Compression Ignition Addict
Join Date: Apr 2007
Location: Spanish Fork, UT
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Black Maxx Towing Results
Just got back from a 2950-mile round trip towing a 34ft gooseneck flatbed trailer with my new 2010 6.4L. Truck had just over 300 miles on it when I left Salt Lake City for San Antonio with the big empty trailer to pickup a truck to haul back. Bought the truck tuesday, installed a gooseneck hitch, 4" HS Performance downpipe back exhaust system and the Black Maxx I had been running in my 08' truck Thursday afternoon, left for Texas Friday. I loaded the 'Easy' files onto the Black Maxx, as this new 2010 is soley a daily driver and tow rig. Don't see reason to run the big 500+ rwhp tunes in it.
Eitherway, I kept very good records of every tank of fuel and the trucks characteristics in the perspective tunes. Made the haul down with the trailer unloaded, ran the Wild tune (80hp) the whole way running 70-80mph depending on the terrain and posted speed limit. Best tank of fuel on the way down netted 12.4mpg, worst was 11.1mpg. And even though the trailer was unloaded, it's still heavy, believe it's right around 7000lbs empty.
Picked up the truck down in Kingsville TX and made the haul back, again running the same 70-80mph depending on the road and terrain. With the trailer loaded my best tank of fuel coming back was 10.6mpg and the worst was 8.9mpg (head wind through New Mexico on a 225-mile uphill stretch).
I absolutely love towing with this setup, the HS tuning works great in conjunction with that 5r110 transmission, especially in the tow/haul mode. EGT's were a non-issue no matter what the speed, grade, and tune I ran. Very hard to get this thing over 1100 degrees, truck works awesome with that big load behind it.
Couple things I did find interesting though, with the trailer loaded, I got the best mileage running the tuner in the Hot tune (130hp) that tune also ran noticably cooler coolant temperatures. Running in the Mild and Wild tunes I was fighting coolant temps running around 210 constantly and even crept up to 220 on a couple long grades. The truck had to downshift to 4th and then run 25-2600rpms up the grade and the coolant temps would come up.
For the last three tanks of fuel for the trip I ran the Hot file, the truck no longer needed to downshift to 4th on the big grades and would just grunt over them in overdrive at 19-2000rpms and the coolant temps stayed consistent down around 201-203. Truck was just way happier in the higher horsepower tune with that big load behind it. EGT's still weren't a problem, tranny temps never got hot either. Even through the constant 100 degree weather. Wish I would've run the bigger tune the whole trip.
Eitherway, just wanted to post my findings. I couldn't be happier with the truck and the tuning software, truck runs amazing with the trailer behind it and the mileage isn't too bad either. Should also note, I crossed the scales when I got home at the local truckstop just to see and it came in right at 21,000lbs.
2002 LB7 Duramax