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Originally Posted by Bimmerista
The fuel in the US has sulphur content as far I know which does not permit the Di engines to do a lean burn like in Europe. I agree that the fuel efficiency increase comes from the DI, but only of permitted by the quality of the fuel to do a lean burn.
I have not driven the new 2.0 litre turbo in the A4 but it is not a new engine, simply a reworking of the 1.8t which I had the pleasure of driving for 4 years before in an A4. In that engine I did not like the lag under 2500 rpm. The engine was very good, its just my personal thing.
I am not making any judgments about the 335, on the contrary, everyone and their grandmother here seems inclined to state that the 335 is revolutionary and eliminated turbo lag. Until we have more info and test results, I reserve my judgement. I hope that in fact the lag has been reduced to a level where it becomes irrelevant (especially since we a talking about a 6 cyl with 3.0 litre displacement to beginn with not a smaller 4), since I certainly like everything elso about the new twin-turbo engine.
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Yes, correct, it is the sulfur issue. As I said though that has been addressed and US fuel by law will be 30ppm everywhere in the US by this summer. Much of the fuel in the US for the past 3 years has been dropping in sulfur content from highs of 300-500ppm down to 30-80ppm and even lower by some fuel makers.
Point is, US fuel is capable of "lean burn", so I don't understand why the new E92 turbo isn't taking advantage of it. Also, BMW is probaby just using the lack of knowledge of low sulfur US fuel to compensate for why they haven't worked out their DI NA engines yet.
The Audi 2.0T FSI doesn't run in "lean burn" mode in the US, but that's because it was released before the full US mandate this summer.
Also, the "lean burn" is all about cat-converters and lower emissions.
Lean burn allows a faster and hotter light off to, which doesn't work well if the fuel used has a high sulfur content.
I don't call that bad "quality" fuel so much as a different formulation and possibly a "cleaner fuel. US fuel is high grade and just as good as any good/high quality fuel in the rest of the world.
The new 2.0T FSI is years beyond the 1.8T and is not simply a "reworking" of the 1.8T. The 2.0T is a new engine, but, it would just be a sematic arguement to go any further.
Point is the 2.0T has quite amazing throttle reponse and a very flat and broad power delivery that is far from the peakier nature of earlier turbo designs.
Yes, we do have to wait and reserve judgement on the BMW 3.0TT
I'll bet it will rock. :rocks: