Like the title says.

I've got the AirDog II 165 installed that is supplying fuel to the upper filter. Blue spring upgrade is installed and I even verified it wasn't collapsed reducing pressure. I'm not to familiar with the whole thing (need to get smarter) but is the blue spring limiting the pressure the pump can supply or preventing the pump from giving to little at a critical time.

I've read that pump can give 75psi and then other places say 8-10psi. Don't think that's really true or my injectors would be toast at 10psi already.

Hope someone with some knowledge doesn't mind sharing.
Thanks!

 

Airdog has low pressure pumps and high pressure pumps depending on the application. I'm fairly certain you have the high pressure pump or your injectors would be toast by now. Do you know if your pump is preset from the factory or do you have the adjustable one? Do you have a fuel pressure gauge?

The blue spring is your "limiting" factor in that it is a "preset" pressure. Typically the factory regulator and AD2 don't play well together.

 

It's adjustable and set to max, which if I'm reading correctly is 75psi. So that brings me back to the front... is the blue spring bleeding me off above its limit? Should I remove the blue spring altogether as it provides more pressure than the spring?

I've also read that since the filter is 2 micron, the 5 micron upper is just a wasted expense.... but haven't really seen more than just a passing comment. Sort of like the updated tranny filter.

 

I haven't run the upper filter since I removed the factory HFCM for that very reason. What's the need?

AFA the blue spring goes, it's only designed to hold so much pressure. Anything above it's "set point" and it's going to return that excess fuel back to the tank. You can't really remove it because you'd have no system pressure. The AD2 can pump so much fuel that it actually blows the blue spring open and you get a pressure drop or bounce from opening and closing. That's one reason I run a regulated return on mine that does away with the spring.

One other thing that people don't realize about these pumps is that they are rated for "X" gpm at "Y" pressure and that higher pressure does NOT necessarily mean more fuel it actually means less. I try to run my pressure at 58-62 so that the pressure drop is minimal at WOT. I can run more pressure but I get a greater drop.

 

and what I thought also...
Time for a regulated return and gauge.
Thanks

 

Get the gauge first and see what it's actually doing. You may not need a regulated return.