The fuel system upgrades and alternatives section covers performance and reliability improvements that go beyond the original equipment specification, addressing the practical challenges of running a fuel system designed in the late 1940s with modern ethanol-blended fuels and contemporary driving expectations.
Performance Fuel Pumps
Modern solid-state electronic fuel pumps offer a significant reliability improvement over the original SU points-type pump. By replacing the conventional contact-breaker points with solid-state electronics, they eliminate the most common cause of pump failure, worn or burned points that fail to make contact. Electronic pumps are available in both positive-earth specification for cars retaining the original wiring polarity and in dual-polarity specification for cars converted to negative earth, and higher-output performance pumps are available for tuned engines that demand increased fuel delivery at sustained high engine speeds, where the standard pump's output may become marginal.
Fuel Regulators
When fitting a higher-output fuel pump, whether for performance purposes or general reliability, a fuel pressure regulator maintains consistent fuel pressure to the carburettors regardless of pump output. Without a regulator, the increased pump output can overwhelm the carburettor float needle valves, causing the float chambers to flood and the engine to run excessively rich. A regulator fits in the fuel line between the pump and the carburettors and is adjustable to match the pressure required by the H2 or H4 carburettors fitted. Regulators are not generally required with the standard SU pump on a standard TD or TF, becoming necessary when the pump output has been increased.
Fuel Hose & Ethanol Resistance
Modern E5 and E10 ethanol-blended fuels present a challenge to the original rubber fuel hoses fitted to the TD and TF, as ethanol degrades conventional rubber from the inside, causing the hose to swell, soften, and ultimately disintegrate, shedding debris into the fuel system that blocks filters and sticks float chamber needle valves. Stainless braided fuel hose provides a durable, heat-resistant, and ethanol-compatible alternative to the original rubber flexible sections, with a stainless outer braid over an ethanol-resistant inner liner, while modern ethanol-resistant fuel hose in a conventional rubber appearance is also available for owners who prefer the original look, either option being fitted in place of any original rubber hose on a car used with modern fuel. When upgrading fuel delivery, the pump output must be matched to the carburettor specification, the H2 carburettors on the standard TD requiring lower fuel pressure and volume than the H4 units on the Mark II and TF, and fuel hose should be ethanol-compatible regardless of whether the car is regularly used with E10, as even occasional filling with ethanol-blended fuel will begin the degradation process in non-resistant hose.