The Official increase your gas mileage thread.
06-16-2008, 12:29 AM
#1
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The Official increase your gas mileage thread.
I guess with gas prices pushing $5 per gallon (as of the time of this writing – mid June 2008), getting the most mileage per gallon is a popular topic these days. While, there have been several gas saving threads, with recommendations to 'only fill up in the morning' or 'use the lowest gasoline dispensing speed', and threads about installing an HHO (Hydrogen, hydrogen, oxygen) system, etc. - and for all I know, those could be valid - I am going to limit this list to recommendations that are fairly easy to do and that I am at least 95% sure actually work.
Also, in this thread, you won't see 'combine errands into one trip', 'take the bus', 'carpool', ‘buy a smaller car’, etc. because, while those do reduce your gas consumption - and I do encourage their utilization - they do not increase the MPG of your car. The intention of this thread is to increase the gas mileage of your current car(s).
I also won't be suggesting things like push your car out of the driveway, draft other cars or turn off your engine while going downhill, etc. One, it's probably not safe, and two, it’s probably not legal.
I will take a first stab at all the things I can think of to raise your MPG. But as you guys provide feedback with corrections/additions, I will update this post #1.
In no particular order:
1.) Reduce weight. Reducing weight is well-known by those wanting to lower their drag strip ETs. But reducing weight also helps with your gas mileage by freeing up the work necessary to propel your car. While mostly for increased acceleration/speed reasons, I have managed to get my fully loaded ’99 Maxima from about 3,200 lb to under 3,000 lb. The level of weight reduction is up to you, but if nothing else, at least remove all unnecessary items like that backpack full of books from last semester or that bag of golf clubs you always carry around. You might consider filling your gas tank to half full +/- since gasoline weighs about 8 lb / gal but weigh that (no pun intended) against needing to make a trip to the gas station twice as often. Reducing rotational weight is very beneficial. When shopping for new rims, make sure you consider light-weight rims. 1 lb maximum for every inch of rim diameter is a good rule of thumb.
2.) Avoid cold starts. Cold starts are rough on a car. Your car is less efficient when the engine is cold and less efficient means more gas consumption. If you have more than one car and you need to go back out, use the car that is already warmed up. Make sure you combine your trips into one outing, not for the sake of driving less overall miles (although that is great to do, of course), but so that you limit your number of cold starts. Also, when you do cold-start your car for the first time of the day (or after it's been sitting for several hours), drive extremely conservatively (slow accelerations, keep it under 2500 RPMs, etc.) until your H/C needle is at the half way mark.
3.) Keep your car maintained. You'll "hear" me mention the term 'efficiency' quite a bit in this list of tips. The more efficient your car, the better your gas mileage. Keeping up with your car's maintenance helps to keep it running in tip-top (read efficient) shape. Follow your owner's manual service schedule. Keep those fluids and filters changed.
4.) Keep your car aligned. A poorly aligned car will spend more gas. It is more work on your car to drive straight when it is being pulled to the left due to a miss-alignment.
5.) Keep your tires balanced. If your car shakes above a certain speed, your tires might need balancing. This causes more rolling resistance which, in turn (no pun intended), lowers your MPG.
6.) Keep your tires properly inflated. This is a big one. Under inflated tires cause the car to work harder as the rolling resistance is increased. Keep your tires inflated to the recommended PSI level written on the side wall of your tires. Remember to fill up your tires when they are hot (after you've driven a good distance) because the manufacturer's PSI recommendation is a maximum. Since air expands when it is hot, if you fill your tires up to the maximum PSI when they are cold, the tire pressure will increase when they get hot, pushing you over the manufacture’s recommended maximum.
7.) Buy skinnier tires. While I know there are more than a few reasons to purchase wider tires, like increased traction, increased handling, etc., strictly speaking from a miles per gallon point of view, narrower tires will increase your gas mileage. 205 mm wide tires compared to, say, 225 mm wide tires, will decrease your rolling resistance, increase your aerodynamics and, therefore, increase your MPG. I believe narrower tires are better for snow conditions too.
8.) Take the route with less lights. If you have a choice to take Washington Avenue to the new Hooters or I-15 south, take the highway! Avoid routes with traffic lights, as possible. Even if the distance is a little longer, it is probably worth it. Stop and go will slurp your gas.
9.) Easy accelerations/stops. I know this sounds simple but you'd be surprised how much will power this takes for some people. Stop and go driving is bad enough for your MPG, don't hurt your gas mileage even more by doing sudden accelerations and hard stops. Get up to speed slowly. Feather the gas pedal. Don't worry about the guy behind you. Let your car brake itself, don’t mash the brakes.
10.) Lower your top speed. Again, this sounds obvious and simple to do, but I know this takes an awful lot of will power for many. But this will really have a big impact on your gas mileage. Gas mileage goes down exponentially as your top speed goes up. Try to keep your top speed at or near the posted speed limit instead of your typical 10 MPH over. Plus, it’s a lot safer! My mom always said: “It’s better to lose a minute of your life, than to lose your life in a minute”.
11.) Drive at a steady pace. This tip kind of piggy backs on some of the other tips listed here. Again, try to maintain a constant speed. This includes trying to time the lights when you are on a street, and staying at a constant speed when on the highway. My sister drives in a “sine wave” – she presses on the accelerator and goes from 65 to 70, then she lets off the gas and drops back down to 65, then she goes back to 70, etc, etc. You see the point. Stay at one, steady speed. Take advantage of your cruise control (on flat terrain - see Tip #12 below). Make (SAFE!) lane changes if you have to in order to maintain your constant speed and momentum. If you are making a right turn (on a street with no Stop sign of course), use the skills you learned playing Gran Turismo - swing wide before the turn, take the turn tight, swing wide out of the turn to maintain a higher speed and a higher gear.
