# 2nd gen real world MPG



## firehawk618 (Feb 24, 2013)

I looked through the top 4 pages on this sub forum and found no active topics.

For those that track it what kind of economy are you seeing in the 2nd gen diesels?

If I missed a relevant thread please link it.

Thanks.


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## johnmo (Mar 2, 2017)

My fuelly history is in my sig.

I just completed my first 800-mile tank this week. The range calculation was estimating that it had 860 or so miles before empty and the refill after that tank wasn't the biggest one I've done.

I'm very happy with the fuel economy.


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## MRO1791 (Sep 2, 2016)

I have a 2017 Auto, and a 2018 manual. The manual has about 1000 miles more, and has a bit more long trip highway miles. The lifetime averages are manual: 45.6MPG, auto: 44.6MPG. with more highway I expect the auto would come out about the same, it has a lower final drive ratio than the manual. I've been very impressed with both. I've had tanks on each that were averages over 50MPG. On a long drive, 55MPG or more is very possible. All with great acceleration and plenty of power. I also have a 2015 diesel. It's lifetime average for about 42k miles: 38.9MPG, and that is also pretty darn good. 

Sent from my Moto G (4) using Tapatalk


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## ganthc (May 25, 2018)

I am only on my second tank of fuel for my 2018 Cruze Diesel HB (9A). My first tank went 514 miles with the computer saying it was 40mpg in mixed driving in the DC area. I am on my second tank of fuel now, and I am still getting 40mpg in mixed driving. I have about 650 miles on the car right now. Onstar has my lifetime fuel mileage at 39.8mpg. That is pretty dang good, and I am happy with it. I was around 29-30mpg with my 2013 Chevy Sonic 1.8L (6A) in mixed driving, with nowhere near the torque power I have in this car. 

I will be taking a road trip from DC to Austin, TX, to visit family. I will update my fuel mileage from that trip. I'm looking forward to getting around 55-56mpg with straight highway driving.


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## firehawk618 (Feb 24, 2013)

Wow great feedback! I am most likely going to pick up a 2018 Cruze hatch diesel with the auto.

I just bought a 17' Volt in January and do like the car however plugging it in at work is getting old for various reasons and there's a few other reasons I might take a bath and get the Cruze. The Cruze is the reason I went car shopping last Jan and ended up in the Volt.


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## rry3158652 (Jan 23, 2018)

I get a pretty consistent 44 mpg mixed driving, 2018 CTD Hatchback, auto. 11k, Very happy with mpg and throttle response.


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## BodhiBenz1987 (Jan 13, 2018)

I have a 6-speed manual sedan with 3,700 miles on it. My economy history is also in my sig, current lifetime mpg is just under 55 mpg and that includes quite a bit of local driving (stop lights, stop-and-go traffic) with occasionally highway runs of about 25-40 miles in between, and a few purely highway trips (my "commute" highway runs tend to include routine traffic jams). Last month I took a trip to Cincinnati and back from Delaware, filled up when I left and did not need to fill up again until pretty far into the way back home at over 750 miles on the tank, and could easily have made it to 800 miles. I filled up a final time once I got home at the same station I began with. The result was an average of 66 mpg for the whole 1,200-mile trip ... almost all highway about 60-70 mph, but also driving in and out of Cincinnati downtown, and poking through horse-and-buggy country at the very end of the trip. With local driving I'm usually in the mid-40s, a bit lower if it's really a lot of stopping and going, but as soon as I do a highway run it pulls the average up ... the "best 25" meter hits 70 mpg during a lot of runs. I hope I get a chance at another proper road trip to see if I can duplicate those results from the Cincinnati trip. Worth noting I have other cars so this one doesn't get ALL of the short, mpg-damaging local runs, but I do use it for some of that so the numbers reflect probably a pretty even mix, maybe a little more highway than local especially considering that long trip accounting for much of the lifetime miles.


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## lbkNhubert (May 18, 2017)

For those of you easily hitting 50mpg or higher averages, what is your typical drive in terms of duration, elevation changes, speed, and so on? My best ever tank average is 57.8mpg, that was fully highway, one 30 minute long traffci jam, 52mph average, with minimal elevation changes. When I am running around town a lot (5-10 mile trips), I struggle to hit 40mpg, only pulling above that for a tank with longer (60 mile each way) runs on errands, with moderate elevation changes. I'm amazed at your averages and genuinely curious if I am doing something that is pulling mine down. For reference, I don't tend to floor it from stops, and I coast downhill in gear when feasible. I will drive about 8-9 mph over the posted limit on the highway, so on anything above 55mph areas that hurts the average. 6sp manual. My all-time average over 19500 miles is 47.1mpg, which I am happy with, but wondering if I can do anything to bump it up.


