Help - Fuel pump question

[Guest]

Hello. I'm building a track day 924. I have purchased a 79 and an 81. The 81 body is very good but has no engine. The 79 is rusty so I'm transferring all the engine, loom etc to the 81. My problem is the fuel systems are not the same. 79 has 1 pump and 2 Fuel Accumulators, 81 has 2 pumps and 1 fuel accumulator. Can I purchase a new style fuel pump and fit it into the 81 with the 81 fuel tank and 81 Fuel Accumulator or do I have to swap the fuel tanks, Fuel Accumulators and find an old fuel pump?

Will the new style pump produce too much fuel pressure for the 79 fuel distributor?

I'm very confused and would really appreciate some help.

 

[924nutter]

It is the metering unit that sets the pressure and according to the PET cd the 924 used the same metering unit throughout its life, so the new pump will not produce too much pressure. My '79 has two pumps and one accumulator, and the wiring loom from my worn out 83 lux fitted in nicely thank you. I am not an anorak expert, maybe the single pump twin accumulator was for a different market. For the 79 model year three different tank layouts are listed.

Porscheshop (usual disclaimers) do a replacement Bosch pump at a competetive price.

Porsche's philsophy of continual improvement tells us that the twin pump system must confer some advantage.

IMO Haynes are not always 100 percent right, but according to their chronological listing of wiring diagrams the single pump was only used up to 78, but there are always going going to be cars built early and registered late.