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X-post from the B6 A4 board. Information on the differences between Euro FSI and US FSI on the 2.0T.

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X-post from the B6 A4 board. Information on the differences between Euro FSI and US FSI on the 2.0T.

Old 02-01-2005, 04:54 PM
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Default X-post from the B6 A4 board. Information on the differences between Euro FSI and US FSI on the 2.0T.

Thanks to Joe and Juergen... from THE source VWVortex....

As of right now, the primary reason for initial non-stratified FSI in the USA involves a significant importation cost premium per unit as well as potential TREAD risk. It is a combination of business case and US-specific circumstances, both technical and regulatory. Its quite shortsighted to assume VWoA and VWAG are depriving US consumers of stratified FSI becasue they don't like the look of us... Many manufacturers, not only VW, have programs and technology waiting in the wings that they simply cannot act upon until the EPA gets its act together.
FSI running in stratified mode requires separate exhaust gas after-treatment using a very expensive NOx catalyst along with separate EGT and NOx sensors. In addition, the intake manifold on stratified FSI engines uses a tumble flap to manage intake air flow during transition between part load (stratified mode) and WOT operation. Of course, this additional hardware requires appropriate software control. With the current Dollar/Euro issues, the importation premium for stratified FSI was a deal-breaker, and I'm sure that customer market research supported the decision to not go with stratified mode in the beginning. Besides, the actual benefit per tankful is not much (compared to non-stratified) and, as has always been the case, depends entirely on how heavy one's foot happens to be. But of course, just the techology by itself can be argued as a marketing feature, whether one takes advantage of it or not.

Another potential reason does involve US fuel quality, or specifically, the lack of it in some regions. All current FSI calibrations are based on the EURO4 emission reg drive cycles using European fuel (which, by regulation is of a higher, consistent quality vs US fuel which can indeed be of high quality, but not consistently throughout all states). As of right now, the impact of using regionally poor quality US fuel in stratified FSI has not been assessed. This is critical because current TREAD initiatives require all Mfrs. to submit emissions component failure warranty data to the NHSTA and EPA. Should NOx catalysts become contaminated and/or EGT/NOx sensors begin to fail in excess of the TREAD thresholds, the importer will be forced to act either via recalls or service actions that they currently cannot afford. Expensive warranty claims for emissions components by themselves are problematic, why risk additional grief through federal regulators.

I believe VWoA is waiting for an overall increase in US fuel quality as mandated in the next steps of EPA's 9 year plan (of which lower S is only a small component). Indeed, the language in many EPA preambles state that the effectiveness of all OEM exhaust gas after-treatment technologies depend entirely on consistently high quality fuel available nationwide.

I'm assuming this holds true for the normally aspirated 3.2L V6 and possibly any other FSI motor.
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