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Date: Thu, 21 Jun 2012 13:00:11 -0400
From: Ernest Christley <echristley@att.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: MAP drop
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Bill Bradburry wrote:
> I don't think I get much pressure drop across the filter, but I don't know
> what the rest of the intake does.  I would like to get a pressure reading at
> the entrance to the rotor to see what the drop is for the entire intake
> manifold and filter.
> 
> It seems like an AFR of 16 is lean for turbocharging during a takeoff run??
> 

Not a turbo.  A blower.  A centrifugal blower from a '67 Corvair cooling fan situated between the engine and PSRU.  I
wasn't expecting to get a lot of MAP boost, but it looks like I'm not getting anything.  The only way to really tell
would be to remove the fan and do a couple runs without it in the system.

  The 16 AFR is at idle, and basically everything below WOT where I'm not trying to make significant power.  After WOT,
the throttle turns into a mixture control and will currently push it all the way down to 11.5.  But I'm seeing RPM drop
off below 12, so I'm going to set that as my bottom limit.

> I don't guess I understand why you want your manifold pressure to read in
> "percentage of ambient"??  Why not just inches??
> 

Don't have a choice in the matter.  That is what the MegaSquirt computer/firmware/software stack gives me, so I deal
with it.  Though, for programming purposes, I can see how it sure would make the computations simpler.