MPG Average
- Thread starter Surfsup
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pjensen641
Member
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- 2013 CX-5 AWD Touring Zeal Red
Only if you could get in to a slightly more efficient BSFC portion of the efficiency map. Even then, the engine load would be maxed out and you would be constantly downshifting to maintain speed over slight inclines. MikeM is right, its more about aero drag and the power required to maintain that speed. A little research on Fueleconomy.gov and or other sites will explain why. Recall the 70's when national speed limit went to 55. It had nothing to do with safety. That is the sweet spot for fuel econ for most vehicles, even modern ones. It strikes a balance between running the engine fast enough in top gear to get in to efficient BSFC and the exponential increase in aero drag. Have to slow down if you want fuel econ, or buy a more aero efficient car where the speed penalty isn't nearly as high. There is a reason the Prius is shaped that way!
In CA where we normally cruise 70-80 mph on flat freeways, I suspect the CX-5 top/6th gearing is optimal for efficiency... Like most, I feel that Mazda did it's homework to achieve best overall highway MPG, not likely a 7th gear would improve that MPG especially at 75.
EPA highway ratings today (2008 model year and beyond) better reflect the higher highway/freeway speeds today in the US, not the sweet spot closer to 55-60 mph.
As I said earlier, "without knowing the what-if gearing of the 7th speed, cannot say what impact on MPG would be", and mileage could actually worsen with some gearing setups. A what-if 7th gear might be exactly the same as our current 6th gear, allowing closer ratios which might be nice to have for improved/smoother mid-range acceleration, with no impact on cruising highway/freeway MPG.
EPA highway ratings today (2008 model year and beyond) better reflect the higher highway/freeway speeds today in the US, not the sweet spot closer to 55-60 mph.
As I said earlier, "without knowing the what-if gearing of the 7th speed, cannot say what impact on MPG would be", and mileage could actually worsen with some gearing setups. A what-if 7th gear might be exactly the same as our current 6th gear, allowing closer ratios which might be nice to have for improved/smoother mid-range acceleration, with no impact on cruising highway/freeway MPG.
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My 6th tank got me 8.6L/100KM ...497KM on 43.32L
That's 27.4 MPG approximately. I just changed my oil at 1600 miles so I'm interested to see if that does anything (no moly). I would like to flush the transmission fluid as well. Maybe I'll do that soon. That fluid has to be pretty grainy at this point. I wonder because others have posted different oil changes cause MPG changes - attributing it mostly to the moly additive.
I have been getting 9.8L/100KM average previous to this. I believe so-called winter gas has been replaced as my driving routine is the same every week.
Vancouver doesn't even need the "winter gas", its oil companies nickel and dimming us. Oh look, a hurricane, a terrorist, a bowel movement, lets raise the gas! I don't know of any other consumable that fluctuates in price as much as gas does. Today it is $1.44/L and late tonight it will drop to $1.36/L ...does this most days.
Well I changed my oil at 1608 miles (wanted to do it at 1500 but stuff gets in the way)...I didn't get a full tank on that fuel in my tank (oil change mid-way through the tank) but I just filled up again at 2173 miles and registered a 28.6 MPG average for the last tankfull which is about 1 MPG better of a jump in efficiency. Was it the oil change? Was it some "break in" period?
^ Hard to tell on such a short sample, but engines do break in as you note. I tend to run the original oil a little longer on new engines as they use less additives to assist in the rings seating properly, not sure what the recommendation is on these Skyactive high compression engines though. Mine has 700 miles on it and so far averaging 27.7 with highway and city mix of about 50/50.
pjensen641
Member
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- 2013 CX-5 AWD Touring Zeal Red
Weather warmed up. I don't think break in or type of oil is anywhere near as significant as weather. I have 30K miles of economy tracking on fuelly. Through two summers and two winters its the same. Average of about 26mpg winter. Average of about 28.5 mpg summer. I live in IA...so similar conditions.
checking weather.com data -
In the morning, lows are relatively the same (when I leave for work). Highs are 5-10 degrees different, and at the high of the day when the day/engine is warmer already, that won't make a huge difference in oil viscosity at all.
I also moved my car into a garage for the last three weeks - covering at least two tankfulls - making the weather factor even less an issue, with no jump in MPG for prior tankfulls. While it may have contributed marginally, I don't think it is the only explanation.
In the morning, lows are relatively the same (when I leave for work). Highs are 5-10 degrees different, and at the high of the day when the day/engine is warmer already, that won't make a huge difference in oil viscosity at all.
I also moved my car into a garage for the last three weeks - covering at least two tankfulls - making the weather factor even less an issue, with no jump in MPG for prior tankfulls. While it may have contributed marginally, I don't think it is the only explanation.
pjensen641
Member
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- 2013 CX-5 AWD Touring Zeal Red
Warm up is a portion of it. However, once the engine is warm, I see significantly lower fuel trims when the weather is mid 60's or above. This is at cruise. I also have a live graph of BSFC on my DashCommand screen. At cruise, I show about .4 when below freezing, .38 when above freezing but below 60, and the .36 when above 65.
This week I had a lot of short trips, not much highway mileage. Still got 27.2 MPG on 11.51 gallons. Pretty good. Long term I'm at 27.6 MPG for the life of the CX5 so far. That's about what is advertised so I'm pretty happy. Tires are kept as close to 41 PSI - I think I'm done tracking gas mileage...it's been pretty consistent.
FWIW the owners manual suggests the break in period to be 600 miles IIRC
Read the whole thread guys, I've been posting the MPG for each fill-up since I got the car...I changed the oil at 1600 miles to see if MPG would improve - changing the initial oil of a new engine out. Chicago resident. Got the car during the coldest winter on record (parked outside until early April). I have a total average of 28MPG right now over the life of the vehicle (~2900 miles)...
Yes we read it, thanks. Were you really expecting mileage to go up just by doing an oil change at 1600 miles?
28 MPG is reasonably close to EPA estimates for 2014 CX-5.