M923A1 vs M923A2

[sandcobra164]

I know the differences between the basics of the trucks. I drove an M923A2 home for an almost new member today and had some questions between the two models. My M923A1 seems alot stronger off the line and through the gears. I know both trucks have the same transmission but it seems the M923A2 only locks up the torque converter in 4th and 5th and it sounds alot more strained getting up to speed. It also sounds more strained at highway speed. The tachometer is not functioning in the A2 so I cannot confirm what rpms it's turning but it almost sounds like the gearing is lower in the A2. They should both have 6.44 to 1 axles but I've never confirmed. Tires are the same size and mine started out as an A0 model. Not official but it is a 250 powered truck that I put 14r20's on. The A2 I drove is quieter all around but it sounds like the 8.3 is working very hard moving the truck down the road. The 250 is louder exhaust note wise but sounds much slower turning and happier running down the road. What have I missed?

 

[98G]

Your experiences parallel mine. This is my experience over multiple trucks...

 

[Suprman]

I have found most of the 6CTA's need 2 turns on their fuel screw to really open up. Once the turbo is fully spooled full power is available.

 

[1 Patriot-of-many]

I've found the opposite. My NHC250 truck M923, M923A2 would run rings around it.

 

[Coffey1]

That's what I experienced the A1 was strong off the line but a dog after that.
The A2 would outperform it all day long pulling trailers and taking grades.
I guess that's why I bought two A2s.
If I ever sold the Hemtt I would be happy going back to the A2s.

 

[simp5782]

There is no replacement for displacement. Well except for forced induction

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[sandcobra164]

I guess I'll have a better perspective when we start to up the fuel rate on the A2. My previous experience was with an M936A2 which of course was slower due to the weight. I expected the cargo variant to feel stronger with it's advertised 745 foot pounds of torque vs the A1's 650 foot pounds of torque. I had read about the turbo lag when starting out and certainly experienced a slight amount of that with this truck.

 

[74M35A2]

250 engine can't pull a string out of a cats a$$...... (Quoted from member: infidel got me).

A2 torque converter locks in at the top of 2nd gear. If you keep the selector in 1-2, it feels like it shifts 3 times, but is not.

 

[simp5782]

All of them lock up in 2nd. I shift mine to 1-3 manually and then back to 1-2 to over come the **** hole that it has. Especially on inclines or towing.

 

[sandcobra164]

Shifter was in 1-5, 1 click back from neutral. I guess the string attached to cats rear ends have some knots from time to time which makes it difficult to pull them out and perhaps a 250 powered truck could not accomplish that. I was socializing for thoughts and that certainly is one. I merely posted my first hand experience and am eager to learn what I am missing. I have also researched how easy it is to turn up the 8.3 for power but that certainly would put alot more stress on the stock drivetrain. I own an older truck and kind of side with the NHC 250 based on my initial assessment.

 

[fuzzytoaster]

I've had 50+ trucks of all the variants and I agree "there's no replacement for displacement"..unless you're trying to make that 250 climb a hill, tow a load, at highway speed, at high altitude, etc.. pick two and it's a turd. Now the 400 is a monster but that's not a fair comparison. Yes, the 250 has a little more power on the low end but the 6CTA has the better top end which (in my opinion) is better as that's where I drive mine 90% of the time. I say unless you get that tach hooked up and reading I wouldn't compare by sound alone. That engine has a higher red-line plus you can't trust military gauges so for all we know you could have been hauling @$$ and not knowing it.

The only time I'd keep a 250 is if I was planning on a 350 or 400 swap, I've let some cherry trucks go waiting for the right A2.

 

[74M35A2]

Shifter was in 1-5, 1 click back from neutral. I guess the string attached to cats rear ends have some knots from time to time which makes it difficult to pull them out and perhaps a 250 powered truck could not accomplish that. I was socializing for thoughts and that certainly is one. I merely posted my first hand experience and am eager to learn what I am missing. I have also researched how easy it is to turn up the 8.3 for power but that certainly would put alot more stress on the stock drivetrain. I own an older truck and kind of side with the NHC 250 based on my initial assessment.

