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How to Get Better Fuel Economy

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227K views 469 replies 100 participants last post by  snowwy66 
#1 · (Edited by Moderator)
Go back to COMG- The Cruze Owner's Maintenance Guide


I wrote this up for another forum I'm on and figured it would be a good basic write-up for this community as well.

How to Get Better Fuel Economy

So I've had my Cruze Eco for about a month and a half now and I've made it a game to see how high of a fuel economy I can get. I drive 75%-90% city driving and manage 36-40mpg on a car rated for 28mpg in-town. I've picked up a few tricks, techniques, and methods along the way which, in light of the expected gas prices this summer, might benefit some of you who want to save a few bucks.

As of the time of writing, I was able to (with my Cruze Eco MT) manage 39.8MPG in my last tank of gas with 80% city driving, and my current tank of gas shows 46.1MPG on the DIC with 170 miles driven at 75% city driving, which is consistently 1.5-2.0mpg too optimistic. I expect 43-44mpg at the next fill-up. Consider that the car is rated for 28mpg city, 42mpg highway. These methods work.



Mechanical


Lets start with the simple stuff; mechanical. The behavioral techniques I'll mention later will be useless if your car has mechanical issues.

A. Tire pressure/Tires. This should be obvious, but some people are too lazy or they just forget. I'm guilty of this. I spent 3 months chasing down a condition in which my car pulled ever so slightly to the right. I only realized when I put snow tires on that one of the tires was low. Facepalm. If you're buying new tires, narrower tires are better than wider tires for fuel economy. Lower rolling resistance, less air drag.

Tire's should be inflated according to the manufacturer suggestion. I say suggestion because its just that; a suggestion. This is a number that is provided for a "best compromise" situation. A lower tire pressure will soften the ride and provide better dry traction, but will cause more heat due to rolling resistance and reduce fuel economy. Too low of a tire pressure can result in catastrophic failure. A higher tire pressure will stiffen the ride and may compromise dry traction, but will improve fuel economy as much as 3-4mpg.

Tires can be safely inflated to their maximum sidewall pressure without any danger of catastrophic failure, as this is set by the manufacturer of the tire. Reports on cleanmpg.com forums indicate that tire life is also greatly extended when tires are inflated beyond the car manufacturer's suggested pressure. Most people who inflate to the sidewall recommended pressure end up replacing their tires due to dry rot well past the tire's warranty mileage, not due to balding, loss of tread depth, or uneven tire wear. It is up to you to determine what the best pressure is for your tires based on the information provided in this section.

B. Mechanical maintenance. This isn't so obvious, but it should be considered. If your fuel economy flat out sucks, something is wrong. Spark plugs/wires and O2 sensors do go bad after a while and need to be replaced. MAF sensors need to be cleaned (CAREFULLY or with a MAF cleaner aerosol can), and a good seafoam wouldn't hurt either. Air and fuel filters are a given. 180 degree thermostats might be nice for performance, but 195 and 215 degree thermostats will get you better fuel economy. If you have a bad wheel bearing or a dragging brake caliper, get it fixed.

C. Fuel/Engine Maintenance. Do not waste your money on mid grade or premium fuel unless you know for a fact it has a lower ethanol content. Higher octane fuel in a N/A low compression motor is a complete waste of money and may even reduce your fuel economy. The opposite is true if you have a boosted motor. Using lower onctane fuel can not only damage your engine, but will pull timing and consequently reduce efficiency. With regard to the Cruze, it has been noted that going up to midgrade or premium fuel will increase fuel economy. I can personally vouch for the truth of this claim and do recommend the use of midgrade or premium fuel in the Cruze.

If you use top tier fuel, it will have detergent additives that claim to allow your fuel to burn cleaner and leave fewer carbon deposits. This is more of a long-term fuel economy technique, as carbon build up will reduce the efficiency of your motor. While porting some cylinder heads on a V12 Jaguar motor, I snapped a photo of one of the valves so you could see what carbon buildup looks like. This had 160k miles on it.



It is highly recommended that you keep your fuel and intake system maintained with fuel system cleaners and intake cleaners such as seafoam that help clean the engine from carbon deposits so it doesn't get as bad as the above picture.

D. Weight. Chances are, you don't need all that junk in your trunk. Less weight means you use less energy to get moving. Your car is not your closet.

E. Brakes. If your car pulls to one side or the other and you've checked the tire pressure and alignment make sure you don't have one or more brakes dragging.



Behavioral

Once your car is running in its optimal conditions and you're getting "decent" fuel economy, we can move on to some behavioral techniques.