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## BodhiBenz1987 (Jan 13, 2018)

lbkNhubert said:


> For those of you easily hitting 50mpg or higher averages, what is your typical drive in terms of duration, elevation changes, speed, and so on? My best ever tank average is 57.8mpg, that was fully highway, one 30 minute long traffci jam, 52mph average, with minimal elevation changes. When I am running around town a lot (5-10 mile trips), I struggle to hit 40mpg, only pulling above that for a tank with longer (60 mile each way) runs on errands, with moderate elevation changes. I'm amazed at your averages and genuinely curious if I am doing something that is pulling mine down. For reference, I don't tend to floor it from stops, and I coast downhill in gear when feasible. I will drive about 8-9 mph over the posted limit on the highway, so on anything above 55mph areas that hurts the average. 6sp manual. My all-time average over 19500 miles is 47.1mpg, which I am happy with, but wondering if I can do anything to bump it up.


For me I think it's just that I don't tend to go long periods without any highway, and even some of my local drives involve decent little stretches where I can go 50 mph for a while. I very rarely drive in actual city conditions ... I see plenty of stoplights and annoying creeping traffic but usually at least a little open space between them. Elevation-wise, not a lot of hills around me, and pretty flat to Philadelphia which is my most common semi-highway destination, but I did a ton of mountains on the Cincinnati trip I mentioned. I start to hit big rural hills when I go to my parents house about half hour from me, but it's hard to isolate how the mileage is in the short time I'm there. My normal tanks seem to always end up in the vicinity of 50 mpg, as opposed to the bonkers ones I had with extended highway driving. If I'm doing a lot of local stuff I see "best 25" go to like 38 mpg, even a bit lower. If I didn't throw in those 30-mile highway runs here and there I suspect my overall average would be a fair bit lower. And I think it will get lower as time goes on, to be honest, because over the long run I'll probably do more local, and it's still benefiting from my big road trip as a big part of the lifetime avg. We'll see.

One thing I'll note is that I think I actually see better mpg numbers around 65 mph than under 60. Yesterday I drove a 30-mile stretch of highway where everyone was flying, and I was running late, so I was over 75 mph and close to 80 the whole way ... when I got off the highway my "last 25" was 68 mpg. When I usually go to Philly I'm probably around 65 mph, sometimes slowing a bit to 60, sometimes speeding up to 70 to keep with traffic ... when I get off the highway there, as long as there's been no traffic stoppages, I'll see those 70 mpg "last 25" numbers. So I feel like I find that sweet spot in the 60-70 mpg range, and I do tend to be very aware of momentum ... using downgrades to give me momentum heading into the ups. For what it's worth I almost never use cruise control, unless my foot hurts on a long trip and needs a rest.


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## 14'ecocruze (Nov 18, 2016)

BodhiBenz1987 said:


> So I feel like I find that sweet spot in the 60-70 mpg range, and I do tend to be very aware of momentum ... using downgrades to give me momentum heading into the ups. For what it's worth I almost never use cruise control, unless my foot hurts on a long trip and needs a rest.


Have been following this post to see if I should have waited for a diesel but haven't found many that push their cars for mpg. I typically push 50 throughout the warm months with gas. Guess if 60 is achievable it could have paid for itself. 20% increase in efficiency is pretty sound. Thanks for sharing.


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## BodhiBenz1987 (Jan 13, 2018)

14'ecocruze said:


> Have been following this post to see if I should have waited for a diesel but haven't found many that push their cars for mpg. I typically push 50 throughout the warm months with gas. Guess if 60 is achievable it could have paid for itself. 20% increase in efficiency is pretty sound. Thanks for sharing.


I'm always impressed with the numbers I've seen people getting in the gas Ecos. For a modern, non-hybrid, gas car in the US, over 50 is pretty awesome. It's kind of like they're European-market cars that Chevy just decided to share with us. Both the Eco and diesels ... you don't really see the kind of numbers they get from cars in the US.


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## 14'ecocruze (Nov 18, 2016)

I am on ecomodder but don't do much of anything for mods other than the grill blocks. Just drive like a grandpa lol. It pays off seeing as I typically smash the highway rating for my car by 8+ mpg in warm weather. Winter here in Wisconsin is rough on the little motor. On top of winter blend. Only have a 5 mile work commute and just barley make it to 50 mpg on my drives now. Not sure how a diesel would hold up to that. 
I must say that people drive terrible. I plan on keeping my cruze to 200k+ if nobody can sway me to desel. I don't plan on having to replace brake pads until after 200k miles. Brake dust is lost mpgs!


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## johnmo (Mar 2, 2017)

lbkNhubert said:


> For those of you easily hitting 50mpg or higher averages, what is your typical drive in terms of duration, elevation changes, speed, and so on?


My daily commute is a few miles over 100 plus 6 or 8 miles at lunch most days. I see a bit of everything -- it's all highway, but there's about 8 miles of rural highway with stoplights and a little congestion through a retail area. I can time the lights a little when traffic isn't too bad. About 10 or 12 miles is interstate, but it's hilly and my rolling average MPG usually drops on that part of the run. It's all hilly. If it was flat ground I don't think I'd ever average less than 60 MPG.


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## IPhantom (Aug 22, 2017)

BodhiBenz1987 said:


> It's kind of like they're European-market cars that Chevy just decided to share with us.


