Straight stacked my M923

[Blind Driver]

I like the exhaust stack, but the air filter is too blingy. I'd like to know how the surface area of the ricer filter compares to the big OEM filter.

The OEM filter can be cleaned out by simply using low pressure compressed air. Use an air nozzle gently blowing from the inside to the outside. I only had to replace the air filter in the dump truck every 18 months.

 

[Ord22]

Looks great and it sounds really deep and mean. sounds like it mean business!!

 

[dieselsmokem35a2]

Looks good, just watch out for one thing. This goes for anyone with any motor that ditches the factory air box or even adds one like this. The factory air cleaner is picking up say -10 to 120 degree F outside air. You will be sucking in 210+ air through the blue one. That air is less dense. So its like having less air. That means less power and higher EGT's. It could also make your turbo apin harder. If you could get that to suck outside air it would be pretty sweet!

Another fix to your problem could be to replace the factory filter with a CAT unit, they have a higher air flow to size rating than alot of the other filter types.

Thanks for the advice! It makes sense. As soon as it gets above freezing again outside I will get a pyro gage on there and see if I can't fab up something to get outside air to the filter. Thanks again.

 

[dieselsmokem35a2]

I like the exhaust stack, but the air filter is too blingy. I'd like to know how the surface area of the ricer filter compares to the big OEM filter.

The OEM filter can be cleaned out by simply using low pressure compressed air. Use an air nozzle gently blowing from the inside to the outside. I only had to replace the air filter in the dump truck every 18 months.

The OEM filter is still operational and also new. The additional blue one just helps with the restriction issues. I am not crazy about the blue one either but it was what I could find at the time. Now I am thinking I might try and find one of the old 5 ton fender mount air boxes and plumb that into the "y" fitting instead of the cone filter. Will just have to see how or where I can mount it since the fenders flip up with the hood. But where there is a will there is a way! Thanks for your input kind Sir!

 

[dieselsmokem35a2]

I like it. You should make a video of it going down the road. I myself plan on straight piping my A3 and going duals when funds allow of course.

This one's for you bud! It's the only other video I have right now until the weather warms up and I can get the old guy out and make a better one with something other than my I phone!

 

[treessw]

I couldnt see anything on my player but great sound!!!!! I like it!!!!! Thanks for giving me more ideas

 

[smoke]

I couldnt see anything on my player but great sound!!!!! I like it!!!!! Thanks for giving me more ideas

ditto

 

[PyroZuki]

Well, you said "Good or bad"...

Personally, I just don’t get it… not on a Dodge pickup, military truck, or any other truck (or even on a car).

The severely oversized exhaust stack is a phenomenon whose appeal eludes me (said in my best Dr. Sheldon Cooper voice).

Maybe I am just suffering from "Stack envy"?!?!?!?

It reminds me of these, which I do not understand either. But, it's a free country, so that is just my .

Agreed, but to each their own.



Pyro

 

[BKubu]

I took a look at a sticker on the door of my recently rebuilt M927A1 and it reads:

Air cleaner restriction gauge
At 1600 engine RPM, red indicator must rise at least to green line.

When red indicator is latched to top at any speed, filter service is required.

I have owned many M939 series trucks and all have shown some restriction on the air filter gauge, even after I replaced the filters. Not sure if this is right or wrong...but, perhaps, it was designed this way. Did anyone give any thought to the idea that, maybe, it is SUPPOSED to be this way? The sticker above reads, at least to my mind, that the gauge should show some amount of restriction..."red indicator must rise at least to green line." It doesn't say anything about not rising above the bottom of the green indicator. Just something to chew on...

 

[dieselsmokem35a2]

I took a look at a sticker on the door of my recently rebuilt M927A1 and it reads:

Air cleaner restriction gauge
At 1600 engine RPM, red indicator must rise at least to green line.

When red indicator is latched to top at any speed, filter service is required.

