CIS operating pressure.

[drcoastline]

At what pressure does CIS work?

[Bob Kontak]

Until someone that knows something chimes in....

Fuel pump pressure around 100 psi
Step down to system pressure in fuel distributor to 65-ish
Injectors spray at system pressure
Control pressure (20-40-ish psi range) regulates how much pressure the FD plunger fights back with against the air sensor.

[fanaudical]

Complicated answer. Start here:

911 CIS Primer - Index

[RarlyL8]

Depends on the application, CIS covers a lot of models.

[drcoastline]

So what would the highest pressure be? Bob has pressure at the fuel pump at 100PSI, anything operate higher? Looking to have fuel lines made and want to make sure the lines can handle the CIS pressure.

[al lkosmal]

regards,
al

[fanaudical]

I thought some of the Bosch CIS pumps would dead-head at ~8.5 bar but can't seem to find that reference.

Is Len (BoxsterGT) still making fuel lines? He's been a good resource in the past.

[al lkosmal]

I went back through my docs and found this, which show max pressure for.....what i have noted as the 979 pump. As you can see...at what appears to be no flow, the pressure is 11 bar. (154psi).

[drcoastline]

Originally Posted by fanaudical

I thought some of the Bosch CIS pumps would dead-head at ~8.5 bar but can't seem to find that reference.

Is Len (BoxsterGT) still making fuel lines? He's been a good resource in the past.

Yes, Len is making lines and I consulted him. I was prepared to pull the trigger on Lens lines until my neighbor offered to make lines for me. My neighbor is rebuilding a Triumph Mark6 that he bought in 1970 when he was over seas. He worked for Sunoco making high pressures lines for thirty years and is making his own brake and fuel lines from a copper/nickle alloy tubing. I read in a thread where Len stated stainless steel is the best material to use. I am trying to make sure the lines I purchase can handle the CIS pressure.

[drcoastline]

Originally Posted by al lkosmal

I went back through my docs and found this, which show max pressure for.....what i have noted as the 979 pump. As you can see...at what appears to be no flow, the pressure is 11 bar. (154psi).

Thank you for the info Al. This is very helpful. Is this the 979 pump you are referring to? So when operating it operates at 5bar but increases to 11 at idle?

You are purchasing a brand new Genuine Bosch inline fuel pump.

Bosch 0 580 254 979 Inline Fuel Pump

Bosch 979 fuel pumps mount inline (out side of your gas tank), most commonly rear center under your car or truck.

Each Bosch 0-580-254-979 fuel pump provides 165LPH of flow and operate at 72.5 PSI.

Bosch 979 Fuel Pump Specs:
Bosch Part Number: 0580254979
Minimum Current: 12 Volts
Operating Pressure: 72.5 PSI (5 Bar)
Minimum Flow @ Outlet: 43.5 GPH (165 LPH)
Fuel Pump Location: In-Line

Fuel Pump Connections:
Inlet: M14 x 1.5
Outlet: M12 x 1.5
Electrical: Positive M5 / Negative M4

[Bob Kontak]

Originally Posted by drcoastline

So what would the highest pressure be? Bob has pressure at the fuel pump at 100PSI, anything operate higher? Looking to have fuel lines made and want to make sure the lines can handle the CIS pressure.

I did say 100-ish psi.

I would go 300 psi minimum for new lines. Steel should be way more than that.

[al lkosmal]

Originally Posted by drcoastline

Thank you for the info Al. This is very helpful. Is this the 979 pump you are referring to? So when operating it operates at 5bar but increases to 11 at idle?

You are purchasing a brand new Genuine Bosch inline fuel pump.

Bosch 0 580 254 979 Inline Fuel Pump

Bosch 979 fuel pumps mount inline (out side of your gas tank), most commonly rear center under your car or truck.

Each Bosch 0-580-254-979 fuel pump provides 165LPH of flow and operate at 72.5 PSI.

Bosch 979 Fuel Pump Specs:
Bosch Part Number: 0580254979
Minimum Current: 12 Volts
Operating Pressure: 72.5 PSI (5 Bar)
Minimum Flow @ Outlet: 43.5 GPH (165 LPH)
Fuel Pump Location: In-Line

Fuel Pump Connections:
Inlet: M14 x 1.5
Outlet: M12 x 1.5
Electrical: Positive M5 / Negative M4

No, I believe that the way to interpret that is it will be at highest pressure, when the flow is completely blocked..........