1400 RPM after you have gone through the gears and at road speed.
Depends what you want, power, economy or low $$$$ For power, go with a CAT For economy Detroit S60 Dor low $$$ Cummins.
The optimum range on that engine is 1100 to 1500 rpm, depending on how it's geared.
12.7 is the best
we use quality 15-40 oil fleet wide. Sample the oil at each change. And change oil. As on your truck manufacturer shedule. We are also in so calif. no extreme cold temps here.
The top makes for Diesel trucks are Ford, Dodge, and Chevrolet. The best selling Diesel seems to be the Ford F Series. The Duramax engine seems to get very good reviews. The Dodge seems to have more problems with it's engine.
If your asking what vehicle or engine get the best mileage, it would have to be either a hybrid/4cyl. compact or a compact turbo diesel 4cyl./manual transmission. The diesel can actually get better economy is certain conditions than a hybrid/gas 4cyl.
It's a title traditionally held by Detroit Diesel's 60 Series motors. Volvo claims their D series motors are, but only under the most ideal of circumstances do you ever achieve what the manufacturer claims you will with them.In the hands of a good driver, I have seen the PACCAR MX-13 average over 9 MPG.
From an 8.2 DD technician that built his house rebuilding these engines use Shell Rotella 15-40 and nothing else.
Pittsburg penguins won the Stanley cup on Friday June 12th 2009. They played the best of seven series against the Detroit Red Wings. The series was tied at 3 and Pittsburgh won 2-1 in Detroit to win the race for the Stanley Cup.
japan has the best economy of 2009
swift diesel give good mileage
The Honda Civic Hybrid Sedan, VW Jetta TDI Clean Diesel, VW Sports Wagon TDI Clean Diesel, and Toyota Prius are all incredibly eco friendly as well as have extremely high mpg ratings.