US E92 M3 less power than the Euro E92 M3

[E90330iS]

So it is not because of the more restrictive Catalyst Converter for the U.S. Spec models?? I thought that was the case for E46 M3s.

[joema]

Originally Posted by E90330iS

So it is not because of the more restrictive Catalyst Converter for the U.S. Spec models?? I thought that was the case for E46 M3s.

That is also a possibility. I was just pointing out the DIN hp has always been more than SAE hp. As of about 2005 the SAE test standard is more conservative, so this would further widen the difference -- in addition to any restrictive US emissions h/w.

[ruff]

So if the M3 DIN HP is 420 and SAE HP is 414, is the RS4 the same or is it 420SAE HP, which would be 6 more horsepower than the M3? I have only seen the RS4 quoted at 420 hp.

[epiphone3]

Originally Posted by lucid

If you get more hp from an engine by supplying it with higher octane fuel than it is designed to use that only means that the engine was NOT OPTIMIZED FOR PERFORMANCE. That would be the case for an Honda Accord, as the designers are keeping other variables in check and have a different intent compared to the M3 designers. We are talking about the M3 engine which should already be optimized for performance. Apart from that, the bottom line is the relationship between octane level and compression ratio; to truly take advantage of higher octane fuel, the compression ratio should be increased (apart from the minor tweaks you can do to engines which are not already optimized for performance.) We are not talking about any "modern BMW." Take an E36 M3, and fill it up with 100+ octane fuel. You will not see any significant improvement unless you change the cylinder piston geometry and alter the compression ratio.

dude... read the other posts. There is more to the equation than compression... there is also IGNITION TIMING!

[lucid]

Originally Posted by epiphone3

dude... read the other posts. There is more to the equation than compression... there is also IGNITION TIMING!

Dude, I read all the posts. Of course there is ignition timing (among many other variables). What do you think I mean by the ECU stepping in? But the timing can be advanced only so much. If it was that simple, we'd keep on pouring higher octane fuel and mess with the timing (manually or automatically) and hp would go up and up!? I'm saying BMW has probably already pushed things to the limit. Yes, I guess you could pick an hp or two by supplying 95 octaine fuel, but there are theoretical limits to that, and my main point has been, from the very start, that you need to increase the compression ratio to take full advantage of the higher octane fuel.