That's exactly what happened. Now that GM sold Opel it will look very grim for compacts / mid size's under a GM badge in future.


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## mr overkill (Dec 1, 2013)

my 50 mile average is typically in the mid 50s on the way to work and mid 40s back home (traffic)


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## pjdvd24 (Feb 28, 2018)

2017 AT Sedan 7500 miles so far. 160 mile daily commute with 99% highway in flat-ish Ohio. lifetime avg mpg is 52 and typical cruise speed is 72mph. Best tank is 56 mpg. Exceeding expectations with the AT.


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## rfhbrando (Oct 31, 2017)

My 2017 diesel manual has 26k miles on it. I drive 70mi one way to Pittsburgh every day. Lifetime mpg is 49 but this summer I have been seeing between 51 - 55 mpg per tank depending on traffic, etc. 65 of the 70 mile trip is highway with cruise control set at 73 mph. I think if I had a relatively flat road and were going 60 mph I could squeeze 58 mpg, maybe... but that's just not what I have to work with. Still, I'm happy with low 50s, better than my old commuter Hemi that does about 14.


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## SilverCruzer (Nov 30, 2010)

51.9 mpg, 76.7 miles.

My total commute to and from work earlier this week. Mostly flat commute, 1/3 stop and go, temperature (most important part) mid-70's. Warm enough for low density, not too hot so no AC.
Usually in the summer this is around 44 mpg, winter much less. In any case, this was WAY better than in my Gen 1.


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## firehawk618 (Feb 24, 2013)

So far at 600 miles I'm averaging around 42. My 25 mile each way commute is mostly gradual inclines on the freeway to work and mostly down hill on the way back.


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## blackbird (Nov 6, 2017)

I'm up to about 5k miles on my 6-speed manual '18 hatch. Measured economy hasn't been bad but it's not that great either. With the worse aerodynamics of the hatch and the larger 18" wheels of the RS package (standard on the manual hatches), I've been averaging about 38 mpg over a tank in mixed driving. That's slightly worse than my first-gen '14 diesel in the exact same mix of driving which does about 40 mpg.

On the few multi-hour highway trips I've taken the second gen car seems to be averaging about 42-45 mpg while the same trips in the first-gen yield about 45-48 mpg.

I will add a caveat that the second-gen car has had electrical/vacuum problems since delivery and is undergoing the lemon law buyback process right now, but assuming the problems aren't impacting economy it seems to be getting pretty close to the official EPA ratings and perhaps slightly better around town, whereas the first-gen almost exactly matches the city rating in worst-case scenarios but with any highway miles mixed in it easily beats the EPA combined and highway ratings.


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## ponyboy (May 18, 2018)

I think your numbers might not be due to any issues with your car as I am getting the EXACT same with a 2018 manual hatch that has had no problems (other than the alignment being off which was fixed today). In my short part town part highway daily commute I get like 34-35 mpg which is not that great. On longer highway stretches I'm getting like 45. The best I've ever gotten was 53 for 50 miles on the interstate in flat Ohio, but I haven't come close to that since. 

I think a lot of the issue is how I'm driving the car, since I don't try very hard to drive efficiently. It seems the upshift recommendation is also straight up wrong as lugging the engine uses way more fuel than cruising at like 2200 rpm.



blackbird said:


> I'm up to about 5k miles on my 6-speed manual '18 hatch. Measured economy hasn't been bad but it's not that great either. With the worse aerodynamics of the hatch and the larger 18" wheels of the RS package (standard on the manual hatches), I've been averaging about 38 mpg over a tank in mixed driving. That's slightly worse than my first-gen '14 diesel in the exact same mix of driving which does about 40 mpg.
> 
> On the few multi-hour highway trips I've taken the second gen car seems to be averaging about 42-45 mpg while the same trips in the first-gen yield about 45-48 mpg.
> 
> I will add a caveat that the second-gen car has had electrical/vacuum problems since delivery and is undergoing the lemon law buyback process right now, but assuming the problems aren't impacting economy it seems to be getting pretty close to the official EPA ratings and perhaps slightly better around town, whereas the first-gen almost exactly matches the city rating in worst-case scenarios but with any highway miles mixed in it easily beats the EPA combined and highway ratings.


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## DarylB (Feb 3, 2011)

Just picked up a 2018 Cruze TD manual this weekend. (Prior owner of a 2011 Eco). From San Antonio back to Little Rock, no fill ups. DIC showed approx 52.4 mpg, hand calc'd I got 50.4. This was driving hard, 80mph + stop and go on I35. Very impressed.


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## rcruze (Mar 22, 2018)

I have a 2018 Manual TD, my best 50 miles average so far is 64 mpg. I get 59-60 mpg on the way to work and 55-59 on the way home. I go from hills to flat land in the morning and flat back to hills on my way home. 99% lifetime highway driving with 20K miles and rising.


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## Rivergoer (Mar 30, 2017)

Well done! Kickin’ butt on the Gen 1...any of you second-gen’ers hitting 60 mpg for an entire tank?


