Love the 4.0? sometimes hate the mpg? share your gas saving tips.

[jaysXJ]

after averaging 20 mpg on my 500+ mile move to Florida(yes, I'm a floridian now) I wanna hear some tips and cheap mods to keep your XJ as versatile as ever. I've heard of some pretty cheap mods on other vehicles that drastically improve the mpg, like the mechanical to electrical fan conversion of the dodge dakota that's rumored to improve over 4 mpg.

do you use ethanol-free fuel, use a certain brand of plugs/oil? got a injector cleaner that actually makes a difference? share it!
:xjtalk:

[nateyz2000]

This question is easy... Don't drive it... Lol

[Paddletrucker]

I generally get 20+ with mine, but it's a 5 speed manual transmission and bone stock. For me, the fuel mileage answer is simple. Accelerate slowly, drive slower on the road, and decelerate a little earlier rather than dive in the brakes at the last minute. If it's a 5 speed, shift as smoothly as possible.

I usually drive my XJ around 60mph, and use a shifting technique that I use in my tractor trailer called 'progressive shifting' Taken from Wikipedia:

"Progressive shifting is a technique for changing gears commonly practiced by drivers of semi-trailer trucks. It is meant to reduce fuel consumption — something very important for drivers who travel several hundred miles each day.
Progressive shifting is accomplished by changing gears upward as early as possible when accelerating, while staying within the torque range. Each shift will go a little higher into the RPM, until the vehicle is in its top gear at cruising speed. After each shift is completed, the engine and transmission should be operating at or near the lowest rpm speeds recommended by the manufacturers of those parts.
When done properly, progressive shifting often results in quicker acceleration because diesel engines produce the most torque in lower rpm ranges.[citation needed] Additionally, this technique reduces wear on the transmission because synchronizers only need to compensate for relatively small differences in rotational speed between different components in the gearbox.
As defined by KE =1/2 mv^2, acceleration is the process of gaining kinetic energy, so the greater the power delivered, the quicker it gains kinetic energy."

My Jeep doesn't seem to care about the ethanol gas, but I try not to buy it any way. My pickup hates it.

[jaysXJ]

I was hoping it'd be significantly better considering i just won my battle against the effin cylinder 3 misfire

[msmoorenburg]

2500 rpm = 65mph i'm getting 17ish


http://i1135.photobucket.com/albums/m639/sellitx/screenshot_zps4fa8f6f4.jpg (http://s1135.photobucket.com/user/sellitx/media/screenshot_zps4fa8f6f4.jpg.html)

[Mudderoy]

after averaging 20 mpg on my 500+ mile move to Florida(yes, I'm a floridian now) I wanna hear some tips and cheap mods to keep your XJ as versatile as ever. I've heard of some pretty cheap mods on other vehicles that drastically improve the mpg, like the mechanical to electrical fan conversion of the dodge dakota that's rumored to improve over 4 mpg.

do you use ethanol-free fuel, use a certain brand of plugs/oil? got a injector cleaner that actually makes a difference? share it!
:xjtalk:

Yep sadly there isn't much you can do. It's a go anywhere vehicle not a go anywhere with great gas mileage vehicle.

Keep it stock. Install a vacuum pressure gauge and drive it in a way that the vacuum stays high.

[olds-cool]

This is gonna sound counterintuitive but I stomp on it when I leave a dead stop. Get it up to speed and back off to a good cruise. I've tried babying it off the line like most seem to think is the best way but when watching the real-time readout on the overhead, it stays in the 5mpg range a lot longer that way. Stomping on it and powering away from a stop gets me up to speed quicker and I can back off the throttle much sooner. Think about it for a min...would you rather get 5mpg for 1.5 min or 20-30 seconds? You could figure that out in distance too but I'm too tired to do that right now. My front end is really loose right now and out of alignment, also the rear tires way out of balance...both causing worse gas milage. I'm still pulling an average 15.1mpg on a 3" lift and 29x10.5 offroad tires. I was in the high 17's with street tires last summer.
Another tip for highway driving, find a semi and draft him. I'm not talking right up on him like a tandem trailer but rather leave some reaction room. If you've ever seen the Myth Busters episode where they cover drafting, they prooved it works. I see the milage increase by 5-10mpg when I draft. Large cargo vans like Dodge Sprinters work pretty good too.