12.) Speed up before a big/steep hill. This might apparently conflict with the top speed and the steady pace tip, but I think this tip is a valid exception. While an uphill drive can easily suck more gas, it won’t suck as much gas if you can gather some momentum to take you all the way up or at least partially up a big hill. It’s easier on your car to accelerate on flat ground before reaching the hill than to accelerate on the hill. Generally speaking, you will only want to use your cruise control on relatively flat ground. Disengage your CC when you re approaching hilly terrain. This will give you more control so you may collect a little more speed before a steep hill or to lower your speed below your CC setting in order to avoid a downshift. Likewise, on a downhill, the CC will hunt between coasting and accelerating. You're probably better off using your own steady foot.
13.) Time the traffic lights. The intention here is to avoid, as much as possible, decelerating to zero MPH and accelerating from zero MPH, at red lights. Try to keep your car rolling at a steady cruising speed. This might include learning the perfect speed to travel down a road with many lights so that you ‘make each green’, or letting your foot off the gas and coasting toward a red light rather than continuing to keep your foot on the accelerator just to get to that red light sooner and then decelerate to zero MPH anyway. Likewise, if you see a green light a block or so in front of you, and there is a car waiting at a red light on the intersecting street, you may consider picking up the pace because you know that your light may soon turn red. If I see a red light in the near distance, I immediately let off the gas and start coasting. Half the time, the light turns green before I get there and I get to cruise on through with most of my momentum. Even if the light doesn’t turn green in time, you were still better off coasting to the light than using the accelerator to get there and then braking harder to stop.
14.) If you drive a stick shift, don't engine brake. Brake pads are cheap, people, gasoline is not. If you’re in 3rd gear going 40 MPH and you need to stop, stick (no pun intended) it in neutral and use the brake pedal. The exception to this might be going down a steep grade for an extended period of time, you don’t want to over heat your brakes. Otherwise, don’t waste gas raising your RPMs unnecessarily.
15.) If you have a stick shift, up-shift at lower RPMs. This one is obvious and is the main reason why stick shifts often have better gas mileage than automatics. While you can, in a sense, cause your automatic to shift at a lower RPM simply by accelerating slowly (the computer makes decisions based on your driving style and knows if you are driving aggressively or conservatively), for the most part, the stick shift driver enjoys the privilege of shifting at any RPM he/she wants. If gas mileage is your main objective, up-shift at a lower RPM (but not too low an RPM) than you normally would. But even if you have an automatic transmission, don't disregard this tip all together. If you accelerate slowly and feather your gas, your Maxima will shift at under 2,000 RPMs, which is excellent for gas mileage. Give it a try.
16.) Increase your aerodynamics. While this is a big one, I have to admit there is not a whole lot we can do to change the aerodynamics of our Maximas. But that doesn’t mean there aren’t some things that can be done. As touched on earlier in the 'lower your top speed' tip, the coefficient of drag on your car is increased exponentially the faster you go. I forget the exact numbers but I remember reading in a car magazine that for every one square foot of vertical plane, you’ll lose X horsepower at, say 50 MPH, but something like 4X at 70 MPH. So, remember to keep your top speed down, but also try to increase your aerodynamics. This should definitely include removing that roof mount ski or bike rack when not in use. Also, if you live in a state that doesn’t require you to install a front license plate, remove it. Remove those mud flaps. As mentioned earlier, buy skinnier tires. Close your windows and sunroof. Buy a Stillen or an Ionic front lip. Perhaps consider taking off your windshield wipers for the summer months. Also, I think there have been a few articles in magazines such as Sport Compact which explore under body paneling for the benefit of increased aerodynamics. Explore your options.
17.) Don't use unnecessary power accessories. Some may argue with this tip by saying that electrical drain does not decrease gas mileage because the car’s belt is already turning the alternator as you drive but I can promise you that increased use of 12 volt electrical power accessories decreases your gas mileage. Your motor is like a generator for these accessories. An increased load on the alternator is an increased load on the engine which, guess what?, is a decrease in your MPG. If you can, do without turning on your heated seats. Try doing without those huge stereo amps (also, see weight reduction above). Charge your mobile phone at home instead of via your cigarette lighter. Turn off your fog lights at night if it’s safe to rely only on your headlights. Bump your air conditioning down a fan speed (if you are driving by yourself, close the passenger vent(s) ). Etc., etc., You get the point. Remember the biggest power hogs, just like in your house, are typically accessories/appliances used for the purpose of producing cold or heat. In your home this would be your refrigerator, your heating/air conditioning, your oven, your dryer, etc. In your car, this would be your air conditioning, heated seats, and the rear window defroster (turning on your heat is economical in a car because your engine produces heat anyway). Conserve electrical power where you can.
18.) Rolling windows up/down versus using your air conditioning. I feel like this is a combination of the aerodynamics tip and the power accessories tip above. I think the rule of thumb is to roll down your windows instead of using your car’s air conditioning, whenever possible, with the exception of when you reach highway speeds. At highway speeds, the increased aerodynamic drag on your car with the windows down robs you of more power (read decreased MPG) than if you just rolled up your windows and put on your air conditioning. Also, consider using your car’s economy feature if you can instead of rolling down your windows or using your air conditioning. Always use your economy for heat, and not the compressor (The Auto button for those with electronic climate control and the AC button for those with manual climate control). The exception to this is when you need to defog your windows – using the compressor will clear up the fog. Also, if you are using your air conditioning, consider switching it to economy, even if temporarily. For instance, when accelerating from 0 to 65 MPH to merge onto the highway, or while going up a steep hill. That way your car doesn’t have to do double-duty.
19.) Avoid idling. Remember, when you idle at 0 MPH, you are, in essence, getting 0 MPG. I’ve heard the rule of thumb is to turn your engine off if you plan to idle more than 30-60 seconds. While that seems a bit premature and not always realistic (you certainly don’t want to turn off your car at a 90 second long red light), avoiding idling, when possible, is something to keep in mind. Again, take routes that avoid stop lights, park your car and walk into Burger King instead of using the drive-through, turn your car off while you run up to the ATM, etc., etc.
