How do I spec out an air filter for a big block engine? I'm dealing with two major engine manufacturers - one has provided me with maximum fresh airflow requirements (kg/min) and the other provided me with maximum air filter restriction (in H2O). Do I have enough information for either engine to determine the air intake requirements/filter that I need for my design?

Airflow requirement is the key information. If you know the cubic inches and maximum rpm required, you can calculate this as long as it is naturally aspirated. Once airflow requirement is known, then you can determine the size required of the filter by knowing how many kg/min can flow through 1 sq in of filter media at the maximum pressure drop allowed across the filter. (max restriction in inches of water column)

Thanks for taking a look at this problem...I still have a few questions. I'm working with Cat and Cummins engines and need to design air cleaner systems for both.

For the Cat I was able to calculate the CFM from the maximum fresh airflow requirements (kg/min) by assuming an air temperature at the intake. I'm confused as to how to proceed. I know CFM, max HP and max RPM.

For the Cummins engine I was only provided with the maximum air filter restriction (in H2O), max HP and max RPM.

Can you offer any further assistance? Thanks!

With regard to the Cummins, max HP will closely equate to a CFM value. I guess if you know the HP, you can calculate approximate fuel consumption/hr. Take that number times air fuel ratio will give you air consumption/hr. It should be close enough to spec an air filter, I would think. Are you actually designing the filter element or determining size and construction of the filter housing? Either way, you have to find out the flow rate of the filter media at the maximum allowable pressure drop per square inch to determine the size of the required element.

I'm designing the filter housing and spec'ing out the filter media. I'm actaully working on class 8 trucks, but I figured someone on this site might be able to help me out (thank you!)

Maybe you can explain away another bit of my confusion. I just received some test results and it showed actual air flow requirements were much higher for the 435hp than the 550hp at the same evaluation rpm and engine model. How is this possible?

air density and humidity not standardized would be my guess.

What are these engines fueled with? N/A or turboed?

garbage - Back to the Future style :)

Diesel. Turbo.

Thanks!

I would guess that the one with higher airflow requirements has more additional hp capability than the other. In other words, it might be rated at 435, but has enough turbo to support quite a bit more than that before the fuel exceeds airflow. The other one may have the turbo sized very close to that hp rating. Since a diesel runs a variable fuel ratio unlike spark ignition engines, most of the time they are pumping more air than they need, only utilizing the oxygen necessary to burn the amount of fuel injected, and pumping the rest of the O2 on through.

That's interesting - I'll find out the hp capability of both setups. Thanks!!