can someone help me out

[kdub41]

yea lol that doesnt do shit lol all that does is tell me is how far off my speedometer is not my odometer.

 

[kdub41]

ok so here is a calculator for figuring odometer out

http://www.miata.net/garage/tirecalc.html

 

[JJacobs]

yea lol that doesnt do shit lol all that does is tell me is how far off my speedometer is not my odometer.

Are you serious? :confused1

 

[wolfpackjeeper]

yea lol that doesnt do shit lol all that does is tell me is how far off my speedometer is not my odometer.

you are kidding right. 4th grade math here.

 

[JJacobs]

it was the swd model if that helps

You mean swb? As in short wheel base?

Because if so, I have news for ya..

 

[hubs97xj]

Just put the right freakin' speedo gear in and forget about it. We don't want you to die from an aneurysm or anything.

http://go.jeep-xj.info/HowtoSpeedoGears.htm

 

[kdub41]

so all i have to do is multiply my mileage by 12% and that will give me the miles i need to add to the odometer to check my gas mileage.

 

[Darky]

Call Partsmike. They will do all the hard math for you and get you the right speedo gear so you no longer have to do math.

 

[IslanderOffRoad]

yea lol that doesnt do shit lol all that does is tell me is how far off my speedometer is not my odometer.

:doh:

 

[Flyfisher]

If your XJ is anything like mine, your speedo will read high by about 5% (someone earlier said 6%...probably variable with tire brand). I'm running 33x10.5 BFG AT's and 4.56 gears. My speedo reads HIGHER that actual speed by only a couple of mph at highway speeds. This means my odometer reads HIGHER than actual miles traveled. So, what ever error you have (5%, 6%, 12%, etc.), if speedo reads high, you need to SUBTRACT from your odometer reading to get to actual.

And, if all you're after is an MPG calculation...what difference is 5-6% gonna make? Is it that critical? Really?

 

[FlexdXJ]

4.56 and 33's needs a 39 tooth speedo gear! A little searching figured that out!

 

[sourblufff]

So I have 33 and stock 3.55 gears. When I use the odometer to calculate mileage it works out to 10 mpg Are you telling me this isn't right :doh:

So if I alter the calculation can you also please tell me how to factor the bald tires, ethanol content of gas and cracked exhaust manifold into the equation

As I have heard it previously described, you are driving a lifted brick into a head wind. If you are seriously worried about mileage all my co-workers seem to like the Prius uke:

EDIT: Sarcasm increased to maximum level to avoid any confusion that I might actually be serious.

 

[kastein]

cracked exhaust manifold is probably causing your engine to run richer than it should (if the crack is upstream of the O2 sensor) due to the extra oxygen from the air leaking into the exhaust tricking the ECU into thinking it's running lean. Other than that, not sure, solve each problem one at a time and see what changes.

EDIT: the rest is still simple math :doh: you have old tire rolling diameter, new tire rolling diameter (measure it), supposed speed with new tires. Solve. It's high school math at the worst, guys.

 

[rocknxj]

This entire thread is NOMINATED.

 

[wolfpackjeeper]

I don't calculate stuff this accurate in the flippin' jet, why do you need to do it now?

 

[kastein]

Have you changed the axles and gear ratio in the jet?

:wierd:

 

[bigalpha]

Have you changed the axles and gear ratio in the jet?

:wierd:

Did any of them come stock with an 8.8?

 

[Mighty.Mighty_XJ]

All this talk about high school math & how simple it is ... pfft! ... I stunk at high school math & I stink at it now. Thank god GoJeep did all the calculations for me and all I had to do was buy the damn speedo gear.

And I still don't know my MPGs.

I gave up a long time ago ...

 

[wolfpackjeeper]

Have you changed the axles and gear ratio in the jet?

:wierd:

Did any of them come stock with an 8.8?

No, the 8.8 was not invented yet when this jet was built, these things are old.

I simultaneously keep track of Ground speed, air speed, and fuel flow. These tell me how long it will take me to get somewhere and if I have the fuel to do so. It really is all 3rd grade math, and I dumb it down and round like a champ.


This is why earlier I said I just use HWY markers to tell me how much the speedo is off. My electric sender is failing and I am too lazy to get under the jeep and change it. I would feel guilty about not changing the gear while I was under there and life is a lot better when you feel good about yourself.

 

[hammondrckr]

if you go one mile, your really going one mile. :twak:

what weighs more, one pound of feathers or one pound of gold?

Technically the pound of feathers, precious metals and narcotics are weighed on a different scale than anything else.