I'm biased also by the 8.3, since that is the only one I have ever had experience with. I bought an A2 becasue I wanted singles and CTIS. The 855 engine sounds like a real truck, the 8.3 sounds like a schoolbus (because it is). I've never even stood next to a 250 powered truck, let alone been in one or driven one, so I do highly value the opinions of people of have had or do own both. They make their power on the opposite ends of the tachometer. Mine runs with good power after say maybe 1400rpm or so, but I have seen a YouTube video of a first gen (A0 some call it) pulling a stump out of the ground barely above idle, no way mine is doing that, a parking curb stone can hold mine back at idle. I wanted a turbo diesel, and later found out the 8.3 has a higher safe rpm capability and can easily be "turned up" to increased power levels, though I have yet to do so.

fuzz has same thinking as myself, I'd get a 250 powered truck if I was intending on a BC400 swap or to an ISX.

 

[infidel got me]

Turning up the fuel-- even a little bit-- makes a world of difference on the 8.3. I have driven both and will stick with my 8.3. The only complaint I have is the fuel shut off solenoid. Oh yeah, as stated by our buddy FUZZYTOASTER-- when pulling a hill or towing, make sure your in the right lane. The 250 does shine in one area though-- a school zone-- most of em' are 10 to 15 mph. It has no problem there!

 

[74M35A2]

Turning up the fuel-- even a little bit-- makes a world of difference on the 8.3. I have driven both and will stick with my 8.3. The only complaint I have is the fuel shut off solenoid. Oh yeah, as stated by our buddy FUZZYTOASTER-- when pulling a hill or towing, make sure your in the right lane. The 250 does shine in one area though-- a school zone-- most of em' are 10 to 15 mph. It has no problem there!

...because you're a creeper.

 

[simp5782]

It all depends on suiting the driver and their likes. I trust my 250 to go anywhere. But ive never owned an A2 other than to resrll. sometimes the 250 can be sloths on hills but the allison doesn't give either engine a wide range of options on power output. Like Ron has said. You get a allows and either engine tuned together right and it will surprise you.
I have about 1500$ into mods done to my engine which is small potatoes. But still with that cost plus my truck costs i am still cheaper than an A2 would cost me.

On a 760 mile recovery on an 923a2. I averaged 48mph from st. Louis to Charlotte. And there are alot of hills and mountains to climb. I averaged 54mph on a 320mi run from csmdavis place to home grossing 71k. But then again whos in a hurry. I dont care if im empty or towing doing 25 or 60 i just enjoy the drive. Oh and my air ride seat.

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[Suprman]

The 8.3 is quieter. Will start easier in the cold. Seems a bit better on fuel. I have had a few trucks with newer dated 250s and they were nice trucks. The 8.3 has a lot of advantages though. It's the same with the older style and newer style trucks the old schoolers seem to prefer what they know and the younger people usually like the newer stuff. The gov had to go with a different engine the 250 was no longer in production. It had a good run though.

 

[Gunzy]

I have the 250 and bought it over the 8.3 because of the bottom end torque. There are +s and -s to each engine and you have to make your own decision there. Yes the 8.3 is easier to tune and get more power, yes super singles will allow you to run at higher speeds(even though they are rated at 55). On Sept. 17 I will be taking my M923(A0) to a sled pull and my friend is bringing his M925A2 also. My 923 has been converted to an M925 winch configuration so our pulls will be an absolutely fair comparison of 8.3 to NHC and super singles to dualies. I will post results after the pulls. I plan on taking my M985 to the pulls too, but that is an unfair comparison to any M939 series truck.

 

[Suprman]

The duals has alot more torque pulling a sled. Low range 1st gear it will pull alot of weight. Singles you need the 8.3 with the fuel turned up you dont realize how much low end power you loose with the larger tires. Stump pulling is childs play. Hooking 30k of concrete to the back of the truck and dragging it thru the dirt is the real test.

 

[74M35A2]

 

[Trailboss]

Got 939 series Duallys, A1s and A2s. Love all three models for different reasons (many stated above). As long as it starts and runs reliably, it's a GOOD truck and I'm proud to drive it.