C7's Declining Fuel Economy Ratings
06-05-2018, 07:26 PM
#41
Drifting
06-05-2018, 07:31 PM
#42
Safety Car
And remember....
....cars' own trip/fuel consumption computers tend to be a bit optimistic; the old school keep track of miles and divide by gallons used is the only reasonably accurate measure....sorry
06-05-2018, 07:37 PM
#43
Drifting
Yep. I've religiously done this for everyone of my cars/trucks I've owned over the last 20+ years. (I file a Schedule C).
06-05-2018, 08:22 PM
#44
Melting Slicks
My '15 Stingray A8 got slightly better mileage than my current '17 GS M7--but it was lighter, the body more aerodynamic, and gearing taller. Still, if I believe the MPG computer I get considerably higher than the EPA ratings for both cars, city and highway. With the GS I can usually muster 20-21 mpg in suburban driving and 30-31 mpg at a steady 70mph cruise with no wind influences in Eco mode, and it has been steadily improving as it breaks in, now at 6300 on the clock. I do practice some hypermiling without letting it detract from driving enjoyment, like when I see a red light ahead that I know I will be stopping for I'll put it in neutral and coast to it. That makes quite a bit of difference and it won't slow you down if you do it right.
What many might not know is that their MPG computer may not be accurate. For each fill-up I log all info into a database and while the '15 car's computer fudged 2-5% (high) the '17 has been 6-10% (high). That miffs me a bit since every other gauge in the car seems to be accurate, including the speedometer. So for example if you crunch the numbers that 30mpg you think you're getting may only be 28, which is closer to the EPA ratings.
What many might not know is that their MPG computer may not be accurate. For each fill-up I log all info into a database and while the '15 car's computer fudged 2-5% (high) the '17 has been 6-10% (high). That miffs me a bit since every other gauge in the car seems to be accurate, including the speedometer. So for example if you crunch the numbers that 30mpg you think you're getting may only be 28, which is closer to the EPA ratings.
Last edited by iclick; 06-05-2018 at 08:24 PM.
06-05-2018, 08:37 PM
#45
Pro
My '15 Stingray A8 got slightly better mileage than my current '17 GS M7--but it was lighter, the body more aerodynamic, and gearing taller. Still, if I believe the MPG computer I get considerably higher than the EPA ratings for both cars, city and highway. With the GS I can usually muster 20-21 mpg in suburban driving and 30-31 mpg at a steady 70mph cruise with no wind influences in Eco mode, and it has been steadily improving as it breaks in, now at 6300 on the clock. I do practice some hypermiling without letting it detract from driving enjoyment, like when I see a red light ahead that I know I will be stopping for I'll put it in neutral and coast to it. That makes quite a bit of difference and it won't slow you down if you do it right.
What many might not know is that their MPG computer may not be accurate. For each fill-up I log all info into a database and while the '15 car's computer fudged 2-5% (high) the '17 has been 6-10% (high). That miffs me a bit since every other gauge in the car seems to be accurate, including the speedometer. So for example if you crunch the numbers that 30mpg you think you're getting may only be 28, which is closer to the EPA ratings.
What many might not know is that their MPG computer may not be accurate. For each fill-up I log all info into a database and while the '15 car's computer fudged 2-5% (high) the '17 has been 6-10% (high). That miffs me a bit since every other gauge in the car seems to be accurate, including the speedometer. So for example if you crunch the numbers that 30mpg you think you're getting may only be 28, which is closer to the EPA ratings.
Last edited by buckeye4; 06-05-2018 at 08:43 PM.
06-05-2018, 08:53 PM
#46
Team Owner
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St. Jude Donor '12-'13-'14-'15-'16-'17
Some severe cases of OCD in this thread.
06-05-2018, 10:59 PM
#47
Melting Slicks
FWIW, I confirmed my 1200 mile trip the "old school way" and calculated 30.6 MPG vice the 30.9 "computed" value...
Last edited by jimmbbo; 06-05-2018 at 11:00 PM.
06-06-2018, 01:39 AM
#48
06-06-2018, 02:49 AM
#49
Team Owner
06-06-2018, 06:56 AM
#50
Corvette Enthusiast
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https://www.fueleconomy.gov/feg/comparempg.shtml
2016 Manual was - 17/29/21 is now 17/28/21
2019 Manual is 16/25/19
So if the "2017 transition" algorithm modifies the 2014-2016 highway mileage only then why is the 2019 so much worse.
That's the odd part. I'd expect the new MPG and the "adjusted" older MPG to be the same.
06-06-2018, 07:48 AM
#51
over the life of my 2014, 20200 miles I have an average of 20.9 MPG (as this morning)... The MPG have gone down since I bought it and installed the range device 
Last edited by cowboy casey; 06-06-2018 at 09:01 AM.
06-06-2018, 07:51 AM
#52
Race Director
06-07-2018, 02:28 AM
#53
06-07-2018, 05:23 AM
#54
picture is proof
06-07-2018, 07:41 AM
#55
Race Director
06-07-2018, 08:00 AM
#56
Drifting
Just saying....
06-07-2018, 07:26 PM
#58
06-07-2018, 07:41 PM
#59
Safety Car
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These numerous postings showing mpg based on the "last 50 miles" or the "last 400 miles" strike me as largely irrelevant. They are examples of cherry picking. If you want to figure out your real world mpg, leave one of the settings on for the life of the car, then show us what your "average" is after 14,000 miles or 20,000 miles or whatever. It makes no sense showing off these high mpg ratings from the top of the pass to the seashore and then leave off the trips to the grocery store and back.
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Skid Row Joe (06-10-2018)
06-07-2018, 09:21 PM
#60
Corvette Enthusiast
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Mines at 19.5 for the life of the car which is 16,500 miles.
My best 50 was 32.2 MPG (or something like that) in Eco going 60 MPH on a road in Michgan's Upper Peninsula (US-2) from St. Ignace toward Wisconsin.
I drive about 50% highway. But who cares that still beat the EPA mileage
My best 50 was 32.2 MPG (or something like that) in Eco going 60 MPH on a road in Michgan's Upper Peninsula (US-2) from St. Ignace toward Wisconsin.
I drive about 50% highway. But who cares that still beat the EPA mileage