20.) Choose your driving time wisely. If you have a choice to vary your driving time, strategically choose the time/day you drive. This might include taking your lunch from 11 to 12 instead of 12-1 allowing you to avoid traffic. If you have the day off and the only thing you need to do that day is run to Wal-Mart, wait until 7pm after traffic dies down and the sun goes down so you don’t need to use your air conditioning, etc. Also, and this might be debatable, try to drive at night. Just as your car has more power in colder ambient temperature, so is your gas mileage increased, due to the increase in efficiency.
21.) Don't be afraid to mod! Contrary to what many people think, performance modifications, in and of themselves, don’t necessarily hurt your gas mileage. In fact, the reason you get more horsepower from the modification is because you’ve increased your car’s efficiency. Increased efficiency not only gives power gains, but it also gives gas mileage gains. The problem lies with human nature – the right foot seems to get proportionately heavier with the number of performance mods the owner does to his/her car. So, if you install some modifications, but follow all the rules listed above (slow starts, lower top speed, slow stops, etc.), you’ll most likely realize a gas savings. With that said, would it be a wise investment to buy that $300 Cattman Y-Pipe just for the sake of getting another 0.XX miles per gallon? Probably not. But my point is, if you were going to buy a Place Racing intake or a Stillen exhaust anyway, don’t let decreased gas mileage stop you. But I do urge you to drive conservatively when you’re not “getting on it”. I would say my car (my ’99 Maxima) is pretty heavily modified and of course I do my share of spirited driving, but when I am not, I drive like a grandma to save gas and wear and tear on my baby.
Again, feel free to comment. If a tip is wrong, I’ll remove/correct it. If you guys come up with additional tips – great! – I’ll add them to this list.
- Josh
Also, in this thread, you won't see 'combine errands into one trip', 'take the bus', 'carpool', ‘buy a smaller car’, etc. because, while those do reduce your gas consumption - and I do encourage their utilization - they do not increase the MPG of your car. The intention of this thread is to increase the gas mileage of your current car(s).
I also won't be suggesting things like push your car out of the driveway, draft other cars or turn off your engine while going downhill, etc. One, it's probably not safe, and two, it’s probably not legal.
I will take a first stab at all the things I can think of to raise your MPG. But as you guys provide feedback with corrections/additions, I will update this post #1.
In no particular order:
1.) Reduce weight. Reducing weight is well-known by those wanting to lower their drag strip ETs. But reducing weight also helps with your gas mileage by freeing up the work necessary to propel your car. While mostly for increased acceleration/speed reasons, I have managed to get my fully loaded ’99 Maxima from about 3,200 lb to under 3,000 lb. The level of weight reduction is up to you, but if nothing else, at least remove all unnecessary items like that backpack full of books from last semester or that bag of golf clubs you always carry around. You might consider filling your gas tank to half full +/- since gasoline weighs about 8 lb / gal but weigh that (no pun intended) against needing to make a trip to the gas station twice as often. Reducing rotational weight is very beneficial. When shopping for new rims, make sure you consider light-weight rims. 1 lb maximum for every inch of rim diameter is a good rule of thumb.
2.) Avoid cold starts. Cold starts are rough on a car. Your car is less efficient when the engine is cold and less efficient means more gas consumption. If you have more than one car and you need to go back out, use the car that is already warmed up. Make sure you combine your trips into one outing, not for the sake of driving less overall miles (although that is great to do, of course), but so that you limit your number of cold starts. Also, when you do cold-start your car for the first time of the day (or after it's been sitting for several hours), drive extremely conservatively (slow accelerations, keep it under 2500 RPMs, etc.) until your H/C needle is at the half way mark.
3.) Keep your car maintained. You'll "hear" me mention the term 'efficiency' quite a bit in this list of tips. The more efficient your car, the better your gas mileage. Keeping up with your car's maintenance helps to keep it running in tip-top (read efficient) shape. Follow your owner's manual service schedule. Keep those fluids and filters changed.
4.) Keep your car aligned. A poorly aligned car will spend more gas. It is more work on your car to drive straight when it is being pulled to the left due to a miss-alignment.
5.) Keep your tires balanced. If your car shakes above a certain speed, your tires might need balancing. This causes more rolling resistance which, in turn (no pun intended), lowers your MPG.
6.) Keep your tires properly inflated. This is a big one. Under inflated tires cause the car to work harder as the rolling resistance is increased. Keep your tires inflated to the recommended PSI level written on the side wall of your tires. Remember to fill up your tires when they are hot (after you've driven a good distance) because the manufacturer's PSI recommendation is a maximum. Since air expands when it is hot, if you fill your tires up to the maximum PSI when they are cold, the tire pressure will increase when they get hot, pushing you over the manufacture’s recommended maximum.
7.) Buy skinnier tires. While I know there are more than a few reasons to purchase wider tires, like increased traction, increased handling, etc., strictly speaking from a miles per gallon point of view, narrower tires will increase your gas mileage. 205 mm wide tires compared to, say, 225 mm wide tires, will decrease your rolling resistance, increase your aerodynamics and, therefore, increase your MPG. I believe narrower tires are better for snow conditions too.
8.) Take the route with less lights. If you have a choice to take Washington Avenue to the new Hooters or I-15 south, take the highway! Avoid routes with traffic lights, as possible. Even if the distance is a little longer, it is probably worth it. Stop and go will slurp your gas.
9.) Easy accelerations/stops. I know this sounds simple but you'd be surprised how much will power this takes for some people. Stop and go driving is bad enough for your MPG, don't hurt your gas mileage even more by doing sudden accelerations and hard stops. Get up to speed slowly. Feather the gas pedal. Don't worry about the guy behind you. Let your car brake itself, don’t mash the brakes.
10.) Lower your top speed. Again, this sounds obvious and simple to do, but I know this takes an awful lot of will power for many. But this will really have a big impact on your gas mileage. Gas mileage goes down exponentially as your top speed goes up. Try to keep your top speed at or near the posted speed limit instead of your typical 10 MPH over. Plus, it’s a lot safer! My mom always said: “It’s better to lose a minute of your life, than to lose your life in a minute”.