[SeniorGustas]

after averaging 20 mpg on my 500+ mile move to Florida(yes, I'm a floridian now) I wanna hear some tips and cheap mods to keep your XJ as versatile as ever.
:xjtalk:

Get the 2.5! I get 25mpg city!! :ass: :poke:

[Paddletrucker]

Another tip for highway driving, find a semi and draft him. I'm not talking right up on him like a tandem trailer but rather leave some reaction room. If you've ever seen the Myth Busters episode where they cover drafting, they prooved it works. I see the milage increase by 5-10mpg when I draft. Large cargo vans like Dodge Sprinters work pretty good too.


I have to disagree with this. As a truck driver with a little over 2.5 million miles under my belt in tractor/trailers, and more miles driving than most folks have in personal vehicles due to me living in the sticks and traveling a lot on weekends, I feel I've seen more of this than most folks have.

If you're close enough for drafting to work, you're too close to be safe. If you get behind a truck, you'll experience a buffering. That's caused by something called "base pressure drag" from the trailer. Any big square object like a trailer or van creates this. It's an area of low pressure behind the trailer. Vortices are caused by the corners of the trailer. This is why airplanes come to a point at the rear of the fuselage, to eliminate as much drag as possible at the rear. It's also why you see those weird looking fins on the tail end of a lot of trailers now days. They're to reduce that base pressure drag. It creates a suction behind the trailer and negatively affects fuel mileage.

As those vortices come off the rear of the trailer, they swirl like small tornadoes out behind the trailer. That's the buffeting you feel in your vehicle when you're following a trailer. The heavier the trailer, the more you'll notice the buffeting and the further behind the trailer it will happen. In order to draft effectively, You need to be between the trailer and the area of dirty air where the buffeting is taking place. That "cone" of clean air directly behind the trailer is where you'll be sucked along with the semi or remain in an area of cleaner, less disturbed air. In my 20+ years of driving trucks, I've NEVER seen that area be far enough from a trailer for it to be safe to drive in. A lot of people may think it is a safe distance, but it's not. That's not opinion, it's science. I've got a lot of highway miles, and as a private pilot and aircraft home builder, I understand my fair share about aerodynamics, too, and I can promise you that if you're close enough to draft effectively, you are putting yourself at risk...period.

It IS true that Myth Busters proved drafting works. NASCAR proves it every weekend. Do you see NASCAR drivers drafting at a car's length back? No. They're almost touching. Myth Busters also said in that episode that there's no way for it to work at a safe following distance. If I need to stop hard, you might not be able to. Semi trucks are designed to stop enormous weights. If I'm loaded around 60,000 pounds in my truck, and the pavement is dry, I PROMISE YOU 100% that I can stop it FASTER that I can stop my Cherokee. You ever seen a 4,000 pound car buried into the back of a 40 ton vehicle? I have...way too many times. The hood will go under the trailer, regardless of the DOT required bumper on the trailer. The floor, and most structurally strong part of the trailer, will go right over your dash and into your windshield. I've seen that horrible scene far too many times.

A rear end collision isn't the only reason you need to stay back. You ever see those big huge tire treads lying on the road way? Most people mistakenly think those are the treads from re-capped or retread tires. That's not true. Some of them are and some of them are from virgin tires. TIre manufacturers will tell you that it's about 50/50. ALL of them are from tires that have not been maintained properly. Most often, it's under inflated tires that have been run until the side wall is damaged and the tread is rejected. You ever picked one up? I have...lots of times. They can weigh 50 or 60 pounds and have all kinds of metal from the belt sticking out all over them. I've seen those things thrown higher than the roof of the trailer and go two trailer lengths rearward. Trust me when I tell you that you absolutely do not want to be anywhere behind that trailer if one of those things separates from the tire. I've seen those things take out windshields more than once. In one horrifying instance, in Colorado, I saw a motorcyclist hit by one of those things because he was following too closely. I'm SURE he thought he had room to stop if the truck stopped, and he may well have had enough room, but he was too close when the tire tread came off of the trailer and, unfortunately, he was pronounced dead on I-70 east of Limon, CO.

