From: "Tracy Crook" <lors01@msn.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-122059@logan.com>
Subject: Re: [FlyRotary] Re: Turbo boost limits in the EC2
Date: Fri, 4 Jun 2004 16:34:09 -0400
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>
> I have some dyno data for a rotary car, 12A, ported, NA, 2x50mm TB, EFI,
> 87 octane fuel. We were in search of real world ground truth on timing
> (split, T&L identical, etc. ). I saw 165 RWHP with stock timing split,
> 167 RWHP firing them simultaneously and 163 w/ the trailing disabled
> though EGT was up ~50F. Leading disabled was a disaster - ~120 RWHP,
> EGTs up 200F, glowing headers. All power figures quoted are at 7500 RPM.
> The motivation for doing this little experiment was the fact that
> Mazda's LeMans winning efforts used 3 plugs per rotor and fired them
> simultaneously while using 80 octane fuel. Conclusion from our little
> test, sample quantity 1, is that you might get a touch more HP firing
> simultaneously. There is some literature that suggests the split timing
> is more for low and mid emissions purposes. It also showed that dropping
> the trailing affected HP very little, well within statistical jitter in
> our case. Dropping leading looked dangerous and seemed to suggest that
> more of the fuel was burning on the way out rather than providing
> combustion chamber/rotor pressure/power. I'm sure this would be a bad
> thing for you turbo folks! I know this is apples and oranges, but ...
> there ya go.
>
>      -Mike

Great data Mike.  It parallels exactly with my results but I didn't have
dyno numbers to go with them.  I also saw a 35 - 40 degree drop (nice thing
on a rotary) when using same timing on lead & trail.

Tracy