2008 getting 11MPG here in Colorado. Mostly city driving- is that common MPG? (1 Viewer)

[COLandCrusher]

I feel that I should be getting closer to 13-14 but I am consistently at 11MPGs. KO2 larger tires than stock on the XD rims. But nothing else is changed, so seems the MPG's are lower than it should. If this is normal here in Colorado, let me know. Perhaps the higher alt living here is the reason?

 

[Markuson]

If truly all city driving? Yeah… That sounds about right.

 

[canyonrider]

Agreed, consistent with my experience here in CO (and with KO2s in the stock size).

 

[ikeb]

yup. i feel that i should be getting 13-14 mpg too... but no. 11.2 is what i average for all-city driving.

 

[Tremek]

We're in Parker; I drive my kids to school each AM, and that's a 16 mile round trip on a 45-55 mph road. Our truck is also on KO2s, and is usually averaging 13.5 mpg by the trip computer.

What PSI do you have your KO2s at?

 

[ethernectar]

11.7 around town based on the computer, so its probably a bit higher than that. The computer is calculated for the stock tire size right? So with each rotation I'm going just a bit further/faster than it thinks. The awning/hilift definitely hurt the highway mileage I think, even more than the rack.

 

[ikeb]

11.7 around town based on the computer, so its probably a bit higher than that. The computer is calculated for the stock tire size right? So with each rotation I'm going just a bit further/faster than it thinks. The awning/hilift definitely hurt the highway mileage I think, even more than the rack.

i thought that would be the case for me too, but when i checked my speed with GPS after switching tires, my speedometer matches GPS perfectly... i wish i had done that check with the stock tires.

 

[gaijin]

i thought that would be the case for me too, but when i checked my speed with GPS after switching tires, my speedometer matches GPS perfectly... i wish i had done that check with the stock tires.

I have done extensive comparison of the effect on odometer and speedometer readings of stock (P285/60R18) tires and larger (LT285/70R17) tires using an outboard GPS.

Bottom line is:
- odometer is correct with stock tires, and reads fewer (3-4%) miles with larger tires.
- speedometer reads fast (3-4%) with stock tires and is correct with larger tires.

If you are not using GPS miles to calculate mileage, and are using larger tires, you should calculate your mileage by increasing the odometer reading by 3-4% before dividing by gas pump volume at fill-up.

HTH

 

[chilibit]

My truck is largely stock except for 17" RW and 33 inch tires. I just returned from St Louis with high side winds, heavy rain, and running 70-75 with a medium load. 19 MPG. Cruise control is better than I am at milking mileage although I frankly don't worry over it much. Around town is a killer but I usually see 13-14 at around 1k above sea level. I was forced to do 55 for a hundred miles of construction once and saw 25 MPH. I towed a race car on an open trailer for 800 miles down to NC and even holding 4th gear all the time and pulling the trailer I got 13-14 at 70 MPH. Better than my FZJ80 and way more power in the mountains. All of this running 87 octane ethanol blended fuel.

 

[TonyP]

Being easy on the throttle is helpful around town. I know the 5.7 is fun but pretend you have a cargo area full of loose eggs. You'll magically gain mpgs.

 

[NLScooby]

Being easy on the throttle is helpful around town. I know the 5.7 is fun but pretend you have a cargo area full of loose eggs. You'll magically gain mpgs.

This is the ticket. If I drive like an elderly grandma I'll average 14.5 or so. I drove 600 miles after I bought it stock and hit 19 mpg once (70-75 most of the way). On a family trip to FL, I averaged 17.8 on larger tires and a heavier load - same average speed (CC).

My trip computer read 18.8 after a 20 mile trip the other day (after I flushed my transmission fluid and changed the trans filter)... I had no traffic and drove 55-70 right on the highway and off. No inclines, 75 degrees outside and just me and a 60 lbs. of stuff. I made the same exact drive yesterday but hit some traffic and my computer read 17.6. Damn traffic!

 

[kevinfoutch]

FWIW, I get about 13~14 mpg...

I have KO2's E rated 285/65/18 @ 40psi, ARB bumper, winch, slee-ders, ARB skids (i.e. a lot of extra weight) and I get 13~14 of mixed driving in Denver (DWTN commute, occasional DTC via I25, etc.)

I don't use ECT in town (although it's a lot more fun) and I have an UltraGauge Bluetooth OBDII monitor with an RPM alarm set to 4k so I don't drive like a complete horse's arse. This same OBDII gauge (calibrated per owner's manual) is how I am citing my 13~14 MPG, not the OEM computer.

Edit - I also fill up at King Soopers / Loaf & Jug for my $0.03 (or more) discount using 87 octane

 

[Tremek]

Interesting that you're running 87; I have been running 85 octane and at our altitude there shouldn't be any need for 87. I haven't noticed any knock, no codes thrown, etc.

