Topic: Gas Mileage Thread

[Jeffy]

it was a rough calc. from fill up to nearly empty. i know it's not the most accurate way to calculate it, but it gives me a rough estimate. sometimes ill calc it to half tank as a rough look.

How'd you calculate your mileage then?  With the speedo off your odometer will also be off.

[sharpxmen]

it was a rough calc. from fill up to nearly empty. i know it's not the most accurate way to calculate it, but it gives me a rough estimate. sometimes ill calc it to half tank as a rough look.

that's not the way to do it though, you fill up, drive about 200 miles then fill up again, divide the miles between fill-ups to the gallons you put in the last fillup and you get your mpg. Otherwise you don't know if you have 1 or 3 gallons left in the tank and that can be the difference you're looking for (like 15 to 18 mpg for that 2 gallon difference). 1/2 tank is even more inaccurate as the sender is very loose in indication.

[stan98tj]

How'd you calculate your mileage then?  With the speedo off your odometer will also be off.

used my gps for milage

[sharpxmen]

used my gps for milage

that is also not accurate (unless the road you drive is a perfect straight line), odometer or known distance on the hwy is the way to do it.

[Jeffy]

used my gps for milage

I don't think a GPS is a good way to calculate your mileage.  Unless you wait for the GPS to connect, you'll get inaccurate numbers.  A GPS is also only accurate up to 15 meters as well.

What you want to do is replace the speedometer gear so it's within 1-2MPH.  Then fill up and drive till you need to fill up again.  Do this a few times and make sure you don't top off.  This will give you more accurate numbers.  Then if you want to get anal about it, get something like the OBD-II ScanGauge II which can give you real time mileage.  This is the one feature I wish my Jeep had.

[sharpxmen]

I don't think a GPS is a good way to calculate your mileage.  Unless you wait for the GPS to connect, you'll get inaccurate numbers.  A GPS is also only accurate up to 15 meters as well.

What you want to do is replace the speedometer gear so it's within 1-2MPH.  Then fill up and drive till you need to fill up again.  Do this a few times and make sure you don't top off.  This will give you more accurate numbers.  Then if you want to get anal about it, get something like the OBD-II ScanGauge II which can give you real time mileage.  This is the one feature I wish my Jeep had.

what do you mean by "don't top off"?

[Jeffy]

what do you mean by "don't top off"?

Top off the tank with gas.

[brokenwrist21]

mileage varies wildly from about 12 to about 14.5 mpg's
ax5 manual, synchromesh fluid
amc 2.5mpfi, pennzoil platinum full synthetic oil
bfg mud terrain ta/km 33x10.50r15
4.88 synthetic rear diff lube.
spedo calibrated
4.0l tb, tb spacer, k&n drop in air filter, flowmaster muffler, high flow cat, msd 8.5mm super conducter wires, bosch iridium +4 plugs,rv cam from delta camshafts, yella terra roller rockers.

[stevenu]

Tried out 93 octane last fill up at 3.799. pulled 18 mpg.

2.5
AX-5
31x10.5
throttle body and spacer
dynomax cat back
speedo calibrated
KnN drop in filter

[Torch_Ind]

Tried out 93 octane last fill up at 3.799. pulled 18 mpg.

2.5
AX-5
31x10.5
throttle body and spacer
dynomax cat back
speedo calibrated
KnN drop in filter

does that make it worth paying more?

[sharpxmen]

Tried out 93 octane last fill up at 3.799. pulled 18 mpg.

2.5
AX-5
31x10.5
throttle body and spacer
dynomax cat back
speedo calibrated
KnN drop in filter

what were you getting with regular (87)?

[stevenu]

Last 87 octane was 16.3mpg.  It works out in my favor paying more but just barely. Please know that this is my first Jeep and my first standard, I'm still figuring the best way to get around. I know in my 4 runner it helped running a higher octane so I'm trying it out. I will post again when i fill up next with 87.

[stan98tj]

really I get 15 with mods and 6inches of lift 4.88's and 33's with open front fenders and a bit top light bar.. I could prob squeeze 17ish if I was easy on it in nice weather and flat strait roads.

also I did a mpg check when I was stock with 31's pulling a small trailer with a min z on it. and all our gear in the jeep we got roughly 22mpg

what do you got for a build ??
also do you run a/c
let it idle a lot?
clutch fan stuck?

stock fan. no a/c. 33s 3.25" lift. 3spd auto. 62mm Tb/spacer. aem intake. banks header and catback. high flow cat.

[RockinH5]

Fully stock 2.5L YJ on 31x10.50 getting about 16-18mpg.

[Jeffy]

Well, the on the last tank of gas I got 17.5 mpg.  Seems to get better mileage as I run the tank dry.  I got over 300 miles out of the tank with 1-2 gallons left.  I think the most I've dared to do was around 330 miles.  On average I've been getting 15 mpg city for the last 3-4 years.  Before that it was 16-18 with a lot of highway driving.  It will be interesting to see how it changes with the new tires.  Although my speedometer is off by a small amount.  I should still be able to get an idea of the mileage since I know how off it is.