2.7L MPG

I have a 2.7 4X4 and the best I ever gotten was about 23mpg. I average about 19. When it comes to MPG I really don't care because I own the vehicle I own and I have to do what I have, or want, to do and need to go or want to go where I want. There has never been an oil or gas shortage so I don't pay any attention to it. I just "afford" it because it's necessary. It's no different than a house payment, rent or paying for underwear.

 

Update?

 

Got my first good mpg read on my 08 MT RC 4x4 which I bought a couple weeks ago. 235 miles on 10 gallons in 50/50 mixed conditions... used the yellow light as my starting and stopping points. Better than I was expecting considering EPA rating is 19 for overall. Plus, I tend to drive kinda fast.
Key to saving gas IMO is driving in a fashion which requires as little braking as possible and I dont downshift to a gear unless Im going to use it. My car which I still drive went 135K on factory brakes and original clutch is still going with 140K.

 

The secret is temperature... wasn't able to get "decent" mpg for a while now. Had my winter tires on and they are heavier than my summer set and I thought I would do better with the summer set on but no... and then this week end and today the weather was nice and hot and guess what? My mpg has improved! Will be able to give numbers tomorrow or wednesday when I fuel up! For now I average 18.5 (whole winter with cold starts, winter tires and fun in the snow). I think I'll hot close to 21 for this tank

 

Given: Actual speed is the same

Questions:

1. Based on the "given", is it true that changing tires from 245/75/16 to 265/75/16 will give me a slightly lower RPM reading?

2. Higher RPM (on the same gear) = higher gas consumption, right?

I'll gladly accept any corrections and clarifications. Thanks.

 

I average 19+ regular city driving and commuting. Road trips are low 20s.
265/75 and 2 inch lift.

I've seriously only seen less than .5 mpg difference from stock.

It's 2-4 mpg better than my previous Rodeo 4x4, so I'm delighted.

 

I'll try to answer this but anyone else feel free to correct me.

1. If the tire diameter is the same (and in this case it looks like they are), they should rotate the same speed at any given RPM. However, weight should be taken into account. The 265s will likely weigh more and that additional load would require more power/higher revs to counteract.

2. Yes.

 

https://www.tacomaworld.com/tirecalc?tires=245-75r16-265-75r16

 

Results are in on my 2nd measurement. 23 mpg ... identical to first run, conditions similar with maybe a little higher percentage of driving in traffic.

 

265/75R16s are a bit taller than 245/75R16s. Therefore, the engine will be turning at lower RPMs at a given speed. The additional weight will have no effect on the engine speed. Any compensation for the extra weight would show up in fuel consumption.

 

You're right about the diameter, I didn't realize there would be a difference.

 

So, it looks like RPM is directly connected to tire revolutions. Am I over-thinking it if I want to factor in the RPM while the engine is on idle?

I just recently did the tire change. I'm at 265/75/16 now. Going to work this morning, I measured the total distance from parking slot to parking slot.

GPS: 27.1 miles
Trip meter (in truck): 26.1 miles
Approx. 3.8% difference

First time I filled my tank yesterday having the new tires installed. I'll report back with my fuel consumption on the next fill.

 

Here is how I improve my MPG. Literally.
https://m.youtube.com/watch?v=pp22seF0Bmg

 

If nothing in the transmission (auto) or clutch (in manual transmission) is slipping, the engine RPM is directly related to the tire revolutions. It could be an interesting exercise in math to calculate the speed at a given RPM, knowing the transmission and differential gear ratios and tire diameter. I recall doing that back in the dark ages before tachometers were common.

I don't understand your second question. I suspect you are overthinking it.

 

I've finally had a decent test on MPG where 95% of the tank was used for home-work-home driving.

• Distance from home to work (relatively flat 100% of the distance): 27 miles (6 city, 21 highway)
• Tires: Cooper ST Maxx 265/75/16
• PSI: Rear: 26, Front: 32 (went with chalk test, about half an inch of chalk left at the edges of the treads on all tires)
• Cruising speed: 55 mph (RPM at about 2,000)
• RPM range during acceleration: 1,200-1,600
• MPG (odometer): 22.184 (+3.831417624521073% for actual GPS distance = 23.033)

 

2011 base 2wd … my last trip 28.3

 

Still 16, but I live in Austin.

 

Good work, I'm getting about the same readings (best is 20-23) on my Scangauge. Still waiting for the second fill up to fully calibrate it, but manual calculations are showing its very close.

 

I got a few 20mpg tanks in Utah last week, usually running 70mph on the hwy in 4th gear, 3200rpm, 700lbs of crap in the bed. Usually accelerated to 4500rpm or so climbing hills. Stock tire size, all 4 at 35psi

 

This was my daily commute of 15miles each way, curvy, hilly roads and in town driving 30-65mph and ~75 highway miles at 75MPH. Been steadily rising since new. Tanks have been 18-22 with this being the best yet.

441.5/18.648= 23.67 MPG