A number of carmakers pride themselves when they improve the fuel economy of newer models over older ones, but how much more efficient have cars gotten over, say, the last 50 years or so?
As it turns out, it sort of depends. The U.S. government didn’t actually track fuel economy until 1964. However, we were able to get a good idea of …
All things considered, it's not exactly a fair comparison. Pre emissions, safety, and relatively low output cars to modern high performance cars that are crash safe (in many areas) and have less than 1% emissions of their old counterparts.
While you are absolutely correct, perhaps an argument could be made for total level of pollution?
Compare all the modern cars and their mileage etc. To those few remaining vintage cars and their lack of use?
alfadriver (Forum Supporter) said:All things considered, it's not exactly a fair comparison. Pre emissions, safety, and relatively low output cars to modern high performance cars that are crash safe (in many areas) and have less than 1% emissions of their old counterparts.
And the way fuel economy is calculated/reported/advertised has changed a few times in that 50 year period as well. Fuel economy.gov did apply retroactive modifiers to change the numbers of cars before the most recent change (2009?), but obviously it wont work for stuff made in 1964. It does go to 1984, so that might be a bit more apples to apples.
The last EPA test change was for the 2008 model year. The current cycle gives cars a lower rated fuel economy than the old cycle would.
Brake Specific Fuel Consumption would have been a fun comparison too, if only the data were publicly available...Although, once again, the old and new would have been skewed from using different HP (gross vs net) rating systems.
Driven5 said:The last EPA test change was for the 2008 model year. The current cycle gives cars a lower rated fuel economy than the old cycle would.
Brake Specific Fuel Consumption would have been a fun comparison too, if only the data were publicly available...Although, once again, the old and new would have been skewed from using different HP (gross vs net) rating systems.
FWIW, the cycles have not changed. How they are calculated has. At least since 2008.
It's still the FTP75, FTP75@50, Highway, US06, and SC03 that are used to calculate sticker fuel economy.
Current cars are pretty amazing compared to those I grew up with. Safer, absolutely. More powerful with still decent fuel economy, absolutely. (I didn’t buy my Mustang to hypermile it and yet I’ve seen over 26 MPG on a tank a number of times on road trips. Not bad for 400+ HP). With that said the advances in safety add weight and the technology to meet the fuel economy with power and low emissions adds complexity. Not to mention everything needs to be an SUV to sell now.
One of my early cars was a MK II Jetta GLI that was stupidly fun to drive even with only around 100 HP. Wasn’t really fast in a straight line but wow was it fun on a twisty road. It would also turn 38 MPG on highway trips because it was light. Probably a good thing I never got in a serious accident though. They wouldn’t be able to sell something like it today and yet it was the “performance” model when I bought it.
Wife's 2014 Accord with 2.4 liter 4 cylinder and CVT and 140k plus miles on it still gets 38-40 mpg while easily keeping up with freeway traffic without us even trying. I am still amazed by that for some reason.
alfadriver (Forum Supporter) said:Driven5 said:The last EPA test change was for the 2008 model year. The current cycle gives cars a lower rated fuel economy than the old cycle would.
Brake Specific Fuel Consumption would have been a fun comparison too, if only the data were publicly available...Although, once again, the old and new would have been skewed from using different HP (gross vs net) rating systems.
FWIW, the cycles have not changed. How they are calculated has. At least since 2008.
It's still the FTP75, FTP75@50, Highway, US06, and SC03 that are used to calculate sticker fuel economy.
The US06 and SC03 came out in 2008. So, while the cycles did not change, new cycles were introduced.
In reply to ProDarwin :
??? I knew them from before 2008. And I know I've ran US06s prior to 2008. I don't remember when they actually came out, but they were in use prior to 2008. I think the SC03 was the result of Cadillac's cheating with the Allante, which totally changed how the car ran with a/c on. That was in the 90's.
Or do you mean in the equation? And even then, "including" them wasn't actually true in 2008- OEM's are still allowed to use a two cycle cert as long as the 5 cycle is close enough. The actual 5 cycle requirement is just now phasing in. I know we've been using the two cycle calculation for most of our products.
alfadriver (Forum Supporter) said:All things considered, it's not exactly a fair comparison. Pre emissions, safety, and relatively low output cars to modern high performance cars that are crash safe (in many areas) and have less than 1% emissions of their old counterparts.
