From my experience engine idle fuel mixture and steady state fuel
mixture ratios are very different. When an engine idles it idles on
the rich side. When one is cruising on the highway the fuel to air
ratio is very lean. So one can't assume that if the idle mixture is OK
that acceleration mixtures and steady state mixtures will be OK or
visa versa!! From what I understand SU and Strombergs rely on engine
vacuum to adjust fuel to air ratios under acceleration. Remember that
they use a rubber diaphram to adjust the height of the mixture needle.
Webers and other carbs use air flow to meter fuel to air ratios. Either
technique is valid but both carbs require different tuning methods. Fuel
injection systems could use both methods depending on the type of sensors
the computer is using to monitor engine parameters. All any carb or fuel
injection computer cares about is air mass flow and the proper amount
of fuel to add to that particular mass flow of air for that particular
engine operating point. (Engine temp, load, atmospheric pressure, rpm's
ambient temperature etc.). So in answer to the question does leaner mean
mean a slower idle. Remember the whole purpose of the choke is to put
more fuel into the engine. When the choke is closed the engine will idle
higher until it warms. At that point the engine can accept a relatively
lower fuel to air mixture. fewww!!!
Any questions or comments??
On the subject of engine swaps:
What engine's in the world have better exhaust notes than British Sports
Cars. I love the sound of my 74 TR-6 as I blast through a tunnel or am
cruising the open highway. No Buick or Japanese engine sounds as good.