Quote Originally Posted by Jake Z. View Post
I was going to start a new thread, but figured I'd just add on to this one regarding my experience these past 3 weeks. 2014 2500 Mega-Cab, 3.42 gears, DRD "sanitized", 4" exhaust, EGR intact (but turned off), stock otherwise. Also important to note that I do NOT have an EGT probe installed, so I monitor engine load, MG/stroke, and RPMs. When I tow, I lock out 6th, which I calculate to be like having 4.10 ratio. I also drive at 65mph max which is around 1800rpm. Trailer is approx 15k loaded.

Just got done towing 3700 miles round-trip from KY to Yellowstone and back. I really got to do a LOT of "playing around". My first observation is, wind speed/direction has quite the affect when towing a 12.5 ft tall fifth wheel! Headwinds suck!

So, heading out to Yellowstone from Kentucky, uphill, locked out 6th, tuner set to "0" as most recommend, set cruise to 65 and GO. Since I was monitoring MG/stroke and load, I noticed that that MG/stroke max out at 150. Of course load max of 100 percent. I figure, the more fuel, the higher EGT, and since I don't have an EGT probe, when I saw the fuel hit 150, I reduced cruise until it backed off 150. Many, many times, on the longer grades, I ended up gearing down to 4th and going maybe 55 mph, but loads and fuel were still pretty high.

On the way back from Yellowstone, I decided to try something different. Locked out 6th as usual, set cruise to 65, but this time had tuner set to "2", the 90hp setting. I actually did this while climbing a small grade - truck was starting to slow from 65mph with fuel at 150 mg/stroke, but as soon as tune "2" kicked in, I felt the power, and the truck quickly, I mean quickly got to 65mph, and the fuel backed of 150 mg/stroke, and load was only around 70. I thought to myself "am I missing something here?".

Bottom line is, and maybe @DRD can answer, isn't EGT directly related to fuel flow (mg/stroke)? If so, then I should be able to monitor that fuel flow and engine load to determine safe operating temps. Also, seems that when I had the tuner set to "2" (90hp), cruise control was able to keep speed right on, fuel was way less in regards to mg/stroke, and load was way less. Turbo even seemed to be working less, and all temps were great! I was really amazed how much power I felt towing our 15k trailer at setting "2".

So, @DRD, as long as engine load and fuel flow are lower at a higher tune, is that better on the engine in regards to EGTs? I must be missing something...
MM3 or fuel quantity display is meaningless on a tuned truck.

Monitor main injection duration and you will see the difference in HP levels.

Then you'll understand why the truck performs differently on the higher HP levels.

Double R Diesel