All the same, the best fuel economy cars I had were from the 80s.
I mean, TECHNICALLY I could hit 42 mpg with my '02 Volvo, but my '89 Golf and '90 Sentra could do it with ease, and no shenanigans.
alfadriver (Forum Supporter) said:In reply to ProDarwin :
??? I knew them from before 2008. And I know I've ran US06s prior to 2008. I don't remember when they actually came out, but they were in use prior to 2008. I think the SC03 was the result of Cadillac's cheating with the Allante, which totally changed how the car ran with a/c on. That was in the 90's.
My mistake, Wikipedia says 2007
https://en.wikipedia.org/wiki/FTP-75#Supplemental_tests
I know we covered driving cycles during my powertrain course in college in ~2005. IIRC the prof. touched on some potentially upcoming tests, but the focus was on the UDDS and HWFET and those were the only two factored into the results.
Without magic electrons, diesel, or other augmentations, have we been able to best this?
ProDarwin said:alfadriver (Forum Supporter) said:All things considered, it's not exactly a fair comparison. Pre emissions, safety, and relatively low output cars to modern high performance cars that are crash safe (in many areas) and have less than 1% emissions of their old counterparts.
And the way fuel economy is calculated/reported/advertised has changed a few times in that 50 year period as well. Fuel economy.gov did apply retroactive modifiers to change the numbers of cars before the most recent change (2009?), but obviously it wont work for stuff made in 1964. It does go to 1984, so that might be a bit more apples to apples.
Lots of changes to the fuels themselves too.
ProDarwin said:alfadriver (Forum Supporter) said:In reply to ProDarwin :
??? I knew them from before 2008. And I know I've ran US06s prior to 2008. I don't remember when they actually came out, but they were in use prior to 2008. I think the SC03 was the result of Cadillac's cheating with the Allante, which totally changed how the car ran with a/c on. That was in the 90's.
My mistake, Wikipedia says 2007
https://en.wikipedia.org/wiki/FTP-75#Supplemental_tests
I know we covered driving cycles during my powertrain course in college in ~2005. IIRC the prof. touched on some potentially upcoming tests, but the focus was on the UDDS and HWFET and those were the only two factored into the results.
I'm pretty sure I was running US06's prior to 2007- I'll have to look on my work computer to see if I still have data. Which I can do since it's just across my living room from me. In 2007, we just started working on the 2010 3.5l GTDI V6 cars, and I am quite sure I was running SFTP tests just to know where we were (cert work didn't happen until late 2008 into 2009).
Perhaps the requirement to pass them was fully phased in for 2007 MY cars.
edit- quick follow up, my data goes back just 10 years, as I'm supposed to do. But I did ask one of our specialists when we first started to run SFTP tests.
STM317 said:ProDarwin said:alfadriver (Forum Supporter) said:All things considered, it's not exactly a fair comparison. Pre emissions, safety, and relatively low output cars to modern high performance cars that are crash safe (in many areas) and have less than 1% emissions of their old counterparts.
And the way fuel economy is calculated/reported/advertised has changed a few times in that 50 year period as well. Fuel economy.gov did apply retroactive modifiers to change the numbers of cars before the most recent change (2009?), but obviously it wont work for stuff made in 1964. It does go to 1984, so that might be a bit more apples to apples.
Lots of changes to the fuels themselves too.
Pretty much all of the adjustments to the FE sticker calculation was due to complaints that cars were not meeting their advertised sticker. A classic change was due to a higher up EPA official getting a hybrid, and finding that the fuel economy was not nearly what was advertised. And it's always adjusted down.
I sometimes question how they get the numbers they do on the tests. A lot of cars seem to reliably beat their EPA highway mpg numbers effortlessly, while others are very close.
The original numbers for my Jeep (98 Grand Cherokee 5.9) were 13/17. 17 - 18 on the highway was about right when it was stock. The adjusted 11/16 was closer in heavy city traffic, but it was pretty rare to see it under 17 on the highway.
The BMW (01 740i Sport) is rated 14/19. The non-sport version with taller gearing was rated 17/23. Both are the adjusted numbers, as I don't know what the original numbers were. I've never driven mine in heavy city traffic for long enough to know what the MPG really is. But on the highway, it beats the 19 by a large margin. Cruising at 65, it'll happily turn in 26 - 27 mpg. At 75, 23 - 24. I don't know what they did to get the 19 number. And the general consensus online is that the taller geared version gets about 2 - 3 mpg better on the highway. So the numbers for it are almost as far off (and the difference in rating is bigger than reality).
