Quote:
Originally Posted by Munit
So the cool knock sensor mechanism this engine has is obviously beneficial in terms of safety by preventing knock much more accurately.
However has anyone who has logged data actually seen if there is any performance benefit from this system in terms of ability to keep timing advanced to the maximum ability that a traditional knock system would be unable to do because of less accuracy and specificity of the knock sensing?
Essentially does this system let the computer ride the knock sensor to get max timing more so than a traditional system? And if it is possible, does the engine actually due this?
I figure that may explain the ability to continue to make more power up to 96 octane or what not
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You answered your own question in the last line!
The reason the engine makes more power with increased octane ratings is due to the knock sensing systems ability to maintain timing at or near the PPP (peak pressure point) in the cylinder up to the max timing advance number written in the map. An acoustical knock system listens for knock and pulls timing from the pre-determined advance number in the map where as the Ionic knock sensing system maintains timing at the PPP point.
The Key to being able to run a knock sensing system as advanced as the one on the S65 is totally dependant on having an ECM (DME in BMW speak) that is able to handle the computational abilities that a system like this requires. The MSS60 is the main reason the the S65 is able to rev as high as it does and make such power for it's displacement......... The MSS60 is one of the smartest ECM's in the the automobile industry and it's ability to process so many input signals and control so many actuators at such a high speed is why the S65 is so good! I read an interesting article about the new 5.0 Coyote/Roadrunner engine in the Ford Mustang about a year ago. The thing that stuck out at me in the article was the admission from ford that the ECM they use in the Mustang is not smart enough to control the engine reliably at engine speeds in excess of 7500RPM. The MSS60 in comparison has been tested at 9000+RPM on the dyno in durability testing.
So the short answer is yes the ionic knock sensing system is able to do things that a traditional acoustical knock sensing system can't.