Fuel pump options
06-10-2018, 01:09 PM
#1
Track Day
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Fuel pump options
1979 928
I'm at the point where I need to make a decision about what external fuel pump to use. I've gone ahead and decided to delete the intank pump. I've read that swapping to a Bosch 044 is one way to go and that requires a wiring upgrade? Also some have said that the stock external pump wasnt strong enough without the intank pump helping out. I'm leaning towards just replacing like for like for now. I believe the part number is
911-608-102-00 for the OEM pump. Any suggestions?
I'm at the point where I need to make a decision about what external fuel pump to use. I've gone ahead and decided to delete the intank pump. I've read that swapping to a Bosch 044 is one way to go and that requires a wiring upgrade? Also some have said that the stock external pump wasnt strong enough without the intank pump helping out. I'm leaning towards just replacing like for like for now. I believe the part number is
911-608-102-00 for the OEM pump. Any suggestions?
06-10-2018, 07:35 PM
#3
Rennlist Member
The in tank pump is just there to prevent cavitation of the main pump in high temperatures and or high altitudes.
If you live in a hot climate or high altitude you need to keep it, if you live in a cooler climate you will be fine deleting it.
As for the pump, you need to be sure that the 044 pump or any other that you install can generate the pressure needed for the CIS system.
It is fairly higher than the EFI the 044 was designed to be hooked up to.
Then you need to redo the pressures in the CIS system to account for the change in pressure and flow.
As for the wiring. You just need to use the old harness as a trigger for a fused relay that powers the 044 directly from the battery. It's easy to do. I recommend you do this same mod for the AC clutch as well.
If you live in a hot climate or high altitude you need to keep it, if you live in a cooler climate you will be fine deleting it.
As for the pump, you need to be sure that the 044 pump or any other that you install can generate the pressure needed for the CIS system.
It is fairly higher than the EFI the 044 was designed to be hooked up to.
Then you need to redo the pressures in the CIS system to account for the change in pressure and flow.
As for the wiring. You just need to use the old harness as a trigger for a fused relay that powers the 044 directly from the battery. It's easy to do. I recommend you do this same mod for the AC clutch as well.
06-10-2018, 11:18 PM
#4
Rennlist Member
My car is CIS, and it went from UK (C16 opts) to Saudi, in Riyadh (120F and ~3000' ASL), where it lived for 10 years. Somewhere in that time its single external pump was replaced by an S4 model pump, which ran fine in my hands for a year. Then migrated to Oz, where it ran for several more years (much cooler environment) before I replaced the tank (stripped threaded insert) and the pump (back to proper CIS model). The S4 pump always managed to produce the necessary system pressure (65-75psi) and delivery rate. So my theory is that any Bosch injection type pump that physically mates to the fittings will do the job, so its not necessary to go to extra lengths here unless you are aiming at significantly more power output.
jp 83 Euro S AT 57k
jp 83 Euro S AT 57k