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Re: [Spridgets] Carburetor Gasketing

To: dmg@bossig.com, Spridgets <spridgets@autox.team.net>
Subject: Re: [Spridgets] Carburetor Gasketing
From: "Robert E. Shlafer" <pilotrob@webtv.net>
Date: Sun, 13 Apr 2008 15:12:11 GMT

I think there's a reason for those different
recommended needles for the stock engine in the factory manuals or they 
wouldn't bother listing them? 

(Then again, they're British so maybe they would!. :).

The SU is a "constant VELOCITY" carb.

"Volume" increases as air valve rises
but "density" of air depends upon "density" altitude (pressure altitude 
corrected for temperature....they haven't found a way to correct for relative 
humidity far as I know).

So a cubic foot of air at 5.000 feet contains
less "air molecules" than a cubic foot of air
at sea level. 

Layman's terms..."what it all means".......

Here's what Burlen told me: "Weak" needle
is basically for motors run at/over density altitudes of 3.000'.

"Rich" needle for "drive it like you stole it"
WOT/redline types, or if you're running lower than recommended octane 
(combustion cooling) or maybe you're running slightly higher than stock 
compression ratio or added a header and maybe free-flow air filters, etc.

Anyhow, that's what they told me. Do I 
"know". No. My area of expertise is safe civilian airplane driving within a 
controlled civilian environment. 

Always willing to learn though and welcome
knowledge, remarks from others 'cause maybe I heard wrong or misunderstood.

Cap'n. Bob      '60 :{)
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