How to improve gas mileage
#1
10-18-2011, 01:46 AM
Join Date: Oct 2011
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How to improve gas mileage
I get an average of 17, about 14 in the morning, and 23 at night when I can go slower. I have an 87 4x4 3.9L 3 speed automatic.
I wrote this as the thoughts came to mind. I have already spent a lot of time on it, and don’t feel like proofreading it. The format may be a bit off, or the grammar a bit poor, but the content is quality, and I hope you can get past the few mistakes. I ran it through Microsoft Word and hit correct all, so I am trusting it. Hopefully it doesn’t make really weird changes...
I have made quite a few improvements to increase the mileage however. The two biggest things are your transmission, and driving habits. I know you have probably head dozens of times that driving habits affect it a lot, and this is true, depending on what the specifications are. I was quite to pass off the advice of driving habits.
I will start with some improvements you could make regarding equipment.
The automatic transmission, in all its forms is a lot less efficient, but this probably isn’t something you are willing to change. If you have a three speed like me, it shifts into third gear around 23 mph, so every mile per hour faster that you go, you are increasing your rpm, and therefore, the amount of fuel burned. If possible, try to keep your speed lower; the most efficient speed of the vehicle is immediately when it hits its highest gear, and not one mph faster. If you have a four speed, your most efficient velocity is higher, but not by a whole lot.
A new air filter can make a dramatic difference on your mpg, it is a very trivial device, but it makes a big deal. They usually cost about $7-15, and take about 45 seconds to change.
Good quality oil and the recommended viscosity is another thing. You want the oil that is least dense, the engine components can move easier, with less resistance. At the same time, you have to consider weather conditions, and the manufacturer's recommendations, because even if it is good for mileage, it may cause your engine to be damaged, quickly negating any gas savings. Use the thinnest oil possible while still giving ample engine protection. I use 5w-30 year-round. Fully synthetic oil wouldn't be a bad idea. It is a bit pricey, but it will allow you a couple thousand miles extra between changes, and give better gas mileage, plus it will help your engine last longer. I recently used Quaker state, but next change (400mi from now), I am going to go with Mobil 1 since I have a coupon for $7 off.
Your electrical system makes a big difference too. The higher quality spark you can get inside the combustion chamber, the better the fuel will burn.
Upgrade your spark plugs; this would be about $15-25. Absolutely stay away from multiple electrode plugs. They are more expensive, and actually have issues with these engines that make them less efficient.
New spark plug wires will help a bit, but they also are up there in price. A good quality set will increase your mileage by a bit, but set you back about $50.
A new distributor cap and rotor will also help. Again, any electrical upgrade that gives you a better spark burns the fuel more efficiently. A new cap and rotor go for about $15. Don’t bother with anything special on this, standard will do. A new ignition coil wouldn’t hurt, but odds are it is not going to make a drastic difference.
If you have ever heard anything about keeping your tailgate down, this is absolutely false. The air flow over the truck creates a low pressure pocket behind the back window. This pulls your truck backwards, and the engine has to fight it. The concept of the tailgate being down is based on it catching the wind, like a scoop. This low pressure pocket makes it to where it doesn’t do that, and it actually would cause the low pressure area to be bigger, and thus, more powerful, to keep the tailgate down.
Vortex generators are a set of 10 small, fin-shaped objects that you mount to the roof of the vehicle. They run about $20 for a set (can only be found online though - try amazon.com). What they do, is disrupt the air flow, creating a bunch of tiny low pressure areas that are quickly destroyed by other air flow currents. This improves mileage by reducing the stress on the engine.
A tonneau cover would also help. It smooth’s the flow of air, and reduces the size of the low pressure area behind the truck, but this costs about $250 for a basic one. It will take a long time to pay for itself in gas, but it is very useful. You don’t have to worry about rain, and, to some extent, it discourages theft.
A big one! - tire pressure. Make sure your tires are inflated to the proper levels. Over-inflating can help with mileage, but you will wear out the tread faster, likely ending up paying more in replacements than gas savings. The inside of the door should have manufacturer's recommendations, but if you have changed the size of tires, or have custom wheels, this may be different. I just inflate to the max pressure posted on the tire. You won’t wear out the tires extra-fast, and you get the best mileage.