A. Turn off your heater. In the winter, if its not unbearably cold, suck it up and leave the heater off till the car warms up. The reason for this is that the car will run in open loop until it reaches ~160 degrees F. During this time, the engine's PCM will ignore some of its sensors (including the MAF) and run rich until it has warmed up enough for the sensors to all be functioning correctly. If you run the heater while the car is dumping fuel to try to warm up, you're just prolonging the time during which it stays in open loop mode and wasting additional fuel. This is because the heater core essentially acts like a radiator through which you're forcing cold air. It may not sound like it, but it does make a significant difference. You can turn the heater back on once you've reached ~180 degrees F.

B. Watch your RPMs. You'll burn more fuel if you accelerate more "spiritedly." Your shift points in an automatic will naturally be quite limited, but your throttle won't be. For manual transmissions, try to get into your highest gears as soon as possible. To use my Cruze as an example, I shift into 2nd gear as soon as possible, hit 2000RPM in 2nd, then keep RPMs below 1500 from 3rd through 6th gear. I'm in 5th gear at 35mph and 6th gear at 40mph, cruising at 1100RPM, quite literally sipping on fuel. Since I know this is easier said than done, here's a method you can use. Pretend there's slushy snow on the ground and accelerate accordingly. If a few people pass you, no big deal. The difference in a few car lengths will be mere seconds added to reaching your destination.

C. Watch your speed. 70mph might get you there 1-2 minutes faster, but you'll burn a lot more fuel. The ideal speed for fuel economy for most cars seems to be 55-65mph. Going from 65 to 75mph drops my fuel economy by 10mpg considering I'm pushing 55mpg at 65mph, and this is a car with several aerodynamic and drag-reducing features. Think of your car as a brick on wheels. It takes exponentially more fuel to cruise for each incremental increase in speed.

D. Turn cruise control off. Unless the road is completely flat. This applies mostly to in-town and back-road driving, as interstate highways/freeways will be limited to smaller and longer grades during which cruise control is fine to use. Your car will automatically adjust throttle to keep the car going about the same speed when it reaches a hill, which isn't ideal for fuel economy. Accelerate lightly before approaching a hill, allow the car to decelerate while climbing the hill, and accelerate lightly as you're going down the hill to get back up to speed. Of course, this only applies to smaller hills, but the concept is still there.

E. Conserve Energy. This one is a complete change in the way some of you drive in-town. Some of you will follow the car in front of you blindly or drive the same speed and slam on the brakes when the light had been red for a while. Every time you accelerate, you use fuel, which turns into energy. As your car is moving, it is carrying energy. That moving energy is lost (wasted) whenever you step on the brakes. So, how does one drive to keep from wasting energy? Let me give you an example scenario. I used google maps for this.



Above is one of the routes I take to get home every day. In the above picture, you'll see a left turn lane as well as a main lane, with peoples' brakes on, as the light is red. Imagine your speed is 45mph as this is a 45mph zone. What most people will do is follow the car in front of them regardless of what the traffic light is. What I do is let off the gas the moment I see a red light at that kind of distance. If the light stays red, I'll have coasted to 25-30mph before I have to hit the brakes. This increases the life of my brake pads and I'll have been in the same position as if I had followed closely and hit the brakes as hard as the person in front of me.

However, what happens 50% of the time is different. Usually, I'll see a red light at this distance, get off the throttle, and coast at a lower speed, and by the time I get closer to the intersection, the light will have turned green and the cars will have started moving. Here's the critical moment. By the time I reach the car directly in front of me, it will have accelerated to 15, maybe 20mph, and I will be able to continue moving at that speed instead of coming to a complete stop. That's 20mph of moving energy I did not lose by watching what was happening in front of me and driving accordingly. If I had followed the car in front of me more closely, I will have come to a complete stop and immediately have to accelerate again from a complete stop. This driving style requires you to fully understand that in 60 seconds, you will be in the exact same position whether you keep a constant speed until you have to brake and come to a complete stop, or cruise without using fuel and reach the intersection at a later time. The fact that it takes you longer to reach the intersection means that the cars are likely to have started moving by then, and you will have lost less moving energy in the process, and used less fuel. You will feel like you're moving slower, but you will notice that you will always be near the cars around you and thus will have lost no time.

Here are some questions you can ask yourself.
1. Could I have avoided coming to a complete stop?
2. Could I have predicted what would happen in front of me?
3. Was it necessary for me to keep a constant speed?

F. Have a Manual Transmission? Keep the transmission in gear while coasting to a stop. So long as you're above idle, the engine will actually shut off the fuel injectors and allow the transmission to turn the motor over, using zero fuel. While automatics will also do this, you have greater control with the manual. Don't put it in neutral when coming to a stop, leave it in gear until your RPM drops low enough to need to shift out of a gear.

