sweet spot in RPMS for fuel ecomony???

[powerstrokeCAM]

I was wondering if there a sweet spot as you're driving?? i notice that going 40mph it hit overdrive going 1200rpms but it still consumes diesel ??? also to have n consideration that i have 35 Inch tire on a 6 inch lift ..... that said ... when i drive a little more aggressive but not too crazy i seen to suck the same amount of fuel??? can some one explain??

Thanks guys

[Raul@Stealth Automotive]

as long as i keep it in the 1800-1900 rpm range it does pretty good...thats about 70mph on my truck right now

[paulgl26]

try to stay under 2000 rpm all the time(even trying to get to highway speeds don't just floor the pedal on ramps) and you will see a big difference

[mas360]

Last weekend I towed a 6,000 lbs travel trailer on a 300 miles trip over hilly terrain and my F250 with 2WD and 20" tires made 10.4 miles/gal. I mixed TCW-3 oil in diesel at 1 oz/gal ratio. I kept rpm at less than 2,000 most of the time. When climbing hills I switched overdrive off and sometimes set gear on 2.

[ridiculously_necessary]

the lower the better, but there comes a point when its so low that your dumping more fuel just to make more power. at the right speed limit i can get pretty good mileage at 1800 rpms. but i think i get much better at 1400 flat groud no load. if i have to struggle to keep power at that speed then its counter productive.

note, those guys that have 6.4's and DMax's in mustangs, nova's, etc. get great mileage 35-45mpg. the are light comparativly, and their gear ratio is set for lwo rpm on this hiway. they can always downshift, and they have so much power on tap from the prorammer that the gear ratio wont matter a whole lot when they mash the loud pedal for a race. iirc, there diesel power mag had an article about a guy that has a 6.4 in a mustang and gets about 45mpg hiway. the tuner allows for something like 800hp. lets combine that with biodiesel - eat that prius!

[NCHornet]

I agree 1800-2000 is the sweet spot. Anything above 2000 is a waste. To bad I have 4:10's and 2000 rpm = 63 mph. Your tires and lift are killing your mpg, have you regeared it? If not I certainly would. Especially if you are still running 3:73's.

[duchevy25]

Originally Posted by ridiculously_necessary

there diesel power mag had an article about a guy that has a 6.4 in a mustang and gets about 45mpg hiway. the tuner allows for something like 800hp. lets combine that with biodiesel - eat that prius!

lol thats is great

[mas360]

Originally Posted by NCHornet

I agree 1800-2000 is the sweet spot. Anything above 2000 is a waste. To bad I have 4:10's and 2000 rpm = 63 mph. Your tires and lift are killing your mpg, have you regeared it? If not I certainly would. Especially if you are still running 3:73's.

I thought the 3:73 would yield better MPG than the 4:10 ???

[powerstrokeCAM]

Originally Posted by mas360

I thought the 3:73 would yield better MPG than the 4:10 ???

please can some one explain??? im going to check tomorrow what ratio i am running???

[JakeLewis79]

I've always heard that an engine is the most efficient when the rpms are kept at the point where the engine makes peak torque. I don't remember what that is on a 7.3, but I believe it's around 1700-1800.