Charles,
A "richer" mixture means more fuel not more air. The way most carbs work
is that the air flow is constant in relation to demand. You adjust mixture
by adjusting the amount of fuel that is mixed with the air. If the oxygen
portion of the air is lower, such as it is here in the mile high city, you
must reduce the amount of fuel added proportionally to acheive the most
efficient explosion.
Since you cannot burn as much fuel as fast at altitude (because your Oxygen
flow is limited) you have a corresponding loss in power. We estimate about
20% in Denver compared to sea level. When motorcycles used to run the
Pikes Peak hill climb they used a little trick. They would set up their
carb very lean and start the race with the choke on. About half way up
they reach down and flip off the choke to lean it out for the higher
altitude/lower O(subscript: 2).
The whole point of a turbo or super charger is to compress the air into a
smaller volume. This way the engine can get more Oxygen and can process
more fuel. Because the preasure acheived by a Kompressor (more accurate
German term) is the roughly the same at any altitude, Turbo and
supercharged systems are less affected by altitude changes. I say less
because there is always some point at which these systems are not under
boost and at those points they have the same drop as non-
Turbo/Supercharged systems. Nitrousoxide injection works the same way by
increasing the amount of O(subscript: 2) available to mix with the fuel.
Herb G.
"Charles D. Sorkin" <cdsorkin@ix.netcom.com> on 10/13/99 10:47:52 AM
Please respond to "Charles D. Sorkin" <cdsorkin@ix.netcom.com>
To: "Spridget List" <spridgets@autox.team.net>
cc: (bcc: Herb Goede/AMS/AMSINC)
Subject: Re: Fuel pump... and Altitude Sickness
Dear List:
Thanks everyone for the sugggestions to alleviate the leaking float
problem.
After whacking the bowls with a plastic screwdriver end, the problem
decreased markedly, but not completely. Inspecting further, I found that
the pressure from the fuel pump had dislodged the fuel line near the
in-line
filter. Apparently, the DPO (does that mean Dumb Prior Owner, or Dead
Prior
Owner?) had attatched the filter using some sort of homemade paperclip type
of wire, instead of a clamp. Installing a new clamp on the hose solved the
problem. Now under normal conditions, idling for instance, how often
should
the fuel pump click? Once or twice per minute perhaps? I never noticed
the
clicking before until this problem cropped up.
Another question about the altitude sickness thread: As someone pointed
out, the problem is not an air deficiency, but an oxygen deficiency.
Oxygen
is only 25% of the atmosphere. Wouldn't one want to enrich the mixture in
order to get more oxygen into the cylinder? Perhaps I should take a trip
out there so as to experiment first-hand.
Regards,
Charles
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