Lower profile tires also provide an improvement, both to handling, and mileage. The tires bend less, and therefore have less resistance due to friction.
If you wanted to take the time to custom-make one, a belly pan helps. It allows the air to flow around all the junk under the truck smoothly, the less resistance the air has as it moves around your vehicle, the better. Air is your worst enemy in this case. Side fairings that redirect air around the rear tires and away from the wheel well also help, but in my opinion, they look a little odd. A hood fairing - as I have heard it called, or a hood scoop, as others call it - is a contraption of sorts that angles the hood to give the air a more smooth flow when it hits the windshield. Notice the new, fuel-efficient cars have windshields that are practically horizontal? That is because it gives the air less resistance. Anything that will help ease the transition from a flat hood to a steep windshield will help.
As for driving habits...
You want to keep your speed down, preferably at whatever speed your transmission shifts into its highest gear. Keep your rpms as low as possible. You also don’t want to be one of those jackasses that cause a disturbance in traffic. This is why I only get 14 mpg in the morning, because there is more traffic and I don’t want to be an imposition, not to mention a hazard. At night, when there is plenty of room, I go 45mph on the highway, it takes my 30 mile drive an extra 7-8 minutes, but I get an improvement of 9mpg... worth it? HELL YEAH!
Accelerate slowly. Pretend you are a semi. Would people have a problem with a slow-accelerating semi-truck? No. So why do they have a problem with you. When you accelerate too fast, you increase your rpm. For every revolution (what R stands for), you burn a bit more fuel. More importantly than slowly, is smoothly, don’t floor it, then coast, keep it steady somewhere in the middle.
If you see a light ahead that you know will be red when you get there, stop accelerating and shift into neutral. The engine actually causes resistance at slower speeds because of back-pressure. Notice, if you are coasting, put it in neutral, you will actually speed up a bit on level ground, and you are using less fuel.
When stopped at a light, put it in neutral, or if you want, in park. If you put it in park, you can let off the brakes, and let them cool down, this increases the life of the pads. Just remember to shift back into drive when you go, otherwise you hit the gas and wonder why you aren’t moving... I’ve done this too many times...
Try to match your speed with upcoming traffic. If you see ahead that people are just starting to go from a red light, don’t accelerate more. Just coast for a while and you will likely be pretty close to their speed, thus eliminating the need to ever hit the brakes, or the accelerator until you are past the intersection.
When you hit the brakes, you are destroying energy that you put into getting the vehicle in motion. If at all possible, avoid using them unless necessary. Brakes are essential to safe driving, and never risk an accident to try to save gas. Just don’t use the brakes unless you need to.
Be courteous, try to stay in the right lane, and move left for merging traffic, speed up though, and don’t get into a lane going 65 if you are going 55... If you need to exit the highway to the left, or if it splits, change lanes in plenty of time, or look far behind you and plan a move that will not disrupt others. If you do get in a lane other than the far right, match your speed with theirs, don’t be going 45, in a 65 lane, and force them to hit their brakes. How many times have you been pissed off at other people for being stupid? To them, this driving is stupid, they don’t understand why you are doing what you are, but unless you have a big bumper sticker that explains it like I do, then they won’t know, and will think you are just an ***.
I wrote this as the thoughts came to mind. I have already spent a lot of time on it, and don’t feel like proofreading it. The format may be a bit off, or the grammar a bit poor, but the content is quality, and I hope you can get past the few mistakes. I ran it through Microsoft Word and hit correct all, so I am trusting it. Hopefully it doesn’t make really weird changes...
I have made quite a few improvements to increase the mileage however. The two biggest things are your transmission, and driving habits. I know you have probably head dozens of times that driving habits affect it a lot, and this is true, depending on what the specifications are. I was quite to pass off the advice of driving habits.
I will start with some improvements you could make regarding equipment.
The automatic transmission, in all its forms is a lot less efficient, but this probably isn’t something you are willing to change. If you have a three speed like me, it shifts into third gear around 23 mph, so every mile per hour faster that you go, you are increasing your rpm, and therefore, the amount of fuel burned. If possible, try to keep your speed lower; the most efficient speed of the vehicle is immediately when it hits its highest gear, and not one mph faster. If you have a four speed, your most efficient velocity is higher, but not by a whole lot.
