Dave Tietz writes:
> I see British Victoria lists a Jet assortment kit for Webers -- might I have
>a
> "Granny" jet (or fuel economy type jet) in the carb. Should I buy the jet
>kit,
> find a bigger, better, whatever jet that will make the car perform
> better ... or are down draft Webers (a two barrel) that much poorer
> performers than dual SU carbs.
I have put 3 Webers (2 sidedraft and 1 downdraft) on 3 different MGs, and
all the intsallations were fairly trivial. However setting them up can be a
nightmare, if you don't know what you are doing.
First get any of the 2 Weber manuals and read them cover to cover. You have to
understand how the carb works before going any further.
There are references in both books for the approximate jetting and that's a good
place to start. I know that in 2 of the Moss "Performance Manuals", they have
tables on the approximate jettings for different stages of engine tune. Once
you have an approxiamte setting, then you can go ahead and "tune: the carb for
you engine and type of driving.
The downdraft is the easiest to tune, but don't confuse what the mixture screw
is for. It only changes the mixture for the idle circuit, not the progressive,
main
or pump circuits.
Find a local specialist who has a variety of jets and experiment (use an exhaust
gas analysier) or better still a rolling road. I would not bother with Brity Vic
jet kit - it'i expensive and may not yield the correct jets.
gerry
ps in all cases that I have fitted a Weber, I have been happy with the
performance.
Although with side-draft fuel economy has gone down.
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