainst.com/

Those who would give up essential liberty to purchase a little temporary safety
deserve neither liberty or safety. Nor, are they likely to end up with either.
                             -- Benjamin Franklin

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