11.) Drive at a steady pace. This tip kind of piggy backs on some of the other tips listed here. Again, try to maintain a constant speed. This includes trying to time the lights when you are on a street, and staying at a constant speed when on the highway. My sister drives in a “sine wave” – she presses on the accelerator and goes from 65 to 70, then she lets off the gas and drops back down to 65, then she goes back to 70, etc, etc. You see the point. Stay at one, steady speed. Take advantage of your cruise control (on flat terrain - see Tip #12 below). Make (SAFE!) lane changes if you have to in order to maintain your constant speed and momentum. If you are making a right turn (on a street with no Stop sign of course), use the skills you learned playing Gran Turismo - swing wide before the turn, take the turn tight, swing wide out of the turn to maintain a higher speed and a higher gear.
12.) Speed up before a big/steep hill. This might apparently conflict with the top speed and the steady pace tip, but I think this tip is a valid exception. While an uphill drive can easily suck more gas, it won’t suck as much gas if you can gather some momentum to take you all the way up or at least partially up a big hill. It’s easier on your car to accelerate on flat ground before reaching the hill than to accelerate on the hill. Generally speaking, you will only want to use your cruise control on relatively flat ground. Disengage your CC when you re approaching hilly terrain. This will give you more control so you may collect a little more speed before a steep hill or to lower your speed below your CC setting in order to avoid a downshift. Likewise, on a downhill, the CC will hunt between coasting and accelerating. You're probably better off using your own steady foot.
13.) Time the traffic lights. The intention here is to avoid, as much as possible, decelerating to zero MPH and accelerating from zero MPH, at red lights. Try to keep your car rolling at a steady cruising speed. This might include learning the perfect speed to travel down a road with many lights so that you ‘make each green’, or letting your foot off the gas and coasting toward a red light rather than continuing to keep your foot on the accelerator just to get to that red light sooner and then decelerate to zero MPH anyway. Likewise, if you see a green light a block or so in front of you, and there is a car waiting at a red light on the intersecting street, you may consider picking up the pace because you know that your light may soon turn red. If I see a red light in the near distance, I immediately let off the gas and start coasting. Half the time, the light turns green before I get there and I get to cruise on through with most of my momentum. Even if the light doesn’t turn green in time, you were still better off coasting to the light than using the accelerator to get there and then braking harder to stop.
14.) If you drive a stick shift, don't engine brake. Brake pads are cheap, people, gasoline is not. If you’re in 3rd gear going 40 MPH and you need to stop, stick (no pun intended) it in neutral and use the brake pedal. The exception to this might be going down a steep grade for an extended period of time, you don’t want to over heat your brakes. Otherwise, don’t waste gas raising your RPMs unnecessarily.
15.) If you have a stick shift, up-shift at lower RPMs. This one is obvious and is the main reason why stick shifts often have better gas mileage than automatics. While you can, in a sense, cause your automatic to shift at a lower RPM simply by accelerating slowly (the computer makes decisions based on your driving style and knows if you are driving aggressively or conservatively), for the most part, the stick shift driver enjoys the privilege of shifting at any RPM he/she wants. If gas mileage is your main objective, up-shift at a lower RPM (but not too low an RPM) than you normally would. But even if you have an automatic transmission, don't disregard this tip all together. If you accelerate slowly and feather your gas, your Maxima will shift at under 2,000 RPMs, which is excellent for gas mileage. Give it a try.
16.) Increase your aerodynamics. While this is a big one, I have to admit there is not a whole lot we can do to change the aerodynamics of our Maximas. But that doesn’t mean there aren’t some things that can be done. As touched on earlier in the 'lower your top speed' tip, the coefficient of drag on your car is increased exponentially the faster you go. I forget the exact numbers but I remember reading in a car magazine that for every one square foot of vertical plane, you’ll lose X horsepower at, say 50 MPH, but something like 4X at 70 MPH. So, remember to keep your top speed down, but also try to increase your aerodynamics. This should definitely include removing that roof mount ski or bike rack when not in use. Also, if you live in a state that doesn’t require you to install a front license plate, remove it. Remove those mud flaps. As mentioned earlier, buy skinnier tires. Close your windows and sunroof. Buy a Stillen or an Ionic front lip. Perhaps consider taking off your windshield wipers for the summer months. Also, I think there have been a few articles in magazines such as Sport Compact which explore under body paneling for the benefit of increased aerodynamics. Explore your options.
17.) Don't use unnecessary power accessories. Some may argue with this tip by saying that electrical drain does not decrease gas mileage because the car’s belt is already turning the alternator as you drive but I can promise you that increased use of 12 volt electrical power accessories decreases your gas mileage. Your motor is like a generator for these accessories. An increased load on the alternator is an increased load on the engine which, guess what?, is a decrease in your MPG. If you can, do without turning on your heated seats. Try doing without those huge stereo amps (also, see weight reduction above). Charge your mobile phone at home instead of via your cigarette lighter. Turn off your fog lights at night if it’s safe to rely only on your headlights. Bump your air conditioning down a fan speed (if you are driving by yourself, close the passenger vent(s) ). Etc., etc., You get the point. Remember the biggest power hogs, just like in your house, are typically accessories/appliances used for the purpose of producing cold or heat. In your home this would be your refrigerator, your heating/air conditioning, your oven, your dryer, etc. In your car, this would be your air conditioning, heated seats, and the rear window defroster (turning on your heat is economical in a car because your engine produces heat anyway). Conserve electrical power where you can.
18.) Rolling windows up/down versus using your air conditioning. I feel like this is a combination of the aerodynamics tip and the power accessories tip above. I think the rule of thumb is to roll down your windows instead of using your car’s air conditioning, whenever possible, with the exception of when you reach highway speeds. At highway speeds, the increased aerodynamic drag on your car with the windows down robs you of more power (read decreased MPG) than if you just rolled up your windows and put on your air conditioning. Also, consider using your car’s economy feature if you can instead of rolling down your windows or using your air conditioning. Always use your economy for heat, and not the compressor (The Auto button for those with electronic climate control and the AC button for those with manual climate control). The exception to this is when you need to defog your windows – using the compressor will clear up the fog. Also, if you are using your air conditioning, consider switching it to economy, even if temporarily. For instance, when accelerating from 0 to 65 MPH to merge onto the highway, or while going up a steep hill. That way your car doesn’t have to do double-duty.