 

[kevinfoutch]

LC200 vs. LX570: HP, Torque, and Required Octane Ratings

Some other discussion on octane - not that I subscribe to any one theory, I mainly pick 87 out of habit.

 

[Mogwai]

I too rock 87 out of habit and around me this is the lowest octane I can find. I avg. 13.5 MPGs w/ my current setup, mixed use, but I enjoy the 5.7L and don't g'ma it. Over my Moab trip I was regularly getting above 17mpg which really surprised me, and I was still hammering the throttle and passing just about everyone on 2-lane roads, speeds 70-100, plus I had 2 other 200+lb guys, 30 gallons of water, and all our gear in the truck.

 

[Tremek]

Mogwai: At sea level, it makes sense that you can't find anything below 87. Up here at 5-6k ft in the Denver area (and of course 2x+ that in the mountains) 85 is almost always the lowest octane you'll find at gas stations here, as the air pressure (especially for an NA engine that doesn't have a turbo or supercharger) is invariably going to result in a lower density AFR.

Incidentally that also means you're probably using less fuel per combustion cycle, but need to rev higher to make the same power you'd make at sea level, so it's not as if it balances out in practice.

On my CTS-V (which is supercharged) I run 91, the highest commonly available octane, and it's tuned and making more power than stock. But curiously as a side-effect of this scenario, I have smaller fuel injectors than I would otherwise need if I lived at sea level because I don't have to inject as much gas to hit stoich.

Also:

LC200 vs. LX570: HP, Torque, and Required Octane Ratings

Some other discussion on octane - not that I subscribe to any one theory, I mainly pick 87 out of habit.

PS, I see something blatantly wrong in that response from Toyota - they wrote "or simply due to the fact that 91 octane fuel has more energy per gallon than 87" - which is 100% false. Higher octane fuels have less propensity to detonate at a given pressure level and also have less power per unit - fewer calories, joules, kilowatt-hours, etc - that can be rendered from them. I'll dig deeper into that thread but if nothing else that's a common fallacy that the Toyota response appears to be perpetuating.

Related, this study from AAA last year was yet another proof point that higher octane (if your car doesn't require it) is a pointless waste of money.

edit: Link to actual AAA study

 

[linuxgod]

I average about 9mpg, +/- in true city driving (and by city I mean there's a stop sign or traffic light every 500'). If I could get 11mpg consistently in Chicago I'd be thrilled. My build is basically stock. Tires are aftermarket Dueler H/T's so I suspect they're not low rolling resistance and as such probably cost me ~5% mpg. 87 octane and 10% ethanol fuels here in the midwest.

I've seen as low as ~6.5 in the winter, which includes idling while waiting to pick up the kids, and get about 10.5 when towing a 5000# trailer. I managed a bit over 18 on the highway once running ~70 with minimal load on very flat land, though normal highway driving I get about 17. I don't know how anyone ever gets 19-20mpg unless they're going downhill or driving 55-60 but props to them.

FWIW I'm no light foot but I also don't drive like a bat outta hell. I do find if I leave the display on MPG I do drive "lighter", but the total difference is <1/2mpg.

 

[Mogwai]

A few months ago I put a new exhaust on, and one of the random outputs that I did not expect was better gas mileage. This is NOT due to the exhaust, but the fact that I can now "hear" what's going on better when I lay-off/lay-on the gas. As sporadic as the shifting can be, I find that by "hearing" the engine I can drive it and get better MPG w/out having to stare at the MPG gauge. Around town I try for MPGs and don't speed, but if it's a trip/long distance/highway involved, just get me there ASAP. In fact, I struggle w/ the concept of a trailer because the thought of 55 - 65MPH over a 2000 miles trip I cannot fathom!!

 

[Tremek]

Less restrictive exhaust actually can result in better fuel economy - if an engine is an air pump, and it doesn't have to work as hard to pump that air, then it can get more work done with less restriction and higher power output for a given cycle. Not unheard of anyway. I do also believe the "hearing" it piece having a stronger affect on your right foot though.

re: trailering - the week after we got the LC I pulled my V out to a hillclimb in Virginia City, Nevada, and the truck did just over ~10 mpg per the trip computer with 2500 miles round-trip of 6000+ lbs behind it.

The LC would do 75 all day without issue; I kept the trans in 4th gear as well so as to not be lugging it in overdrive and heating up the trans. No issues. If I did it again I'd get airbags for the rear coils and ensure the jackass that rented the trailer to me didn't try and give me one with the trailer brakes disconnected, but that's another story. The LC still triumphed!

 

[MisterScott]

We are up near Morrison and getting around 16. 50 percent highway. I used the shifter to hold gears going up into the foot hills as she wants to lug a lot in higher gears. Too much for 7k pounds.