And it's not just tire treads. I've seen big rocks get jammed between the dual tires and then spit out once the truck reaches highway speed. I saw a drive shaft go bouncing out from underneath a truck once and bounce over a pickup and totally destroy the camping trailer it was pulling. Have you ever seen a gigantic sheet of ice go flying off the roof of a trailer going down the highway? Saw that just a month or so ago. A HUGE piece of THICK ice about 15 feet long and the width of the trailer landed in front of me on the highway. It left the trailer I was following and impacted the road way about two and a half trailer lengths behind the trailer it came off of. I ALWAYS see cars following trucks closer than that. That could have been deadly.

And then you have the truck drivers. I'll be honest. Trucking ain't what it used to be. There are LOTS of drivers on the road today that have NO business behind the wheel of a semi. I check my tire pressures when I do a pretrip inspection on the trailer and every four hours on the road after that. That's how I was taught, and after seeing some of the things I have, I always will do that. I can promise you, however, that most guys don't. Heck, I watched three guys hook trailers where I was last night and left without even walking around the trailer. They could've had flat or even MISSING tires and they would've never known until the parts started flying at 65mph. Can you be absolutely sure that the flatbed in front of you is being operated by a driver who's properly secured the load that he's hauling? No. I see it every day, especially with the huge companies who have almost 100% driver turnover each year. You might not know what to look for, but I do. I don't get anywhere NEAR some of those guys when I can see from 100 yards that their load isn't secured properly.

I'm not trying to be a jerk or call anyone out, but simply disagree that you can draft from a safe distance. It's aerodynamically impossible. I've seen far, far too many wrecks that were absolutely catastrophic and in the vast majority of those cases, someone was following too closely for the conditions. In the millions of miles I've driven both professionally and personally, I've been very lucky to not have been involved in any kind of accident. I've never lost a tire tread, even though I run recaps, but I keep up with my tires and watch the pressure. I have lost a hub with two wheels on it after a bearing went out. I had a deer one time run under my trailer and then thrown by the wheels onto the car behind me. No damage, but a lot of blood and a scared old lady.

I wish they'd teach new drivers a lot more about sharing the road with trucks. Don't linger beside them. If you're going to pass, do it and go on. You don't know if that guys awake or paying attention and it's just not safe to be beside a truck for any longer than need be. If you can't see the driver in his mirrors, he can't see you. Always make sure you can see him in his mirrors. If you're behind a semi, imagine something coming off of it and heading straight for you. Would you have room to stop. Are there pathways to the left or right to leave yourself an out to take evasive action?

Oh, and one more thing that's completely unrelated. Please, please, PLEASE don't flash your brights into a trucks' mirrors for ANY reason. Don't use your high beams to let him know it's safe to come back into the lane and UNDER NO CIRCUMSTANCE flash the high beams to "let him know you're there" when you pass a truck!!!!! I think this is being taught as I'm seeing it more and more. If I find out who's teaching people that, an ass whoopin' is in order! We can see you coming. We have about five or six mirrors facing rearward. Some of those are convex mirrors and make lights even brighter. When you flash the brights in my mirror as you pass, you blind me and cause me to momentarily lose the road. Don't put yourself in the situation of being beside a blind trucker. Please, just pass and go on.

:thanx::sign0013::sign0101::rant::rant:

[Mudderoy]

I never understood the flashing of lights, of course I've seen people pull up to the back edge of the trailer and just sit there. Too scared to pull along side and pass. I don't like riding along side semi's but it's simply because I know how much pressure and damage can be caused when one of those wheels separate.

[4.3LXJ]

I have to agree, you shouldn't try to draft. I would add one other thing. You cannot see around the truck and you cannot see what is coming at you. If the truck has to drive defensively and avoid something, you cannot and cannot even know why. I stay away from them.

