Bruce;
First, much of the complexity of the CD175 on your TR7 is the result of
trying to meet EPA standards I would guess that a Holly of the same period
would also be more complex than one from the 60's.
If you define ' complex ' as number of moving part, yes the constant
depression carb is more complex, however if you define complex as routes the
fuel must take to get into the engine it is much simpler than a conventional
carb. .
The advantage of the CD carb is that it easily over comes one of the major
problems of carburetion. Engines require a mixture which varies with the
engine speed. and load and that ratio is not linear , as RPM increases it
goes up down and back up .
Standard carbs meet this need by offering three or so mixture ratios,
using the one that comes close for a given RPM or load. Harry Miller, the
race car builder of the 20's actually made his money on a racing carb design
that offered 12 mixture ratios in one carb.
The CD carb is designed such that the mixture ratio is totally variable for
any RPM or load need..
Basically the conventional carb is a fuel spigot with three settings and the
CD has a infinitely variable fuel ratio.
+Bob
----- Original Message -----
From: <Eganb@aol.com>
> Probably a dumb question on my part, but why are SU and Zenith-Stromberg
> carburetors so complicated, compared to something like a Holley or
Rochester
> carb?
>
> I'm always amazed at all the separate components that make up the carbs
you
> find on LBCs, whereas a Holley four-barrel proabably has less than half
the
> moving parts.
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