I'd venture to guess that most Webers on most street cars are set up
wrong. In fact, I'm pretty comfortable saying that most alternative
carburetors people purchase and mount are set up wrong, as well as often
being just plain too big. Be it Webers or a Holley. Lots of V8
motorheads love the Holley 750 double pumpers [without knowing what that
actually means and what models there are], even though it's actually a
very poor carburetor for street use.
Certainly a Weber can be set up to perform well. The Italian car
companies seemed to specialize in doing this all the time. It's a
matter of matching the components properly to the application. This
starts with venturi sizing, something people never seem to notice.
Folks get very busy in discussing "Do I need a 40 DCOE or a 45?" when
the question is meaningless. You need to size the venturi to the
engine, and then select the main body for that venturi. Right there,
that took out 99.9% of the folks that buy a Weber; they have no idea
what I just said.
You've then got to follow through with determining the right jets, the
right emulsifier tubes, etc. None of which is cheap with a Weber. So
lots of folks just buy one "preset" from some vendor, mount it, and get
the classic poor fuel mileage and lousy performance a Weber is noted
for. It's not the Weber's fault, it's that it's not selected for and
set up for the engine and application. This applies to Webers,
Holley's, SU, ZS, and every other form of carburetor known to man.
>>> Bill Gunshannon <bill@cs.scranton.edu> 05/23/02 08:30AM >>>
On Thu, 23 May 2002, Nolan Penney wrote:
> Lots of wrong myths about the DCOE abound. Two 40 DCOE, even with
the
> smallest venturi's available, flow far more air then the most highly
> reved Spitfire engine can pull. Translation? Far more carburetor
then
> engine, and typical lousy fuel mileage and poor lower rpm
performance
> when operating anywhere but on the race track. A single 40 DCOE
will
> perform better. Look at the Weber information for selecting venturi
> sizes and you will see what I mean.
So, is this unique to the Spit?? I drove an old Alfa-Romeo for
quite some time when I lived in Europe (back in the days when you
could still go fast in most places) and it not only had better
gas mileage than my Ford Capri, but performed quite well at both
low and high speeds. (As an aside, while difficult to do things
like valve adjustment it was one of the best engineered engines
I ever ran or worked on.)
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