I have owned many M939 series trucks and all have shown some restriction on the air filter gauge, even after I replaced the filters. Not sure if this is right or wrong...but, perhaps, it was designed this way. Did anyone give any thought to the idea that, maybe, it is SUPPOSED to be this way? The sticker above reads, at least to my mind, that the gauge should show some amount of restriction..."red indicator must rise at least to green line." It doesn't say anything about not rising above the bottom of the green indicator. Just something to chew on...

Hmmm. Interesting. Could be a valid point. Could it be possible that another component of the truck requires a certain amount of vaccuum in the intake for whatever reason? And by adding this other filter I now have reduced the pull of air through the OEM pipe. I will have to see what else is tapped into that intake tube. That said, I am no diesel mechanic, but I have played with all kinds of engines over the years and I have never heard of a motor getting too much air. Rather not enough fuel. There are however acceptions to everything.....running rich or lean. And like I said, I am no mechanic.......just on weekends! I do intend to turn up the fuel a bit so I believe this added supply of air will be a good thing. Yes I will be watching the pyro and I know I could blow up my motor and all that. But I am sure I won't be the first or last to try and get a little more out of their rigs. Anyway, I appreciate the input and encourage anyone else to chime in here. I definitely come to this site to learn so the education is greatly appreciated. Thanks to all for your thoughts, opinions, and input! Your a good bunch.

 

[Bolkbich]

Ive owned a bunch of truck over the years. Big motors and small. Some trucks are spec'd out by salesmen that have no clue and or just dont care. My 1987 autocar dump with a 425 cat on a hard pull would put the restriction gauge in the red from the factory, so i added a second and it was fine. I think the 8.3 cummins in the m939 needs a higher cfm filter setup. Honestly its all about the $ in the pocket of whos building/spec'ing these trucks. Who would put a cat diesel in a m35 then put the smallest cheapest auto behind it? Even if it only go's 45mph , they dont care. Who would put a 250 hp motor in a 38,000 lb wrecker, they struggle with no load. The answer to the problem is if it bothers you modify it,just like dieselsmokem35a2 did.

 

[emr]

Your truck rule in place

 

[BKubu]

Ive owned a bunch of truck over the years. Big motors and small. Some trucks are spec'd out by salesmen that have no clue and or just dont care. My 1987 autocar dump with a 425 cat on a hard pull would put the restriction gauge in the red from the factory, so i added a second and it was fine. I think the 8.3 cummins in the m939 needs a higher cfm filter setup. Honestly its all about the $ in the pocket of whos building/spec'ing these trucks. Who would put a cat diesel in a m35 then put the smallest cheapest auto behind it? Even if it only go's 45mph , they dont care. Who would put a 250 hp motor in a 38,000 lb wrecker, they struggle with no load. The answer to the problem is if it bothers you modify it,just like dieselsmokem35a2 did.

Yeah, but did the owner's manual or, as in this case, a sticker or data plate indicate that this would happen with your Autocar? If it did, that might be evidence that it was designed this way. Why? I have no idea. It could be for the reasons you mention. Or, it could be for some other reason that we have not discovered. I am not sure one way or the other. I only threw this out there because no one had mentioned that just maybe it was designed to be like this. Another thing, there is a difference between a gauge going into the red and the gauge creeping up into the green somewhere.

 

[Bolkbich]

Yeah, but did the owner's manual or, as in this case, a sticker or data plate indicate that this would happen with your Autocar? If it did, that might be evidence that it was designed this way. Why? I have no idea. It could be for the reasons you mention. Or, it could be for some other reason that we have not discovered. I am not sure one way or the other. I only threw this out there because no one had mentioned that just maybe it was designed to be like this. Another thing, there is a difference between a gauge going into the red and the gauge creeping up into the green somewhere.

no the manual doesnt tell you that your truck was spec'd wrong. It wont tell you that a 17 yd tandem dump truck with 44,000 lb rears is to light. why? Because they cant warn you about people that spec trucks that dont drive trucks. As far as they're concerned if it looks good on paper ...it must be good. Which alot of times it isnt.

