Skip to comments.Why car makers lie about fuel consumption (in Europe)
Posted on 04/28/2012 12:06:31 PM PDT by Olog-hai
There are lies, damn lies, statisticsand official EU car fuel consumption figures. I and others have been banging on about this for years; the figures quoted by manufacturers in their ads usually (but, interestingly not always) bears absolutely no relation whatsoever to what happens in the real world.
To get those official figures, new cars are subjected to something called the New European Driving Cycle, a series of short runs on a rolling road where the car is accelerated, put on a short cruise and decelerated under laboratory conditions. All the car makers have to put their cars through the same test, so on this level, there is no trickery involved. The idea is that the EU has created a level playing field upon which the performance of all cars can be judged.
But it is not as simple as that. Because this is where it gets clever, and some trickery DOES creep in. Some years ago, manufacturers realized that to score well on the official tests, they could tune their engines for maximum efficiency on the rolling road cycle. This was particularly the case for small turbocharged diesel or petrol engines and hybrids. For instance, the engine could be set up so that the turbocharger simply does not kick in during the cycle. But take the car out onto a real road and to get the thing to move at all, the turbo will be needed, massively increasing consumption.
(Excerpt) Read more at hanlonblog.dailymail.co.uk ...
This is the type of car I was talking about, and not with the powerglide slushbucket...I've heard and seen 21 mpg or better.
If you consider the weight of the Bel air, which had a full frame, and compare it with modern cars, I think it fares pretty well. The V8s and automatics not so much, and certainly not the muscle cars.
The advent of fuel injection could have made cars very fuel efficient were it not for overkill by the emissions freaks.
EFI, electronic ignition and the converter all vastly improved the driveability, fuel mileage and emissions of any gas powered vehicle. Other "improvements" did not.
The "smog pumps" AIR tubes, miles of vacuum line and closed loop carburetors were all crap and have for the most part disappeared from production vehicles.
I fully believe that a good portion of the fuel consumed in today's cars is not for the operation of the engine, but to optimize the burn in the converter, hence the downstream O2 sensors.
If they were to simply shoot for the leanest possible fuel ratio at any given time, without compromising performance when needed, nor jeopardizing combustion chamber components, they would have accomplished the same or similar emissions results.
After all, it would seem that the less fuel consumed per mile, fewer emissions would be created.
Aerodynamic are a big plus (but often result in some butt-ugly cars) and the ubiquitous automatic is a minus on mileage.
My point in a nutshell; currently the producers are forced to tune for emissions, your mileage and wallet be damned.
Those 0-60 times from the sixties were high because of poor tires.
from memory so I may be wrong on some of the details:
The 1970 Chevelle 454 SS was the fastest factory-stock car in the world in the 1/4 mile ever made and remained so until the Buick turbo GNX of the 80s surpassed it. I don’t know what car ended up beating the GNX in the 1/4 mile but my guess would be a turbo porche of some kind. The Chrysler hemis were faster than the chevelle but not while in stock condition. They made more stock horsepower but couldn’t hook up well enough to make use of the power and possibly had the wrong gear ratios. The chryslers needed to be tinkered with to get them work right in a 1/4 mile. The hemi had a lot more potential than the chevy but you had to work at it.
We should compare the ‘70 chevelle SS and the late 80s model buick GNX to a current mustang and camero and see what those 0-60 times look like.
Modern engines run lean compared to old engines. The old method of tuning the really old carburetors(1950s) was to richen the mixture to prevent detonation, over heating, and hard starting, and backfiring out the carburetor. Hot rodders would lean out the mixture to get more power but this caused other problems.
The function of a throttle is to impede the flow of air into the engine. This has two effects: (1) reducing the amount of air per stroke; (2) adding drag by forcing the engine to work pumping vacuum. The latter effect is in many cases the more significant one, but the work spent pumping vacuum, which can be significant at low throttle, is essentially wasted. Such waste is much greater in a large engine at low throttle than in a small engine at wide-open throttle.
I do drive conservatively on the highway. I accelerate rapidly to the speed of traffic (that 5.7 liter engine does a good job of it) then kick it into cruise control. In town is another story.
I bought the car used, mint condition and 5 years old with just over 50,000 miles. The used car sticker on the widow showed 18 mpg and I think that chased people off. I didnt care and wanted it, the price was far below Blue Book. It was comfortable, looked new and was a true luxury car my first one. My old car was an 83 Camaro Z28. Great handling, great acceleration but I blew the engine. Not all that comfortable either.
My 2010 Camry has 268 ponies, hits 60 in a squoonch under 6 seconds, will top 140mph 9still pulls strong at 120) and gets 23 mpg locally and has hit 32 mpg on the highway at 65 mph (will get the advertized 28 mpg and up to 30 mpg at 70-75 mph). A lot of today's cars combine some pretty good power/performance and mileage.
I remember mileagae taking a hit when they introduced the "pollution pumps" and the seemed to lower the horsepower to help compensate, but the combination of performance/economy stayed in the "suck" mode.
Although not interesting for any other reason. I’d like to see what would happen to the mileage figures if you took the 1961 Bel air, straight six, three speed manual, and field-tested it for mileage with the 10% ethanol.
Then retrofit it with an engine, same CID and compression ration, equipped with a monitored EFI like Megasquirt, a stand-alone EFI, EGR valve, PCV, and converter.
Then run the same tests with a 5 speed and higher final drive ratio.
It would at least be a pretty good old car to drive around in.
“a stand-alone EFI”
Sorry, I meant a stand-alone HEI.
“Higher power would mean less throttle required to match the acceleration graphs on the test equipment ,, should mean higher mileage ... “
That’s just silly.
