I have been pondering this while i drive the 60 miles back and fourth to college on the interstate. At times, there are hills where I can maintain 75 mph or drop down to maybe 70 mph, but my foot is all the way to the floor in high gear at 2,000 rpms, or i can drop to 4th gear and be at 2400 rpm's and half to 3/4 throttle, and hold 75 mph. which of these two will get the best mileage? 2,000 rpm's at full throttle, or 2,400 rpm's at half throttle? any ideas or theories?

 

have u done the geo metro mod? its where u park the xj and drive your metro to school... jk

 

LOL!!!!!


Anyway, full throttle should be avoided as the ecu will enter power enrichment mode and dump lots more fuel in.

 

x2

 

Or the toyota corolla mod. 1992, stick, 40mpg. *****en

 

Nah, Tercel coupe I got 45 with it.

 

no i do the kawasaki ninja thing, 52 miles per gallon lol, but thats a summer thing. i wish i could commute in a car, i have friends that live places that i cant get to in a car like that lol have to use 4wd in my jeep just to get through their driveway...the vehicles we have here are a 2001 F-250, 1997 F-250 powerstroke, 1986 dodge ramcharger, 1985 dodge ramcharger, 1976 ford F-250, 1973 F-100, 1987 cherokee, my 93 cherokee, my 2008 ninja 500, my dads 2008 wr-250r duel sport, can am 4 wheeler, yamaha raptor 700, and a 199??? honda 250 2-stroke, lol other than the bikes and 4 wheelers nothin that gets that good of mileage.....

so ya think 2,500 rpm's at half throttle will use less fuel than full throttle at 2,000 rpm's?

 

My bet would be 2500 at half.

My recommendation would be, I'm not sure if your driving 60 miles each way or round trip, if it was each way, I would say fill up in the morning, drive it one day in 5'th. Fill up when ya get home, check MPG, then the next day, drive it in 4'th, and check mpg. See if there's a difference. If it's 60 miles round trip, I would do it over 2 days instead of 1. That should give you all the data you need.

 

Lower RPMs, try to avoid 100% throttle.

 

But if he's lugging at 100% Then it would be better for the motor to shift down and get into higher RPM's

 

More than likely 100% throttle isn't going to make any more power than 70% in his situation. If he cannot maintain speed then there is no choice but to downshift.

 

Agreed, My rule is if your having to floor it to maintain speed.... downshift.

 

full throttle in 5th gear and just maintaining speed, sounds like lugging the motor, very bad

 

it makes a small difference, but only of a few hills where its right on the verge, i can make it up at 70 mph in 5th at full throttle, or down shift to 4th and make it at 75. i cant make it up bigger hills in 5th, i slow from 75 mph down to about 55-60 by the top of the hill, if i shift down to 4th, i can hold 70-75 at around half to 3/4 throttle, there is one hill i shift down to 3rd, its at 3,500 rpms and holds 75 easy, but if i stay in 4th on that hill, again i slow down to 55-60. and round trip is 120 miles. pretty steep hills, with an average of 20 mph head wind alot of times. ya know that country song by chris ledoux, "chug-a-luggin up one side, slidin down the other, o im a lover of the other, side of the hill" well he is singin about some of the hills that im going over. we call them the sisters, they are between fort bridger wyoming and evanston wyoming

 

but anyway i have just been down shifting anytime i feel it get to full throttle, and been surprised with my mileage. i have been comparing octane, and at least in my jeep, it makes a big difference. my driving is pretty consistant, one trip to work at 60 miles round trip, one trip highway to school, 120 miles, one trip to work, then fill up, if i havent already, drive to school, drive to work, fill up, then its the weekend, hang out. i have found with 85 octane from maverick (pretty much only option around here) i average 16.8-17.6, average 17.1, and its been very consistant, and that is calculating in the extra miles gained from the 31 inch tires over the stock tires. but moving up to 91 octane, i average 18.6-19.7, average 19.15, and have gotten over 20 a couple times, thats with a 4" lift and 31x10.50 tires, so from what im seeing thats only an average of 2 mpg drop over the stock set up. and, when its $0.20 more a gallon for premium, if im totally empty, it would take right at 20 gallons to fill it up. so, 0.20 times 20 is 4, so im paying a maximum of $4 more for a fill up to run premium over 85, and im getting an average of 2.05 mpg increase, so for 4 dollars more if i run all 20 gallons out, im getting 41 miles farther, and its probably better for my engine anyways.........so i have pretty much decided that it saves money to run premium, just for the gas mileage, if not for the life of the engine