200miles per tank (1 Viewer)

[SirGX]

Hey guys

I did some searching and didn’t really see the answers I was looking for. Recently bought a GX off a friend on mine. I’m getting 200miles per tank, my buddy said that was his normal when have had but just seems like super s***ty mileage. I know the GX didn’t boast about its great gas mileage when stock and I know the extra weight isn’t helping. Just curious to see what others are getting mileage wise fill up to fill up. Also the mods/weight to my truck are;
Demello off-road front bumper
Demello off-road sliders
Full RCI skids
2.5in lift with 34s

 

[nkowi]

Have you actually checked your mileage or are you going by the fuel gauge and computer readout? I ask because mine recently started reporting faulty information - if I were to rely on them I'd also be stopping for fuel every couple of hundred miles. Until I take the time to fully address the issue I'm now going by my odometer. According to my fuel gauge and computer I'm driving well over 100 miles on an empty tank.

Fill your tank, drive a hundred miles or so then fill it again. Then do the math.

_

 

[MrTorgue]

What ^ nkowi said. Generally better to calculate yourself. I will say my two previous Dodge Charger R/T’s were pretty damn close to accurate on the electronic MPG / distance screen.

 

[SirGX]

Have you actually checked your mileage or are you going by the fuel gauge and computer readout? I ask because mine recently started reporting faulty information - if I were to rely on them I'd also be stopping for fuel every couple of hundred miles. Until I take the time to fully address the issue I'm now going by my odometer. According to my fuel gauge and computer I'm driving well over 100 miles on an empty tank.

Fill your tank, drive a hundred miles or so then fill it again. Then do the math.

_

I’m going off the trip odometer. Which has to be correct as it a counting the mileage on the vehicle. Right? Every fill up I zero my trip out and go til the next fill up which is about 200miles

 

[nkowi]

How do you know when to fill up?

 

[WaterGeo]

Keep in mind that you have changed the rolling revolutions per mile by running 34" tires so your odometer/mpg/mph are all going to be off by a certain percentage. For example, I run 255/75r17 and so my mpg and mileage are both off by ~5%. Seems small but will change my mpg calculations significantly.

 

[SirGX]

How do you know when to fill up?

When the light comes on or close to when the light comes on.

Keep in mind that you have changed the rolling revolutions per mile by running 34" tires so your odometer/mpg/mph are all going to be off by a certain percentage. For example, I run 255/75r17 and so my mpg and mileage are both off by ~5%. Seems small but will change my mpg calculations significantly.

Yes I understand that but distance traveled (trip odometer) is not changing. Going off the trip odometer is telling me 200miles a tank

 

[SirGX]

I’m curious to see what others are getting fill up to fill using the trip odometer, or if you have calculated or how ever you get your number... is roughly 200 +/- 10 miles about what I should be getting with the lift and added weight to my truck

 

[WaterGeo]

Not trying to be difficult but your trip odometer is changing. Assuming your 34" tires are 315/70r17 (34.4"), your trip odometer is underestimating by 12.4% when compared to the 265/65r17 stock tires. So your 200 miles/tank, would be comparable to 232 miles/tank on stock tires.

For what it is worth, I am getting 15.2 mpg highway/city on my 255/75r17 (32.1") tires when corrected for revs/mile over the past 8 tanks.

At least I think I'm doing that math right, if anyone else would like to weigh in, that would be appreciated.

This website (Tire Size Calculator) is helpful when figuring this out. The circumference/diameter comparisons will give you a % difference between sizes for correcting for all these things.

 

[McDuff123]

When the light comes on or close to when the light comes on.



Yes I understand that but distance traveled (trip odometer) is not changing. Going off the trip odometer is telling me 200miles a tank

The distance traveled with larger tires is NOT accurate on your trip odometer. Unless an odometer uses GPS to measure distance (ours don’t), they calculate by counting the revolutions of a tire.
Stock tires are about 31“ in diameter, so they travel approx 98” per revolution.
Your 34” tires travel roughly 106” per revolution.
Your odometer doesn’t know you have bigger tires...it knows that 646 revolutions of the stock tire equal 1 mile.
In reality, 646 revolutions of your bigger tires equals 1.08 miles (all numbers approx...you get the idea).
So, for each mile your odometer THINKS you traveled, you actually rolled 422 feet more.
Your 200 mile tanks actually is netting you 216 miles.

 

[McDuff123]

Or Watergeo is correct with his numbers...either way, you get the drift.

 

[nkowi]

Have you actually checked your mileage, versus relying on what might be incorrect indicator (your Miles-to-Empty readout and fuel gauge)? As I noted, once my light comes on I have about 150 miles before empty and once my computer readout show zero miles remaining I have around 100 miles remaining. Even if you're averaging only 12mpg and you run the tank down until there's only a gallon left, you'll have a range of over 260 miles.