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## johnmo (Mar 2, 2017)

Rivergoer said:


> Well done! Kickin’ butt on the Gen 1...any of you second-gen’ers hitting 60 mpg for an entire tank?


Four times so far plus one at 59.6 MPG. Lots and lots of high 50s. Only 9 tanks out of 57 below the 52 MPG EPA highway rating.

If life and traffic don't interfere, I could probably hit 60 MPG on a tank at will, but it's a weeklong commitment and sometimes I just want to set the cruise control and not think about the throttle position for 2 hours a day for 8 days.


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## BodhiBenz1987 (Jan 13, 2018)

Rivergoer said:


> Well done! Kickin’ butt on the Gen 1...any of you second-gen’ers hitting 60 mpg for an entire tank?


Yes, had a tank of 65 mpg, 758 miles. Then had a half-tank of 68 mpg before that trip ended. Total 66 mpg for 1,100 miles, Delaware to Cincinnati and back. Those are hand calculations. Just drove to Boston and back (689 miles) ... DIC (usually about 1.5 mpg low) said 60.7 for the trip, but my hand calculation said 66 mpg. I feel something may be off with the hand calculation. Filled up at literally the same pump start and finish and double-checked my numbers, but I'm dubious because usually the DIC isn't THAT off, and also this wasn't nearly as smooth a trip as the Cincinnati one ... more traffic and had to go through NYC which is an mpg-sucker, plus it was 100 degrees both ways. Still I am guessing based on previous DIC vs. reality ratios, I did at least 62. I'll probably find out how accurate the hand calc was next time I fill out ... if it was a short tank it'll come up low next time. Either way super impressive ... Delaware to Boston and back, no need to fill up and had estimated range showing at 130 miles left at the end.


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## firehawk618 (Feb 24, 2013)

Crazy. I'm around 40. Car in sig.

It's gotta be the constant changes in elevations around here.


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## BodhiBenz1987 (Jan 13, 2018)

firehawk618 said:


> Crazy. I'm around 40. Car in sig.
> 
> It's gotta be the constant changes in elevations around here.


From most of the (few) reports I've seen the hatches just don't seem to hit the numbers the sedans do. One thing I'd be really curious to see would be if someone swapped the smaller sedan wheels onto a hatch, would it improve mpg? I know some of it is aerodynamics but it'd be interesting to see the wheel factor equalized. 

Big elevations changes probably make it hard to get in a groove too. Most of my normal driving is pretty flat. My long trips have had some mountains and hills but mixed in with flat. I've always paid attention to mpg in my other cars and enjoyed trying to get good numbers, but never paid so much attention as I do now to all the little factors ... these cars are making me fascinated with it. Not sure if it's a good thing lol.


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## firehawk618 (Feb 24, 2013)

Good points you bring up.

I also wonder if the RS with the bigger wheels has a different shift algorithm. I would like mine to shift sooner. It seems to want to stay in a lower gear vs what I would like it to do although I suppose this is a moot point when on the highway. My car will get into 9th at right around 60mph and stay there unless I really get on the throttle.


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## Diesel4Ever (May 30, 2018)

Diesels are always more efficient in warmer weather.

Also, hot 100+ degree air has a lower density and is thinner. This makes a significant difference in freeway travel as wind drag is the primary load on the engine.

Wind resistance is exponential, there is 4x more WR at 75 mph than 55 mph.

Drafting 3-4 car-lengths behind a high profile truck, suv, van or bus will also boost MPGs due to reduced drag and WR. You can get even closer, however it gets dangerous as your visibility and reaction time is is reduced the closer you get.

It’s relatively easy to boost you MPGs 20% or more by keeping speed reasonable and drafting.


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## BodhiBenz1987 (Jan 13, 2018)

Diesel4Ever said:


> Diesels are always more efficient in warmer weather.
> 
> Also, hot 100+ degree air has a lower density and is thinner. This makes a significant difference in freeway travel as wind drag is the primary load on the engine.
> 
> ...


I was thinking at that temperature engine performance would not be optimal as far as intake air ... but maybe that would affect power and not efficiency ... or maybe I'm wrong altogether. I mean obviously I assumed there is some optimal temperature but I would have thought more like 80. Had not really thought about the air temp effect on aerodynamics though; I suppose it being humid would help in that case too. What about need for A/C? Per the DIC A/C was using .08 gal/hour, over a 12-hour drive that adds up (not sure I believe it's that much though). I.e., is the drag benefit at 100 degrees better enough than at 70 degrees to offset the fact I need no A/C at all at 70 degrees?

As far as drafting, that's something I'm sure I benefit from in spurts because whether you want to or not you end up behind trucks on the interstate. But I draw the line at tailing one intentionally for that purpose ... just not worth it safety-wise. Plus I only have so much patience.

Reasonable speed is probably my best weapon because mpg in mind or not, I just tend to be a right-lane speed-limit-or-slightly-above type. Not always. But enough.

How much do you think weight in car counts? Enough that driver weight, or adding a passenger and luggage weight is relevant?