19.) Avoid idling. Remember, when you idle at 0 MPH, you are, in essence, getting 0 MPG. I’ve heard the rule of thumb is to turn your engine off if you plan to idle more than 30-60 seconds. While that seems a bit premature and not always realistic (you certainly don’t want to turn off your car at a 90 second long red light), avoiding idling, when possible, is something to keep in mind. Again, take routes that avoid stop lights, park your car and walk into Burger King instead of using the drive-through, turn your car off while you run up to the ATM, etc., etc.
20.) Choose your driving time wisely. If you have a choice to vary your driving time, strategically choose the time/day you drive. This might include taking your lunch from 11 to 12 instead of 12-1 allowing you to avoid traffic. If you have the day off and the only thing you need to do that day is run to Wal-Mart, wait until 7pm after traffic dies down and the sun goes down so you don’t need to use your air conditioning, etc. Also, and this might be debatable, try to drive at night. Just as your car has more power in colder ambient temperature, so is your gas mileage increased, due to the increase in efficiency.
21.) Don't be afraid to mod! Contrary to what many people think, performance modifications, in and of themselves, don’t necessarily hurt your gas mileage. In fact, the reason you get more horsepower from the modification is because you’ve increased your car’s efficiency. Increased efficiency not only gives power gains, but it also gives gas mileage gains. The problem lies with human nature – the right foot seems to get proportionately heavier with the number of performance mods the owner does to his/her car. So, if you install some modifications, but follow all the rules listed above (slow starts, lower top speed, slow stops, etc.), you’ll most likely realize a gas savings. With that said, would it be a wise investment to buy that $300 Cattman Y-Pipe just for the sake of getting another 0.XX miles per gallon? Probably not. But my point is, if you were going to buy a Place Racing intake or a Stillen exhaust anyway, don’t let decreased gas mileage stop you. But I do urge you to drive conservatively when you’re not “getting on it”. I would say my car (my ’99 Maxima) is pretty heavily modified and of course I do my share of spirited driving, but when I am not, I drive like a grandma to save gas and wear and tear on my baby.
Again, feel free to comment. If a tip is wrong, I’ll remove/correct it. If you guys come up with additional tips – great! – I’ll add them to this list.
- Josh
Last edited by ptatohed; 08-07-2008 at 04:17 PM.
06-17-2008, 09:11 AM
#5
Member
Join Date: Sep 2007
Posts: 92
But still theres something wrong. USE engine brake! What's wrong with you Americans? Here in Finland it is taught already in Driving school that always use engine brake! It is also taught in econimical driving classes etc. At our driving school,there was fuel consumption meter in all the cars (not the cars original ones,but more accurate ones) and we had to drive 2 rounds with and without using engine brake. Guess wich was better? Why? Let me tell you.
When using engine brake,the cars ecu reads that TPS shows that you dont push gas pedal,but RPM's are high and youre still moving,so it cuts off injection as it is not needed. Why it is not needed? Because your car takes the already existing power to run the engine.Just like when you push the gas,but in reverse direction. The power comes from running tires,goes through the transmission to the crankshaft and keeps it spinning.With no gas! When you press the clutch or put in neutral,the car has to keep the engine running as the power stops to the clutch. This is hard to explain in different language so hope you got what I meant. The more you use engine brake,the better.
One thing that also is taught here,is shifting. Fast acceleration to the desired speed is more economical than slow. I dont mean that you push the pedal all thw way to the floor,but slow acceleration is bad!
Also learn to jump over gears. 1,2->4,5 or,1,2,3->5. This makes a big difference!
When using engine brake,the cars ecu reads that TPS shows that you dont push gas pedal,but RPM's are high and youre still moving,so it cuts off injection as it is not needed. Why it is not needed? Because your car takes the already existing power to run the engine.Just like when you push the gas,but in reverse direction. The power comes from running tires,goes through the transmission to the crankshaft and keeps it spinning.With no gas! When you press the clutch or put in neutral,the car has to keep the engine running as the power stops to the clutch. This is hard to explain in different language so hope you got what I meant. The more you use engine brake,the better.
One thing that also is taught here,is shifting. Fast acceleration to the desired speed is more economical than slow. I dont mean that you push the pedal all thw way to the floor,but slow acceleration is bad!
Also learn to jump over gears. 1,2->4,5 or,1,2,3->5. This makes a big difference!
Last edited by antti; 06-17-2008 at 09:18 AM.
06-18-2008, 04:31 AM
#8
@antii
Here in Germany my mechanic told me on the other side to never use engine break, since it increases the wear on all parts involved, such as transmission crankcase everything. In the long run having to replace breakpads is much cheaper than if one of those parts should fail.
Here in Germany my mechanic told me on the other side to never use engine break, since it increases the wear on all parts involved, such as transmission crankcase everything. In the long run having to replace breakpads is much cheaper than if one of those parts should fail.
06-18-2008, 06:53 AM
#9
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Posts: 92
well,it harms the engine as much as regular driving,no more.Of course you dont put 1st gear in 100km/h! Just take your foot off the gas and shift lower when necessary. You'll learn. If you have high RPM's during engine break,you have too small gear.
06-18-2008, 07:52 AM
#10
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Join Date: Apr 2008
Location: Vermont
Posts: 158
Although i have no idea if its is bad, inefficient, or more efficient, I drive a CVT with Tiptronic and will drop it from auto to the tippy when i would normally use a downshift. I dont actually downshift, but when you pop it from auto to tippy it seems to drop a 'gear' on its own.
I am used to driving automatics with push button overdrive, i have used this for years when i would normally downshift. Not sure if thats bad for it but o well.
I am used to driving automatics with push button overdrive, i have used this for years when i would normally downshift. Not sure if thats bad for it but o well.