I remember being able to drive all week on $10 in gas in my little CRX. I'm getting old
In reply to rslifkin :
It's just math.
Tests are run, FE is measured on that test (or tests), and then math is done to turn that into a window sticker number. FWIW, I don't actually know the math, I just know that's how it's done.
The reason it's easy to beat it is that nobody complains when they beat the number, but everyone complains that they didn't reach the number. So by the nature of the public's reaction, the sticker will be on the low side of reality.
That being said, since every car is tested in the same manner, the math should be the same, comparing Car A with Car Z or Truck M is valid for personal "who's going to be best".
One interesting note that almost nobody knows- the Fuel Economy measurement isn't measuring fuel used. It's measuring the sum of all CO2, CO, and HC's in the tail pipe. And the fuel is fixed for all testing, which means the H-C-O ratio is well known and constantly tested. So converting the constutuents into fuel used is quite accurate and consistent. It also includes fuel used from the EVAP system.
Pete. (l33t FS) said:alfadriver (Forum Supporter) said:All things considered, it's not exactly a fair comparison. Pre emissions, safety, and relatively low output cars to modern high performance cars that are crash safe (in many areas) and have less than 1% emissions of their old counterparts.
All the same, the best fuel economy cars I had were from the 80s.
I mean, TECHNICALLY I could hit 42 mpg with my '02 Volvo, but my '89 Golf and '90 Sentra could do it with ease, and no shenanigans.
Probably because most of those cars were designed when gas was still “expensive”. I think fleet fuel economy in general took a hit after gas got cheaper, and looked to continue staying cheap. Although that was mostly because people starting buying bigger, more powerful vehicles. I mean, there were still some mileage stars in the 90’s, a lot of compacts/subcompacts could still manage 40+ MPG on the highway, and do pretty well around town. Nowadays, a midsized car with the base engine will touch that highway mileage, just not do as well in the city, likely due to the added weight.
eastsideTim said:Pete. (l33t FS) said:alfadriver (Forum Supporter) said:All things considered, it's not exactly a fair comparison. Pre emissions, safety, and relatively low output cars to modern high performance cars that are crash safe (in many areas) and have less than 1% emissions of their old counterparts.
All the same, the best fuel economy cars I had were from the 80s.
I mean, TECHNICALLY I could hit 42 mpg with my '02 Volvo, but my '89 Golf and '90 Sentra could do it with ease, and no shenanigans.
Probably because most of those cars were designed when gas was still “expensive”. I think fleet fuel economy in general took a hit after gas got cheaper, and looked to continue staying cheap. Although that was mostly because people starting buying bigger, more powerful vehicles. I mean, there were still some mileage stars in the 90’s, a lot of compacts/subcompacts could still manage 40+ MPG on the highway, and do pretty well around town. Nowadays, a midsized car with the base engine will touch that highway mileage, just not do as well in the city, likely due to the added weight.
Well, also a Sentra is a more economical vehicle than a Volvo.
If you want the best mileage, nothing made from that era will touch a Prius.
alfadriver (Forum Supporter) said:In reply to rslifkin :
It's just math.
Tests are run, FE is measured on that test (or tests), and then math is done to turn that into a window sticker number. FWIW, I don't actually know the math, I just know that's how it's done.
I know the old math. I am curious to see the new math if you know anyone that knows. Also if you know anyone that could explain the math for calculating the CAFE # for the car (which is calculated differently).
I geek out on this stuff. I'd love to see GRM do a detailed article on it.
Fueleconomy.gov goes back to 1984. I decided to run a comparison between my daily driver, a 2013 VW Passat TDI, and a VW Quantum (Passat) Diesel from 1984, using the DSG and automatic transmission.
My car: 34 combined, 30 city, 40 highway.
1984 counterpart: 27 combined, 25 city, 31 highway.
So - not only did the 1984 version of the Passat get less mileage, it was a slightly smaller car with about half the horsepower.
Just got a note from my friend at work, who says he was running the US06 in 1996. So perhaps the test was officially included into the window sticker equation in 2007.
Back to the original question, gas mileage for equivalent weight and horsepower has improved dramatically.
However, nobody builds a VX Civic anymore.
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