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## Diesel4Ever (May 30, 2018)

BodhiBenz1987 said:


> I was thinking at that temperature engine performance would not be optimal as far as intake air ... but maybe that would affect power and not efficiency ... or maybe I'm wrong altogether. I mean obviously I assumed there is some optimal temperature but I would have thought more like 80. Had not really thought about the air temp effect on aerodynamics though; I suppose it being humid would help in that case too. What about need for A/C? Per the DIC A/C was using .08 gal/hour, over a 12-hour drive that adds up (not sure I believe it's that much though). I.e., is the drag benefit at 100 degrees better enough than at 70 degrees to offset the fact I need no A/C at all at 70 degrees?


Cold, boosted intake air is denser and contains more oxygen which is beneficial for making HP. 

Theoretically, diesels are heat engines. They convert heat into work. More heat = more work. However modern diesels are choked by emissions system which reduce their efficiency to limit Nox production. Hotter intake air also will slightly advance fuel ignition timing by reducing delay which is a benefit as well. 

Air temp and density is also governed by elevation. 100F air in Denver, CO will be thinner than 100F air in Death Valley, CA. 

I do not believe Relative Humidity has any significant effect on engine efficiency, as water stays as a gas phase throughout the combustion process. I also don't believe RH influences aerodynamic drag. RH does effect thermal loading on A/C though, as the water vapor adds latent heat to the evaporator which must be removed to cool the air. So high RH will require extra HP on the A/C compressor to make the interior comfortable which will increase fuel consumption.



BodhiBenz1987 said:


> As far as drafting, that's something I'm sure I benefit from in spurts because whether you want to or not you end up behind trucks on the interstate. But I draw the line at tailing one intentionally for that purpose ... just not worth it safety-wise. Plus I only have so much patience.


When I said "truck" for drafting, I meant either a pickup truck or box truck. Ideally, a 2wd full size pickup with a camper shell. Lifted 4wd trucks are not good drafting as air is forced under the front end and will cause turbulence and drag. Semis and big-rigs typically drive too slow and throw up rocks and debris. It's not a good idea to draft behind and 18 wheeler, however it works. One time in southern Texas I drafted behind an 18 wheeler traveling over 100+ MPH for a couple hours. I was in a late '90s integra and I averaged over 40+ MPG on that tank as I was essentially travelling at a high speed in a partial vacuum with very low wind resistance.

The perfect vehicle for drafting is a high roof van or bus. MB Sprinter, Promaster, Transit, Etc all are very common, great wind blockers and typically travel at 70 MPH +. 



BodhiBenz1987 said:


> Reasonable speed is probably my best weapon because mpg in mind or not, I just tend to be a right-lane speed-limit-or-slightly-above type. Not always. But enough.
> 
> How much do you think weight in car counts? Enough that driver weight, or adding a passenger and luggage weight is relevant?


Weight is a factor, which is compounded by grade. Climbing a hill, weight will influence fuel consumption more so than driving on flat terrain. Going downhill, extra mass will cause additional acceleration. However diesels and electric motors usually have extra torque so weight is less of a factor than if it were a gasoline engine.

I forgot to mention, Diesel fuel quality is another factor which can increase your MPGs. Diesel cetane values of 50-55 CN have been shown to increase engine efficiency, power and enhance combustion. There are also some organo-metallic additives like Ferrous/Ferric Picrate which act as combustion catalysts. I've used the traditional additives like 2-EHN and aromatic hydrocarbons and documented a small increase in MPGs. Never tried the metallic type, so can't comment on those.

By using these techniques and information it is possible to get excellent fuel economy, even while still travelling at a high rate of speed. I've been doing it for years and I think it fun, kinda like a game.


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## BodhiBenz1987 (Jan 13, 2018)

Diesel4Ever said:


> I do not believe Relative Humidity has any significant effect on engine efficiency, as water stays as a gas phase throughout the combustion process. I also don't believe RH influences aerodynamic drag. RH does effect thermal loading on A/C though, as the water vapor adds latent heat to the evaporator which must be removed to cool the air. So high RH will require extra HP on the A/C compressor to make the interior comfortable which will increase fuel consumption.


I was thinking of it in terms of drag ... I believe humid air is less dense, and density would effect drag ... but I guess that's also relative to viscosity which is higher I would assume. Unfortunately I chose English as a major despite being good at math and science as a kid, and now my brain just doesn't grasp stuff like this. If you don't use it, you lose it, I guess, ha.

For sure it's kind of fun, and I do like trying to challenge my mpg marks. I do try to stay behind a Sprinter if I get one that's going at a speed I can do so reasonably and safely ... anything that's a big box and not high off the ground I figure is pretty good. I just don't have time to focus it on it 100% of a lengthy trip. And on highway commutes it's hard to focus on it. It would be neat to see what kind of tank I could get if I did. Per the DIC I've had a few 50-mile or even longer stretches at 70+ mpg. Unfortunately I don't have many chances at substantial roads trips. No more planned this year, but maybe something will come up.


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## Rivergoer (Mar 30, 2017)

Not a fan of drafting for safety reasons. 