[olds-cool]

I had a feeling I was gonna catch some flak over that one. :sign0181:
In most cases I leave at least 2 car lengths between me & the guy in front of me. When behind a semi, I can see his mirrors. If not, I'm too close and at that point I pass and move on. I won't argue that there are dangers driving behind of beside them. You've done an excellent job covering some of them and for that I've thanked you for your post. I've been next to a truck when a steering tire blew and it dang near left a brown streak in the undies. Luckily he was a top-notch driver and was able to control the truck and make it off to the side safely.

I took this quote from the Wikipedia on drafting where they directly reference the Myth Busters example. While the increase in economy is only rated at 11% for as far back as I drive, risk aside it is still an increase.

On the show Mythbusters, drafting behind an 18-wheeler truck was tested and results showed that traveling 100 feet (30 m) behind the truck increased overall mpg efficiency by 11%. Traveling 10 feet (3.0 m) behind the truck produced a 39% gain in efficiency. Of course, they warn that this type of driving "is insane" because the truck's blind spot is in that area, and if the truck stops quickly there is much less time to react.[9] Truckers are not fond of the extra stress this puts on them, worrying about cars on their tail.[according to whom?] Additionally, on the same episode, Mythbusters demonstrated that it can be very dangerous for the following car if one of the truck's tires (or their recaps) delaminate, as the chunks of ejected rubber can be large enough to cause serious harm, even death, to a driver following too closely.

I guess I should have made a DO AT YOUR OWN RISK statement.
Then again I'm one of those people that doesn't need something printed on my cup to know that my coffee is hot.

Here are some much safer suggestions...

Get an overhead console with the real-time mpg readout and leave it on that setting. It will make you super conscious of how deep your foot is in the pedal. You'll be surprised how little movement it takes from your foot to make a 2mpg increase.
Keep it under 70 there Hoss, this ain't no racecar. The ideal speed for a XJ is right around 55 but of course you'll tick off a lot of folks on the highway at that speed so keep it reasonable. I make an indicated 68 (65 by GPS) my limit and it not only saves me some gas but saves me some speeding tickets too.
Perform regular maintenance. Oil, plugs, air filter. These make a big difference in the efficiency of an engine, especially a clean air filter.

[gary63]

All I know around here the teens run right up to my bumper and I got tirered of it so I modafide my rear window washer sprayer I have 2 now 1 that sprays the window and the other that looks and acts like the sprayer is broken.I have given meny cars free washings LOL and they back off.

[Mountain Goat]

Nice post Paddletrucker....Thanks for the info

[prerunner1982]

I generally get 20+ with mine, but it's a 5 speed manual transmission and bone stock. For me, the fuel mileage answer is simple. Accelerate slowly, drive slower on the road, and decelerate a little earlier rather than dive in the brakes at the last minute. If it's a 5 speed, shift as smoothly as possible.

I usually drive my XJ around 60mph, and use a shifting technique that I use in my tractor trailer called 'progressive shifting'

Yep me too... except I usually drive at 45mph as I stay off the highway.

[XJ Wheeler]

Other than the drafting thing (because i would just be speculating either way), i agree with EVERYTHING Nate said. Some of the truckers of today are a bunch just thrown into a truck without proper training and have not a care because if it. All the miles spent out there with them shows the ignorance running 80k lbs down the highway. Pretrip is a mere rumor to most and i'm guessing they never learn to use a strap winch or chain binder either. Some of the laziness when strapping a load is appalling. Just make you want to stop them and ask what were they thinking. Two straps MINIMAL, no matter what! I've had several instances where I've almost been injured by a cotter pin braking on a strap winch and coming loose, a sharp corner cutting a strap (always protect your straps from corners ;) ), or a worn winch slipping. Just imagine it happening on the highway. As i tightened down a load i always tried to think of the impossible, the unprobable. Because what happens out there is never scripted. Most of the loads i secured looked like spider webs. And i NEVER lost ANY part of a load.

