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Date: Mon, 30 Oct 2006 18:55:51 -0700
From: Bob White <rlwhite@comcast.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Injector bosses
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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.)


-- 
N93BD - Rotary Powered BD-4 - http://www.bob-white.com
First engine start 1/7/06 - Special Airworthiness Certificate 10/1/06
Cables for your rotary installation - http://www.roblinphoto.com/shop/