My best MPG results have come when I’ve been able to:

- plan for favorable winds
- avoid traffic (travel early in the morning or late at night)
- steer clear of construction zones
- minimize stops (push 3-4 hours between stops)

AC, hills and weight, while they are indeed factors, seem to be minimal compared to the above influences.

By far tailwind and lower speeds are the biggest positive factors. Headwinds, as well as speeds above 60 mph, are MPG killers.


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## firehawk618 (Feb 24, 2013)

Well for some reason my car shows a 25 mile high of 50.1 mpg now. It was stuck at 46 for a while.

I changed nothing. Didn't try to increase economy. Didn't drive a different route to work.

I have no idea why it suddenly gained.

I have a feeling over time my real hand calculated average will increase slightly from the ~40 I'm seeing now.


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## MRO1791 (Sep 2, 2016)

firehawk618 said:


> Well for some reason my car shows a 25 mile high of 50.1 mpg now. It was stuck at 46 for a while.
> 
> I changed nothing. Didn't try to increase economy. Didn't drive a different route to work.
> 
> ...


Any change in fuel? Not all Diesel will get the same MPG. 

Sent from my Moto G (5) Plus using Tapatalk


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## firehawk618 (Feb 24, 2013)

MRO1791 said:


> Any change in fuel? Not all Diesel will get the same MPG.
> 
> Sent from my Moto G (5) Plus using Tapatalk


So far both my fill ups have been at the same station. I have no idea if blends have changed.

I was thinking that perhaps some regens have been cutting into it.

I have a Scan gauge due to be delivered tomorrow so I can monitor it.

I have a nice Snap-On Solus that can look at all the soot stuff but it's very inconvenient to carry in the car and monitor with. I do not like the idea of leaving it in the car unattended ever.

Maybe when the car sat at the dealer and accumulated the 100 miles it had when I bought it those miles were LOTS of very short cold start trips causing high soot load in a very short time.

Just a thought I had.

EDIT: Also, I need to be consistent when filling the car. I need to either fill to the first cut off or go ahead and trickle fill it to the top of the filler neck.

I want to say the first fill up I didn't go to the top and the second I did squeeze more in but not to the top.

I'll pick one method and stick with it to get a better idea of what's going on when hand calculating. Otherwise hand calculating could be off ~8% pretty easily however even if I were inconsistent it wouldn't matter much over time because it would all average out.


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## MRO1791 (Sep 2, 2016)

firehawk618 said:


> So far both my fill ups have been at the same station.  I have no idea if blends have changed.
> 
> I was thinking that perhaps some regens have been cutting into it.
> 
> ...


For gen 2, fill up with the slowest setting on the nozzle. When it automatically stops, slowly add another 1 to 1.5 gallons. That will get you a full tank, and it's pretty consistent with my 2 gen 2 diesels. It's very likely the 100 miles from the deal were short test drives, which starts you off at a lower average, that would also explain some of the increase, as well as engine break in, which normally causes an increase in efficiency as well.

Sent from my Moto G (5) Plus using Tapatalk


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## Rivergoer (Mar 30, 2017)

Yep, regens suck down diesel without generating any power in return so mpg suffers. City driving DOES affect regen interval. I’ve seen regens on the Scan Gauge at 900 miles (all highway) and 350 miles (all city).

There’s definitely lots of room for hand-calc error if not topped completely full. I always top off and pretty consistently get another 3 gallons in after the pump clicks off (Gen 1). That adds another 120-150 miles of range between fill-ups.


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## firehawk618 (Feb 24, 2013)

I just looked in the PCM and it looks like my car has only done 2 regens so far and i'm sitting at about 1700 miles. It shows the average mileage between regens to be around 800 which seems about right considering it's done 2 in 1700 miles.

It does log all this stuff for the dealer in case they need data which IMO is a great tool for troubleshooting.

It appears these logs and histories cannot be deleted out of the PCM without an advanced scan tool at a minimum.

I was thinking about doing a forced regen right before I fill up to make sure I get a whole tank with no regen just to see what the car could do......


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## johnmo (Mar 2, 2017)

firehawk618 said:


> I was thinking about doing a forced regen right before I fill up to make sure I get a whole tank with no regen just to see what the car could do......


It's so frustrating when you've committed to more than a week of throttle micromanagement to get 800+ miles out of a tank and you see your instant MPG drop into the 30s on a stretch of road where you normally see 70+.

What's even worse is when that regen hits during the last 100 miles of your remaining range and you suddenly go from stretching it another day to I guess I'm filling up on the way home tonight.


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## firehawk618 (Feb 24, 2013)

Yes that would suck.

I cannot do that. I don't have the patience.

If you get a Scangauge you can gauge when to expect a regen.


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## blackbird (Nov 6, 2017)

BodhiBenz1987 said:


> From most of the (few) reports I've seen the hatches just don't seem to hit the numbers the sedans do. One thing I'd be really curious to see would be if someone swapped the smaller sedan wheels onto a hatch, would it improve mpg? I know some of it is aerodynamics but it'd be interesting to see the wheel factor equalized.