A new air filter can make a dramatic difference on your mpg, it is a very trivial device, but it makes a big deal. They usually cost about $7-15, and take about 45 seconds to change.
Good quality oil and the recommended viscosity is another thing. You want the oil that is least dense, the engine components can move easier, with less resistance. At the same time, you have to consider weather conditions, and the manufacturer's recommendations, because even if it is good for mileage, it may cause your engine to be damaged, quickly negating any gas savings. Use the thinnest oil possible while still giving ample engine protection. I use 5w-30 year-round. Fully synthetic oil wouldn't be a bad idea. It is a bit pricey, but it will allow you a couple thousand miles extra between changes, and give better gas mileage, plus it will help your engine last longer. I recently used Quaker state, but next change (400mi from now), I am going to go with Mobil 1 since I have a coupon for $7 off.
Your electrical system makes a big difference too. The higher quality spark you can get inside the combustion chamber, the better the fuel will burn.
Upgrade your spark plugs; this would be about $15-25. Absolutely stay away from multiple electrode plugs. They are more expensive, and actually have issues with these engines that make them less efficient.
New spark plug wires will help a bit, but they also are up there in price. A good quality set will increase your mileage by a bit, but set you back about $50.
A new distributor cap and rotor will also help. Again, any electrical upgrade that gives you a better spark burns the fuel more efficiently. A new cap and rotor go for about $15. Don’t bother with anything special on this, standard will do. A new ignition coil wouldn’t hurt, but odds are it is not going to make a drastic difference.
If you have ever heard anything about keeping your tailgate down, this is absolutely false. The air flow over the truck creates a low pressure pocket behind the back window. This pulls your truck backwards, and the engine has to fight it. The concept of the tailgate being down is based on it catching the wind, like a scoop. This low pressure pocket makes it to where it doesn’t do that, and it actually would cause the low pressure area to be bigger, and thus, more powerful, to keep the tailgate down.
Vortex generators are a set of 10 small, fin-shaped objects that you mount to the roof of the vehicle. They run about $20 for a set (can only be found online though - try amazon.com). What they do, is disrupt the air flow, creating a bunch of tiny low pressure areas that are quickly destroyed by other air flow currents. This improves mileage by reducing the stress on the engine.
A tonneau cover would also help. It smooth’s the flow of air, and reduces the size of the low pressure area behind the truck, but this costs about $250 for a basic one. It will take a long time to pay for itself in gas, but it is very useful. You don’t have to worry about rain, and, to some extent, it discourages theft.
A big one! - tire pressure. Make sure your tires are inflated to the proper levels. Over-inflating can help with mileage, but you will wear out the tread faster, likely ending up paying more in replacements than gas savings. The inside of the door should have manufacturer's recommendations, but if you have changed the size of tires, or have custom wheels, this may be different. I just inflate to the max pressure posted on the tire. You won’t wear out the tires extra-fast, and you get the best mileage.
Lower profile tires also provide an improvement, both to handling, and mileage. The tires bend less, and therefore have less resistance due to friction.
If you wanted to take the time to custom-make one, a belly pan helps. It allows the air to flow around all the junk under the truck smoothly, the less resistance the air has as it moves around your vehicle, the better. Air is your worst enemy in this case. Side fairings that redirect air around the rear tires and away from the wheel well also help, but in my opinion, they look a little odd. A hood fairing - as I have heard it called, or a hood scoop, as others call it - is a contraption of sorts that angles the hood to give the air a more smooth flow when it hits the windshield. Notice the new, fuel-efficient cars have windshields that are practically horizontal? That is because it gives the air less resistance. Anything that will help ease the transition from a flat hood to a steep windshield will help.
As for driving habits...
You want to keep your speed down, preferably at whatever speed your transmission shifts into its highest gear. Keep your rpms as low as possible. You also don’t want to be one of those jackasses that cause a disturbance in traffic. This is why I only get 14 mpg in the morning, because there is more traffic and I don’t want to be an imposition, not to mention a hazard. At night, when there is plenty of room, I go 45mph on the highway, it takes my 30 mile drive an extra 7-8 minutes, but I get an improvement of 9mpg... worth it? HELL YEAH!
