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      04-30-2011, 08:50 PM   #106
4th down; 4th quarter? Renegade.
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Drives: 09 SSII E92 M3; 12 AW X5d
Join Date: Aug 2008
Location: Pittsburgh, PA

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Originally Posted by dexx View Post
The computer only adjusts the timing in response to knock. The design tolerances are for fuel, not what some monkey might do to their well engineered system. Changing[/b]anything[/b] in the exhaust means immediately the "correct" timing advance for any given RPM or load point has changed. Unfortunately, freer flowing exhaust means better exhaust evacuation from the cylinder, which means the optimal timing point is retarded compared to it's previous location. This means the first guess by the computer is much too advanced. What happens when you run too much timing? RIGHT.
Better call BMW and tell them to recall their performance exhausts. Timing adjustments and fueling adjustments are a normal fact of life with this, and other, modern ECUs. Some handle it far better than others. The same adjustments must be made at altitude and when fuel quality changes. None of these adjustments will put the engine in as dramatic a danger as you would have people believe. Although getting a crappy tank of gas is never good.

You have to be a scientist and a computer engineer to understand how it really works, there is no explanation that will be satisfactory for any layman, but if you're curious as to how these things work:
People don't need to be able to reverse engineer an ECU to understand how one works. Openecu is a great resource, but what do you actually know about this ecu and engine? At the time of it's release, it was the most powerful processing ecu in the world. So you are sadly mistaken if you think it is the same as a Subaru legacy ecu from 6 years prior; or even one from 2011.

You are also stating that many respected tuners on this board are committing fraud by lying to their customers in stating that these exhausts keep the engine within acceptable limits. They are concealing and/or falsifying data. Your statements also conflict with various respected members as well as posted data. But, by all means, continue to scare people out of modifying their exhausts.