You can’t get free power, it all has to come from the fuel.
I’ve been saying for years there’s no reason to buy a sports car/muscle car anymore. A plain old basic model ford taurus is about as fast as a mid 70s vintage firebird. A new mustang or camaro with a v8 will give you somewhere around 175MPH...around 200MPH if you get the *special* v8. I do not see the point.
We live in an era when a HONDA CIVIC SEDAN(Si version) has nearly 150hp from a 100cubic inch non-turbo 4 cylinder and will do 0-60 in 6 seconds flat, 0-100 in 8.3 seconds and 1/4 mile in 14.5 seconds.
Then you can add an aftermarket computer chip and an air cleaner and see substantial gains for not much effort. And it should be noted that Honda has not yet begun to upgrade their engines with direct injection as the other brands have already done. When that happens, there will be a dramatic increase in performance AND efficiency. Honda has always been “anti-turbo” so they will not be using turbos any time soon. I think the direct injected motors will be out this fall.
earlier in the thread I mentioned the 1970 chevelle SS454. It was the fastest production car(showroom stock configuration) in the quarter mile ever made and held that title until the 1987 buick GNX. The 1970 chevelle would do 0-60 in 5.5 seconds. the GNX would do it in 4.7 seconds. Granted, the chevelle would be much much faster with just a few simple mods, like better tires, traction bars, and removal of the mufflers. But as soon as you start allowing these kinds of mods, then the 1970 chevelle is no longer the king of the hill...the chrysler hemi is.
But the point is, a basic sedan is plenty fast enough nowdays.
So what is the engine for?
Well then how much of the energy in fuel is converted to power, and how much is converted to heat?
“I accelerate rapidly to the speed of traffic (that 5.7 liter engine does a good job of it) then kick it into cruise control.”
In the early 1980s BMW gave your driving method, as their recommendation for maximum mileage.
Accelerate quickly to desired speed, then hold steady.
You cant get free power, it all has to come from the fuel.
You must look at the LOAD ,, my car produces more power at larger throttle openings when TOWING at 55mph than when it isn’t towing at the same 55mph (or add any other load you want ,, windows open , car loaded with lots of weight..) ... smaller throttle opening , SAME RPM , different power levels (despite same RPM and same engine/car etc.) and LOWER fuel consumption ... the same can be said of different engines in the same chassis ... you have some cars where the engine is too small/overworked and it uses more fuel than the larger optional engine.
Your THEORETICAL info is good in theory ,, and is repeatable on a dyno as you simply run WOT against a big load and measure fuel flow and power output but in the REAL WORLD where PART THROTTLE is the NORM , results will vary considerably. You can’t take simple minded “most efficient at WOT” thinking into a “I just need 15 of those 300 available horsepower” to maintain a 60mph cruise world and expect them to correlate.
Honda has always been anti-turbo so they will not be using turbos any time soon.
Honda has had turbocharged micro cars (2 cylinder 550 or 600 cc) in Japan for many decades... and they certainly know how to tune for boost ,, remember F1 with 1200hp (qualifying) 1.5 liter turbo cars!
“Your THEORETICAL info is good in theory”
The only “THEORETICAL info” I stated was that you can’t get free power, it all comes from the fuel.
Not sure where there is any wiggle room there.
Blanket statements that big old cars use less gas than smaller new cars are silly. Of course, the whole “Cars were better in the 60s” thing is silly too. But every car thread gets pasted with those same tired old silly posts.
They don’t build ‘em like they used to. And it’s a good thing they don’t.
Styling is a whole different issue. Cars look so much alike today because of Government regulations that dictate so many parameters of a cars design that it is a miracle they aren’t identical in every way.
I think a lot of the “old cars are better” thing is because people long for the old styles (I liked the looks of the older cars too) and they long for the OLD DAYS. But that doesn’t change reality.
And reality is that a big old Caprice, or a Newport, or a Galaxie from the 60s was NOT built as well as today’s cars, and it was NOT safer, and it was NOT getting 20 MPG.
The only THEORETICAL info I stated was that you cant get free power, it all comes from the fuel.
Not sure where there is any wiggle room there.
If you looked at the rest of my statement you would see that I wasn’t “dissing” you ..
Under light throttle conditions (which cars operate under the vast majority of the time) , efficiencies have NOTHING to do with rated power ,, we’re talking at MAYBE 10% of available power being used ,, of course all power comes from fuel (DUH!) .. what makes the difference is load ,, (notably aerodynamic above 40mph) ,, rolling resistance is more or less a straight line ,, aero is cubed by the speed.. the difference in an engine running at 10% load and 15% load isn’t that big ,, you don’t increase your fuel burn by 50% by going from 10 to 15% power ... most engines have a sweet spot for best efficiency that the engineers tune for ,, 10-15% power at a rpm equal to about 50mph , you need a certain amount of velocity in the airflow for things to work well.. that’s all ... you seem stuck on theoretical efficiencies ... I was there 30 years ago ..
If you were talking light aircraft engines or auto racing engines that run 100% of the time between 50% power and 100% power then your ideas would be valid ...
“you seem stuck on theoretical efficiencies”
No, I am not stuck on anything. Nor am I arguing with your technical analysis. It is obvious that you are more knowledgeable on the subject than I...I believe this because I am aware of about half of what you are talking about, and didn’t smell any BS there so I conclude you must be right. The rest I will take as free education.
My original post on this thread was merely a response to the tired old “bigger is better, older is better” theme that always pops up on an automotive thread. It is tiresome, and generally wrong.
I’m with you ,, the old cars were fun but the advances today are unbeievable... I just wish I could afford a new Elantra... or maybe a Focus.
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