Accelerate slowly. Pretend you are a semi. Would people have a problem with a slow-accelerating semi-truck? No. So why do they have a problem with you. When you accelerate too fast, you increase your rpm. For every revolution (what R stands for), you burn a bit more fuel. More importantly than slowly, is smoothly, don’t floor it, then coast, keep it steady somewhere in the middle.
If you see a light ahead that you know will be red when you get there, stop accelerating and shift into neutral. The engine actually causes resistance at slower speeds because of back-pressure. Notice, if you are coasting, put it in neutral, you will actually speed up a bit on level ground, and you are using less fuel.
When stopped at a light, put it in neutral, or if you want, in park. If you put it in park, you can let off the brakes, and let them cool down, this increases the life of the pads. Just remember to shift back into drive when you go, otherwise you hit the gas and wonder why you aren’t moving... I’ve done this too many times...
Try to match your speed with upcoming traffic. If you see ahead that people are just starting to go from a red light, don’t accelerate more. Just coast for a while and you will likely be pretty close to their speed, thus eliminating the need to ever hit the brakes, or the accelerator until you are past the intersection.
When you hit the brakes, you are destroying energy that you put into getting the vehicle in motion. If at all possible, avoid using them unless necessary. Brakes are essential to safe driving, and never risk an accident to try to save gas. Just don’t use the brakes unless you need to.
Be courteous, try to stay in the right lane, and move left for merging traffic, speed up though, and don’t get into a lane going 65 if you are going 55... If you need to exit the highway to the left, or if it splits, change lanes in plenty of time, or look far behind you and plan a move that will not disrupt others. If you do get in a lane other than the far right, match your speed with theirs, don’t be going 45, in a 65 lane, and force them to hit their brakes. How many times have you been pissed off at other people for being stupid? To them, this driving is stupid, they don’t understand why you are doing what you are, but unless you have a big bumper sticker that explains it like I do, then they won’t know, and will think you are just an ***.
#2
10-18-2011, 01:48 AM
Join Date: Oct 2011
Posts: 47
Likes: 0
Received 0 Likes
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#3
10-18-2011, 02:52 AM
Just my 
,
I wouldn't put synthetic in a motor that isn't next to new. Synthetic and conventional motor oil have different wear patterns, and this may allow oil to get by the rings. Also the molecules in synthetic are half the size of regular oil, and will result in leaks. You might not be aware of a bad gasket or seal because sludge build up from conventional motor oil, is masking it. I've been there too many times in the past. And if you do take that route always use a high quality synthetic (royal purple or red line, and I wouldn't settle for anything else. 9k miles per oil change w/ royal purple and up to 16k miles with red line) Sounds un-real, but read the faq on both their web sites.
Synthetic transmission fluid is another story. Never had any problems switching that over, and I recommend it. May even improve mpg a bit.
IMO, Not always the case. Depends on the vehicle, and you have to take into consideration tool boxes and such. Many debates about this on ecomoder.com.
If your inflating to the max pressure on tire, your OVER INFLATING. The max on most tires is like 45 psi, I've never seen a manufactures recommendation that is more than 35 psi. I run 38 in ever thing I drive. Not too much over manufactures recommendations to cause uneven wear but still helping with mpg.
Why not lol? Sometimes I even get off on it 
,
Fully synthetic oil wouldn't be a bad idea. It is a bit pricey, but it will allow you a couple thousand miles extra between changes
Synthetic transmission fluid is another story. Never had any problems switching that over, and I recommend it. May even improve mpg a bit.
If you have ever heard anything about keeping your tailgate down, this is absolutely false. The air flow over the truck creates a low pressure pocket behind the back window. This pulls your truck backwards, and the engine has to fight it. The concept of the tailgate being down is based on it catching the wind, like a scoop. This low pressure pocket makes it to where it doesn’t do that, and it actually would cause the low pressure area to be bigger, and thus, more powerful, to keep the tailgate down.
A big one! - tire pressure. Make sure your tires are inflated to the proper levels. Over-inflating can help with mileage, but you will wear out the tread faster, likely ending up paying more in replacements than gas savings. The inside of the door should have manufacturer's recommendations, but if you have changed the size of tires, or have custom wheels, this may be different. I just inflate to the max pressure posted on the tire. You won’t wear out the tires extra-fast, and you get the best mileage.
You also don’t want to be one of those jackasses that cause a disturbance in traffic.