MPG Ratings Will Drop Under EPA Proposal

375 messages, Last post on Oct 02, 2008 at 9:08 PM

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What is this discussion about? Fuel Efficiency (MPG)

See this Edmunds.com article! EPA Overhauls Fuel Economy Estimates for 2008 - As the 2008 model-year cars hit the lot, shoppers will notice a big difference — the EPA has changed its fuel economy testing methods to produce mileage estimates that reflect "real world" driving habits. - (more)

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#21 of 375 CAFE by mirth Jan 13, 2006 (9:27 am)
Actually, CAFE will still be based on the old EPA test, so nobody will be getting hit any harder than they were before. Replies to this message: rorr (Jan 13, 2006 9:58 am)
#22 of 375 Re: CAFE [mirth] by rorr Jan 13, 2006 (9:58 am)
Replying to: mirth (Jan 13, 2006 9:27 am) Makes sense in the short term. I'd be interested to know (long-term) how this is supposed to work as new models are introduced. Will each model carry two sets of EPA ratings? (one figured the 'old way' for CAFE purposes and one figured the new way for the window stickers/consumer information). This could work AGAINST the reasons behind CAFE. As a manufacturer, why would I make an attempt to increase my REAL-WORLD mileage by 10% if it would require the vehicle to be certified under the new EPA guidelines resulting in an EPA number 10% less than the old number under the old guidelines? Heck, I'd just leave the thing alone for as long as the EPA let me use the old numbers for CAFE. Personally, I'm glad the EPA methodology is being revised. For too long, the EPA numbers have been unrealistic. The problem now though is that, while it would be 'fair' to adjust the CAFE requirements in line with the new tests, it would be political suicide for someone to actually propose this. Too many folks educated in government schools to understand the rationale behind adjusting the CAFE numbers.
#23 of 375 I say... by mirth Jan 13, 2006 (1:20 pm)
...scrap CAFE altogether. At this point, any manufacturer that let's their MPG numbers slide are going to take a hit in the market anyway. Replies to this message: rorr (Jan 13, 2006 3:16 pm)
#24 of 375 Re: I say... [mirth] by rorr Jan 13, 2006 (3:16 pm)
Replying to: mirth (Jan 13, 2006 1:20 pm) YES!!!!! Thanks for ending my week on a high note!
#25 of 375 Actually, there's already a discrepancy... by 210delray Jan 14, 2006 (9:49 pm)
...between CAFE and the mileage ratings on the window stickers. Those of you who say the CAFE ratings use the "old" EPA method are correct, but since the 1985 model year, the posted numbers on the window stickers have been reduced by 10% for the city and 22% for the highway. Under the new proposed scheme, window stickers will have to reflect the new test results, but CAFE for manufacturers will still be figured the old way. Otherwise, they WOULD be screaming bloody murder, especially those who make the most gas guzzlers!
#26 of 375 . by sls002 Jan 17, 2006 (8:50 am)
The FWD Cadillac Seville was rated 18 city 27 highway for 2003. The unadjusted numbers were 19.5 city, 34.5 highway. My 2002 Seville actually gets 27 easily, and 29 if one takes it easy on long trips. For city driving or local driving, I average more than the 18 MPG or even the 19.5 MPG that the EPA got. However, 34.5 on a long highway trip would probably only be possible if one cruised at 50 MPH. In my opinion, rating the MPG at a steady cruising speed of say 50, 60 and 70 MPH or perhap 50, 65 and 80 MPH would really show buyers what sort of MPG they might expect on long trips at whatever sort of speed they like to cruise at. Also, showing the effect of speeding on MPG would be quite instructive. A cold start, short trip MPG is very sensitive to the length of the short trip. This is why everyone gets a different city MPG. I get quite good city mileage because I currently live 10 miles from anywhere worth going to, and most of that ten miles is highway. I also limit my speed while the engine is warming up to 50 MPH till the temp gauge is fully warm, which takes about 5 miles on winter days.
#27 of 375 sls by nippononly Jan 17, 2006 (11:17 pm)
5 miles? It should warm up sooner than that, and then you could get better city mileage. Shouldn't it? They run the EPA test at 52 mph max for the highway portion, right? It's no wonder the current ratings are so hard to achieve for most folks. Automotive News had an article this week about how AAA did an owner survey and then did their own alternate test, and neither one got close to the EPA ratings. Prius gets a 56 mpg combined EPA rating, owners are reporting an average of 37, in the AAA test it got 44. Explorer got 16.8 in the AAA test, as well as in the owner's reports, but 18.3 from the EPA. Silverado got 17.8 from the EPA, but only 15 mpg among the owners, and 13.9 in AAA's test. I always manage to get close to the highway figure in around-town driving, and 10-20% above the highway figure on long highway drives. The key to city driving is smooth acceleration and letting off the gas if you see a stoplight ahead you know you are going to have to stop at anyway. Plus combining errands as much as you can. On the highway, the key is to keep speed as constant as possible, without a lot of accelerating to pass, and letting up on speed a little on long grades. Replies to this message: sls002 (Jan 18, 2006 9:09 am) 210delray (Jan 18, 2006 10:36 am) sls002 (Jan 18, 2006 10:57 am) robertsmx (Jan 24, 2006 10:30 am)
#28 of 375 Re: sls [nippononly] by sls002 Jan 18, 2006 (9:09 am)
Replying to: nippononly (Jan 17, 2006 11:17 pm) My Seville does take about 5 miles to warm up when I am cruising about 50 MPH on the highway (say 6 to 7 minutes) when the outside temperature is about 10 degrees Farenheit. What I mean by warmed up is when the temperature gauge reaches the center (normal) position. The oil is still warming up at this point, and probably takes 10 miles to reach operating temperature. I am getting around 23 to 25 MPG in local driving. The computer says about 23 in winter driving, but my computer is goofy since the transmission was worked on. It randomly adds about a half gallon of fuel to the fuel used which then lowers the average MPG.
#29 of 375 Re: sls [nippononly] by 210delray Jan 18, 2006 (10:36 am)
Replying to: nippononly (Jan 17, 2006 11:17 pm) As I recall, the current highway EPA test has a maximum speed of 60 mph, an average of 48 mph, and no full stops. The highway test is also run on a warm engine. Replies to this message: sls002 (Jan 18, 2006 10:57 am) robertsmx (Jan 24, 2006 10:30 am)
#30 of 375 Re: sls [210delray] by sls002 Jan 18, 2006 (10:57 am)
Replying to: 210delray (Jan 18, 2006 10:36 am) I do not think that the EPA testing can predict what everyone will get in city driving. Everyone has a different route to and from work. The best the EPA can do is predict some average, but that is more or less where they are now. I think that a more useful set of information would be steadystate fuel consumption at 3 different highway speeds: 45 MPH, 60 MPH and 75 MPH. The cold start city test is also useful. Replies to this message: robertsmx (Jan 24, 2006 10:30 am)