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Discussion Starter · #1 ·
After many different attempts, I have finally figured out how to extract all of the gas mileage I can out of my 2011 Cruze LTZ with an automatic. For starters, this car is not modified in any way and now has 14k miles on it. My best tank of gas was 41.2mpg, and y worst tank is 36.3mpg. This Cruze also has the awful transmission issues experienced by other 2011 owners with the automatic. This terrible shifting was responsible for a 4mpg decrease since it would not want to shift until 3k rpm when it was cold. So, the fix for these applications is to always drive in "Manual" mode. I found that by driving in manual mode, the car will let you shift it bewteen 1500 and 1700 rpm. By doing this, you will see a giant pickup in mpg. In this process, never use the 'downshift' feature or you will kill your mileage. Lastly, it has been determined that puting the transmission in neutral and coasting to stops is the absolute best way to conserve gas. If you concentrate on these two driving changes, you will definitely see a huge increase. To see for yourself, fill your car up, reset your AVG Fuel Economy meter, and then run that tank of gas out. Repeat this entire proccess for a few tanks (need to reset the AVG Fuel economy meter at each fill up) and you will notice that you will have drastically improved gas mileage.
 

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This terrible shifting was responsible for a 4mpg decrease since it would not want to shift until 3k rpm when it was cold. So, the fix for these applications is to always drive in "Manual" mode. I found that by driving in manual mode, the car will let you shift it bewteen 1500 and 1700 rpm. By doing this, you will see a giant pickup in mpg
Yeah I remember giving this a try. Unfortunately, if we wanted a manual, we would buy a manual car. Trifecta essentially does the same thing in 'Eco' mode, never letting it rev above 2500 RPMs unless you mash it. It rows through all the gears quickly - immediately into 2nd out the gate, 5th gear by 24 mph, and 6th gear by 33-34 mph on level terrain.

Lastly, it has been determined that puting the transmission in neutral and coasting to stops is the absolute best way to conserve gas.
This is dangerous and your car already goes into neutral when coasting. Deceleration fuel cutoff. It's also in neutral at idle. Features of the transmission....
 

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Yeah I remember giving this a try. Unfortunately, if we wanted a manual, we would buy a manual car. Trifecta essentially does the same thing in 'Eco' mode, never letting it rev above 2500 RPMs unless you mash it. It rows through all the gears quickly - immediately into 2nd out the gate, 5th gear by 24 mph, and 6th gear by 33-34 mph on level terrain.



This is dangerous and your car already goes into neutral when coasting. Deceleration fuel cutoff. It's also in neutral at idle. Features of the transmission....
Agreed with the last point. The cruze actually consumes gas when In neutral (as with all other cars). But it does not consume any gas when coasting in gear (not the same as all other cars). Don't believe me? Try resetting your avg fuel consumption while coasting in neutral and while coasting in gear. You will see a difference.
 

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Discussion Starter · #4 ·
Agreed with the last point. The cruze actually consumes gas when In neutral (as with all other cars). But it does not consume any gas when coasting in gear (not the same as all other cars). Don't believe me? Try resetting your avg fuel consumption while coasting in neutral and while coasting in gear. You will see a difference.
Negative. I have posted on this before and shown that the neutral coast is much better on gas. The trans also does not shift into neutral on decel... You can see the rpm still remain high. I have driven every way possible with this car and what I described in the original post was the only way to achieve that best mpg.
 

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Discussion Starter · #5 ·
Also, the neutral coast is not unsafe. If you know you have a stop coming up, just throw it in neutral and coast in. Definitely a huge improvement in gas mileage.
 

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This is dangerous and your car already goes into neutral when coasting. Deceleration fuel cutoff. It's also in neutral at idle. Features of the transmission....
Not on my 2012. When coasting, the engine provides braking and the transmission downshifts when the speed is within the appropriate range for each gear.
 

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Correct - Mine does the same thing if I do not put in neutral. Trust me - I have tried everything out there, and the combo I described in the original post is the ony way to conserve gas. The best opportunity to sav on gas is to shift the auto manually so that you can get the shift in before 2000rpm. Use crusie control whenever possible, and always shift into neutral if you know you have a stop comming up.
 

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Correct - Mine does the same thing if I do not put in neutral. Trust me - I have tried everything out there, and the combo I described in the original post is the ony way to conserve gas. The best opportunity to sav on gas is to shift the auto manually so that you can get the shift in before 2000rpm. Use crusie control whenever possible, and always shift into neutral if you know you have a stop comming up.
You shouldn't use cruise control except for when you're on the highway. In-town, you'll get better fuel economy if you drive with your own foot on the pedal.

Shifting in neutral is fine if you're coasting and need to continue driving, but leaving it in gear is better if you're coming to a complete stop as that will shut off the fuel injectors and allow the transmission to turn the motor over until you need to come to a stop. It saves you a very small amount of fuel, but it saves it nonetheless.

Crank your tire pressure up a bit. The 32PSI the car is set with from the factory is for comfort. If you want to keep some comfort, I'd go to about 38 or 40psi. Experiment and see which works best for you. Your tires will not wear unevenly, they will be at less of a danger to explode with higher pressures, you'll have no consequence in stopping distance, and will actually have better hydroplaning resistance. Fuel economy will go up and you'll get significantly more mileage out of your tires. Just make sure to keep them rotated at 5,000, which is what tire companies require anyway to honor warranties.

