DDK - Die Deutschen Klassiker

Hello,

I have a 911 E (2.4) MFI fuel pump in working order. Can this be uprated to deliver more fuel at higher RPM for a 2.8 litre engine?

Thanks for any help.

Regards,

Kirk

I'm not very knowledgeable about MFI but suspect the fuelling for 2.4 or 2.8 is down to the metering unit and its space cam not the pump.

Of course if you are using it for a 2.8 on carbs it will be too high on pressure in any case. You would be better changing the pump in that instance. I think Chris at Fenn Lane had sourced one for that application which doesn't need pressure regulation to achieve the usual 3.5 psi.

Andy

Andy,

Thanks very much for the reply. Should have made it clear that the car is going on to MFI. Have been advised this morning that the pump should do the job and that the MFI pump is what actually needs to be set correctly.
Any further information from anyone gratefully received.

Regards,

Kirk
PS Andy are you going to Wilton House on saturday?

Kirk, that's good info'. Yes I'm at Wilton on Saturday , parking on the lawn...dontchaaknow!!! Then Simply Porsche at Beaulieu on Sunday if Mrs H agrees. ( If not, Swanage Fish Festival .........)

If you need to modify the MFI pump to an RSR Spec then using a 2.4 pump will be more difficult that using the earlier 2.0 and 2.2 pump.

In order to improve the resolution of the space cam and hence give better progression the 2.4 pump used a wider space cam than the early pump. The RSR used a pump with a narrow space cam which doesn't fit the later pump body.

It is possible to buy RSR Space cams which fit the early pump body.

It may be possible to machine the existing space cam to suit but I think you would be better off using a 2,4T space cam as this is easier to modify than the E, S or RS space cams.

Obtaining the correct fuelling for Wide Open Throttle is not too difficult but grinding the cam for smooth progression is apparently a bit hit and miss.

I also think you will need to modify the plungers to prevent rotation and also fit the in-line control parts from a Benz Pump.

Chris,

Thank you very much for the information. Most helpful.

Andy,

See you on saturday on the lawn. Been practising my forelock tugging.

Regards,

Kirk