06-18-2008, 10:59 AM
#13
avoiding hard "jack-rabbit" starts has added about 50-60 miles to my 4th gen tank. i went from 320mpg (city) to about 370 before hitting the bottom line.
two tanks ago i started recording my MPG with the two driving styles. in a couple of months i will post my results with concrete figures.
basically, as a rule of thumb, i tried to keep my rpms under 2k ALL THE TIME, which means very slow starts at intersections.
two tanks ago i started recording my MPG with the two driving styles. in a couple of months i will post my results with concrete figures.
basically, as a rule of thumb, i tried to keep my rpms under 2k ALL THE TIME, which means very slow starts at intersections.
06-20-2008, 06:50 AM
#17
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Join Date: Mar 2008
Posts: 157
if thats the case then i'm prob losing about 15% 
I remember when i first got my car. First stick, first sports car...said i was getting about 17-18mpg. now it says i get about 26. driving habbits are so crucial. Got 31.4mpg on a trip to FL
I remember when i first got my car. First stick, first sports car...said i was getting about 17-18mpg. now it says i get about 26. driving habbits are so crucial. Got 31.4mpg on a trip to FL
06-23-2008, 05:51 AM
#19
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Join Date: Sep 2007
Posts: 92
No CC please. I dont know whats wrong with people who say cruise control reduces fuel consumption. Nothing beats a steady foot! In older cars CC doesnt use engine brake,but keeps the car at idle even in downhills when you could go with zero consumption..
06-23-2008, 12:16 PM
#20
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njmax, clint and 19max, thanks for the kind words and thanks for the thanks.
shady, That's all you have to say? I'm glad I spent 2+ hours putting this together to help the .org so that you can provide such a grateful and profound statement!
shady, That's all you have to say? I'm glad I spent 2+ hours putting this together to help the .org so that you can provide such a grateful and profound statement!
06-23-2008, 12:24 PM
#21
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But still theres something wrong. USE engine brake! What's wrong with you Americans? Here in Finland it is taught already in Driving school that always use engine brake! It is also taught in econimical driving classes etc. At our driving school,there was fuel consumption meter in all the cars (not the cars original ones,but more accurate ones) and we had to drive 2 rounds with and without using engine brake. Guess wich was better? Why? Let me tell you.
When using engine brake,the cars ecu reads that TPS shows that you dont push gas pedal,but RPM's are high and youre still moving,so it cuts off injection as it is not needed. Why it is not needed? Because your car takes the already existing power to run the engine.Just like when you push the gas,but in reverse direction. The power comes from running tires,goes through the transmission to the crankshaft and keeps it spinning.With no gas! When you press the clutch or put in neutral,the car has to keep the engine running as the power stops to the clutch. This is hard to explain in different language so hope you got what I meant. The more you use engine brake,the better.
One thing that also is taught here,is shifting. Fast acceleration to the desired speed is more economical than slow. I dont mean that you push the pedal all thw way to the floor,but slow acceleration is bad!
Also learn to jump over gears. 1,2->4,5 or,1,2,3->5. This makes a big difference!
When using engine brake,the cars ecu reads that TPS shows that you dont push gas pedal,but RPM's are high and youre still moving,so it cuts off injection as it is not needed. Why it is not needed? Because your car takes the already existing power to run the engine.Just like when you push the gas,but in reverse direction. The power comes from running tires,goes through the transmission to the crankshaft and keeps it spinning.With no gas! When you press the clutch or put in neutral,the car has to keep the engine running as the power stops to the clutch. This is hard to explain in different language so hope you got what I meant. The more you use engine brake,the better.
One thing that also is taught here,is shifting. Fast acceleration to the desired speed is more economical than slow. I dont mean that you push the pedal all thw way to the floor,but slow acceleration is bad!
Also learn to jump over gears. 1,2->4,5 or,1,2,3->5. This makes a big difference!
Thank you!
@antii
Here in Germany my mechanic told me on the other side to never use engine break, since it increases the wear on all parts involved, such as transmission crankcase everything. In the long run having to replace breakpads is much cheaper than if one of those parts should fail.
Here in Germany my mechanic told me on the other side to never use engine break, since it increases the wear on all parts involved, such as transmission crankcase everything. In the long run having to replace breakpads is much cheaper than if one of those parts should fail.
06-23-2008, 12:37 PM
#22
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This thread is about increasing your MPG. Combining trips does not increase your MPG. 
avoiding hard "jack-rabbit" starts has added about 50-60 miles to my 4th gen tank. i went from 320mpg (city) to about 370 before hitting the bottom line.
two tanks ago i started recording my MPG with the two driving styles. in a couple of months i will post my results with concrete figures.
basically, as a rule of thumb, i tried to keep my rpms under 2k ALL THE TIME, which means very slow starts at intersections.
two tanks ago i started recording my MPG with the two driving styles. in a couple of months i will post my results with concrete figures.
basically, as a rule of thumb, i tried to keep my rpms under 2k ALL THE TIME, which means very slow starts at intersections.
Again, glad I spent 2+ hours so that some people can make such beneficially contributing comments like this. Sure. It's an example. You be creative. But the wipers pop right off. I have no wipers, wiper motor or washer fluid tank in my '99.
Well, maybe. It might help with aerodynamics a little. But I doubt too many people would want to look at tape on their car. And I think most seams are air tight. And if they aren't sometimes it's for a reason - to let air into the engine (like some gaps around the headlights). I think most aerodynamic gains can be realized with under body paneling. But I won't go into detail here.
06-23-2008, 01:14 PM
#23
Good tips. Agree with all of them.
On the highway, I tend to drive 5MPH under (55MPH to 60MPH) on my work commute (about 80% highway). I coast to lights that are red, slowing down gradually. The light usually changes to green before I get there and I can continue without having to stop completely. Windows down around town (when weather permits) and use the AC on the highway.
Prior to these measures, I'd usually get 250 miles to the 1/4 mark on the gas guage. Post these measture, I can hit 350 every time. I've even seen 400 at the 1/4 mark on a trip from NC to De. The 3.5 with 4AT can be driven efficiently, but you have to use restraint and control.
On the highway, I tend to drive 5MPH under (55MPH to 60MPH) on my work commute (about 80% highway). I coast to lights that are red, slowing down gradually. The light usually changes to green before I get there and I can continue without having to stop completely. Windows down around town (when weather permits) and use the AC on the highway.
