On Mon, 30 Oct 2006 20:36:17 -0500
"Ed Anderson" <eanderson@carolina.rr.com> wrote:

>
> >
> > I may have some (a lot of) mis-information in my head.  I had assumed
> > that the injectors in the block were the secondaries because those
> > ports are smaller.  I'm not actually using injectors in that location
> > as all of my injectors are in the tubes feeding the ports.  Will I have
> > any problems using the smaller ports as secondaries and the larger ones
> > as primaries?  Would it be different if I had the injectors in the
> > block?
> >
> > Bob W.
> >
> >>
>
> No, just the opposite, Bob.  The injectors in the center housing are the
> primary injectors fed by the two small port openings in the center of the
> intake manifold (stock).  The secondary runners are larger in diameter than
> the primary runners in the stock manifold.  This permits the secondary
> runners to flow more air easier as the demand for air increases as rpm and
> power goes up.  Generally the primary injectors are on all the time from
> idle to WOT (one reason they are called primaries) whereas the secondary
> injectors are normally only on when the demand for more fuel (rpm and power
> increasing) reaches a certain point.  This is referred to as "Staging" where
> it goes from 2 injectors (primaries) to 4 injectors (Primary + Secondary)
> working.  If you are using stock 13B Mazda injectors the engine will run at
> approx 90 % power on either pair of injectors.
>
> Also the intake port   timing is different (in the stock block), with the
> primary ports opening sooner than the secondary ports and the secondary
> ports closing later than the primaries (it varies a bit from one year and
> model (N/A vs Turbo)).
>
> But, its really not a problem Bob.  All you have to do to make the two
> center housing intake ports correspond to your primary injectors is to make
> certain the electrical connectors from the primary injector wires of Tracy's
> EC2 go to the injectors feeding those ports.  Wait, I guess it could make a
> difference if the flow rate of your primary injectors and secondary
> injectors are considerably different.  Mine are the same flow rate - so it
> doesn't matter.  If your injector flow rates are different then you want the
> smaller flow injectors feeding the center housing ports and the larger flow
> injectors feeding your secondary ports.
>
> Your engine would run with either set up - but I would highly recommend
> setting it up conventionally.
>
> Ed
>
> Ed Anderson
> Rv-6A N494BW Rotary Powered
> Matthews, NC
> eanderson@carolina.rr.com
> http://members.cox.net/rogersda/rotary/configs.htm#N494BW
> http://www.dmack.net/mazda/index.html
>
Thanks Ed.  That all makes sense.  I'll see what I've actually got
wired up next trip to the airport.

Bob W.  (Still working on my tailwheel endorsement.)


--
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