From: Randall Parker 

Phil Payne wrote:

> According to ETKA (Audi's "Elektronische Teile Katalog - a comprehensive
> parts database on CD, known to Audi fans as the "Family
Album") there are no
> major differences in the pollution control equipment fitted on European vs.
> US cars.

We have differences within the US. California has tougher standards (and some states
- particular in New England - have adopted Cal standards). This results in two
phenomena:

1) Some cars aren't available in California. This happens mostly for diesels.

2) Some cars have calibrations and other differences to run cleaner in California. I
do not know how much this happens now. I think it used to be more common.

There are also calibration differences between markets to trade-off differently for
performance versus fuel efficiency.

> Wouldn't make any sense, either.

There are lots of rational reasons for differences between markets. For example, fuel
standards are different and that causes differences in how engines get calibrated and
what equipment gets put on them. We see this with diesels right now with the attempts
to meet harder US standards and the even harder Cal standards.

There have even been debates about fuel formula changes that might negatively impact
old cars but which can get supported by  newer cars. With better sensors and ECU
algorithms the cars can adopt more easily to changes in fuel formulas.

Another cause of differences: California on-board diagnostics standards. The ECUs
have got to report standard emissions info when in emissions testing stations. Those
standards become de facto US standards though and then  perhaps de facto
international standards. I do not know about the last bit. But I know
experts who I
could ask. In fact, it is an interesting question and so I'll try to ask. Though
that's chiefly a software difference for reporting info.

--- BBBS/NT v4.01 Flag-5