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Date: Tue, 13 Mar 2007 12:53:25 -0400
From: Ernest Christley <echristley@nc.rr.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Engine noise and changes in timeing and mixture.
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WRJJRS@aol.com wrote:

> For Tracy,
>  When I was actively tuning race cars we had a truism that I often 
> used, "everything changes everything". This was a drastic 
> oversimplification, but none the less was true. If you have an engine 
> running very well, a seemingly minor change WILL change exhaust note 
> or timber. On the dyno you would find some adjustments did little, 
> others a great deal. The fact is as you get the mixture closer to 
> right I am afraid you will hear the exhaust not come back up in volume.
> Bill Jepson

Maybe not, Bill.  Without the snubbers, there would be some unknown and 
possibly variable delay in the closing.  There would also possibly be 
varying delays between different injectors.  This variability might not 
be enough to feel a vibration, but the exhaust pulse would be slightly 
stronger from one chamber than the other.  It would only be detected as 
more noise and would express itself as a slop factor in tuning.  Remove 
the variability and the tuning can be more exact since the same amount 
of fuel will be delivered every time, giving Tracy that extra 100RPM.

Possible?

-- 
         ,|"|"|,              Ernest Christley       |
----===<{{(oQo)}}>===----    Dyke Delta Builder      |
        o|  d  |o        http://ernest.isa-geek.org  |