G. Choose your route wisely. If you have several stops to make during a single drive and are not limited on time with regard to when you get there, drive to the farthest destination first, then work your way back. Otherwise, you may never allow the car to reach optimal operating temperature.

H. Don't idle. Your car doesn't actually need to warm up for minutes when you first start it up before you leave. This only applied to older vehicles that needed a substantial amount of time to allow oil to circulate and to fill the hydraulic lifters and is not an issue with newer cars. Get on the road soon after you start your car. If you're waiting for someone, turn your car off until they get there. Basically, unless you're moving or know you will be moving soon, turn the car off.

Here are things you should NOT do to increase fuel economy.
A. Drafting (closely following) a truck. People love doing it, but its not only unsafe, but also illegal. You're a pain in the ass of any truck driver because they can't see you, and you have zero time to react to debris that gets shot in your direction out from under truck tires. Trucks will kick up rocks and shoot them into your front fascia and windshield. Not only does it ruin your paint, but it can also crack your windshield. I've seen a truck kick up a broken hammer head that someone lost on the side of the road. Take a guess as to what happens if that comes flying toward your windshield at 70mph. I'll give you a hint; it doens't bounce off like a pebble. However, following an SUV or a Van at a safe distance is a good alternative.

B. Using higher octane fuel. Its useless and will not improve your fuel economy unless you're boosted or your car has a higher static compression from the factory (e.g. Northstar V8). This applies to the 1.8L, but not the 1.4L Turbo in the Cruze. The 1.4L Turbo motor benefits from higher octane fuel.

C. Driving significantly under the speed limit or accelerating like you were down a few cylinders. This makes you a road hazard. Drive the speed limit or 5 over (that's what they teach kids in my area) unless you expect to come to a complete stop or are approaching a small hill.
 
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#2 ·
Cliff notes: Maintain your car and don't drive like a d0uche :)

I too let off the gas as soon as I see break lights or a light change. What cracks me up is the ricers that slam the gas at a light and 10 seconds later I pull up right next to them at the next light. Or the guy weaving in and out of traffic on the freeway and 8 miles later i'm sitting behind him at our exit.

Props for taking the time to write that though.
 
#14 ·
cliff notes: Maintain your car and don't drive like a d0uche :)

i too let off the gas as soon as i see break lights or a light change. What cracks me up is the ricers that slam the gas at a light and 10 seconds later i pull up right next to them at the next light. Or the guy weaving in and out of traffic on the freeway and 8 miles later i'm sitting behind him at our exit.

Props for taking the time to write that though.
^^^this is me as well^^^^^
 
#3 · (Edited)
We appreciate the the write-up! Thanks. This is quality stuff everyoe!

There a few things that aren't based on fact though...

C. Fuel. Use Top Tier gasoline.

With regard to the Cruze, it has been noted that going up to midgrade or premium fuel will increase fuel economy. I can personally vouch for the truth of this claim and do recommend the use of midgrade or premium fuel in the Cruze.
These two. Top Tier gasoline generally is good, but there is no proof that it actually gives you better fuel mileage. Everyone has fuel preference. My car HATED Exxon and loved Sunoco. However, Sunoco is actually not top tier. What gives?

And there is still no hard evidence that premium fuel on the 1.4T = better gas mileage. This was 100% not true for me and several other users. There is no scientific evidence for this whatsoever, since octane is not connected at all to fuel consumption. There are 2 plausible explanations for this:

A) The premium fuel at some smaller market stations probably has a lower ethanol content.. or in contrast the lower octane regular fuel has even higher ethanol than it is supposed to :(

B) The "placebo effect." There is a general consensus that the Cruze 1.4T runs smoother premium fuel. Myself and other users have complained of hesitation under heavy acceleration using heavy fuel. If this is the case, the car is more responsive to most people, and thus easier to drive more efficiently.

D. Turn cruise control off - unless the road is completely flat. Your car will automatically adjust throttle to keep the car going about the same speed when it reaches a hill, which isn't ideal for fuel economy. Accelerate lightly before approaching a hill, allow the car to decelerate while climbing the hill, and accelerate lightly as you're going down the hill to get back up to speed. Of course, this only applies to smaller hills, but the concept is still there.
I'm a stickler for cruise control. People just need to be mindful of what hills actually are. Backroads typically have a ton of them and that is fine and dandy.. but interstate highways.. they don't exist enough to make it worth turning off the cruise control. The 6% grade limitation makes for some very long ascents and descents, so the dfco technique isn't nearly as beneficial as it should be in theory due to how much of an affect drag and rolling friction will have in the process (which is amplified by high speed travel).
 
#4 · (Edited)
We appreciate the the write-up! Thanks. This is quality stuff everyoe!

There a few things that aren't based on fact though...



