Horsepower question

Very likely. The big engines peak torque around 1300-1400 rpm, then peak hp around 1600 or so. So will do best when at one or the other. best designed fuel economy engines will have both peak together. 63 mph is in the middle.

 

hi my truck run only 67 miles por hours,i think to take the limiter out from the truck when i have more speed i have a better mpg is this true or not thanks for the answers

 

I have a 2004 Pete 387 with a c 15 twin turbo. I have it turned all the way up, but could one of you tell me what the optimum gear setting/ratio would be for this truck as far as fuel mileage and pulling. I mainly run west coast, and do a lot of climbing as well as flat desert running.

 

why dooes hiher hp get you better mpg's its confusing but i know it works i just need someone to explain it for me i had my 3406E set at 475 and was gettig 5.5 ran it up to 660 right now im getting 5.8-6.2

 

Your question can't really be answer with the info you gave. We need to know what HP/TQ setting you are running, how fast you normally want to run, sometimes what type of equipment, and how heavy you run. These all figure into the proper gear ratio.

The gain in MPG comes mostly from the extra torque that the new tune gives. Many people believe its all from HP, but that isn't true. The extra torque lets a driver keep a steady and constant speed when he approaches a hill. Where as with a lower HP/TQ tune the driver feels as if he needs to accelerate before starting the hill. Also the extra TQ lets a driver stay in a higher gear a little longer, which in turn makes for less shifting and lower fuel useage. The higher HP/TQ tunes from the manufacturers also alter the fuel curves more and offer a better power band than before if the engine is ran properly.

 

in my schneider truck (century), i believe its 325 or 350hp with a 12l detroit i can get 12mpg bobtail at 60 mph on pretty flat ground, just as a reference number

 

Talk to the engine mfg rep and get him to give you your ideal cruise rpm then go to the road ranger site and use the gear speed calculator to dial in your rpm for the mph you want to run. price out what a ring and pinion job would cost for both diffs and see if the mpg savings will pay for the gear swap.

 

now my truck run whitout limiter ,the truck go better and after the first fueling was close to 0.5 mpg better then before i hope this was not only for 1 fueling iam posted my mpg in 2 weeks the new here

 

Not totally sure of my torque... I'm running around 475 hp with a C15 twin turbo Cat, 13 speed, and I drive at about 70-72 mph at 1500-1550 rpm on an average.. my av weight is 38,000 to 42. I don't need absolutes, just a round about gear ratio for this set up and the terrain I'm driven in, I will fine tune my foot from there.. BTW, thanks for responding.