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      10-18-2010, 11:09 AM   #598
shifterboy45
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Drives: 2009 335i Coupe
Join Date: Feb 2009
Location: North by Northwest

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Quote:
Originally Posted by Ilma View Post
Don't believe the DME is seeing the spike, but if the AF ratio is going lean for a split second then I can see the logic in a knock event occuring.....especially if the DME is riding along the inception of knock.
this is a very good discussion of some of the basics required to accurately tune a car. but there is something i would like to add as food for thought...

to get maximum drivabilty, factors other than boost, timing, octane, cylinder environment, etc.. have a substantial effect on the outcome. one factor this is commonly overlooked is road speed and actual load. if these elements are not a part of your equation nothing will make sense. the road is not a static environment, nor is every street the same.

road simulation on a dyno is required, the operators' ability to induce incremental loads through the power absorbsion unit can make a big differnce is locating (isolating) less than optimal performance.

unless you find the optimal road conditions, and use them for every test, every run.. your documented results will vary from a little to a whole hell of a lot. this includes ambient temp, generated road heat, traction, or lack of it ...

thats only if you want to be accurate and reproducible
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