M939 air filter mod

[big block 88]

Yep sorry digging up old threads i saw it was old but was hoping for an answer. I will hit up those military guys thanks

 

[MtnSnow]

http://www.thosemilitaryguys.com/air-cleaner-custom-kit/ for the TMG Air Cleaner Mod kit

 

[TCD]

FYI

https://www.youtube.com/watch?v=c8TeD04Qdoc&list=PLSw6mhcLSL-MQ8nkmYpUSF1vaMhU2rTV4&index=9

YMMV,

tom n tyler

 

[shootist]

Just wanted to post an update from the 8/12/15 post I made regarding the tmg air filter mod. Now that it's been used
for 8 months.
i have noticed since installed, although the truck performs better,
the air filter minder it's constantly showing 80% or basically it Max's out after a few miles of driving.
at idol it can sit all day the minder won't move but under a load she Max's out
And doesn't return to the lower percentile on meter when returning to idol.
and yes with the maxed out minder the power loss returns to a certain degree.
ive replaced the filter multiple times and the same cycle happens.
filters are pretty clean when replaced to. The tmg filter holder design is really ingenious, but the filter box design
plain sucks as with most of our toys.......built by lowest bidder.

 

[PapaPumpSD]

Just wanted to post an update from the 8/12/15 post I made regarding the tmg air filter mod. Now that it's been used
for 8 months.
i have noticed since installed, although the truck performs better,
the air filter minder it's constantly showing 80% or basically it Max's out after a few miles of driving.
at idol it can sit all day the minder won't move but under a load she Max's out
And doesn't return to the lower percentile on meter when returning to idol.
and yes with the maxed out minder the power loss returns to a certain degree.
ive replaced the filter multiple times and the same cycle happens.
filters are pretty clean when replaced to. The tmg filter holder design is really ingenious, but the filter box design
plain sucks as with most of our toys.......built by lowest bidder.

I too am noticing this with my M925A2 with the TMG filter mod. My filter minder doesn't read max but it's probably 1/2 way. I'll have to look into why this is happening. TMG should too.

 

[Those Military Guys]

Hey guys have you tried removing the mushroom cap in a lot of cases we have found them to be a big problem,one thing we see a lot is it pushed down so far that it cuts air off from reaching the engine as fast as it should but we really need to get your feed back on stuff like this so we can see what the problem is one thing have done to help air flow is the ram air system we sell I'm going to contact one of you guys in the thread to run it and see if it cures this issue
Thanks
TMG

 

[adamsoffroadperformance]

The air filter is next on my list of modifications. On my 8.3L I've cut out the muffler, added the 4k governor springs, and modified the injection pump. I am now installing a radiator/ intercooler from an MRAP and will be gutting the aftercooler to see how much I can drop the egt's. The airfilter is next I'm either going to put in a different element or modify the housing.

 

[PapaPumpSD]

We did some testing on the air filters today to see if we could figure out why the filter minder was reading so high. We reset the minder and removed the air filter and took it for a spin. Interestingly, the minder read well over 60% "high" on the gauge. That is odd because you'd think it would have no restriction as the filter wasn't in. I removed the small "fluid filter" element that is screwed into the air intake section that is located under the hood (driver's side) and looked for a clogged "fluid filter" (what the manual identifies it as). I soaked it in degreaser and rinsed it and blew it out w/compressed air. We put Those Military Guy's customer filter assmebly back in and drove it and the filter minder still showed it as ~50% "full". At this point, I'm looking for some assistance from you guys. Photos attached.

 

[MtnSnow]

Have you pulled the Mushroom cap off and tried it?

 

[PapaPumpSD]

Have you pulled the Mushroom cap off and tried it?

We pulled the mushroom cap off today to inspect inside and it was unobstructed and then put it back on. We did not drive it around w/the cap off. When we had the stock air cleaner in there was a little vacuum on the minder. After we installed the TMG's customer air cleaner it increased. I do not believe the mushroom cap is influencing the reading. Rather, something else is and perhaps it's a faulty minder or that small fuild filter (located under the hood) that leads to the minder. I appreciate your thoughts.

 

[Capehenery]

Just a thought. The new filter is smaller and will have less surface area than the larger filter. It could also be that the original filter media is different, as in more pleats or paper that is more porous.

 

[shootist]

I pulled the intake cover and ran it today. Not a lot of difference, maybe 10% less on minder to 65 % after 15 mi.
may look into ram air cover myself to see what happens.

 

[MtnSnow]

The Ram Air will not totally solve the problem but it has shown that it flows better than the stock mushroom cap along with being better looking.
The main problem is the overall length & number of bends many of which are 90* in the intake plumbing that is/cause the largest restriction(s).
The other is the actual Donaldson filter as they are rated to about 550 CFM if I recall correctly.

 

[MtnSnow]

http://india.donaldson.com/en/engine/support/datalibrary/065857.pdf for how to calculate CFM for Diesel engines. You can also take note that Donaldson says the stock 250 HP 6CTA 8.3L engine requires 632 CFM @ 2500 rpm and 1592 CFM out of the exhaust at 900* F. which when you divide the exhaust CFM by intake CFM gives the Turbo motor approximately a 2.5 VE (volumetric efficiency) 1.5 to 3.0 VE is pretty standard for Turbo charged Diesel motors as noted)

In turning up the 6CTA motor with my raised RPM of 2800 & tweaked IP and plugging in the 2.5 VE that Donaldson used for the 6CTA gives me 1024 CFM needed to achieve optimal results

 

[infidel got me]

I installed a k&n air filter in mine a while back- cross ref.# is 38-2013s. I have looked for over a hour trying to find the cfm rating on this one, but I'm outta' time. I am sure that it is waaaaaay better than stock and it will last forever. The filter was in the $150 price range. A lot of diesel truck shops/mechanics recommend these, and k&n is a quality product.

 

[Those Military Guys]

We did some testing with k&n they did let a little more air in but a lot more dirt got through and not hurting the engine is our first concerne that is why we went with the filter we did but we are trying a different brand I don't think it will be any big change tho. The ram air scoop will move a little over a 1000 cfm easy we are still working to get better air flow with out any major mods we will keep everyone updated keep your feed back coming.
Thanks
TMG

 

[Those Military Guys]

Also something else we have found some of the air minds have very weak springs so from one to the next they will read different

 

[shootist]

I've put 3 filter minders in thinking bad spring, bad from factory etc all related the same. wondering, I don't run the truck in water or deep water. What about removing the entire military air intake and using one of the high performance k&n diesel racing air filters directly at the air intake on engine same as on a boat with these engines marine version. It would more than likely eliminate all that restriction through the pipe box, filter etc by removing it.

 

[Those Military Guys]

Pulling off the mushroom cap can make it worse it will act like blowing a cross the top of a straw and watch the liquid come up the straw. In drag racing I have watched people put forward facing scoops and the car falls on its face do to wrong location and or wrong designed air pan

 

[Those Military Guys]

That would work just the dirt that gets through the K&N filter would be a concern. If just a street truck it would be fine but I would bet most use them in dirt and the dirt getting through would take its toll on the engine.