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Re: Spit intake/exhaust manifold

To: triumphs@autox.team.net
Subject: Re: Spit intake/exhaust manifold
From: lmdpth@lmd.ericsson.se (LMD/T/TB Peter Thorsen)
Date: Sun, 20 Oct 1996 11:09:15 +0200
Hi,

> >  What
> > is the point of running the water through the intake manifold?  Does this
> > heat up the manifold and help in cold weather or something?
> 

I'm still no expert but this is my best shot:
To make a short explanation long - for the electrical spark to be able to
ignite the air/gas mixture, the ratio between air and gas _vapors_ needs to
be in a certain interval (~ 11:1(rich) - 17:1 (lean)). The carburetters job
is to inject just the right amount of (liquid) fuel into the air that flows
through it. However in cold weather the injected fuel may not fully evaporate,
staying as very small drops in the mixture or condensing on the sides of the
manifold. The result is that the air/fuel ratio gets to lean, resulting in
poor running.

By heating the intake manifold, the air that flows through it
is heated and better able to evaporate all the fuel. Also condensation on the
sides is avoided.

When the engine is cold, the only way to keep the mixture ratio in the
right interval is to inject more fuel to compensate for what doesn't
evaporate or condense - this is the carburetter choke.

 - Peter



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