These two. Top Tier gasoline generally is good, but there is no proof that it actually gives you better fuel mileage. Everyone has fuel preference. My car HATED Exxon and loved Sunoco. However, Sunoco is actually not top tier. What gives?

And there is still no hard evidence that premium fuel on the 1.4T = better gas mileage. This was 100% not true for me and several other users. There is no scientific evidence for this whatsoever, since octane is not connected at all to fuel consumption. There are 2 plausible explanations for this:

A) The premium fuel at some smaller market stations probably has a lower ethanol content.. or in contrast the lower octane regular fuel has even higher ethanol than it is supposed to :(

B) The "placebo effect." There is a general consensus that the Cruze 1.4T runs smoother premium fuel. Myself and other users have complained of hesitation under heavy acceleration using heavy fuel. If this is the case, the car is more responsive to most people, and thus easier to drive more efficiently.



I'm a stickler for cruise control. People just need to be mindful of what hills actually are. Backroads typically have a ton of them and that is fine and dandy.. but interstate highways.. they don't exist enough to make it worth turning off the cruise control. The 6% grade limitation makes for some very long ascents and descents, so the dfco technique isn't nearly as beneficial as it should be in theory due to how much of an affect drag and rolling friction will have in the process (which is amplified by high speed travel).
I'll explain why I said some of what I did. I tried not to make it too extremely long.

With regard to the fuel grade, I personally noticed a smoother running car with the 89 "midgrade" octane than with 87 octane in low RPM acceleration, which is all I ever do. 80% of my driving is done between 1100 and 15000 RPM. I guess you're right in that its not fact, but enough people have reported this, and people with the ability to scan for knock have proven that these engines will retard timing with 87 octane. For fuel economy, spark advance is our best friend. That, and I'm seeing a ~4mpg improvement from my previous tank according to the DIC with identical driving to and from work after filling up with 89 octane, having done nothing differently.

With regard to top tiers, I'll update that. I think the core of what I was trying to get across is engine maintenance, whether its top tier fuel with additives or a seafoam every few thousand miles to remove carbon deposits, its really all the same.

I will update the post to clarify the point about cruise control. I had intended it to refer to in-town driving.
 
#5 · (Edited)
Overall good post. Yes, it's crazy where you see people accelerating to and racing to red lights. Your engine's done all this work to accelerate you and you're throwing it all away by using the brakes. Then, you're sitting there idling, getting 0 mpg.

I think you should add a couple things, mainly focused on reducing useless idling (such as the above). Examples: not sitting around to let the engine warm up (just go, but be gentle on the accelerator on a cold engine), not using drive thrus esp. if there's a long line, parking face out (backing in or pulling straight ahead into a spot so that you're facing out) and shutting of your engine before coming to a stop in a parking spot.

When I last had a non-hybrid, I shut my engine off (aka FAS) and coast into the spot. Once stopped, I THEN shift into park and turn the key to lock. Almost all automatic drivers pull into a spot, stop, shift from D to P, then shut off their car. Well, that's extra useless engine runtime. Car's getting 0 mpg that whole time.

Parking facing out can be super helpful if you're in a very busy parking lot where everyone's leaving at once (e.g. sporting events). Your fuel consumption is high w/a cold engine, right after you've started, so you can minimize that by being ready to go and facing out w/a better view. Your fuel consumption is lower when you park as the engine should be warmed up by then..

To steal from Beating the EPA - The Why’s and How to Hypermile - CleanMPG Forums (which has some good tips along w/some that aren't the safest or legal. Article on Gerdes at This Guy Can Get 59 MPG in a Plain Old Accord. Beat That, Punk. | Mother Jones.)
Drive to your farthest destination first and then as you are heading home, stop at the closer destinations in order from furthest to closest as the car is warmed up for longer portions of your drive.
If you do the opposite, your engine may never get fully warmed up, then it cools down, and is wasting fuel each time, trying to warm up.

Regarding lower rolling resistance tires, one Priuschatter has been compiling info on LRR tires and Tirerack.com tire tests (http://priuschat.com/forums/gen-iii...esistance-replacement-tires-current-list.html and http://priuschat.com/forums/gen-ii-prius-fuel-economy/98592-new-tire-tests-tiarerack-com.html). If you just buy any random tire as a replacement, there's a good chance it might not be very low in rolling resistance.
 
#8 · (Edited)
Overall good post. Yes, it's crazy where you see people accelerating to and racing to red lights. Your engine's done all this work to accelerate you and you're throwing it all away by using the brakes. Then, you're sitting there idling, getting 0 mpg.