It sound as if you haven't actually checked your mileage (or at least you've given no indication of having done so). Next time you fill up, stop when the pump first clicks off, then reset your trip odometer. Then the next time, if you can, use the same pump, again stopping when the pump clicks off. Divide the miles traveled (the odometer reading) by the number of gallons you just put in the tank and you'll have your real-world mileage. Multiply that by 23 and you'll know how far you can drive until you empty the tank.

 

[greenscobie86]

FWIW, my 2004 with stock size rubber/no mods at all gets about ~220 miles per tank(before the low fuel light illuminates) when driving in the city. If I don't drive like an undertaker.

 

[SBANGLICO]

Tire size throwing off the Odo and armor weight. Only way to truly calculate is to fill up, then drive a course of known mileage (using GPS, etc.) and end back at the same pump. Then calculate.

 

[SirGX]

Not trying to be difficult but your trip odometer is changing. Assuming your 34" tires are 315/70r17 (34.4"), your trip odometer is underestimating by 12.4% when compared to the 265/65r17 stock tires. So your 200 miles/tank, would be comparable to 232 miles/tank on stock tires.

For what it is worth, I am getting 15.2 mpg highway/city on my 255/75r17 (32.1") tires when corrected for revs/mile over the past 8 tanks.

At least I think I'm doing that math right, if anyone else would like to weigh in, that would be appreciated.

This website (Tire Size Calculator) is helpful when figuring this out. The circumference/diameter comparisons will give you a % difference between sizes for correcting for all these things.

The distance traveled with larger tires is NOT accurate on your trip odometer. Unless an odometer uses GPS to measure distance (ours don’t), they calculate by counting the revolutions of a tire.
Stock tires are about 31“ in diameter, so they travel approx 98” per revolution.
Your 34” tires travel roughly 106” per revolution.
Your odometer doesn’t know you have bigger tires...it knows that 646 revolutions of the stock tire equal 1 mile.
In reality, 646 revolutions of your bigger tires equals 1.08 miles (all numbers approx...you get the idea).
So, for each mile your odometer THINKS you traveled, you actually rolled 422 feet more.
Your 200 mile tanks actually is netting you 216 miles.

Thank you guys, I had a conversation with a friend after reading your original comments. I couldnt wrap my head around the fact that my odometer wasnt reading true. But he broke it down to me and explained it like you did.

 

[WaterGeo]

Thank you guys, I had a conversation with a friend after reading your original comments. I couldnt wrap my head around the fact that my odometer wasnt reading true. But he broke it down to me and explained it like you did.

Glad we could help, that’s why we are all here! To learn and tinker with vehicles we are passionate about!

 

[SirGX]

Have you actually checked your mileage, versus relying on what might be incorrect indicator (your Miles-to-Empty readout and fuel gauge)? As I noted, once my light comes on I have about 150 miles before empty and once my computer readout show zero miles remaining I have around 100 miles remaining. Even if you're averaging only 12mpg and you run the tank down until there's only a gallon left, you'll have a range of over 260 miles.

It sound as if you haven't actually checked your mileage (or at least you've given no indication of having done so). Next time you fill up, stop when the pump first clicks off, then reset your trip odometer. Then the next time, if you can, use the same pump, again stopping when the pump clicks off. Divide the miles traveled (the odometer reading) by the number of gallons you just put in the tank and you'll have your real-world mileage. Multiply that by 23 and you'll know how far you can drive until you empty the tank.

So you’re saying your low gas like comes on, the needles is all that pegged out at empty and you still have 100-150 miles left!?

 

[nkowi]

Yup, that's what I'm saying. I haven't had time to diagnose the issue (began a month or so ago) but suspect it's the sending unit, as it's affecting both the fuel gauge and the computer.

 

[SirGX]

Yup, that's what I'm saying. I haven't had time to diagnose the issue (began a month or so ago) but suspect it's the sending unit, as it's affecting both the fuel gauge and the computer.

okay m gonna assume that’s not my issue. But for the hell of it, are you lifted and or have any armor or bumpers.Have you calculated what you’re getting

 

[nkowi]

Two-and-a-half inch lift with 255/75/17 tires. Most of my miles are on rural freeways and highways. Actual mileage at 80-82 mph ranges from 14 mpg to 17 mpg, depending on wind speed and direction. On rural highways, again, depending on the wind (I spend a lot of time driving on the great plains of Colorado and Nebraska) I typically get 16-20 mpg. These are actual numbers, by the way, calculated on miles driven divided by gallons burned.