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General => Chatter => Topic started by: Tony on March 15, 2013, 12:14:52 AM

Title: EU car manufacturers cheat for MPG tests!
Post by: Tony on March 15, 2013, 12:14:52 AM
http://www.guardian.co.uk/environment/2013/mar/14/car-manufacturers-manipulating-fuel-efficiency-tests

You think they would have to test the car "as sold" not with interiors ripped out and tape over body gaps.

So that's why their MPG figures are so high...
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: 1958steveflying on March 15, 2013, 12:12:15 PM
http://www.guardian.co.uk/environment/2013/mar/14/car-manufacturers-manipulating-fuel-efficiency-tests

You think they would have to test the car "as sold" not with interiors ripped out and tape over body gaps.

So that's why their MPG figures are so high...

I understand all the claims other than the "high altitude thinner air" I was always lead to believe denser air was more fuel efficient, and altitude reduced power .
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: therecklessengineer on March 15, 2013, 12:42:23 PM
I understand all the claims other than the "high altitude thinner air" I was always lead to believe denser air was more fuel efficient, and altitude reduced power .

Modern engines have a mass air flow sensor that allows the ECU to measure the actual mass of the air flowing into the engine. The fueling is then adjusted to compensate. So whilst thinner air will give reduced power, the economy doesn't suffer.

Where the gains are made though are in the lower air resistance to movement - so it requires less energy to push the car along.
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: Jamesrl on March 15, 2013, 08:09:10 PM
http://www.guardian.co.uk/environment/2013/mar/14/car-manufacturers-manipulating-fuel-efficiency-tests

You think they would have to test the car "as sold" not with interiors ripped out and tape over body gaps.

So that's why their MPG figures are so high...

And you think this comes as a surprise to use?

I've been around motors for donkey's years and never known any owner achieve manufacturers economy, used to do economy testing when I was a lad.   
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: Julian on March 15, 2013, 08:33:58 PM
... used to do economy testing when I was a lad.   

Wasn't that when they were still pulled by horses?
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: Tony on March 15, 2013, 08:36:14 PM
Miles per carrot, you get more if you tape the ears flat
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: Jamesrl on March 15, 2013, 09:00:02 PM
Miles per carrot, you get more if you tape the ears flat

Oh yes, streamlining will always improve CPM and always use a mare, less dangley bits to slow things down you see.
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: greasemonkey on March 15, 2013, 09:08:10 PM
Makes you laugh, don't it? So the car manufacturers look good by backing environmental legislation, put loads of electrics on the car to reduce emissions, making some of them as good as disposable to the diy mechanic.
Then they go fiddle the tests the best they can. Meanwhile, we get to drive cars that do 30 to 40 MPG, instead of cars that do 100MPG, which is what we'd be getting if they focused on fuel consumption, instead of emissions.

just another marketing ploy, like the 0-60 time used to be. Vauxhall cavalier with a third gear hardly any higher than second, just to get the 0-60 time a fraction quicker than the competition, coz they knew that's what the motoring press would highlight, giving them more sales. Now its all about the smell of the flowers coming out of the exhaust.
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: Jmg on March 16, 2013, 02:09:24 PM
Given that the old XUD and TUD pug engines could match (and sometimes beat) the economy of the modern stuff in real life driving rather than test track conditions it doesn't surprise me at all, I never hear anything from the Father in law other than complaints about how little mpg his new tdci???? focus gets.
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: Head Womble on March 16, 2013, 04:41:50 PM
Given that the old XUD and TUD pug engines could match (and sometimes beat) the economy of the modern stuff in real life driving rather than test track conditions it doesn't surprise me at all, I never hear anything from the Father in law other than complaints about how little mpg his new tdci???? focus gets.

I know what you're saying, my daughter had a 1.5D (TUD) 106,
she now has a 2L HDI 306 (90bhp) and complains that she's using more fuel now than she did,
the 2.0 HDI in a 306 is well under worked, and supposed to be a very efficient engine.
I know the TUD is renowned for it's mpg but I didn't expect a big difference between the two cars.
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: Tony on March 18, 2013, 10:39:14 PM
How does she drive it?  I guess if it has more grunt it must use more fuel if you accelerate hard all the time?
Title: Re: EU car manufacturers cheat for MPG tests!
Post by: Jmg on March 18, 2013, 11:58:29 PM
How does she drive it?  I guess if it has more grunt it must use more fuel if you accelerate hard all the time?

Funny you should say that, when I had my zx 1.9td I used to hammer it everywhere, never managed much better than 42mpg but it was too much fun not to.