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You're absolutely correct. The pressure ratio has
nothing to do with MAP. I knew I should have had a second cup of
coffee this morning. Back to trying to get a graphical LCD to work -
hopefully with more success than encountered on this topic {:>)
Duh!
Ed
----- Original Message -----
Sent: Monday, September 05, 2005 2:39
PM
Subject: [FlyRotary] Re: Another great
flying day = another day of troubleshooting
Ed I am talking MAP in both cases. I don't see how 26" MAP is
higher than 36"MAP. But I learned the old math :-)
Dave
On 9/5/05, Ed
Anderson <eanderson@carolina.rr.com>
wrote:
Well, actually it is absolute pressure that the spark
plug is reacting to. In this example, the absolute pressure in the
intake is 1.234" HG higher at 10,000 with your 26 " boost than at sea level
with your 36" of boost.. This would contribute to an increased
pressure in the combustion chamber when it is compressed over the sea level
compression pressure. Therefore, the spark plug is facing a tougher
task at 10,000 than at Sea level (in this example).
Ed
----- Original Message -----
Sent: Monday, September 05, 2005
12:57 PM
Subject: [FlyRotary] Re: Another
great flying day = another day of troubleshooting
Actually, Dave you had a higher pressure ratio (manifold to
ambient) at 10,000 feet with 26" boost than at sea level with
36". At sea level the pressure ratio would be 36/29.92 =
1.20. At 10,000 ft ambient pressure = 20.57 " hg , so the
pressure ratio would be 26/20.57 = 1.26.
Not much greater, but it was higher by approx.1.23" Hg. (1.20 -1.26 =
.06 *20.57 = 1.234" Hg).
Ed
A Right. But what does the
plug know about the ambient pressure? I thought that it was just the
absolute density of the charge that was contributing to SAG.
--
Dave Leonard
Turbo Rotary RV-6 N4VY
http://members.aol.com/_ht_a/rotaryroster/index.html
http://members.aol.com/_ht_a/vp4skydoc/index.html
--
Dave
Leonard
Turbo Rotary RV-6 N4VY
http://members.aol.com/_ht_a/rotaryroster/index.html
http://members.aol.com/_ht_a/vp4skydoc/index.html
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