I have a mixed feeling "aboot" the gobment here. First, I think the new Drive Clean program is a mistake since it relies on OBDII readings and not an actual exhaust test. Scrap it alltogether OR make sure that if some boy racer removes a catalytic converter for example, or runs a custom engine mapping, they will never pass.
What does a custom engine mapping have to do with it? You custom map your engine controls so it will run better with other changes made, it's not to defeat emissions testing.
Modders will define "better" as more powerful while the car MFGs will be after fuel efficiency and level of emissions. Cars whose engines use custom ECU settings and other mods almost certainly will have different FE and emissions than those stated by the car maker.
You're kind of the opposite of a car enthusiast. Please don't ban the things you don't understand.
If you alter ignition and valve timing or air/fuel mixture in order to increase power, it will affect FE and emissions. Can't have the cake and eat it.
There, you just proved what blur911 said. There are several subsequent posts including mine that attempt to add more clarity, but its not "zappy" so I suppose we write "into the wind", so to speak..
Can't be seen to have an eco backing smart performance technology, even if it saves a little of the planet.......
EDIT; I was a little harsh, comes from many years of people refusing to listen about the benefits of performance, always negative. Back in the "old days" it was cams, head work and headers. Frequently if those were kept within limits, it resulted in both improved fuel economy and performance. Now its ECU tunes and (still) cat back exhaust flow, and its so much easier and more effective now. Simply put, a well developed tune will explode all the fuel, more often.
So the obvious question is, why don't manufacturers just provide the better performance and economy if both are possible? Three reasons, perhaps more. 1: Reliability, they need a buffer. Not just component engine parts but driveline components too are engineered for the base engine with a tolerance to accommodate an optional engine but not a whole lot more. Also fuel octane ratings, with a tune you don't want to be like lots of buyers who may well put 87 octane in some times or all the time into their turbo. 2: Drive-ability. Manufacturers often want a smoother throttle input response, or a wider torque band. As an example, several manufacturers have dropped power ratings on turbos to get those conditions (eg: Hyundai). 3: Costs. Those of us who have burned out a clutch on a chipped Audi can imagine what the manufacturer wants to avoid paying for....