I was thinking the same thing, but then remembered the automatic hatches don't include the RS package with bigger wheels as standard, and those hatches also seem to be down on average mileage compared to the sedans. While they very likely do contribute to the lower mileage, it may just primarily the extra drag that's common on most hatches compared to sedans.




firehawk618 said:


> I just looked in the PCM and it looks like my car has only done 2 regens so far and i'm sitting at about 1700 miles. It shows the average mileage between regens to be around 800 which seems about right considering it's done 2 in 1700 miles.


You got me curious since I haven't checked since the car was newer. I pulled out my OTC scan tool and checked and I'm at 13 regen cycles in just under 6k miles. That means about every 460 miles, which seems to be once per tank and about what I've noticed when watching the fuel economy trend drop to mid-20s for about 15 miles in around 30 minutes for the cycle to complete driving slower speeds.


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## firehawk618 (Feb 24, 2013)

blackbird said:


> I was thinking the same thing, but then remembered the automatic hatches don't include the RS package with bigger wheels and standard, and those hatches also seem to be down on average mileage compared to the sedans. While they very likely do contribute to the lower mileage, it may just primarily the extra drag that's common on most hatches compared to sedans.


I may be reading this wrong but my Auto hatch has the RS package.





blackbird said:


> You got me curious since I haven't checked since the car was newer. I pulled out my OTC scan tool and checked and I'm at 13 regen cycles in just under 6k miles. That means about every 460 miles, which seems to be once per tank and about what I've noticed when watching the fuel economy trend drop to mid-20s for about 15 miles in around 30 minutes for the cycle to complete driving slower speeds.



I can look later but there is a parameter showing the number of seconds it took to complete the regen. I don't remember if this reading is the lasts regen or average seconds per regen.

If it matters my driving is 85% highway. That may explain the 8xx miles between the 2 regens so far on my car however when I bought it new it had ~100 miles and almost certainly a bunch of short drive cold starts which would add a bunch of soot to the DPF much sooner than full drive cycles would.


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## blackbird (Nov 6, 2017)

Sorry, typo. Edited now and should have read that the bigger wheel/tires are optional on the automatic RS hatches. Kind of odd choice but who knows the reasons. Maybe GM didn't want them affecting the economy numbers as much as the manual cars.

With my OTC Genisys I'd have to scrub through the other logging options, but under the exhaust emission section it shows the number of regen cycles and miles since last regen. I don't think I saw the time it took for the last cycle.

All my drives get the car up to full temp and are usually around 20-30 minutes, minimum, but I've been doing a heavier mix of around town, city-type driving which likely explains the increased regen cycles intervals I'm seeing which is probably to be expected as you mentioned.


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## dlmetzger63 (Sep 28, 2017)

Did my fuelly sig show up?


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## dlmetzger63 (Sep 28, 2017)

Again


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## viper3k (Jul 18, 2018)

2018 Hatch 6M - First road trip was over two mountain passes. DIC said 42, hand calculated at 52. Don't know why there is such a discrepancy. I have 500 miles on the odometer.


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## crunch21 (Jul 16, 2018)

i would be curious about light weight rims, the racing type. Theoretically lighter weight rims should improve MPG and a whole host of performance and handling aspects. Probably not much though.


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## johnmo (Mar 2, 2017)

viper3k said:


> 2018 Hatch 6M - First road trip was over two mountain passes. DIC said 42, hand calculated at 52. Don't know why there is such a discrepancy. I have 500 miles on the odometer.


The DIC economy is generally pessimistic. I almost always calculate higher, especially in warmer weather.


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## karmatourer (Jul 6, 2018)

BodhiBenz1987 said:


> I was thinking at that temperature engine performance would not be optimal as far as intake air ... but maybe that would affect power and not efficiency ... or maybe I'm wrong altogether. I mean obviously I assumed there is some optimal temperature but I would have thought more like 80. Had not really thought about the air temp effect on aerodynamics though; I suppose it being humid would help in that case too. What about need for A/C? Per the DIC A/C was using .08 gal/hour, over a 12-hour drive that adds up (not sure I believe it's that much though). I.e., is the drag benefit at 100 degrees better enough than at 70 degrees to offset the fact I need no A/C at all at 70 degrees?
> 
> As far as drafting, that's something I'm sure I benefit from in spurts because whether you want to or not you end up behind trucks on the interstate. But I draw the line at tailing one intentionally for that purpose ... just not worth it safety-wise. Plus I only have so much patience.
> 
> ...


Since we're on the subject of drafting,I thought I'd share my thoughts on owning a '17 C7. I thought about following for increased gas mileage for a moment but it got such great gas mileage,I didn't. But you mentioned following for that purpse and having reduced reaction time since you can't drive 2-3 cars ahead. Also,tail-gaters never bothered me more in 50+ years of driving because the brakes on my car were better than the vast majority of cars on the road and if I had to make an emergency stop,I was sure the car behind me could not stop as quickly as me. That really bothered me the entire time I owned that car. Sorry for the off topic rant but it's the 1st chance I've had to share.


