Fuel Saving Ideas.............

including using some form of a Chip or Resistor, Ideas?

No lift,stock well aired tires,good oil/fluids,and a tuneup!(and dont forget a wax job)

RCP Phx said:

No lift,and a tuneup!(and dont forget a wax job)

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Well, that counts out at least half of us!

Im trying to stop driving like an asshole, that seems to do me most good MPG/ticket wise.
Regearing was also a huge help.

ride a bike , I have heard from another source if you keep it around 55-60 you save some gas.

during my 100 miles per day i've come up with a few things i'm in progress on, and one that helped significantly.

- Better Tires
not tryin to start a war or anything, but a tire with lower rolling resistance will increase your milage. part of this is the width of the tread, and the air pressure inside the tire. I replaced my old worn Kelly Safari AWRs with some juicy new BFG A/T KOs (31x10.50x15) and went from 17-18 hwy to 19-20 hwy.

-sensor manipulation.
air temp sensor, MAF, MAP, O2, all can be tweaked and persuaded to help your milage. when i decide on a solution, i'll be sure to post up.

-cruise control.
this one's a double hitter. with cruise, i will maintain a steadier throttle, and not waste fuel constantly overaccelerating. also, not forcing myself to have full control over my (6drifting towrds faster) speed will allow me to stay closer to an even 70 (pushing the shoebox much faster takes too much more fuel)

-manual control of the AW4
i'm workin on designing my own controller for the AW4 (as much as a design project as to use it), which will provide me better control of what gear i am in.

also, yes, 100 miles per day at just under 20 mpg DOES equate to over $100 a week in gas.

redXJlimited said:

Regearing was also a huge help.

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Is there an ideal gear for best mpg for stock tire sizes or does it really make a difference?

An article on gearing and drag: http://www.bwbmag.com/output.cfm?id=989335

Driving habits are the largest factor.

Second would be gearing/tyres relative to the engine's torque curve. There seems to be an ongoing experiment here - I've found my "idea cruise" at 2600-3000rpm, on 30's with 3.07's. Since I quit using fifth gear, that worked out to a cruise at about 65mph (good freeway speed) giving me about 2-3mpg more than crusing in fifth at that speed.

The AW4 is handily complemented with it's 3.55 gearing with OEM tyres, 30's, and (just barely...) 31's - beyond that, stop using overdrive (drive in "3" instead of "D".) AMC just dropped the ball when they put 3.07s in behind the BA-10, and ChryCo left it on the ground when they didn't change ratios behind the AX-15 (3.73-4.10 would probably have been better, but I don't recall the math and I don't have my notes to hand. Even 3.55 would have been a significant improvement, tho.)

I've found that vehicle speed has much less of a bearing on fuel economy than crankshaft speed - this "drive 55 to save gas" is more hokum than anything else. If you're at or near peak torque production at 55mph, it will work for you - otherwise, it won't. Period.

Ask any A&P or pilot that handles piston-driven aircraft, and he'll tell you that you get best range/best cruise at best torque. For the AMC242, that's somewhere around 3000rpm (RENIX seems to run a bit slower than ChryCo for that - I've got best cruise, as I said, at 2600-3000rpm. For you HO guys, you'll probably do better at somewhere around 3000-3400, at a guess. I'd have to look up the torque curve again.)

With any lift tire configuration, I've found that I get the best mileage around 2300rpm, in my 98, 4.0. AW4. I drive rather conservatively all the time.

I have also found that short trips kills my fuel mileage as mush as any other factor.
320 highway miles = 240 mix of highway/city

5-90 said:

The AW4 is handily complemented with it's 3.55 gearing with OEM tyres, 30's, and (just barely...) 31's - beyond that, stop using overdrive (drive in "3" instead of "D".) AMC just dropped the ball when they put 3.07s in behind the BA-10, and ChryCo left it on the ground when they didn't change ratios behind the AX-15 (3.73-4.10 would probably have been better, but I don't recall the math and I don't have my notes to hand. Even 3.55 would have been a significant improvement, tho.)

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Hard to believe driving in "3" instead of "O/D" would make a differerence, but it does!! Presently I have a 90 with a 00 dis motor/tranny(AW4) combo and 31" tires (3:55 gearing) and am not real happy with the mileage. I drive about 50-60 miles each way to work and back everyday, so a couple miles per gallon make a big differerence. I started driving in 3 untill a bout 65-70 on the highway and I bet I get at least 3-4 mpg better. I couldn't believe it, before I had to fill up every 2 days, as I couldn't quite make it all the way home on the 3rd day, now I can do it, barely but I can do it.

Can't wait to install my 4:10's.

Hey guys... thought I'd add:

I have a '93 and was getting anywhere from 280-320 miles a tank. I cleaned out my flat K&N filter, put on Autolite wires, Bosch Fusion plugs, after an ordeal with tranny fluid now running Merc V. I have 28 inch Dueler Revos. With regular driving and usually doing 75 on the highway, I broke 22mpg. However, the gas gauge hardly moves after the engine warms up and running 70-75 on the highway... about 105 miles to the quarter tank (87 octane). In my area, we have to run 10% ethanol. On old plugs/wires and no K&N filter, old exhaust/cat, the best I got was 330 a tank with 89 octane and no ethanol (in Canada). Oh.. I also put 2-3 more psi in the tires without a load.

