Quote:
Originally Posted by jamesm
FWIW:
"The idea of tuning any closed loop system is to dial in the raw tables/compensations so as to minimize reactive closed loop corrections. This is done when controlling boost, fuel and timing. With timing control being the least tolerant positive error. Defending the undefensable suggests either ignorance or the attempt to maliciously deceive."
- Shiv... http://www.e90post.com/forums/showth...=493245&page=4 post #71. |
This is example of you taking something completely out of context. In the context of Seimens MSD80 ECU (BMW), there is no long term ignition trim applied. You simply detonate and then retard timing. Rinse and repeat.
In the context of Denso ECU fuel control, there a long term fuel trim that constantly learns in an effort to minimize short term fuel trims and fueling error. This is what LTFT active is designed to do. And it works on any kind of fuel formulation assuming that the feedback authority range is sufficient. I appreciate the search though.
Quote:
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Vishnu sells a Flex Fuel kit for E90 BMWs. Coincidence, I'm sure.
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Yes, we sell Flexfuel kits for the BMW. It's quite useful since, depending on ethanol content (E50 to E85), power gains of 100-180whp can be had through appropriate tuning. An NA FA20, on the other hand, will make 30whp regardless of running E50 or E85.
Why you ask?
Since it is not turbocharged, it doesn't start off (low E%) with a low lambda target for knock suppression. So there isn't anything to be gained by en-leaning the fuel target map as ethanol content increases. Also unlike the BMW, it doesn't need high ethanol content to achieve MBT so adding timing beyond what i possible with E50 is actually going to result in power LOSS, not GAIN.
So I think we are talking about two different things, no? And again, perhaps this discussion is best left to another thread.
Shiv