I think you should add a couple things, mainly focused on reducing useless idling (such as the above). Examples: not sitting around to let the engine warm up (just go, but be gentle on the accelerator on a cold engine), not using drive thrus esp. if there's a long line, parking face out (backing in or pulling straight ahead into a spot so that you're facing out) and shutting of your engine before coming to a stop in a parking spot.

When I last had a non-hybrid, I shut my engine off (aka FAS) and coast into the spot. Once stopped, I THEN shift into park and turn the key to lock. Almost all automatic drivers pull into a spot, stop, shift from D to P, then shut off their car. Well, that's extra useless engine runtime. Car's getting 0 mpg that whole time.

Parking facing out can be super helpful if you're in a very busy parking lot where everyone's leaving at once (e.g. sporting events). Your fuel consumption is high w/a cold engine, right after you've started, so you can minimize that by being ready to go and facing out w/a better view. Your fuel consumption is lower when you park as the engine should be warmed up by then..

To steal from Beating the EPA - The Why’s and How to Hypermile - CleanMPG Forums (which has some good tips along w/some that aren't the safest or legal. Article on Gerdes at This Guy Can Get 59 MPG in a Plain Old Accord. Beat That, Punk. | Mother Jones.)

If you do the opposite, your engine may never get fully warmed up, then it cools down, and is wasting fuel each time, trying to warm up.

Regarding lower rolling resistance tires, one Priuschatter has been compiling info on LRR tires and Tirerack.com tire tests (Low Rolling Resistance replacement tires: Current List - PriusChat Forums and New Tire Tests from Tirerack.com - PriusChat Forums). If you just buy any random tire as a replacement, there's a good chance it might not be very low in rolling resistance.
FAS is something that most people will not be willing to consider. I've read the above article and I believe some of the advanced techniques are not reasonable for daily commuting. FAS for example will wear out your starter, and starters are not particularly cheap to replace. I will add a note about not sitting around to let the car warm up or idle.

With regard to LRR tires, these are not for everyone. Their low rolling resistance compromises other attributes of the tire, such as traction and road noise. I personally don't mind them, but someone else might. They do also seem to carry a higher cost, making one wonder if they actually do save you money. The stock tires on the Cruze Eco are about $144 apiece on tirerack. By comparison, you can get a great all-season tire for between $105-$120 in the same size. At 4 tires, that's a difference of at least $100. How many miles do you have to drive on a set of LRR tires to save $100, and is it worth the compromises? That's a discussion for another day, but my point is that this article was intended to be a list of simple techniques that everyone can use that don't require any significant compromises or significant additional effort on the driver's part.

With regards to your item C are you saying higher octane will help in the 1.4 turbo?--Mike
Yes. I have experienced it, and others have verified it with knock scanning on this car. It will run smoother and get better fuel economy for a small increase in price. There's a 14+ page thread around here about it. When the engine's PCM detects knock, it will retard timing. This Knock retard (KR) is noticeable and definitely causes a reduction in power and therefore efficiency.

Xtreme Revolution, really good post! Good information, and for those up to speed on these things, still really good reminders.

My wife and I have always gotten above our car and truck's EPA/manufacturing fuel average ratings, and a lot of it has to do with exactly what you posted. We don't drive conservatively-- going 7 mph over speed limit when safe, but do what you have suggested. Two other good ones are planning your trip (if you have multiple stops) to do the longest trip first, as you car will get up to its efficient temperature rating better than if you have multiple short stops first -- with your car not ever getting up to temperature. In this regard, I have two vehicles which tell me oil temperature (by degree) and even on a moderately warm day, it takes over 5 miles for the car to fully warm up. Also, if possible, we plan our route to reduce as many left turns as possible (waiting to make that turn burns fuel).

Thanks Xtreme!
Thanks! The above is a good point, which I will also add when I get more time to update the main post, hopefully later today. I'm trying to keep this a simple guide. Some people may have additional things they do, such as avoiding left turns, but those require additional effort on the driver's part. I fully support them, but I don't think they are in the scope of this article. I would certainly be open to compiling an additional article with more advanced techniques based on what you and cwerdna have suggested for those who want to go the extra mile.
 
#7 ·
Xtreme Revolution, really good post! Good information, and for those up to speed on these things, still really good reminders.

My wife and I have always gotten above our car and truck's EPA/manufacturing fuel average ratings, and a lot of it has to do with exactly what you posted. We don't drive conservatively-- going 7 mph over speed limit when safe, but do what you have suggested. Two other good ones are planning your trip (if you have multiple stops) to do the longest trip first, as you car will get up to its efficient temperature rating better than if you have multiple short stops first -- with your car not ever getting up to temperature. In this regard, I have two vehicles which tell me oil temperature (by degree) and even on a moderately warm day, it takes over 5 miles for the car to fully warm up. Also, if possible, we plan our route to reduce as many left turns as possible (waiting to make that turn burns fuel).

