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Originally Posted by DLSJ5
I directed it toward Sal because he would probably know more about those specific questions, and he's the one who's saying that Meth could blow up your S65, not the owners of the cars, and frankly I'm amazed by the claim, but I am not an expert on ion-flow and I would say 99% of the enthusiasts here are not as well, lol. I have no ill toward Sal he is not offending me, I just had some simple/basic questions.
I think some important info can come out of this, but I'd like to know why the burning properties of Meth deactivate KD? Don't you? Would C16 race fuel do the same? It burns different than 91, etc.
But if KD is simply turned off to run a SC, then it would seem that Meth would actually help control knock, not the other way around, so some clarification is in order.
A main question is what was the timing set at on these two cars? What actually happened? Cracked piston? Ring lands gone? Also now, unless I'm taking this out of context, Sal is hinting that race fuel could possibly do the same to the S65 KD?
It appears there is no middle ground here, no opinions, either Meth blows up the S65 and makes ion flow shut off for some reason or it doesn't, there is No definitive explanation here on how or why.
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Remember BMW runs a dynamic ignition system which tries to advance timing as much as possible (to configurable limits) without knock. If the knock control system is not working as expected, it's feasible the ECU could advance timing too much without detecting the resulting knock.
One way around this would be to tune conservative timing limits although that defeats the purpose somewhat of dynamic ignition control.
Ion sensing knock control is far more complex than acoustic sensing knock control - as I understand it, it allows the ECU to model cylinder pressures, temperatures and so on to detect knock (and which would also give it the ability to predict knock as well) - if methanol has different burn and pressure characteristics, I can see how this could affect the knock control system.
One real valid point brought up earlier by LMB is the whole failure scenario - if that meth pump fails, you are royally screwed unless the ECU can somehow detect the failure and apply corrections to address the failure (I've seen this with aftermarket ECUs like Motec and Autronic, but probably not possible with the Siemens ECU in its BMW configuration)...