Mechanical v Electric fuel pump?

[David C]

On further reflection it isn't just after long periods of standing. It gets fairly hot under the hood and fuel evaporates when the engine is shut down. An electric pump will also help with hot starts. I think the Filton engineers must have had good reason to replace the mechanical pump with the SU.

There are many opinions on the electric pumps. Several have become infuriated with the SU and gone to Holley, Mallory etc. The latter have good output and are reliable but have been criticised for being noisy and may generate more pressure than you need, lifting the needle valve and causing a rich mixture.

The main problem with the SU was its mechanical points. The AUF404 was double ended and had twice as much to go wrong. The later, solid state, switching seemed much better and was a fairly easy retro-fit. I modified my pumps in this way and was very happy with the result. New pumps with this type of switching are available in the UK for about £300.

If you do go for a racing style pump you need to make sure it is mounted on a suitably compliant base with flexible hoses so vibration isn't transferred to the car.