Fuel Economy Figures and Actuals - Sale of Goods Act

Ultrasonic

GolfBravo wrote: »

And don't forget to ask the manufacturer for the "alternative" ECU software that they use for these official tests - the engine will not last very long, but the fuel economy will be amazing.

Do they really do this? I have no issue at all with running the test with the AC off (in fact I'd want them to), but not running the same ECU software is a totally different ball game.

Joe_Horner

Ultrasonic wrote: »

Do they really do this? I have no issue at all with running the test with the AC off (in fact I'd want them to), but not running the same ECU software is a totally different ball game.

Different ECU mapping*, alternator disconnected (and even removed), A/C off, electric power steering disabled, even electric water pump (if fitted) and cooling fans disabled because it won't overheat in the time the test takes.

All the above and more are acceptable as far as the test is concerned.


*eta: As gloomendoom says, same software but different timing / fuel etc maps for the software to work with.

Gloomendoom

Ultrasonic wrote: »

Do they really do this? I have no issue at all with running the test with the AC off (in fact I'd want them to), but not running the same ECU software is a totally different ball game.

As I understand it, they don't.

The cars submitted for the tests have the same software as the cars sold in the showrooms. Unfortunately, it is optimised to get the best results in the tests and not real world conditions. Hence the common disparity between official and actual.

Mobeer

I've never seen anything to say the ECU is changed.

But:
Gear change indicators fitted to indicate when to change gear (so the standard rules on gear changes car be ignored)
CO2 figures can be under reported by a 4% margin of error
Different oils etc rather than those normally used
Tyres pressures altered for fuel economy concerns only (high pressure)
Everything removable removed

Joe_Horner

Mobeer wrote: »

I've never seen anything to say the ECU is changed.

The engines are "optimised" for economy - in other words, re-mapped (the only way to optimise an ECU controlled engine) for maximum economy. Those maps used may not be suitable for long term reliability but the test only lasts about 20 minutes, so no worry there.

Gloomendoom

Joe_Horner wrote: »

The engines are "optimised" for economy - in other words, re-mapped (the only way to optimise an ECU controlled engine) for maximum economy. Those maps used may not be suitable for long term reliability but the test only lasts about 20 minutes, so no worry there.

Do you have a credible source to back up this assertion?

Ultrasonic

Mobeer wrote: »

Gear change indicators fitted to indicate when to change gear (so the standard rules on gear changes car be ignored)

Sorry, I don't really understand the point you are making there?

Herzlos

Ultrasonic wrote: »

Sorry, I don't really understand the point you are making there?

The indicators can be set to indicate the most optimal time to change gears in terms of economy, to the detriment of everything else. i.e. they don't have to drive to the conditions and aren't worried about performance, just getting the optimal economy.

The test is pretty lax too, I can't remember the actual figures but you get so long to get up to speed you could lose a drag race with a tractor (it's something mental like 2 mins to get up to 60).

Joe_Horner

Gloomendoom wrote: »

Do you have a credible source to back up this assertion?

For which part?

That they optimise engine settings for the test, or that the only way to optimise an ECU controlled engine is to play with the mapping, or that they play with the mapping for the fuel tests?

First and second parts, yes I can probably find you references. Third part, probably not but it's a logical inevitability from the first two

GolfBravo

Ultrasonic wrote: »

Do they really do this? I have no issue at all with running the test with the AC off (in fact I'd want them to), but not running the same ECU software is a totally different ball game.

Yes.

Very easy to do. Impossible to get caught.

Small low pressure turbo engine? Perfect. You start with turbo boost levels.