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## Cruz15 (Mar 17, 2016)

I am getting worse mileage than my 2015 no doubt about it. Maybe i just got a bad one. I cant average less than 4.3 on highway no matter what I do. My 2015 as long as the map sensor was clean I could get much lower than that.


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## firehawk618 (Feb 24, 2013)

Cruz15 said:


> I am getting worse mileage than my 2015 no doubt about it. Maybe i just got a bad one. I cant average less than 4.3 on highway no matter what I do. My 2015 as long as the map sensor was clean I could get much lower than that.



Sedan or hatch?


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## BluezCruze2018 (Aug 10, 2018)

I’m averaging 42.4 highway, and 28-31 city with heavy traffic. The best I’ve seen so far is 44.8 highway. I have a 2018 Cruze LT sedan with an automatic transmission.


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## BluezCruze2018 (Aug 10, 2018)

I also notice that I get better gas mileage when I use premium 93 octane. My car has VERY bad spark knock with 87 for some reason or another. Especially in 100+ degree weather. The LE2 apparently does NOT like regular fuel in hot weather conditions.


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## firehawk618 (Feb 24, 2013)

BluezCruze2018 said:


> I also notice that I get better gas mileage when I use premium 93 octane. My car has VERY bad spark knock with 87 for some reason or another. Especially in 100+ degree weather. The LE2 apparently does NOT like regular fuel in hot weather conditions.


Odd since 93 octane is more resistant to burn vs lower octane. BTW this is a diesel mpg thread.


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## BobJacobson (Jan 10, 2018)

I just finished my longest distance tank. I have questions.










The last 60 miles of this trip my DIC was stuck at 52 miles to empty. It didnt move at all.

When I filled up I put in 14.5 gallons

My question is does anyone know how big the tank actually is yet when you fill it all the way to the top? 

I'm confused that the DIC says I still had 52 to empty and had said that for about 60 miles.

My next tank I'm going to try for better mileage, I can pretty easily get my mpg in the low 60s by going the speed limit. I'm just normally impatient.

Assuming the DIC is right and there was still fuel in the tank; from full to the top I'm assuming there is about 15 gallons available. So a 1000 mile tank might be possible.

I might have a jug of diesel in the trunk and try it out.


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## 4burning (Jun 3, 2018)




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## Barry Allen (Apr 18, 2018)

BluezCruze2018 said:


> My car has VERY bad spark knock with 87 for some reason or another. Especially in 100+ degree weather. The LE2 apparently does NOT like regular fuel in hot weather conditions.


It's a turbocharged gasoline engine. No matter what the instruction manual says, 87 octane is not the best fuel. The engine will constantly be running rich, pulling ignition timing, and pulling boost to keep on the ragged edge of detonation. All this ESPECIALLY in hot weather conditions. Use at least 89 octane, probably 91-93 is ideal.


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## johnmo (Mar 2, 2017)

4burning said:


> View attachment 267165


I've seen this before. Was it towed for 25 miles? What's the 450 look like?


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## Diesel4Ever (May 30, 2018)

johnmo said:


> 4burning said:
> 
> 
> > View attachment 267165
> ...


Hypermiler. I’ve seen a hypermiler get 47 mpg on a Chevy Colorado CCLB 4x4 2.8 Duramax on a 75 mile test. He had the CC set for 57 mph, I could see that on the display but other than that I have no idea how he did it. Drafting behind a high profile vehicle on flat ground is my best guess.


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## Rivergoer (Mar 30, 2017)

Yep, it’s credible to achieve impressive numbers on the DIC under the right conditions.

There’s a 200+ mile stretch on I-40 between Flagstaff, AZ and Needles, CA where the altitude changes from 6,910 feet to 495 feet.

Driving west down this predominantly downhill road can yield some wildly amazing mpg figures, especially in the absence of the typical West winds.


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## firehawk618 (Feb 24, 2013)

viper3k said:


> 2018 Hatch 6M - First road trip was over two mountain passes. DIC said 42, hand calculated at 52. Don't know why there is such a discrepancy. I have 500 miles on the odometer.



The DIC in my car is extremely close to my hand calculated numbers. I am consistent in filling to the top of the filler neck. My car tends to take ~1.2 to 1.5 more gallons by trickle filling this way.

Perhaps the fill up in your hand calculation wasn't filled to the same level as your previous fill up?

1 to 1.5 gallons can skew the numbers quite a bit since our cars only hold ~13 gallons.


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## firehawk618 (Feb 24, 2013)

BobJacobson said:


> I'm confused that the DIC says I still had 52 to empty and had said that for about 60 miles.



Did you leave your ignition on when filling? If so it your calculation will be delayed quite a bit.

If the car was off during your fill up then I have no explanation.


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## firehawk618 (Feb 24, 2013)

johnmo said:


> I've seen this before. Was it towed for 25 miles? What's the 450 look like?


I'd love to see the 450 also.

My 25 mile high is ~80mpg. This was down a long mountain pass that was mostly down hill.

My car's average is really ~41 that that's mostly highway driving.


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