Prior to these measures, I'd usually get 250 miles to the 1/4 mark on the gas guage. Post these measture, I can hit 350 every time. I've even seen 400 at the 1/4 mark on a trip from NC to De. The 3.5 with 4AT can be driven efficiently, but you have to use restraint and control.
Last edited by 2002 Maxima SE; 06-23-2008 at 01:18 PM.
06-24-2008, 10:00 AM
#24
i already do almost all of these.
for the tire pressure it is more accurate to follow Nissan's PSI when cold then to fill to the Max when hot. that makes almost no sense at all. how do you know you have them at the hottest? just check them in the morning and fill to what the manual states.
The 2 I have wanted to do but would like to see more information is the weight reduction and aerodynamic under body panels. I bought polycarbonate, but hit a road block on how to install it while removing it easily for maintenance.
adding mods usually adds more weight. I used to take out my spare, but that is worth more the one time i might need it than gas saved. maybe i'll think about only leaving it in for long trips only.
Here is a tip not many think about.
WAX
may seem silly, but you will have a lot less drag with a clean and waxed surface. It also motivates you to keep her looking clean. 2 birds with one stone.
for the tire pressure it is more accurate to follow Nissan's PSI when cold then to fill to the Max when hot. that makes almost no sense at all. how do you know you have them at the hottest? just check them in the morning and fill to what the manual states.
The 2 I have wanted to do but would like to see more information is the weight reduction and aerodynamic under body panels. I bought polycarbonate, but hit a road block on how to install it while removing it easily for maintenance.
adding mods usually adds more weight. I used to take out my spare, but that is worth more the one time i might need it than gas saved. maybe i'll think about only leaving it in for long trips only.
Here is a tip not many think about.
WAX
may seem silly, but you will have a lot less drag with a clean and waxed surface. It also motivates you to keep her looking clean. 2 birds with one stone.
Last edited by NismoMax80; 07-02-2008 at 10:44 AM.
06-25-2008, 07:34 PM
#25
i say remove the spare then keep yourself stocked with like 4 cans of Fix-A-Flat. Can't go wrong with that right??
and of course, if you're doing a long trip than you could easily take the spare with you especially since you already get better gas mileage anyway. otherwise, if similar to my case you only drive in the city, or mostly in the city, go spareless and invest in a few cans of Fix-A-Flat, it's probably what i'll do. you could even just call a friend or your parents to pick up your spare at home. or get your friends to bring you their spare.
and of course, if you're doing a long trip than you could easily take the spare with you especially since you already get better gas mileage anyway. otherwise, if similar to my case you only drive in the city, or mostly in the city, go spareless and invest in a few cans of Fix-A-Flat, it's probably what i'll do. you could even just call a friend or your parents to pick up your spare at home. or get your friends to bring you their spare.
Last edited by rex3001; 06-25-2008 at 07:39 PM.
06-26-2008, 08:22 AM
#27
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Join Date: Jun 2005
Location: Philadelphia, PA
Posts: 2,898
When using engine brake,the cars ecu reads that TPS shows that you dont push gas pedal,but RPM's are high and youre still moving,so it cuts off injection as it is not needed. Why it is not needed? Because your car takes the already existing power to run the engine.Just like when you push the gas,but in reverse direction. The power comes from running tires,goes through the transmission to the crankshaft and keeps it spinning.With no gas! When you press the clutch or put in neutral,the car has to keep the engine running as the power stops to the clutch. This is hard to explain in different language so hope you got what I meant. The more you use engine brake,the better.
06-26-2008, 12:29 PM
#28
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I just got 410 miles on my trip odo before filling up. And this included towing my trailer for about 60 of those miles, lots of stopping and going and idling (house shopping), and several "high speed"/agressive runs to work (30 miles away) because I was running late, and I had the AC on almost every day. The rest of the time I followed all my rules above. This next tank I am working on now I am trying to grandma it for the whole tank to see what I can get. So far I have driven about 200 miles and am well above half a tank.
06-26-2008, 10:47 PM
#29
Cruise Control is better than a steady foot. Bumps and imperfections in the road can cause certain jumps in RPM consistency using your foot. Use Cruise Control when you can.
btw, ptatohead: great suggestions, although I still drive like I usually do. Nothings changed except for my diminishing wallet :P
btw, ptatohead: great suggestions, although I still drive like I usually do. Nothings changed except for my diminishing wallet :P
06-27-2008, 12:16 AM
#30
turn your engine off if you plan to idle more than 30-60 seconds.
06-27-2008, 09:06 AM
#31
ptatohed: combining trips helps MPG if it means your engine doesn't cool down, and therefore stays in closed-loop.
also wrt downshifting... if I am in gear and braking from >2000rpm, i can feel a "kick" at 1600rpm and the car's deceleration rate increases. That's because the fuel injectors kick back on at 1600rpm and start putting power to the wheels again, even though you are braking. this is especially noticeable in 1st, not to mention that teasing the throttle in a parking lot is WAY more violent at 1700 than 1500, due to the fact that the injectors turn off when you lift, so it shuts power off instantaneously. when coming to lights I usually DC downshift to 3rd and brake until i hit 1000rpm then clutch it into neutral. It would maybe be more efficient to put it in neutral as soon as the injectors refire at 1600 tho, because once they refire, RPM affects fuel consumption.
coyuma: you can fully press the gas pedal during a warm restart to make it start without the extra gas. just release the pedal as soon as it hits like 500 (gotta be quick)
o and my trip odo read 496 miles driven on my last tank... 30.89mpg filling up 16.??? gallons
also wrt downshifting... if I am in gear and braking from >2000rpm, i can feel a "kick" at 1600rpm and the car's deceleration rate increases. That's because the fuel injectors kick back on at 1600rpm and start putting power to the wheels again, even though you are braking. this is especially noticeable in 1st, not to mention that teasing the throttle in a parking lot is WAY more violent at 1700 than 1500, due to the fact that the injectors turn off when you lift, so it shuts power off instantaneously. when coming to lights I usually DC downshift to 3rd and brake until i hit 1000rpm then clutch it into neutral. It would maybe be more efficient to put it in neutral as soon as the injectors refire at 1600 tho, because once they refire, RPM affects fuel consumption.
coyuma: you can fully press the gas pedal during a warm restart to make it start without the extra gas. just release the pedal as soon as it hits like 500 (gotta be quick)
o and my trip odo read 496 miles driven on my last tank... 30.89mpg filling up 16.??? gallons
Last edited by CapedCadaver; 06-27-2008 at 09:09 AM.
