Power Driven Diesel Air Filter Restrictive?

[MCTNKR]

Based on some information I saw on a YouTube video about the benefits of installing the "Dust Bowl" PDD air filter, I decided to try it out. Completely stock 1971 M35A2. IP is still sealed with the lead tags. After installing I went for a spin on my usual route. I immediately noticed on the upgrade section of my route that my full throttle EGT went from the usual 900 degrees to 1100 degrees and that instead of 5 PSI of boost I was reading none. Truck still seemed to perform the same but I am not happy with these numbers. After re-installing the stock air filter my readings were back to normal. I am wondering if this filter is very restrictive and making the truck run rich?

I contacted the vendor for an answer and never received a response. Wondering if anyone else has had a similar experience?

 

[Fatalid]

I don’t have any experience with that particular filter, but based on those numbers, I would come to the same conclusion - too restrictive. A less restrictive filter will lead to lower egt numbers.


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[Jeepsinker]

You might have seen better results if you skeletonized or removed the step in the sump that blocks the front of the filter. Quite a bit of surface area there.

A stock 5.9L Cummins breathes more air than the multifuel does, so...

 

[Jeepsinker]

Just an idea; try it again but leave the bottom off. Just don't put the can on. The filter connects to the top plate, so it isn't needed. That'll tell you if it was the filter itself causing a restriction, or flow interference with the filter from part of the box.

 

[MCTNKR]

Thanks Garrett. I will give that a try.

 

[Jeepsinker]

Probably help a bit to leave the side panel off for the test drive too, just so you get more cool outside air instead of hot underhood air.

 

[NebraskaFan]

Probably a long shot on this, but any updates on the test? I also tried this filter initially it seemed to work alright but after driving ~ 30 miles egts started to climb, boost dropped, and I triggered the air filter indicator. The 5.9 should definitely pull more air, so I'm surprised i had this issue. I took it out and cleaned it, got some dust to blow out, so I'll try it again and see, but if its going to clog up every 30 miles I'll probably have to go back to the old filter.

 

[Jeepsinker]

I put quite a few miles on mine. Granted, I am running the 5.9L, but I've seen no negative effects.
Did you remove the hump that is spot welded into the bottom of the canister? Try it with the can removed.
I'm firmly of the belief that the canister is restricting flow to the face of the filter and that's causing this issue. The face of the filter is roughly 30-35% of the filter surface.

 

[NebraskaFan]

I put quite a few miles on mine. Granted, I am running the 5.9L, but I've seen no negative effects.
Did you remove the hump that is spot welded into the bottom of the canister? Try it with the can removed.
I'm firmly of the belief that the canister is restricting flow to the face of the filter and that's causing this issue. The face of the filter is roughly 30-35% of the filter surface.

I'll try running without the can and see what it does, I'm guessing you're right though. If that works then I'll cut out the hump. Are you using the 7" or 9" filter? Either way it really doesn't seem possible that the multi can out flow the 7" one that I have.

 

[Jeepsinker]

I'm using the 7" filter.

 

[NebraskaFan]

I'm using the 7" filter.

Awesome, I'll report back when I get a chance to try it out.

 

[NebraskaFan]

I'm using the 7" filter.

So I tried without the filter housing, and it seemed to help, though i was only getting ~10-11 psi vs usually I can hit 12-13, but egts didn't seem awful. So I cut the bottom of the filter housing out, and it seemed good for about the first 90 miles (I cleaned the filter too FWIW) but then I started losing boost egts became an issue. I contacted PDD and they said the 7" filter is good for about 800 cfm, so it should be more than enough. They recommended I try the performer filter, but I'm not sure if i want to risk letting dirt by. So maybe I need to try the 9" dust bowl? Or perhaps look to other filters?

 

[V8srfun]

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[davidb56]

So I tried without the filter housing, and it seemed to help, though i was only getting ~10-11 psi vs usually I can hit 12-13, but egts didn't seem awful. So I cut the bottom of the filter housing out, and it seemed good for about the first 90 miles (I cleaned the filter too FWIW) but then I started losing boost egts became an issue. I contacted PDD and they said the 7" filter is good for about 800 cfm, so it should be more than enough. They recommended I try the performer filter, but I'm not sure if i want to risk letting dirt by. So maybe I need to try the 9" dust bowl? Or perhaps look to other filters?

what are your readings EGT/Boost with the stock filter?

 

[NebraskaFan]

Does anyone have a way to look up donaldson filters by size? These look like they'd be worth a shot.

Donaldson Blue® Air Intake Filters | Donaldson Engine & Vehicle

Donaldson Blue® air filters with Ultra-Web® media protect engines by providing better initial and overall efficiency compared to conventional cellulose media.

www.donaldson.com

I'm going to try calling their customer service line to see if they can look them up by size.

I would think the 9" PDD filter would flow enough, but I'm not sure I want to gamble. The surface area on the 9" filter is roughly 70% of the stock deuce filter, so that has me concerned. Although, the 9" filter has 29% more surface area than the 7" filter... so maybe that's enough? Perhaps I just send it with the 9" performer filter and just hope for the best.

 

[NebraskaFan]

what are your readings EGT/Boost with the stock filter?

Stock filter I would normally hit 12-13 psi, egts in the mid 1100s to 1200*.

 

[NebraskaFan]

So just to update this again, the filter is definitely plugging up. I cleaned it yesterday and went for a drive, back to 11 psi and egts staying in the mid 1100s on hills. I like that the filter is apparently doing its job catching particulate, just need more capacity.

 

[davidb56]

maybe you could "snorkel" your air intake to cab top height. I don't have a clue what setup you got without a pic.

 

[NebraskaFan]

maybe you could "snorkel" your air intake to cab top height. I don't have a clue what setup you got without a pic.

Mine has the stock side panel inlet right now.
That would probably help with the loading up of the filter.. might be worth a shot. I'll probably try a different filter first though, since this one seems to be cutting boost by a psi or two, even when clean. A snorkel is still a good idea though, the less dirt it eats the better.

 

[davidb56]

Mine has the stock side panel inlet right now.
That would probably help with the loading up of the filter.. might be worth a shot. I'll probably try a different filter first though, since this one seems to be cutting boost by a psi or two, even when clean. A snorkel is still a good idea though, the less dirt it eats the better.

I bought the fittings from Summit Racing out of NV for under 75$ . I reused to mushroom cap and u clamp to remove it from the side and access the panel.