What do HS2/HS4/HIF44/etc mean?
They are model numbers of SU (Skinners Union) carburettors, the type of carburettor fitted to all Minis until the arrival of fuel injection in the 1990s. HS2/4/6/8 – the number represents the size of the carburettor, in eights of an inch plus one inch. So HS2 is 1.25 inch, HS4 is 1.5 inch, HS6 is 1.76 inch and HS8 is 2 inch. HIF carburettors are a more recent design than HS carburettors. HIF stands for Horizontal Integral Float, meaning that the float bowl is integrated into the carb body instead of being to one side as on the HS carburettors. This counteracts fuel starvation during hard cornering. These carburettors also have a few other features to make fuel delivery more accurate provide compatibility with turbochargers. HIF carburettors are found on many British cars from the 1970’s onwards including the Metro. HIF carburettors may be specified as per HS carburettors, i.e. HIF4, HIF6. These carburettors are more commonly named HIF38 or HIF44, which are the equivalent sizes in milli