Thanks Xtreme!
 
#9 · (Edited)
A friend of mine from the w-body.com forum made this post, which I thought would be very beneficial:

the "manual coast down in gear" thing? applies to all engines, ever. carb/FI/DI/diesel/etc.

when you coast down while in gear, if you have a vacuum gauge you'll notice it can almost peg the meter at 30" in the right situations. LOTS of vacuum means very little air is actually flowing through the engine since the throttle is blocking **** near the entire supply. very little airflow means very little fuel flow.

now, when fuel injection started getting phased in, one of the first things that also caught on was DFCO(decel fuel cut off), which means that in extreme situations, fuel flow is cutoff entirely and the motion transmitted via the road/tires/drivetrain are what is turning over the engine. this applies to both manual and auto trans vehicles. jump on the highway, get up to ~70MPH in 4th gear(assuming a 4T60 or something like it), then force a downshift into third, hold 70MPH for at least another couple seconds, then remove your foot completely from the throttle. you'll notice you will slow down naturally (engine braking), and that after a short delay if you had a way of monitoring injector pulsewidth, it will drop to 0 and the engine will still be turning over at a decent speed.

once you drop to a low enough speed, not enough energy will be transferred back to the engine and your RPM will be low to the point of where the PCM kicks the fuel injectors back on. with a good calibration, most if not all of this is relatively seamless.



so, yes, chalk this one up to the "fact" category.
 
#13 ·
lol, count me as part of that too. I averaged 17-19mpg with my old car...80% highway driving. Supercharged 3800 with headers and a smaller pulley was a little too much fun. Still is, but not as a commuter car.

Its become a bit of a game for me to see how high I can get the fuel economy numbers.

Thanks by the way. I completely agree that GM should print something like this and put it in every new car. I've met people who have absolutely no idea how to drive more efficiently, even if they wanted to.
 
#16 · (Edited)
I've spent a while on CleanMPG.com forums and have learned a few things about tire pressure.

It seems that the most significant reason why tires need replacing when worn is due to the outer edges wearing more quickly than the inner, likely attributed to the front wheels turning. This is while using manufacturer recommended tire pressures.

The problem people on CleanMPG forums have is that their tires last too long when "overinflated" (compared to manufacturer spec) and they start to dry rot before they get fully worn down. People are pulling 60-100k miles on tires rated for 45k and are replacing them due to age, not wear. There is also reportedly even wear when over-inflating tires, which makes one of the points I made earlier invalid.

It turns out that tires never really blow from being "overinflated", but rather from being "underinflated" or very old, and that the only real determents are traction and ride quality.

If no one has any objections, I will update the initial post to reflect these findings.
 
#18 ·
I disagree about throwing it into neutral. I have an automatic LTZ and I still throw my car into neutral when I know a stop is coming up. This has positively increased my mpg from 31mpg to 33mpg.
Also, I have a 2010 Cadillac CTS-V with a 6spd manual and operate the same way. That car sees gas mileage in the 21-24mpg range. That is very fair for a 550 rwhp / 533 rwtq car!! Throwing it into neutral is your friend!
 
#19 ·
I disagree about throwing it into neutral. I have an automatic LTZ and I still throw my car into neutral when I know a stop is coming up. This has positively increased my mpg from 31mpg to 33mpg.
You are doing yourself a disservice sir. Not only is this extremely dangerous, but your car already does this. Taken from a website:

"One additional feature new to the 6T40 automatic is an idle-neutral mode. When the vehicle comes to a stop, the transmission automatically goes into Neutral and then re-engages the gear when the brake is released."

If your doing that coming to a stop... your car also has deceleration fuel cut off, another feature already thought of. That is not the cause of your fuel mileage bump, sorry.
 
#20 ·
Behavioral

Once your car is running in its optimal conditions and you're getting "decent" fuel economy, we can move on to some behavioral techniques.

A. Turn off your heater. In the winter, if its not unbearably cold, suck it up and leave the heater off till the car warms up. The reason for this is that the car will run in open loop until it reaches ~160 degrees F. During this time, the engine's PCM will ignore some of its sensors (including the MAF) and run rich until it has warmed up enough for the sensors to all be functioning correctly. If you run the heater while the car is dumping fuel to try to warm up, you're just prolonging the time during which it stays in open loop mode and wasting additional fuel. This is because the heater core essentially acts like a radiator through which you're forcing cold air. It may not sound like it, but it does make a significant difference. You can turn the heater back on once you've reached ~180 degrees F.