I will add i do flash trucks say to let them know they're clear to return to the lane or something... But its by turning off the headlights for a second (but not parking lights), not to brights. And its common to get the "thanks" sign from them turning on their hazards for a second, the good ones anyways.

[Mudderoy]

I had a feeling I was gonna catch some flak over that one. :sign0181:
In most cases I leave at least 2 car lengths between me & the guy in front of me. When behind a semi, I can see his mirrors. If not, I'm too close and at that point I pass and move on. I won't argue that there are dangers driving behind of beside them. You've done an excellent job covering some of them and for that I've thanked you for your post. I've been next to a truck when a steering tire blew and it dang near left a brown streak in the undies. Luckily he was a top-notch driver and was able to control the truck and make it off to the side safely.

I took this quote from the Wikipedia on drafting where they directly reference the Myth Busters example. While the increase in economy is only rated at 11% for as far back as I drive, risk aside it is still an increase.

On the show Mythbusters, drafting behind an 18-wheeler truck was tested and results showed that traveling 100 feet (30 m) behind the truck increased overall mpg efficiency by 11%. Traveling 10 feet (3.0 m) behind the truck produced a 39% gain in efficiency. Of course, they warn that this type of driving "is insane" because the truck's blind spot is in that area, and if the truck stops quickly there is much less time to react.[9] Truckers are not fond of the extra stress this puts on them, worrying about cars on their tail.[according to whom?] Additionally, on the same episode, Mythbusters demonstrated that it can be very dangerous for the following car if one of the truck's tires (or their recaps) delaminate, as the chunks of ejected rubber can be large enough to cause serious harm, even death, to a driver following too closely.

I guess I should have made a DO AT YOUR OWN RISK statement.
Then again I'm one of those people that doesn't need something printed on my cup to know that my coffee is hot.

Here are some much safer suggestions...

Get an overhead console with the real-time mpg readout and leave it on that setting. It will make you super conscious of how deep your foot is in the pedal. You'll be surprised how little movement it takes from your foot to make a 2mpg increase.
Keep it under 70 there Hoss, this ain't no racecar. The ideal speed for a XJ is right around 55 but of course you'll tick off a lot of folks on the highway at that speed so keep it reasonable. I make an indicated 68 (65 by GPS) my limit and it not only saves me some gas but saves me some speeding tickets too.
Perform regular maintenance. Oil, plugs, air filter. These make a big difference in the efficiency of an engine, especially a clean air filter.


I look at it like this. You are the one behind the wheel and you are "pilot in command" It's your responsibility. You should do what you feel best.

For example. I get sick of hearing the "News" people talk bad about people driving through high water. Listen genius do you have ANY clue about what you're talking about? They were specifically ragging on a bus drivers in Illinois that drove though what looked to be 6 to 12 inches of water in a FRICKING full sized school bus. The driver was alone.

I don't know about you but I think I'm smart enough to be able to size up the situation and make my own decisions. Further more if I **** up it will be me paying for it.

So just so we're clear I personally support your decision to draft those big rigs if you want to! Can't drive off road because you might damage a tulip, can't have a gun because some mental deficient might get a hold of it. Can't tell a woman that she looks good because you might offend... Good God this country is becoming a nation of sheep! :drinking: :smiley-whacky119: :sign0013:

[Paddletrucker]

I guess I should have made a DO AT YOUR OWN RISK statement.
Then again I'm one of those people that doesn't need something printed on my cup to know that my coffee is hot.





I don't know about you but I think I'm smart enough to be able to size up the situation and make my own decisions. Further more if I **** up it will be me paying for it.

So just so we're clear I personally support your decision to draft those big rigs if you want to!:

We'll just have to agree to disagree, I suppose. I'm a pretty libertarian kind of guy. THe less government involvement, the better. If you want to drive into a river that you think you can make just fine, great. I'll look at it and if I think I can also make it, hell, I'll follow you. Might be fun! I like to fly little bitty 700 pound airplanes upside down. I want to catch a shark from my kayak. I know the risks involved and take full responsibility for whatever happens top me as a result of my crazy proclivities.

My problem with that where this is concerned is that you're NOT drafting trucks at your own risk. You're doing it at your risk, at my risk, and the risk of everyone else around.

