Thread: air filter housing

Slightly larger in diameter, but slightly shorter in length than the fleetguard.

Inlet and outlet are about the right size, so should be OK - unless you are planning to increase power a lot?

Looks like a modern version of what I have now. Going by the inlet and out let sizes you should not have any problems with restricting the air flow. Good too that it is a standard Donaldson filter element, so should be easy enough to get one. I have a indicator that lets you know if the filter needs changing. A extra that could be a good thing. Given how much a Isuzu diesel shakes, and then the rest of the vehicle would one mount be ok? Mine has two mounts and is mounted to a bracket of the bell housing.
Cheers Hall

Hall, I think its two mounts pushed together in the photo.
Think I'll buy it and see how it goes.

Originally Posted by isuzurover

Inlet and outlet are about the right size, so should be OK - unless you are planning to increase power a lot?

At the moment I plan to fuel it, boost around 25psi, inter cool and that's it. I do have a spare engine that may get some real work one day if I get bored or time. Will cross that bridge when/if I have to.

This housing is rated at 240-450 CFM. A turbo diesel of 3.9L with a volumetric efficiency of 3 requires over 500 CFM at 2500 RPM. The maths say this housing does not flow enough.

The fleetguard that people are using flows 280cfm. I don't know the maths but its approx the same size, inlet and outlet are bigger on the Donaldson, so one would assume.

Originally Posted by inside

This housing is rated at 240-450 CFM. A turbo diesel of 3.9L with a volumetric efficiency of 3 requires over 500 CFM at 2500 RPM. The maths say this housing does not flow enough.

That is about the same as the OE 4BD1/T housing. A bigger filter would be better, but hard to fit in the space.

Increases in pressure drop are linear in the range we are talking about. So putting 500 cfm through a filter "rated" for 450 cfm will see about an 11% increase in pressure drop.