The factory V8 fuel system was specified for the standard 137bhp 3528cc engine. For cars used hard, fitted with capacity-upgrade engines (4.0 or 4.6 litre), or seeking improved fuelling consistency, the available upgrade routes cover air filtration, carburettors, fuel pumps and fuel pressure regulation.
Performance Air Filters
Performance air filters offer freer airflow than the standard paper element, allowing higher peak power on engines that have been opened up elsewhere. They typically use a foam, gauze or cotton media, often re-oilable for long service life.
Where engine specification has been raised significantly above standard, breathing improvements at the air filter end are often a worthwhile small gain alongside more substantial work elsewhere.
Performance Carburettors
Performance carburettor options include larger SU HIF carburettors for engines built to higher power levels, and four-barrel carburettor conversions for capacity-upgrade engines. Selecting performance carburettors should be done as part of a coherent engine specification, carburettor sizing must match camshaft, head and exhaust specification to give a balanced result.
Performance Fuel Pumps and Regulators
Higher-output engines require greater fuel flow than the standard mechanical pump can deliver. Electric fuel pumps with appropriate flow ratings are the typical upgrade, fitted in addition to or in place of the mechanical pump. A fuel pressure regulator allows the carburettor inlet pressure to be set to the appropriate value, avoiding the float-chamber flooding that can occur if pump output pressure is allowed to rise unchecked.
Sub-Sections
Performance Air Filters, Performance Carburettors, Performance Fuel Pumps, and Fuel Regulators each cover their respective upgrade options.
MGOC Spares
MGOC Spares supplies fuel system upgrades for the MGB GT V8, see individual sub-sections for details.