06-27-2008, 09:35 AM
#32
I have two options for going to work. Take the highway which is about 12miles but it makes a U shape. Maybe a total of 5 lights and I usually hit 3 of them green. Or take the direct route which involves driving downtown. It is only 7miles but is alot of stop and go. Probably 10-15 lights/stop signs and I usually have to stop at atleast 10. Both routes take about 20 minutes. What should I do? I take the downtown route cause 7 miles is almost half of 12 and I doubt downtown driving knocks my 28mpg highway mileage down to 14. This question isnt really for the best MPG cause obviously thats the highway but its about the least $ to get to work.
here are my routes:
here are my routes:
Last edited by black_maxed95; 06-27-2008 at 09:39 AM.
06-27-2008, 02:57 PM
#34
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Join Date: Apr 2008
Posts: 213
just thought i would come confirm the engine braking theory. when you engine brake at a high enough RPM (1600 like someone said could be right, i dont know, but its not above 1800) the injector pulse width goes to essentially 0 (i think its actually 2ms) and your afr shoots up. i can tell you that i know this FOR A FACT, seeing as i have confirmed it via wideband O2. the afr when you engine brake shows 21:1, which is max lean. in fact the mixture is far leaner than 21:1, but you get the point. so instead of having to feed gas to the engine in order to stay at idle, it uses basically no gas. obviously, dont downshift so youre at like 5k RPM cause that probly uses the same as idle so...
and BTW, the through city route is probly better. going out of your way to get better MPG's doesnt make sense. if you could go 300 mi highway or 100 mi city to get somewhere, say you get 30mpg highway and probly 16-18 city, youre using LESS gas going the city route, even though you get worse mileage. its all about how much you use, not your mileage.
and BTW, the through city route is probly better. going out of your way to get better MPG's doesnt make sense. if you could go 300 mi highway or 100 mi city to get somewhere, say you get 30mpg highway and probly 16-18 city, youre using LESS gas going the city route, even though you get worse mileage. its all about how much you use, not your mileage.
06-28-2008, 01:38 AM
#35
you can fully press the gas pedal during a warm restart to make it start without the extra gas. just release the pedal as soon as it hits like 500 (gotta be quick)
06-29-2008, 10:35 AM
#37
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Posts: 92
just thought i would come confirm the engine braking theory. when you engine brake at a high enough RPM (1600 like someone said could be right, i dont know, but its not above 1800) the injector pulse width goes to essentially 0 (i think its actually 2ms) and your afr shoots up. i can tell you that i know this FOR A FACT, seeing as i have confirmed it via wideband O2. the afr when you engine brake shows 21:1, which is max lean. in fact the mixture is far leaner than 21:1, but you get the point. so instead of having to feed gas to the engine in order to stay at idle, it uses basically no gas. obviously, dont downshift so youre at like 5k RPM cause that probly uses the same as idle so...
and BTW, the through city route is probly better. going out of your way to get better MPG's doesnt make sense. if you could go 300 mi highway or 100 mi city to get somewhere, say you get 30mpg highway and probly 16-18 city, youre using LESS gas going the city route, even though you get worse mileage. its all about how much you use, not your mileage.
and BTW, the through city route is probly better. going out of your way to get better MPG's doesnt make sense. if you could go 300 mi highway or 100 mi city to get somewhere, say you get 30mpg highway and probly 16-18 city, youre using LESS gas going the city route, even though you get worse mileage. its all about how much you use, not your mileage.
Exactly. Engine brake really works. Its just law of physichs. You know,the car goes downhill even if the engine is not running as long as it gets a little push to get moving. Engine brake uses the same force,if the gear is on it gives the engine its power to stay running.You dont have to be a rocker scientist to get that. But this works only for "intelligent" cars. I mean ones equipped with ECU,TPS, etc.
06-29-2008, 04:54 PM
#38
well i usually complain about getting crappy mileage even on hwy...i use to get about 19-20'ish on my route to work (25 miles on hwy) but that's when i drive about 75-80 most of the way. lately i've been driving 60-65mph all the way to work and i've been getting 22-23mpg...not the greatest but better than before lol...i don't know tho...on city i still get horrible mileage (about 16-17). i drive on the slow lanes now lol and i still see people driving fast up behind me and then cutting me off but whatever, i just laugh at them wasting their gas like that lol
07-02-2008, 12:49 AM
#39
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Rad! I met my goal of 450 miles on a tank. I had 454.2 miles on my trip odo. before I filled up today. I filled up with 16.4 gallons. Mileage = 27.7 MPG. Not too bad. That is following most of my rules, but not all. My '96 Maxima. 180,000 miles. Well maintained. 70% highway. AC on almost 100% of the 450 miles. Included a weekend of carrying 4 passengers around. I always do 60 MPH on my way home but I always snooze one too many times in the morning and need to speed at 80+MPH to work. So, I'm sure I could do better if the weather was cooler (less AC) and if I could get up earlier! lol
07-02-2008, 10:39 AM
#40
check the post in my signature. more and more people are improving their MPG by making the front and underbody more aerodynamic.
i wish you would correct your advice on tire PSI. they need to be checked cold for the manufacturer's cold PSI. going below this can hurt MPG, but studies show over inflating to the MAX PSI does not benefit MPG.
i wish you would correct your advice on tire PSI. they need to be checked cold for the manufacturer's cold PSI. going below this can hurt MPG, but studies show over inflating to the MAX PSI does not benefit MPG.
Last edited by NismoMax80; 07-02-2008 at 10:45 AM.
