FASS in a M923 with Cummins 250

[Vintage iron]

It is a 24V 150 GPM unit.

 

[Elideclan2]

I called FASS directly. You will need to tell them the specs on the a2 motor. There are different flow rates for different motors. The tech line staff at FASS are very knowledgeable.
Vintage iron (Matt) my mechanic can also help you he is on the fourm.

 

[Csm Davis]

The model for the 855 Cummins requires an oil pressure switch so that leaves out doing it with cheaper parts I guess. $697 for the FASS unit.

Why would it need a oil pressure switch?

 

[muthkw25]

I am sure with this addition along with adding another fuel line to the back of the motor it will run like a champ.

 

[Vintage iron]

csm davis, the oil pressure switch that comes with the unit will turn the unit on. I did the install by the book to keep the operation of the truck simple for the customer. I think when I do this on my truck I will wire it to run off my main switch.

 

[swbradley1]

Matt, So that means the switch doesn't have anything to do with the engine operation it just tells the FASS unit to power up when the oil pressure gets to a certain point?

In that case I would do what you are doing and wire it to the switch.

That also means that a lift pump and filters may work as well but without the air reduction.

 

[Stevepala]

I run a few different fass pumps on diesel motors and I noticed a noticeable difference on a 5.9. After the install the rpm at wide open shift was 150 rpm greater which was a very helpful on a stock motor. On my highly modded duramax there was also a noticeable increase in fuel flow with the fass allow longer duration of fuel injection with larger injector tips. I'm able to read fuel pressure at the rail and with the fass on it helps maintain higher rail pressure. On the big cam 400 I bought from Matt I don't run an oil pressure switch. The PT pump likes to be force feed at start up and helps the motor start quicker and run smoother. I'm not sure of the benefits of the removal of air but cleaner fuel from the better filters the fass offer and force feeding the injector pump is well worth it.

 

[Vintage iron]

Stevepala was one of the first people to telling me about the benefits of a FASS. I did a ton of research and discovered the benefits to the Cummins 250. I do agree that adding a lift pump and better filter would help the Cummins motors but they would not remove the air from the fuel.