Here's something that 4.3LXJ brought up that hasn't happened to me once, but happens routinely. I'm cruising along, minding my own business, listening to the XJTalk Show podcast.:cheerleader::driving::D Another motorist catches up to me and is now tailgating me. We drive along like that until we come over a little rise. Bam. All of a sudden, here's a car on the shoulder, a guy sitting on the white line, the car's on a jack, and and the guy is pulling the tire off. Now, I get in the brakes so that I can make a lane change quickly without fear of overturning my trailer. Remember when I said I can get my semi at 60,000 pounds from 65 to 0 mph FASTER than I can get my Cherokee from 65 to 0 mph? The guy tailgating me realizes that he can't get shut down, so he takes the only other path, to the right of my semi. The problem is, since he's been following too closely, he didn't see the guy changing a flat tire. I haven't yet been able to make it all the way into the left lane, and the tailgater has to hope and pray he doesn't hit the guy sitting on the ground or veer into the side of me. Now I've got a potential disaster at my passenger door. So, this guy tailgated me and put himself, me, and another motorist at risk. Luckily, even though this happens, I've been lucky and it's always ended with a scare and hasn't yet led to carnage and mayhem.

Last year, a guy in a pickup realized at the last minute he was about to miss his exit. He dove from the far left lane, all the way across four other lanes, and cut my brother off to make his exit. As he crossed in front of my brother, some lumber came off of his pickup and my brother had no choice but to run over it, not with his tires, as he was able to straddle it. The car behind him, however, was following too closely and hit the lumber. After running over the lumber (he wasn't able to straddle it), it flew up and went over two other cars, and hit the windshield of the third car. It shattered the windshield and caused a major accident in which two people in totally different cars were taken by ambulance to the hospital. The guy tailgating my brother said that he thought that he had left plenty of room, since he figured he could've stopped faster than my brother's truck. You're risking more than just your life when you're following too closely.

I can even be a selfish jerk and inhumane about it. Sometimes, I'll haul really expensive cargo. the most expensive load I ever hauled was worth 5 million bucks. If you're tailgating me, I might need to take a corrective action I wouldn't have otherwise needed to take if there'd been nobody behind me. IF that cargo is damaged in the process, you've just cost somebody a LOT of money. Sure, I had additional insurance on that load, but I'll probably never again be considered to haul for this outfit again.

You just can't know until you've driven a large commercial vehicle how much additional stress there is for me, as the driver, to have a car following me too closely. MOst people haven't seen all the different scenarios play out that I have. It's all about the numbers and the law of averages. I'm GOING to see more crazy stuff on the highway because I spend more time on it. Most folks drive 20 or so miles to work. I drive 40 miles to where I keep my truck and then 500-600 miles per day after that.

I do understand the "I'll be responsible for my own actions" argument. The problem with that in this case is that your actions are risking far more than just you, whether you realize it or not. You can't see upcoming hazards. You are forcing me to change the evasive action I need to take in the event something does happen. My attention while driving with someone following my semi is now taken partially away from other important things so that I can monitor you. Some would say not to bother and let the guy following too closely deal with whatever comes his way, as he's made that choice for himself. Well, I don't know if it's a guy who's knows and accepted the risks, or your 16 year old son or daughter that just isn't very experienced at driving. No matter who it is, I DO NOT want to go to sleep every night knowing someone died in an accident I was involved with wondering what I might have done differently to cause a better outcome. Why would anyone purposely put someone else into the position of living with that kind of emotional stress? I've seen two people die from the cab of my truck and neither one involved me, but it was something that did affect me negatively. I can only imagine if I'd been involved, whether I was at fault or not.

Now, it's not likely you'll ever follow me too closely, because if I'll slow down until you go on around or back off. I've seen too many crazy things in my time behind the wheel to let you chance it behind my truck. There are times, however, when I just don't have that option.

Oh, and remember that just because you can see the mirrors of a truck, doesn't mean that the driver can see you. You need to see the driver in the mirrors to ensure that he can see you.