85 % Torque on Brand new Engine

I don't know. They can do all kinds of crazy things with ecms now. Maybe it's a factory set protection to keep truckers from ruining the break in period by running the engine too hard? 85% seems like an oddly specific number for it to be something natural. Seems more like an ecm protection setting to me.

 

I would call BS on what the shop told ya. But what do I know every engine I have built and ran had peak tourqe and hp from day one.

 

My Detroit’s have done that for my 2012 and 2016.
After about 50,000 miles they came alive.
Used to be the driver had to break in a new engine, now the computer programming does it.

 

Lmao at “the motor is tight and needs to break in”

 

Is yours 1850 torque?

Your gauge most probably shows J1939 parameter Engine Actual Torque %.

In that case it is pretty common on Cummins and Detroit (at least Series 60) engines to not go to the full 100%. I have seen it many times.

It is all based on Engine Reference Torque (another J1939 parameter).
In many engines Cummins set the Engine Reference Torque really high, for whatever reason. Much higher than the real maximum torque the engine develops.
And they often use the same Engine Reference Torque value for different torque ratings, and limit Engine Actual Torque % to different levels.

As a result, the Actual Engine Torque % may never go higher than (as an example, I don't know the exact number) 85% on an 1850 engine, mid-high 90's on a 2050 torque engine.

From what I have seen in the J1939 CAN data for Cummins I would say it is pretty normal.

A few examples of J1939 Actual Engine Torque % vs rpm, as I measured on dyno:

ISB 520 lb-ft


ISX12 425 1450 lb-ft


ISX15 425 Smart Torque in high gear (13):


Same engine, 11th gear :


ISX15 EPA13 500 1850 lb-ft:

 

That gauge is a feel good gauge at best. Same dpf level full gauge.

Run it til it breaks in then let the dealer know if you still arent satisfied.
Is this a fleet truck?
525 or 565 tune?