Safeway Gas

[Alltornup]

Since I lifted the TJ and put on 33's I don't even bother with gas mileage.  It's pathetic.  Like less than 300km to a tank.  Good thing I only drive it on the weekends.

[AstraX]

Like less than 300km to a tank.

 

How big is the tank?

[Alltornup]

Not sure how big the tank is.  I think it's 72L but I could be wrong. Its a 2002 TJ Sport 4.0L w Auto with 3.73 gearing.  I've lost alot of gas mileage with the 33's.  Maybe regearing to 4.10 or 4.56 would gain me back what I lost.  It really wouldn't take that long to pay for the regear if it brang back the mileage i'm losing

[Tinkerer]

I'm sure I'm going to take flak for saying this, but now I'm a bit lost.  Since as someone pointed out air+fuel at a given F/A ratio or A/F ratio if you want means that for a given amount of air, whether dense or thin requires a proportionate amount of fuel, then how does making an engine turn over faster at a given road speed (aka higher numerical gears), which pushes more air+fuel mixture through the system improve mileage?  If that were true, our best mileage would be in first gear if taken to the logical conclusion!

The only way I can see that happening is if you are so deep into the throttle with the lower numerical gears that you are at a higher F/A mixture, therefore using more fuel for the smaller amount of air+fuel mixture being pushed through the engine.

Now if you want more "Oomph", aka acceleration aka hill-climbing ability aka power etc. in a given gear, then it makes sense to use the higher numerical gears.

[Alltornup]

Well I step on the gas pedal more with the loss of power from the 33's.  If I had it geared correctly I wouldn't step on the gas near as much.  Makes sense to me.  

[FiEND]

Not sure how big the tank is.  I think it's 72L but I could be wrong. Its a 2002 TJ Sport 4.0L w Auto with 3.73 gearing.  I've lost alot of gas mileage with the 33's.  Maybe regearing to 4.10 or 4.56 would gain me back what I lost.  It really wouldn't take that long to pay for the regear if it brang back the mileage i'm losing

you might get a lot back if you fix your speedo gear.  quite important for an automatic.

[FiEND]

our best fuel economy is in first gear.

[Tinkerer]

Perhaps best efficiency, best power due to torque multiplication from the gearing, sure, but economy? Not according to the ScangaugeII on my dash, which is setup to use the vehicle's own readings to display instantaneous fuel economy.... even idling down deerfoot in first gear is HORRIBLE economy compared to idling down deerfoot in 4'th or 5'th.

[w squared]

our best fuel economy is in first gear.

Not true. My best fuel economy invariably occurs when I select "Mexican Overdrive".

[Immortal]

Not true. My best fuel economy invariably occurs when I select "Mexican Overdrive".

That would be downhill, in neutral?

[w squared]

 

[Alltornup]

you might get a lot back if you fix your speedo gear.  quite important for an automatic.

Why is that? 

[silverfox]

Not true. My best fuel economy invariably occurs when I select "Mexican Overdrive".

Shows what you know not true again, my best fuel economy is in reverse

[Jrama]

I thought coasting down a hill in gear uses zero gas if you have a modernish engine

[TL-Iguana]

Your best bet is to kick it into neutral, bacon grease those tires for less friction, and then shut the jeep off to go down the hill. Then your using no gas! Dont forget though at the bottom to spray the belt dressing back onto the tires, to counteract the effects of the bacon grease so you again get traction to go back up said hill, but then also dont expect your mileage to be any better going up. Unless your in a lifted Mango Rubi, and reversing apparently!