If you haven't yet, check out the link in my signature titled "How to Get Better Fuel Economy."

Was the mileage you measured in your original post according to the DIC or what you calculated by hand at the pump?
 

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Negative. I have posted on this before and shown that the neutral coast is much better on gas. The trans also does not shift into neutral on decel... You can see the rpm still remain high. I have driven every way possible with this car and what I described in the original post was the only way to achieve that best mpg.
Yes of course the transmission stays in gear while coasting because it needs to turn over the engine as no fuel is being fed to the cylinders to burn. If it went into neutral and no fuel was being fed the engine would stall. It's a simple principal. Coasting in gear: no fuel burned, stays in gear to turn engine. Coasting in neutral: small amount of fuel burned, engine not connected to wheels therefore nothing to keep it running but fuel and combustion.
 

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I can also get my DIC to average high 30s and low 40s for an entire tank without using any of these methods.

Being at 3K RPMs does not burn a lot of fuel unless you are using a high throttle position to get there....If you are light on the throttle you will get good mileage, don't worry so much about the tach.

Also, never shift into neutral while coasting. You lose the benefit of DFCO and you also can't move should an erroneous driver head your direction. What are you going to do, rev at them?

If you are willing to sacrifice a healthy spine I agree, raise your TPs. ;-) Personally, I think hydroplaning is a hoot so I roll with 20 psi all day (jk).

One other thing, go 60 instead of 70, good for 7 MPG on the highway for me....ouch.
 

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does anyone on here have any tips/basic knowledge for driving in manual mode on an auto car? ive tried looking it up but havent found anything and im afraid ill mess something up with the transmission. i know when to shift up but when should i downshift if coming to a stop? any other basic tips would be helpful
 

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does anyone on here have any tips/basic knowledge for driving in manual mode on an auto car? ive tried looking it up but havent found anything and im afraid ill mess something up with the transmission. i know when to shift up but when should i downshift if coming to a stop? any other basic tips would be helpful
Yeah, heres a tip, don't do it. Buy the trifecta tune.. it will shift early enough. If you want a manual car buy a manual car.

But for real advice - You don't have to downshift at all. The car will naturally downshift in manual mode once you reach the "lower limit" of the gear paramenters.
 

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Yeah, heres a tip, don't do it. Buy the trifecta tune.. it will shift early enough. If you want a manual car buy a manual car.

But for real advice - You don't have to downshift at all. The car will naturally downshift in manual mode once you reach the "lower limit" of the gear paramenters.
Thanks, i would get a manual but i didnt exactly buy this car myself, my dad bought it for himself then decided it wasnt for him so luckily i was going to college so i got the car. And as you can tell by my fuelly, my LTZ isnt exactly getting great gas right now so i could use all the help to save money on gas. Thanks though ill look into the tune
 

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Slow down, 65 mph max, never over 2500 rpms taking off, you will see 5-7 more mpg.
 
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I llike your comment, "If we wanted a manual, we would buy a manual." Great line! I like to trust my brother who is a certified jet engine mechanic and a commercial pilot on a 747-400. He advises that, with few exceptions, the design of an engine and its instructions that come with it should be adhered to. The Cruze AT, ECO, was designed with very specific performance in mind and we, as drivers, should drive them using the designed and computer-programmed software as is. Driving habits may need to change for better mileage but not driving in manual mode all the time or coasting in neutral. That won't help.
 

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For economy and daily driving, keeping the transmission in auto mode can't be beat. Best economy will happen that way and it's very difficult to match that by manually shifting. For fun and some driving situations such as a long, steep downhill where shifting down helps maintain speed, manual is preferred.
 

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I llike your comment, "If we wanted a manual, we would buy a manual." Great line! I like to trust my brother who is a certified jet engine mechanic and a commercial pilot on a 747-400. He advises that, with few exceptions, the design of an engine and its instructions that come with it should be adhered to. The Cruze AT, ECO, was designed with very specific performance in mind and we, as drivers, should drive them using the designed and computer-programmed software as is. Driving habits may need to change for better mileage but not driving in manual mode all the time or coasting in neutral. That won't help.
...it's easier to "re-train" pilots than to "re-train" jet engines (ha,ha)!
 

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does anyone on here have any tips/basic knowledge for driving in manual mode on an auto car? ive tried looking it up but havent found anything and im afraid ill mess something up with the transmission. i know when to shift up but when should i downshift if coming to a stop? any other basic tips would be helpful
You can't mess any thing up because the car won't let you. The most you can do is forget you are in manual mode and rev the rpms up because you forgot you needed to up shift. As for tips, I up shift as soon as possible (1500 rpms). I don't like to let it get above 2000 rpms. Keep it in the highest gear possible. Let the car do all of the down shifting. I have also found that in town if your speed is just a tad too slow to get the car into 6th gear you can you can usually give it a quick rev. When it is above 1500 rpms it will let you to put it in 6th. It will usually stay in 6th till you slow down.
 
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