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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-340605@logan.com>
Subject: SAE Paper was Re: Turbo and the EC2
Date: Sat, 31 Jul 2004 09:07:07 -0400
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----- Original Message ----- 
From: "Mike Robert" <pmrobert@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, July 31, 2004 8:19 AM
Subject: [FlyRotary] Re: Turbo and the EC2


> DaveLeonard wrote:
>
> > That's great data to have Rusty, thanks for the contribution.
> >
> > Now I just need to figure out a way to make it useful.
> >
> > Dave Leonard
> >
> >     -----Original Message-----
> >
> >     It could be that   with faster combustion wave propagation that
> >     you would want the timing of the lead and trail closer in timing
> >     rather than further or possibly vice versa {:>).
> >     .
> >     Ed Anderson
> >
> >     Exactly right Ed, or vice versa  :-)
> >
> >     Through the miracle of copy and paste, I'll attach the timing
> >     split from my old FD engine computer.  Keep in mind that this is
> >     NOT the stock Mazda timing, though it's probably close to it.  The
> >     top row is the scale in RPM, and the first column is the scale in
> >     inches of mercury.   The numbers in the box represent the
> >     difference in degrees between when the leading, and trailing
> >     ignition will fire.  Positive numbers indicate that the leading
> >     fires before the trailing.
> >
> >     It's interesting to note that aside from the idle range, the
> >     timing split is 0 until you get to around sea level pressure.
> >     From there, it quickly increases to about a maximum level for the
> >     rest of the boost range.  From this, I would assume that
> >     increasing the split reduces the chance of detonation.
> >
> >     Still hard to say how important this is for us.  How much greater
> >     is the chance of detonation?  How much power would you lose if you
> >     had to run on trailing ignition only with the split built in?
> >
> >     Cheers,
> >     Rusty (doing my turbo duties, though I'm not sure why)
> >
> The auto people generally converge on a zero split at 100 kpa then head
> for an 8 degree split under any significant boost. An 8 degree split at
> idle makes for smoothness. I use L-32 T-30 degrees timing at max load
> (>80 kpa MAP, > 6K rpm) in a ported NA 12A - that's dyno proven to make
> the best power. One must remember that there are significant changes in
> emissions related to the split, the factory ECU parameters are more for
> emissions than max power and reliability. I have a Mazda authored SAE
> paper here somewhere that explains this in detail, I'll be looking for
> it. There was tons of good stuff in it that was written by the actual
> engineers that developed the rotary.
>
>      -Mike
>

Hi MIke,

    Great to hear from sources with hands-on experience on a topic.  Would
love to get a copy of the SAE paper if you can find it.

Ed
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC