MPG Real MPG (1.8)

[Kremmen]

Here is my real world MPG figures.

The weekly trip computer reading is always 4mpg - 5mpg higher !



My mpg is also based on 95% dual carriageway and motorway, non urban driving and few hold ups. I cannot see town driving returning much more than 33(ish) mpg although the trip comp would likely show 38(ish) mpg.

[illegalhunter]

Well pointed out car makers are allways economical with the truth on fuel consumption.

[GHGH]

I've followed Mustang Sally for 7500 km now.
My experience so far is that in LIGHT non urban driving, the real MPG is about 6 to 8 % poorer than the computer claims (which again is poorer than promised).
When driving in rough terrain - with many steep climbs and descents -the computer error becomes twice as large, again in my disfavour.

[Charles_Harding]

Kremmen

You may be right with those figures.

But does it relly change anything?

Probably ALL motor vehicle manufacturers use similar 'outstanding' figures.

All I know is that Millie excites me as soon as I see it before going on a drive and she continues to excite during and after.

That's the main thing I reckon!

Not worried about consumption at all!

Just fill her up when the tank shows I'm running low.

"I've found an amazing new diet.
You can eat whatever you like!
You can whenever you like!
You can eat as much as you like!
You don't lose any weight but it's very easy to stick to!"

Charles H.

[elfa7]

Perhaps its time all motor manufacturers gave more realistic mpg figures.

[GHGH]

How does they find these figures?
I've heard rumours of test running the engine in bench

[Charles_Harding]

Originally Posted by elfa7

Perhaps its time all motor manufacturers gave more realistic mpg figures.

Don't really see the point.

Even on this site some guys rush around all day and others stay in the fast lane @ 49 mph.

So whatever the charts say others would always prove different.

As long as the criteria (even tho' often inacurate) is the same for each vehicle who really cares anyway, I certainly don't.

Even if my Millie's consumption was the worst in it's group I would still be driving her around, and still be enjoying it.

"I think the best way to diet is to eat what you like and let the food fight it out inside you!"

Charles H.

[romatic]

I agree with Charles. My computer is showing my car's petrol consumption at 38.1 or 38.2 mpg. All sorts of driving conditions, slow slow quick quick slow. Also rev the doo-dahs out of her on one particular bendy stretch. I love the car and the petrol consumption is more than fine. Still smiling.

[Charles_Harding]

Originally Posted by romatic

I agree with Charles. My computer is showing my car's petrol consumption at 38.1 or 38.2 mpg. All sorts of driving conditions, slow slow quick quick slow. Also rev the doo-dahs out of her on one particular bendy stretch. I love the car and the petrol consumption is more than fine. Still smiling.

More power to your elbow 'romatic'.

We are lacking the definite postive feeling on this site lately!

"Exercise?
I tremble and shake every morning just lately!"

Charles H.

[Kremmen]

I'm not criticising the MPG at all. My last car only did 28MPG with a following wind so the Civic is a lot lighter on the pocket when I fill up.

I was just intending to give any future buyers a real world example of my actual MPG figures as opposed to the brochure figures.

[romatic]

Originally Posted by Kremmen

I'm not criticising the MPG at all. My last car only did 28MPG with a following wind so the Civic is a lot lighter on the pocket when I fill up.

I was just intending to give any future buyers a real world example of my actual MPG figures as opposed to the brochure figures.

Brochure mpg figures are always optimistic. Not real world but test track. Your real world figures are very good. 28mpg in your last car? What was it, if you don't mind me asking?

[Kremmen]

Lexus IS200 Auto

and... the paintwork was atrocious - now that was soft paint that chipped easily.

and... what comedian decided that dark blue paint should have a light grey primer ?

Slightest nick and it showed up light a belisha beacon!

[Topcat]

Originally Posted by Kremmen

I'm not criticising the MPG at all. My last car only did 28MPG with a following wind so the Civic is a lot lighter on the pocket when I fill up.

Same here 1.8 Ford Focus gave me 26 - 28 mpg the Civic is between 32 - 35 with about town driving - but I get far more on longer journeys so I am happy with that.

[Pottsy]

Originally Posted by GHGH

How does they find these figures?
I've heard rumours of test running the engine in bench

• The test is outlined in Directive 93/116/EC as amended by 1999/100/EC and provides results that are more than representative of actual average on-road fuel consumption than previous tests. There are two parts: an urban and an extra-urban cycle. The cars tested have to be run-in and must have been driven for at least 1,800 miles (3,000 kilometres) before testing.
• Urban Cycle
  The urban test cycle is carried out in a laboratory at an ambient temperature of 20oC to 30oC on a rolling road from a cold start, i.e. the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerating and idling. Maximum speed is 31mph (50km/h), average speed 12mph (19km/h) and the distance covered is 2.5 miles (4km).
• Extra-Urban Cycle
  This cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving and the remainder accelerations, decelerations, and some idling. Maximum speed is 75mph (120km/h), average speed is 39mph (63 km/h) and the distance covered is 4.3miles (7km).
• Combined Fuel Consumption Figure
  The combined figure presented is for the urban and extra-urban cycle together. It is therefore an average of the two parts of the test, weighted by the distances covered in each part.

[terry]

Is all of the test on a rolling road?
Also I think the manufacturers also have a few tricks, like over inflating the tyres to reduce rolling resistance, and removing unecessary things to reduce weight (although perhaps that is why there is no spare wheel or rear wiper!).

Terry

[Kremmen]

I think the test strategy is flawed in as far as taking wind resistance into account is concerned.

It is a known fact that most cars have a 'sweet speed' of about 56mph where the highest mpg is usually to be achieved. Above this speed and the mpg drops in line with the increased speed.

I find it odd that my previous 4 cars have all had quoted combined mpg figures about 4mpg lower than what I was able to achieve due to my daily free-flowing route. The Civic however is 4mpg less than the quoted combined mpg!

It will be interesting when I fill up this weekend because the trip comp is currently showing an average of 47mpg, it has only ever shown a maximum of 45mpg on previous weeks. Maybe the engine is finally loosening up at 3k.

[GHGH]

So far (7500 km/4700 miles) my experience is that the urban consumption is more in line with the promised numbers than the extra-urban consumption.
Only at very easy driving at flat roads (which are scarce in my part of the world) at lower speeds (lower than the sweet spot at 55mph) my extra -urban consumption get close to the promised consumption (have I said this before?).

[Pottsy]

Originally Posted by terry

Is all of the test on a rolling road?
Also I think the manufacturers also have a few tricks, like over inflating the tyres to reduce rolling resistance, and removing unecessary things to reduce weight (although perhaps that is why there is no spare wheel or rear wiper!).

Terry

Yes all on a rolling road.

Tyres and weight are all covered in a long spec. The car is driven by a robot on a rolling road which is calibrated to reflect the effect of weight and other losses. It's all very complicated, but the figures are designed to be relative, not absolute (since no two drivers drive the same way).

5.3. Tyres
The tyres must be of one of the types specified as original equipment by the vehicle manufacturer, inflated to the pressure recommended for the test load and speeds (adjusted, where necessary, for test-bed operation under test conditions). The pressures used must be indicated in the test report.


6.2.1. Reference mass
Mass of the vehicle in running order less the uniform mass of the driver of 75 kg and increased by a uniform mass of 100 kg.

graph.jpg

[GHGH]

At first glance, this looks OK, and should copy real driving.

But they don't, as it seems what is the general interpretion of real driving results in higher consumption.

So, since the tests are so elaborate, why not finish the job and adjust them so they come closer to reality??

[Pottsy]

I think because "reality" is so different for each person. So they acknowledge that the real world is impossible to replicate consistently, and adopt an unrealistic test that is consistent.

At least we can compare two moderately gentle slow drivers...