Carburettor
Tuning
During
the '80s and '90s an old gent in Falmouth used to keep my SUs
in perfect tune and rebuild them when required, but he phoned
me in 2002 to say that, as no series production cars had been
built using carburettors since 1993, his business was no longer
viable so he was closing it down. It is well known that modern
fuel injection systems atomise the fuel/air mixture far better
than carburettors also they are able to inject the mixture into
the engine more precisely, and at greater pressure. By comparison,
as I understand it, the SUs are low-pressure devices with the
mixture sucked into the compression chamber by the vacuum created
by the down-stroke of the Otto cycle. I have not been able to
find out how many cars were built between 1993 and 1998, but
over the last ten years some 552 million cars have been built
world-wide using fuel injection.
Following on from the rolling road test described in Safety
Fast! recently I have been doing some research into the
constituent parts of modern petrols which are designed to meet
the demands of modern fuel-injection engines rather than our
ancient carburettor engines. The modern petrols differ widely
from those that were around when our SU setup was designed .
Gordon Hesketh-Jones (13.4.09)
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SU HIF carburettor fitted to the Factory MGBGTV8 |