Expected more power from the 8.3 cummins

[trooper632]

Let me start off by saying I bought a M931a2 with the 8.3 cummins and auto transmission and I love the way it drives and is super quiet, I was just very dissapointed with the low end torque. My M818 truck tractor had not been started in about a year and it has an air leak somewhere in the fuel lines I havent tracked it down yet, so instead of wearing on the starter and batteries i decided I would pull start it with the M931a2. The M818 does have a 40 foot triple axle trailer attached to it so yes it is heavy and has been sitting for a while but when I hooked up to the M818 I didnt think I would need to go to low range. Wrong, It wouldnt even budge the M818, So I put it in low and pulled it that way with no problem. I was just not expecting it to be so gutless, I figured the turbo might spool up enough but I didnt want to stay on it that long. When the M818 started I drove it around for a while and man it has alot more low end torque than the new one, just suprised.

 

[patracy]

That's a lot of weight for a 250hp engine to move. (22K, 22K, plus whatever that triple axle weighs...) Was the trailer's brakes free?

 

[trooper632]

yes air brakes, but they dont work. I just thought it would at least maybe at least budge it, buy the way I got the stack thanks again

 

[patracy]

I wirebrushed and primed it for you. I just couldn't stand it going out dirty.

 

[Suprman]

My 931a2 flies compared to my 923a2. It's gotta be a good 1500 pounds lighter plus I turned up the fuel and rev limit a bit. Look for nevrenufhp's posts there are videos how to turn it up. Don't do more than one click on the governor springs. I did 4 turns up on my fuel screw it's a noticeable improvement.

 

[Karl kostman]

All the 939 series trucks are very heavy and do remember that in the best conditions you only are working with 250 HP, it only goes DOWN from there. If your trying to compare this truck with a modern semi tractor, well forget it you are trying to compare apples and hockey pucks. The 939 series of truck is a great reliable platform can it keep up with a 450 HP modern tractor, NO WAY nor was it ever designed to!
KK

 

[Derrickl112]

Something must've been dragging. My m931a2 can pull my 36k wrecker without struggling..