My question:

This question is for those of you with an additional mounted numeric graduated water temperature gauge-better than the OEM, or plug in diagnostic tool. From a cold start, for the 1.4L ECO engine, can you tell us what graduation marks on the OEM gauge does 160 Deg. F & 180 Deg. F equal(on the OEM, 4 marks is ¼ the way, 8 marks is ½ the way, etc..)?

Also, at full running temperature, my OEM gauge shows a hair width before the 7[SUP]th[/SUP] mark and stays there in any condition. What actual water temperature range is this?
 
#22 ·
greatr info, I hate my cruze for its mpg, 32 max, but it did improve when I started using premium fuel. I accelerate like a dead grandma and am often honked at, but it still doesn't help mpg. I tried letting the gas go and cruising to a light, but it doesn't slow down fast enough. With gas prices rising, I ma go back to regular. Anyone wanna buy a cruze? I bought this thing for better mpg and it is the same, probably worse than my 09 altima was.
 
#23 ·
What's your typical route to work and back? Miles, type of driving, speed you're driving, etc. What's your tire pressure? Auto or manual trans?

You're averaging 29.6 Its not a Cruze Eco and its not a Prius, and you'll need to get used to that. An 09 Altima will not average 29.6mpg. Most people with the 4-cyl Altima average 25-26mpg on fuelly.com.
 
#24 ·
My commute is about 17 miles each way, 3 blocks of which are city, the rest highway. I live in Texas and the highway is very hilly. I coast with the downhills when I can, . I average between 60-66 mph, speed limit is 65mph. The dealership overfilled my tires after a recent oil change, so they're 34psi. I drive a 2011 cruze 1.4t auto 2LT. I say my altima was better, but I never used fuelly before my cruze, I'm just estimating by how much money I spent on gas and how often I filled up.
 
#25 ·
I guess technically, my tires are overfilled too as they all read 35psi.

Very hilly is going to kill your fuel economy no matter how you look at it. Going over one hill and coming back down the same hill will not be equivalent to going straight on the same route, as you use additional fuel just getting up that hill.

My fuel economy might look impressive, but I have an Eco Manual and most of my driving is done at 45-55mph. I call it city driving, but its technically "in-town" driving, where I have a few longer lengths of road where I can maintain that speed for a few minutes.

Here's a bit of advice I can give you. Get your tires inflated to 40psi. Rotate them every 8-10k miles. They should exceed their treadwear rating easily. This will allow you to maintain your speed better while coasting down those hills.

Bypass the factory air intake resonator and put a drop-in K&N filter in there if you want to spend the $50. This will further improve fuel economy whether or not you get the K&N filter. You'll be limited to how well you can do, but hills really do suck your fuel economy down pretty badly. Increasing tire pressure and bypassing the intake resonator should give you a few more miles per gallon.
 
#26 ·
Thanks. I'll give it a look. I had a CAi, but didn't see much improvement in mpg, so I took it off, now selling it. There is a straighter shot to work, but it would take me an extra 20 minutes to get to work on that 45mph stretch. how do I bypass the factory intake resonator, and will that void my warranty?
 
#28 ·
Doesn't void your warranty. Remove the air intake duct directly underneath the airbox. Once you get the airbox out, you'll know what I mean.

Or, put your intake back in as a SRI. Seems your fuel economy is pretty close to what most people are getting with their Cruze. 30mpg is seriously not bad.
 
#30 ·
Thought I would through my 2 cents in I filled up with sunoco ultra for the first time and my MPG went from 27.5 to 31.3 on this tank driving same times and same route to work. I only get 365 miles out of the tank on REG when light comes on I have 390 miles on the ultra tank still no light cant believe it made that much of a difference in MPG let alone throttle response. Don't know if its worth the extra money paid 3.65 gallon for ultra verse 3.46 for REG. 2011 1.4 turbo auto LTZ drop in K&N that's it for mods.
 
#34 ·
65 on the highway? cruise control on hills? those both sound like bad ideas, and worse when combined. Also, we rarely go below 50 degrees in South Texas. I'll try it next week. I'm soon to trade this thing in and grab something that'll actually save me money at the pump.
 
#36 ·
I'm not trying to be an ass, but you sound more resentful than anything and you're not willing to consider that your circumstances are causing your fuel economy to drop and that they will stay the same regardless of what car you drive unless its a hybrid. If you think 30MPG average is not saving you money at the pump, perhaps you should look at buying a Prius.

Don't expect to be getting better fuel economy with an Altima. I mentioned it since you think you're getting worse than your old Altima did. The numbers aren't looking good according to fueleconomy.gov or fuelly.com.

Gas Mileage of 2012 Nissan Altima

Cruise control was recommended on hills because highway grades are not steep or short enough to provide any benefit by driving it with your own foot. They're both actually good ideas on the highway.

