Quote:
Originally Posted by skyking
Bravo! I think respecting peak torque when your engine has a boatload of it to spare is not necessary 
If I light-foot my auto it stays around your goal RPM with the 3.55s. 55~60 MPH is around 1700~1800. |
Thanks. I've been running country miles at 1,725-rpm or 58-mph since earilest 2009. I'll find a calculator and post what the numbers "should" be with a gear swap from 3.73 to 3.42 on these stock spec tires.
Loaded or empty, rain or shine, day or night, I put 16k on the truck commuting back and forth to another Texas city twice monthly that year and into 2010. Had to cross Houston each leg of the trip. Never saw lower than 24-mpg, with some highs around 27 (shown in fuel log where I went for "racetrack mpg": filled after warm-up and re-filled before shutdown to see what potential highest could be). Also, I kept the tires at the factory spec of 50/50 in psi FF/RR.
As to torque, it was pointed out that, again, the 6.7L (with a different manual transmission: the Mercedes-sourced G56) has an engagement torque of 400-ft/lbs. I'll assume my eariler New Venture 5600 (behind a motor with lower HP/TQ numbers) is similar. Indeed, I have to
really come back in at a low rpm (sub-1,000) before I hear the auto-throttle take over and get a touch of rattle.
EDIT: Next step is in weighing this truck on a CAT Scale to get the current "solo" weight per axle and combined (driver, full fuel plus current bed load anticipated to change little) so as to dial in tire pressures ideally. I've experimented with 52/73 FF/RR recently and today dialed it back to 55/55 [hot] as the higher pressure in the rear screws the handling too much.
I have to move the trailer in another one or two weeks, and I'll get numbers for it as well at that time. As I have to install a new hitch receiver I'll be able to crank in the weight adjustment better than before.
Afterwards I'll have both solo and towing tire pressure numbers to work from.
.