Nothin' fancy. Might be my imagination, but it seems the new plugs and wires have my engine running 100-400 rpm less with the greatest gains when running mid-40s to low 60s.

Also, I probably spend too much time watching PBS, but after 55mph on most vehicles, drag doubles for nearly every 1 mph increase (...something like that -- it's been a while since I've seen the show). Remember, in many states freeway speed limits were reduced to 55 mpg during the mid-1970s and held through much of the 80s due to oil scares and tough economic times to conserve fuel and help keep prices lower. Anyhow -- it was a catch-all "most vehicles", not XJ specific.

I also read that a drop in 10 degrees equals about a 1 degree in hp. Seems some guys on here like the cowl induction hood and say it drops their engine temp to 20 degrees above ambient. Since the hood rises above the wipers a bit, I wonder if there is a slight drop in drag as well...?

Perhaps voodoo, but there is a Hydro-Assisted Fuel Cell (HAFC) out there that has a money back guarantee that you'll get 50% better mpg. It looks like some old tricks re-arranged with a computer tuned to your engine. There's a guy in central Wisconsin that installs them for around $1500... but there are plans online for $150 to make your own... yet there isn't a computer with those plans that governs your existing computer. I read a testamonial that a lady installed one in her Chevy Venture -- a couple years old -- and is now getting 57 mpg. And, Reedsburg, WI police department were considering using it in there cars. Anyhow -- I've been trying to get a hold of the installer. I don't know if there are performance concerns, if the HAFC works with existing bolt-ons/mods... but it is a universal set-up outside of the vehicle specific tuning.

im moving within 100 yards of my work...walking it

Has anyone tride this HHO technology, where you fill a mason jar with distilled water and through electrolitic plates you convert it to HHO and send that down your intake. It is supposed to help 30 to 40 percent. I am looking into it.

5-90 said:

Driving habits are the largest factor.

Second would be gearing/tyres relative to the engine's torque curve. There seems to be an ongoing experiment here - I've found my "idea cruise" at 2600-3000rpm, on 30's with 3.07's. Since I quit using fifth gear, that worked out to a cruise at about 65mph (good freeway speed) giving me about 2-3mpg more than crusing in fifth at that speed.

The AW4 is handily complemented with it's 3.55 gearing with OEM tyres, 30's, and (just barely...) 31's - beyond that, stop using overdrive (drive in "3" instead of "D".) AMC just dropped the ball when they put 3.07s in behind the BA-10, and ChryCo left it on the ground when they didn't change ratios behind the AX-15 (3.73-4.10 would probably have been better, but I don't recall the math and I don't have my notes to hand. Even 3.55 would have been a significant improvement, tho.)

I've found that vehicle speed has much less of a bearing on fuel economy than crankshaft speed - this "drive 55 to save gas" is more hokum than anything else. If you're at or near peak torque production at 55mph, it will work for you - otherwise, it won't. Period.

Ask any A&P or pilot that handles piston-driven aircraft, and he'll tell you that you get best range/best cruise at best torque. For the AMC242, that's somewhere around 3000rpm (RENIX seems to run a bit slower than ChryCo for that - I've got best cruise, as I said, at 2600-3000rpm. For you HO guys, you'll probably do better at somewhere around 3000-3400, at a guess. I'd have to look up the torque curve again.)

Click to expand...

Most everyone that has ridden with me says I have a binary foot. It's either all the way off (the gas), or all the way on...

After reading several posts here I've done two things.

1) Accelerate slowly, to pretty much any speed I want to go.
I've only measured the MPG on one tank but my figures show that I am up from 10.5/11 mpg to 16 mpg!

2) I ordered 4.56 gears today. My rpm at 80 mph is 2200. I am expecting my RPM to be 3200 at 80 mph once the new gears are installed.

RCP Phx said:

No lift,stock well aired tires,good oil/fluids,and a tuneup!(and dont forget a wax job)

Click to expand...

I actually read an article (I'm going to try and find it, and it wasn't from some joe blow newspaper) that keeping your tires aired doesn't really help with gas mileage too much. I beg to differ.

LOSTXJ said:

Has anyone tride this HHO technology, where you fill a mason jar with distilled water and through electrolitic plates you convert it to HHO and send that down your intake. It is supposed to help 30 to 40 percent. I am looking into it.

Click to expand...

I've read a ton of articles about that BS, but wikipedia really sums it up nicely.

http://en.wikipedia.org/wiki/Oxyhydrogen said:

"Klein's design
HHO gas or Klein gas is an oxyhydrogen mixture made by water electrolysis, which has been trademarked Aquygen by the firm Hydrogen Technology Applications. Dennis Klein's patent states that his electrolyzer differs from Yull Brown's in that it lacks the electric arc feature.[11] The claimed applications of HHO are practically indistinguishable from the original claims of Yull Brown. The HHO trademark is associated with an unproven state of matter called magnegases, and a discredited theory about magnecules,[12] which is the basis for a number of fraudulent claims, and third party water-fuelled car scam attempts."

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Get a honda.

Ramsey said:

Get a honda.

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Thats what I did. 2005 civic, pulling 40 mpg avg if I drive it right.

After factoring the car payment + insurance vs fuel + tires with the xj, I'm coming out ahead about $40 a month.

Picked up a used one for 2k, i guarantee its already paid for itself at least once.