Quote:
Originally Posted by Kodename47
If only the access to the per cylinder knock thresholds were logable or accessible like they are on the FA20DIT or on the Motec, that would allow a little part of the picture become more apparent. A lambda sensor in every exhaust port would be ideal but as Tim said it's a big investment. You just have to be aware that this is the case.
So on the stock manifold the front 2 cylinders will run richer than the rear based on the TB to runner angle? If so, is this something that increases as RPM increase?
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That is the beauty of having an ecu like the Motec. It allows all this stuff to be logged and experimented with. Knock for example, all 4 cylinders run differently. Even when fuelling is improved, the air path and firing order robbing other cylinders leads to some cylinders knocking before others.
In answer to your two questions. Its not the case they run richer, at some points they run leaner. The required fuel difference crosses over. In other words, at a certain rpm cylinder 3 requires more fuel than cylinder 1 and at another rpm it requires less. It's due to the tuned length and airflow issues.
My concern was that if the stock ecu has cylinder fuel offsets buried within it then not being able to adjust this with an aftermarket table will lead to a proper manifold then not working as good as it can do.
I'd be surprised if the stock ecu hasn't got individual mapping buried deep within as the stock ecu runs smoother than an aftermarket one without individual cylinder mapping. Be nice for an expert on the stock ecu to chime in that has actually dug around inside it and knows exactly what tables are in there. I could be wrong here.