 

[Csm Davis]

Why not get filter housing off of truck with 400 cummins should have more than enough air, and no diesel I have ever worked on or heard of needs any restricted air flow in or out

 

[emr]

It... a owners manual may not say like this should read off, but there are alot in the military instances were a bulletin has said stuff like, this item will read leaning one way or another and this is ok, like in the pm mag it happens all the time, the item mentioned in this thread, if it reads a little on the same side to almost all trucks, its the item not the truck, I know this sounds vague , I hope my point is getting across, This simple sensor we are talking about is the same in quite a few vehicles, it may very well not read the same in all, and that may be just fine, as for needing to change the air flow because of it, I think its just being said by some very knowledgeable members its a common thing with new clean filters soo, Its just fine.

 

[dieselsmokem35a2]

It... a owners manual may not say like this should read off, but there are alot in the military instances were a bulletin has said stuff like, this item will read leaning one way or another and this is ok, like in the pm mag it happens all the time, the item mentioned in this thread, if it reads a little on the same side to almost all trucks, its the item not the truck, I know this sounds vague , I hope my point is getting across, This simple sensor we are talking about is the same in quite a few vehicles, it may very well not read the same in all, and that may be just fine, as for needing to change the air flow because of it, I think its just being said by some very knowledgeable members its a common thing with new clean filters soo, Its just fine.

This is a good point. Perhaps they are just trying to suggest that the gage needs to read "something" or else it may not be the right one for the job. i.e., a reading of some kind demonstrates that the gage is working and has the right resistance. If it wasn't moving at all maybe that could mean that the gage is for something much bigger that requires a great deal more air and thus has stronger springs or something. Dunno. In any case, I feel confident in my setup for now but I do realize that a Pyro gage is the only thing that I should have done prior to this mod. It is on order as we speak. Anyone have any suggestions were on the manifold to put the sensor? I definitely would prefer to go pre turbo. I have it this was on all my other trucks and am used to reading the pyro in "pre-turbo" setups. Thanks again guys for great feedback and constructive criticism.

 

[Varyag]

Is the passenger side center tire backwards?

 

[BKubu]

Is the passenger side center tire backwards?

While the Michelin XLs LOOK to be directional tires, Michelin asserts that they are non-directional. I usually like to mount my tires all in the "correct" direction. However, I was told by a guy in the military that they often do this purposely so your average enemy soldier won't have any idea which way they were going. Not sure if that would work as I would think you'd be able to tell, but I was told this by a guy in the Army nonetheless. The other thing I will add, and this probably has the most relevance, is that they did not care if the tires faced the same direction. They just mounted them and drove the truck until a tire was worn out. This seems like the most likely explanation given that Michelin asserts that they are non-directional, although I don't recall where I read that. Perhaps, John Winslow had some tire literature. I think that was it.

 

[emr]

Like said above, No soldier is going to brake down a tire to put the tread in another direction, so they all match ,and no one would want him to, I will say i have seen a few vids of new m939s that came with the michelins, and from factory all were in the correct way of driving, they may say they are technically not a directional, but they sure are, maybe the amount of difference in traction is not enough so they can say they are not, and they may also say they are not because uncle sam did not want directionals, there are tms that state directional tires should at all possible times face the same direction, with the exceptions of trailers, trailers with directionals should have the directional tire facing the opposite way because there will be a longer tread life this way and traction is not an issue with a trailer, i have the tm in my collection, I also like all my tires to face the same way, it is just cooler to me, but when needed i will put anything on , just like in service. Directionals work, and i am the type that wants to go forward as far as i can I think when a guy says that in service it is alot of opinion, unless he is on a test group like in Aberdeen, I have had a Soldier who had/has a ton of miles in a few conflicts, say to me hey look at those ol ww2 double clutchers in a line back on a base i was on, they looked old and run down, only problem was , i said actually they are not older than 1982 , and they are automatics, I also have experience at the maintenance shop where a lot of soldier mechanics, who do alot of great work on these trucks, never know what they actually other than 5 ton or other basic generic terms, I have been asked alot over the years, hey rand whats this one again, Its just not as important to those guys as it is to guys like us.