Impressed with fuel mileage. Should I be? (1 Viewer)

[bryson]

I've got 4.88 gears and 35" tires. I get 12.5 most of the time on the highway. I did tow a deep hull, full windshield fishing boat to Lake Michigan and managed to still get 11.5.

My correction factor is exactly 25% more mileage more than reported on the odometer. I've checked with road markings and with GPS...

25% ?!?
With 4.88s and 35s you should be pretty darn close to stock ratios, and the speedo should be fairly close as is. I have a very hard time believing you have to add 25% to your odo to be accurate... Am I missing something? 12.5mpg sounds about right though.

 

[yOHda]

325 miles on 285 Falken Rocky Mountains

200-225 miles on 37" Pitbull Rockers. This is the same mileage i got on 275s towing my trail truck and trailer.

 

[devildogcruiser25]

Are you guys talking about getting nearly 400 miles per tank?!?!?!?

Most I ever got in one trip, on flat road, without stopping, cruise control at 65, running into until it literally ran out of gas, was 320 miles. Everyday driving I get about 220 miles per tank.

I get better mileage than that and I have 35" km2's

 

[sdnative]

25% ?!?
With 4.88s and 35s you should be pretty darn close to stock ratios, and the speedo should be fairly close as is. I have a very hard time believing you have to add 25% to your odo to be accurate... Am I missing something? 12.5mpg sounds about right though.

I have 4.88 and 315s. My scangauge correction factor is -8%.

Speedo says 65, I am actually going 60.



EDIT: this is easy to see doing the math.

Tires are 11% larger than stock (315/75 vs 275/70) and gears are 19% lower than stock (4.88 vs 4.10)

Another EDIT: According to the math, 4.56 gears (-11%) with 315s (+11%) will put you back to stock ratios.

 

[Funner]

All this "I got 240 miles on a tank" is useless information. The more I hear those type of comments in these gas mileage threads the more I realize that people aren't actually calculating their mileage. One poster said he got x miles before his light came on leaving him with 5 gallons. My light comes on with 8 gallons left in the tank...
Gas mileage should be calculated as follows:
1) At gas station write down your odometer reading and completely fill your tank.
2) Drive until most of the tank is gone.
3) At gas station again, write down odometer and completely fill with gas.
4) Subtract original odometer reading (step 1) from 2nd odometer reading (step 3) to get miles traveled.
5) Divide the miles traveled (step 4) by the number of gallons it took to fill your tank the second time (also step 4), this = miles/gallon or MPG.

If you have installed larger tires, then your odometer will reflect fewer miles traveled than you actually drove. Without correction you will end up showing lower fuel economy than actually attained. My truck has 285/75/16 AT's. My GPS shows I am traveling at 71 MPH when my odometer is reading 65. I have not corrected my odometer to reflect my tire size.

I have an Ultraguage to monitor my mileage along with a bunch of other things. When I calculate mileage and adjust for the final drive ratio change caused by my tire size and check that against my calibrated Ultraguage, I consistently get 13MPG in mixed driving. I wish it were better.

I have never owned a vehicle that averaged better mileage than the manufacturer reported on the window sticker, in fact I think it is widely accepted those numbers are "overly optimistic" which is why fed has started regulating how they are calculated.

All said and done, sorry, not believing anyone consistently gets 16-17mpg. Maybe once in a while, on the highway, while you are creating a traffic jam doing 57 in a 75 with an occasional tailwind and flat ground, with outside temperatures below 70 and altitude below 1500 feet, sure

 

[Bearcat80]

5) Divide the miles traveled (step 4) by the number of gallons it took to fill your tank the second time (also step 4), this = miles/gallon or MPG.

p

6) Do this several times to negate the occasional tank that fills 2 gallons short of full

Added another step for ya.

Also, pre-OBD II 93-94 models get consistently 1-2 mpg less than the newer 95-97 OBDII engines. Ethanol also affects my truck hugely. I ran one way to Boise on 10% ethanol, got 13.5 mpg. Filled on non Ethanol in Boise, that leg of the return trip got 15.5, and it has all the hills. I think it screws up the O2 sensors.

 

[slancey]

Using Funner's formula, between fills in the suburbs during work weeks my LX450 gets:

14.7-15.4



On road trips it gets about:

17.5-17.7

My '97 has stock wheels, stock size Michelins, and 170,000 miles. It's actually in the hospital right now for new catalytic converters and oxygen sensors. I'm hoping that the mileage actually improves.

 

[Fosters]

Do the math every time I fill up...yup...light comes on at exactly 5 gallons left in my case...typically that yields me 300-320 depending on driving conditions..which works out to 15-16mpg...consistently

 

[bcaskey08]

I have an Ultraguage to monitor my mileage along with a bunch of other things. When I calculate mileage and adjust for the final drive ratio change caused by my tire size and check that against my calibrated Ultraguage, I consistently get 13MPG in mixed driving. I wish it were better.

How do you calibrate an ultragauge? I calculate the milage the old fashion way with the odometer and get about 260 miles per tank which turns out to be 12 mpg but I don't have speedo correction done for my 285s. The ultragauge wont give real milage without speedo correction will it?

 

[Pilotboy84]

You guys are doing extremely well. Aussie spec fzj80 97 with sfa mods. 320km to the primary. Works out to roughly 29l / 100km. In old speak thats 8.5mpg

Sent from my GT-I9305T using IH8MUD

 

[Pilotboy84]

Also even though ethanol has a higher octane rating, its specific energy capacity is lower than 81 octane fuel. Just a little food for thought.

One last thing. The above figures are based on 110km in 5th, on 285s at 40psi.

Before anyone asks Aussie fzj80's have no o2 sensors from factory and even though they should be obdii compliant, they aren't

Sent from my GT-I9305T using IH8MUD

 

[SIZZLE]

I like milage threads, they make me feel normal.

315s, 4.88 gears and a 2.5" lift and i usually get 13.5 mpg (i correct down 7%). Never worse than 12.5, never better than 14. Don't underestimate the impact of a lift on milage.

Besides, i love gas--LOVE IT! Can't get enough of it!

 

[FZJOverland]

Very will said.

 

[92LXAZ]

13.25 with 315s, 2" TJM lift. A/C on most of the time. About 13.8 before lift. We'll see what this winter brings here in AZ, should improve slightly.

 

[bobbyp]

OME stock height, stock tires with a BIG Thule box on top. Long Island Expressway traffic, Manhattan traffic, Route 80 to the Poconos. Staying at the posted speed limit trying to save gas due to the shortage of fuel in the area: 15.5 mpg.
Generally going a bit faster and lose about 1mpg.

 

[brian]

285s. the trucks runs 5550 lbs as i have it.
i get anywhere from 200-250(uncorrected) miles from total fill to light on. best i ever got was 300ish when the truck was totally stock.

 

[Stainlessdoctor]

I get about 11mpg with 35 and a lot of gear and a RTT.

 

[Sohk2yota]

97 fzj80 315s stock gears highway or city I get 14.5-15.5 I run 55psi in tires and never do over 65mph and coast whenever I can oh and egr deleted with bad o2sensor

 

[Sport Hunter]

Bad mileage

I only get about 10-11. Recently I drug an empty trailer and only got 7.

 

[LandCruiserPhil]

My previous post on the subject - How to get 15MPG using a ScanGauge

Im on 35's w/ stock gears @ #5980 BTW