So many variables could be affecting your fuel economy that its not even funny. Even the type of gas you're using could have a 3-4mpg difference on your fuel economy. Do you drive this car elsewhere on the weekends in town? Do you drive in stop and go traffic? Any of those will take a big hit on your fuel economy.
 
#35 · (Edited)
Looks like maybe I'll have to start experimenting with "top tier" gas and maybe mid-grade or premium fuel to see if my mileage goes up. It does confound me that using mid-grade or premium in a 4 cyl. engine should not be necessary to get better mileage. Would I need a few tanks to see if there is a difference? I just put all my gas mileage data into Fuelly since 2/14/11 when I got the car. You can see that my mileage is not great. Some of it is highway, but most is local with not a lot of stop and go or hills.
 
#37 ·
Looks like maybe I'll have to start experimenting with "top tier" gas and maybe mid-grade or premium fuel to see if my mileage goes up. It does confound me that using mid-grade or premium in a 4 cyl. engine should not be necessary to get better mileage. Would I need a few tanks to see if there is a difference? I just put all my gas mileage date into Fuelly since 2/14/11 when I got the car. You can see that my mileage is not great. Some of it is highway, but most is local with not a lot of stop and go or hills.
Keep in mind, the number of cylinders mean nothing when considering a car's fuel octane. It might be a 4-cyl, but it has a turbo and its dynamic compression is much higher than your typical N/A 4-cyl motor.

Many factors will determine what kind of fuel economy you get.
 
#39 · (Edited)
Extreme
I just went through my first tank using your shifting techniques. I do 95% city driving @ mostly 25mph speed zones whith constant stop signs/lights.but I do get to 35mph areas which make the biggest difference.
The way I use to drive was keeping the rpms @ 1500-2000 while cruising; shifting @3k.
I was averaging 28-29mpg on DIC.
320miles per fill up @11 gallons

When I started the test I made sure i only filled up till the first click on the gas handle.to keep it as close to 12.6 without going over. since i know my Eco has 3 more gallons of room in the tank.

fueling up again, I calculated 32mpg(not DIC) which gave me an extra 33 miles to the tank353 miles @11 gallons.

Well you saved me $4 so far :)
With a 10% gain in miles per tank

Sent from iPhone 4
 
#40 ·
Here's another tip - when you visit a fast food restaurant, don't use the drive thru. Why run the engine at 0MPH when ordering and waiting? I have found that most fast food restaurants are just as fast inside as out. In addition, you can't use the bathroom from the drive thru lane.

Also, what does "FAS" mean? I saw it in several posts and couldn't figure it out.

I just taught a teenager to drive. I stressed following distance (two seconds is hard to maintain) should be such that you never have to use your brakes for small changes in speed. If you're on your breaks frequently other than for stop signs and lights, you're simply following too close.
 
#63 ·
Here's another tip - when you visit a fast food restaurant, don't use the drive thru. Why run the engine at 0MPH when ordering and waiting? I have found that most fast food restaurants are just as fast inside as out. In addition, you can't use the bathroom from the drive thru lane.

Also, what does "FAS" mean? I saw it in several posts and couldn't figure it out.
Yep, reduce the amount of useless idling. You're getting 0 mpg doing that, w/the ICE uselessly idling away.

FAS = Forced Auto Stop aka shutting off your engine. I think it makes perfect sense to FAS a non-hybrid while pulling forward into a parking spot, esp. one where you'll be facing outwards. That's better than leaving it running, stopping, shifting to park and then shutting off the engine that 99.9% of automatic drivers do.
 
#41 · (Edited)
Forced Auto Stop, term used for driving with the car off (like down hills, off ramps).
Don't do it! A life is not worth fuel savings.

I always turn of my car at drive troughs. Usually only 2 start UPS needed. If its a long line, I choose something else to eat.

Also, not sure if you taught your teen the 2 second rule my counting after car in front passed a mark but I think a car length would be easier to remember. Not too much more or you'll have someone jump in between which will make you slam on your breaks.
 
#42 ·
I taught him both the two second rule and how to tell if you're following two closely via the brake check usage. He knows if someone jumps in front of him he needs to reset his following distance for the new car. I also taught him to watch not only the car in front of him, but also the cars next to him and behind him. If the car behind is too close he knows to back off the car in front. He's also been taught to watch as far in front as he can see - it's amazing how many times you can avoid brake usage simply by noticing that four or five cars in front has tapped their brakes.

For anyone with a teen getting started, I highly recommend having them go through a driving school that does skid pad training (MasterDrive in Denver does). The first time he started sliding on US 6 (Loveland Pass in Colorado) he not only didn't panic but he kept the car in the driving lane. If you're interested in fuel economy, don't let him drive your ECO - the turbo will get a lot of work.
 
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