Bigger Under Hood Air filter?

[Wildchild467]

Has anybody ever done a successful swap or modification of the under hood air filter assembly on a Deuce? Stock air filter is about 410 CFM I believe and I was wondering if anybody was able to put something else in that was up around 540CFM? from the numbers I crunched, it looks like 810 CFM might be the "in the middle" sizing chart for our engines.

Here is the Donaldson guide to sizing air filters:

View attachment Donaldson Air Filter Sizing Guide.pdf

According to their formula:

4-Cycle Engine Airflow Calculation = (Engine Size (CID) x RPM)/ 3456) x VolumetricEfficiency= Intake Airflow CFM

* If VE rating is not available, Donaldson recommends usingthe highest value to insure proper airflow. For Turbo Diesels, VE is between 1.5 and 3. For non turbo the VE is about .7 - .8

For the Turbocharged Deuce that would be: ( 478 (CID) x 2600)/ 3456) x 1.5 (Lowest VE) = 540 CFM.

540 CFM is a lot more than the factory rated 410 CFM Filter. It seems like the engine needs a larger filter.

For the Non-Turbo Deuce, That would be : ( 478 (CID) x 2600)/ 3456) x .75 (guess) = 270 CFM.

270 CFM requirement is sized right for the factory filter rated at 410 CFM. Its overkill, but the military has spec'ed out later filters to reduce downtime.

Maybe the clean air kit was an after thought and nobody thought about increasing the air filter size as well? Possibly due to cost?

At any rate, I have been playing with the idea of finding a bigger air filter assembly and putting it in my truck. I don't know if anybody has done it before and has been able to fit it all under the hood.

 

[jasonjc]

I've been thinking of using a LAF-3233. As I can get bearly used ones from work , like 8-10,000 miles on them. They are from a 6.7 cummins , should be big enough.

 

[pjwest03]

When our family was running semi pulling trucks, we generally judged things by a vacuum gauge post filter. For the E7 motor we ran, keeping the vacuum down below 30" H2O seemed to be adequate. Above that you start to crush the intake tube and the filter. Of course, we ran 115-125 lbs of boost @ 3600 rpm. I would guess that number would be more like 15-20" for the deuce. I'm not sure what the specs are on the stock restriction gauge.

 

[rustystud]

Has anybody ever done a successful swap or modification of the under hood air filter assembly on a Deuce? Stock air filter is about 410 CFM I believe and I was wondering if anybody was able to put something else in that was up around 540CFM? from the numbers I crunched, it looks like 810 CFM might be the "in the middle" sizing chart for our engines.

Here is the Donaldson guide to sizing air filters:

View attachment 642575

According to their formula:

4-Cycle Engine Airflow Calculation = (Engine Size (CID) x RPM)/ 3456) x VolumetricEfficiency= Intake Airflow CFM

* If VE rating is not available, Donaldson recommends usingthe highest value to insure proper airflow. For Turbo Diesels, VE is between 1.5 and 3. For non turbo the VE is about .7 - .8

For the Turbocharged Deuce that would be: ( 478 (CID) x 2600)/ 3456) x 1.5 (Lowest VE) = 540 CFM.

540 CFM is a lot more than the factory rated 410 CFM Filter. It seems like the engine needs a larger filter.

For the Non-Turbo Deuce, That would be : ( 478 (CID) x 2600)/ 3456) x .75 (guess) = 270 CFM.

270 CFM requirement is sized right for the factory filter rated at 410 CFM. Its overkill, but the military has spec'ed out later filters to reduce downtime.

Maybe the clean air kit was an after thought and nobody thought about increasing the air filter size as well? Possibly due to cost?

At any rate, I have been playing with the idea of finding a bigger air filter assembly and putting it in my truck. I don't know if anybody has done it before and has been able to fit it all under the hood.

That's why a lot of us are using A3 filter housings. More room inside the engine compartment and better CFM's .

 

[doghead]

How many better cfms?


Sent from my iPhone using Tapatalk

 

[Eliteweapons]

Not sure of the cfm rating, but here is the part number.
M35A3 truck air filter. P/N 5743562, W250C300. NSN 2940-01-400-3846

 

[rustystud]

How many better cfms?


Sent from my iPhone using Tapatalk

View attachment Scan0153.pdf 580 CFM's . So that's a 170 CFM's better then the A1 or A2 Deuce.

 

[Wildchild467]

Well that's not bad I suppose. I just wish it was an over the counter easy to get filter. Obviously we don't need to replace them all of the time, but it would be nice if it was an item we could get at Napa instead of mail order.

I would still like to see where somebody built a new air filter housing for a Deuce. Or I could just turn my fuel down so I don't hit 17 PSI of boost. at that boost pressure, I will pull about 7 inches of vacuum.

 

[wdbtchr]

How about a m39 series 5 ton mounted reversed on the fender? Would give you way more room under the hood to work.

 

[rustystud]

How about a m39 series 5 ton mounted reversed on the fender? Would give you way more room under the hood to work.

That has been done in the past. Takes up more fender space though.

 

[Wildchild467]

I don't have access to a filter housing right now, but does somebody know the inside diameter of the filter housing on a Deuce?

 

[74M35A2]

sell it, the 109, both trailers, and get a 925A2 with working ctis. Faster and quieter. Use the remains to make it really nice (A/C, dump, radio, cargo cover, etc...). 8.3L gets 10mpg w/no blow-by, and has the air brakes you adore.

 

[Wildchild467]

sell it, the 109, both trailers, and get a 925A2 with working ctis. Faster and quieter. Use the remains to make it really nice (A/C, dump, radio, cargo cover, etc...). 8.3L gets 10mpg w/no blow-by, and has the air brakes you adore.

The 939 has an even worse stock air filter set up than the deuce!

 

[infidel got me]

nice