How are Co2 emissions calculated - auto v manual

[Sneaky Schnell]

Most of us are aware that modern 'clever' automatic transmissions can perform better than their equivalent manual car in order to get a lower Co2 rating from European emissions tests

Some colleagues have dismissed this as complete nonsense claiming the opposite.

I remember reading an article in Evo and seeing a thread on here which specifically mentioned at what speed the manual transmission had to be changed at and for how long certain speeds/gears had to be maintained with the auto being allowed to shuffle up to top asap.

My search has been fruitless. Would anybody have a definitive link which explains things?

Thank you.

[havoc]

Haven't got a link, but manuals are required to change up at a set % of max rpm, which not only disadvantages manuals vs autos, but disadvantages high-revving engines vs low-revving ones (hence the demise of the last CTR), and to a lesser degree disadvantages n/asp vs turbo.*

It's all a complete joke as in the real-world you could compare the 3 cars below:-
- CTR (or Clio 200)
- Golf GTi Manual
- Golf GTi DSG

...and the DSG would have the lowest 'emissions' but the worst real-world economy.




* Although a lot of this is because a turbo engine can be made a lot lower-revving for the same performance as an n/a engine. S'charging is no better than n/asp as boost is proportionate to engine speed.

[Sneaky Schnell]

I agree. The system is obviously flawed. I would like to know the exact methodology though....

[Crusoe]

European Steady Cycle is the procedure, read about it online with plenty of documents on how they try to improve their results.
http://www.dieselnet.com/standards/cycles/esc.html