Upgrading Air Intake for ISL 400

[KentandJoyce]

Hello everyone!, We're new here. We bought our Windsor new in '06 and now have 41k miles on her. I'm doing past due maintenance and have a question on the engines air intake. I believe that the intake (stock air filter) is very constricted (in new and clean condition) and that I could increase the fuel mileage with a larger filter. We travel off highway fairly often, meaning we travel maintained dirt or gravel roads for distances of up to 30 miles after asphalt. Sometimes these roads are very dusty and I'm concerned about filter contamination due to the filter being mounted in the engine compartment aft of the drive wheels. Lots of dirt and dust kicked up back there. We previously owned a '92 Dynasty and did filter and exhaust upgrades that helped our fuel economy and engine cooling. My question is ( Is there an upgrade that takes advantage of the air inlet piping that allows a larger filter?) I would also like to know of any computer upgrades to help with performance with the ISL03 400 engine. Thanks in advance for any advice and help.
Kent

[Twomed]

Which filter do you have now? The -001 is 9.75/24" -002 is 11/24" -003 is 13.5/24 different size intakes too, but doable if you have the room. Check the air flows on the Donaldson site for these filters. Their engineers are good about answering emails and could probably answer this for you. Mine came with the -002 but I've seen some smaller configs for the ISL.

[KentandJoyce]

Thanks Twomed, I'll have to measure, but my minds eye tells me that I have the 9.75. I have a fleetguard part #AF25354 but I don't have any specs for this number. If I have room for the 13.5 that would be what I'm after, more air flow. Thanks again.
Kent

[Steve Ownby]

You might email Cummins with your engine # and ask what their CFM recommendation is on an air filter for that engine configuration. I have found them to be responsive to owners with specific questions.

Steve O

[EngineerMike]

If nobody w/your precise config can give you part numbers, you will need to check this out w/measurements of your existing filter and existing filter housing. The sealing of the filter is CRITICAL which you can see here. The growing problem w/this type of search is the parts look-up available at truck parts outfits- they want a part# and may only have limited info on specs (dimensions in this case) without that part#. You have to locate a parts house that has somebody who knows how to look things up by matching parameters.
You may find a part# on the filter housing and be able to match that to larger diameter filters thru its mfgr.
Aside from that its a matter of a tape measure, brute force and awkwardness.
I would never recommend a low-restriction air filter for exactly the reasons in the referenced thread. You might have options to raise the air intake on your coach to get above some or most of the dust.

[KentandJoyce]

Thanks Steve and Mike, I've removed my old filter housing and taken measurements and have spoken with FleetPride, they sell Donaldson filters, when I make a decision on what to do, I'll post it.
Kent

[Twomed]

www.donaldson.com/en/engine/support/datalibrary/056798.pdf
www.donaldson.com/en/engine/support/datalibrary/000622.pdf

Airflow, case sizes, filter cross references, also note that Donaldson says filters flow the same mounted in either direction, there is no in/out for their ECO series. Sounds weird, but I have the email from one of their engineers after this was discussed last fall. Knowing this stuff might help you figure out how to fit something for your project. Good luck.

[KentandJoyce]

Thanks Twomed, I''ll take that info. and my old filter to Fleetpride and see what we can come up with. My inlet and outlet are both 6" and it then necks down to 5" going into the motor. I'd like to go with 7" inlet/outlet but I would have to find new adaptors to accommodate the 7" ports. I'll post what I find out.
Kent

[Twomed]

Connectors and reducing elbows.

www.donaldson.com/en/engine/support/datalibrary/055474.pdf

[KentandJoyce]

I just finished my project last night. It was somewhat of a chore with several trips to the truck shop for parts, here is what I did.
I removed my stock filter (disposable type 9.75" dia. w/6" inlet/outlet) and the old hump hose 6"x5" that goes to the motor. I then bought the same type filter, except it is the 11" diameter w/ 7" inlet/outlets ( Donaldson part# AH8503). I then ordered two rubber adapters (1- 90 degree w/7" and 6" opening (part # RE70x60 intake side), and 1- hump hose that goes from 7" to 5" openings (part # HH70x50 outlet side to the motor) along with the additional 7" hose clamps. I installed the filter and new hoses/adaptors and clamps and made sure the engine housing cover would still swing down and lock, it barely fit, but still closed and locked without any interference. I then bought a 2 foot length of 10 gauge x 1.25" strap steel to lengthen the holddown straps for the air filter housing. This was the pain in the butt part. I cut two pieces in 7" length from the strap and formed them to the curvature of the filter housing. I then put the strap into my vise and bent one end into a 90 degree so that the original camlock will attach to the strap and lock down the filter housing. Once I had the two pieces of strap ready to go, I then got my Mig welder out and welded the two new straps to my existing straps that hold down the filter housing (before I did any welding, I disconnected my batteries and turned off all master switches). I then cleaned and painted the new straps and locked the new filter in place.
Next, I test drove my rig for several miles up and down Highway 50 where there are several steep climbs for a mile or so. She seemed to have slightly more power but I couldn't tell for sure. When I got back to my house I opened up the engine compartment to check the vacuum gauge for the filter and it was in the neutral position, whereas with the old filter ( in new condition) it would have registered in the red. I am very pleased with the new upgrades, I just hope I get better performance and mileage when we go out for our next trip (which will be soon). Hope this is helpful for anyone who wishes to do the same thing.
Kent