more power for m923?

[fultonfire]

hello i built a brush truck out of a 923 i replaced the stock military muffler with one to help it breathe better was wondering if anyone had any hints or pointers to help me get more power out of the cummins? ty for any help

 

[jwaller]

ya add a turbo. look at all the pics of my turbo swap and thats what you need to do with yours.

 

[BKubu]

Are you finding a lack of power with the truck empty, or loaded with a water tank? Did you swap out the original tires with larger tires? A lot of guys do this and they cost themselves power that is already in short supply. If you installed larger tires, I'd suggest pulling them off. If you have not changed the fuel filter, I recommend doing that. If you have not run the truck much, run a bunch of clean fuel and conditioner through it. I have found noticeable increases in power simply by doing this. Although this seems obvious, make sure your tires are properly inflated. Finally, make sure your brakes are adjusted properly.

 

[M1075]

hello i built a brush truck out of a 923 i replaced the stock military muffler with one to help it breathe better was wondering if anyone had any hints or pointers to help me get more power out of the cummins? ty for any help

How much water are you hauling? These trucks were never designed to run fast on the highway, but they have great power, torque and gearing for low-speed off-road use. Real power improvement will only come from 400 cummins w/ turbo!

 

[halftrack]

Is this a straight 900 or A2????

 

[fultonfire]

i am hauling 890 gallons of water and i have added alot of plate steel to it . im not looking to go fast just need the best low end power possible beacuse i am knocking over trees .as far as a turbo its a great idea but i am in a vol. fire dept and the vote for a turbo would never pass but injectors or anything of that nature would not be a problem. i am not a diesel guy by any means i took over the truck and built it beacuse nobody else would step up to the plate. i will put pics in forum when i get a chance i put a slide show on you tube under 5 ton brush truck its the big blue one . i will change the fuel filter and add some conditioner. will lucas work or is there something else i should try? as far as tires i have the goodyears that came with the truck at least untill i get into the heavy brush because iim sure the sidewalls will get cut up. ty for the help

 

[BKubu]

I use PowerService conditioner, but I bet Lucas makes a similar product. Even in low range you don't have power? Watch out...do not use reverse in low range. Some on here have done so with no ill effects, but, with that much weight and the torque necessary to move the load and push down trees, you are liable to split the transfer case.

In terms of the tires, are they 1100 X 20s or 1400 X 20s?

 

[emr]

I have said there are no ill effects in low reverse BUT A novice with a laoded truck will crack that trans like an egg. U have a great truck, i think u expect more from that truck than it will ever give U, this power u ask for will never happen . These trucks are designed to be in off road condions most of there lifes and maintenence at very close intervals through out ALL there life, this is why almost all fire and other depts, find they are not good for them, DO NOT EVER SHIFT FROM Drive to reverse and or the other way with the R's up at all, even if u are stuck be paitent and get help all u wil do is ruin the truck, It will last forever if taken care of, it is a robust and strong truck thru and thru. DO NOT let just anyone drive it in low reverse like said, this was only a problem in the Military in the first years of the truck, then only mildly after that , once they brought the speed limits down and improved driver training. In the first years of Iraq, They saw more miles than truck companys in Vietnam, and they served with outstading durability. Drive it for what it is and do not try to make it something it is not, Hope u do not mind my input, it is from experience and from others who know first hand. Good luck. Oh one more thing that whine of the 250 cummins is dangerous and keeps the R's up a little longer than expected, that is why U must wait a second untill R's are down before shifting and moving out...

 

[fultonfire]

thank you for everyones imput. k for the low range reverse i have heard not to do it does this mean at all rpms or just high rpms?we get into some crazy stuff from time to time and i dont want to put my men at risk. there are only three people that are going to drive this truck i put more than 2k hours building it ..it is my baby and almost lost a wife in the process.i will get a fuel filter for it and tha addative in the morning. what is the best filter to use on it ?ty all for the help any comment are thankful negative or positive like i said im new at this and yall have more expirence and i would rather learn from others mistakes. thanks again

 

[jwaller]

thank you for everyones imput. k for the low range reverse i have heard not to do it does this mean at all rpms or just high rpms?

there is a waring right on the dash plate. it says do not use low range and R. read the warning label on the dash. top left hand side. I think it's even in yellow.

rpm's make no difference. it say NO USING R WHEN IN L RANGE.

 

[fultonfire]

k will tell the other guys i saw the plate and have not used r in low range thanks fr the input

 

[fultonfire]

well yestarday i changed the mufler , fuel filter, and put addative in. wow what a diffrence i am suprised the truck even ran before i had a little black smoke before now there is not any. does anyone know where to get a manual for this truck ? i got one but when it came in it is just filled full of stuff that they came with like for spare tire holders and such but nothing to do with engine,electrical etc. the reason is my trans. temp gauge is not woking and need a schematic for it so im not looking in the dark with fixing my problem. ty again for all the help

 

[emr]

Good luck, as long as U come to a complete stop and let it relaxe and shift with brake on and let it finish U will be fine, actually they can take alot more than that but in my view why not make it last. There is no warning label on mine, i did get the label in the window about the max speeds in all conditions ...they got em after the guys rolling them with the big tires.

 

[Crash_AF]

You can download the Army TMs for the truck from the Army's LOGSA site for free. They are in PDF format. Don't worry about logging in or anything. Just click 'I accept' on the first page and then 'Enter the site' on the second.

https://www.logsa.army.mil/etms/online.cfm

You are looking for 9-2320-272 series of TMs. Just search for that exact number with dashes in Pub number field on the site.

You want all of the following
Operator's Manual
9-2320-272-10
Service Manuals
9-2320-272-24-1
9-2320-272-24-2
9-2320-272-24-3
9-2320-272-24-4
Parts Manuals
9-2320-272-24P-1
9-2320-272-24P-2

Does your 923 have the ABS MWO completed on it? There will be an ABS light on the dash if it does. If so, you should bookmark:
https://www.absmodtrack.com/M939/DesktopDefault.aspx
This has a wealth of information about the M939 series ABS systems including schematics and other diagnosis charts and information.

Good luck with it.

Later,
Joe

 

[emr]

there is a waring right on the dash plate. it says do not use low range and R. read the warning label on the dash. top left hand side. I think it's even in yellow.

rpm's make no difference. it say NO USING R WHEN IN L RANGE.

actually they make all the difference. that trans is fine in low, and they have millions of miles on em in low, but as a rule the novice driver should never put it in low because they will find they want to shift an auto like a car and the sideshaft trans will smak the case. and walla, a split case, it is ALL R' s and thats a fact, all 3 test say so, the Army Allison and AM general