You can calculate this. Take TDC as your starting point. Then add you IPW + latency and you can convert that to crank angle degrees with some math. Generally when factoring in latency (and the distance of the injector nozzle from the valve) I think we're safe in saying that overlap shouldn't play too much a role with PI on the FA20 with reasonable IPWs. With DI though it is a rougher calculation since you can specify start of injection much more precisely with the DI angle, and as a result have a much higher chance of hitting that overlap point. The variable here is that even with overlap, since the piston is moving down you may not necessarily have the fuel go out the exhaust valve. It may move down the combustion chamber instead. You'd need to do some flow analysis to really find this out, but this is exactly the kind of situation we can see on the dyno, and where the AFR in the cylinder vs pipe becomes important.
Quote:
Originally Posted by arghx7
Nobody has come up with a RAM value from the FA20 ECU or a calculated parameter to determine the end of injection timing for the FA20's PFI system. If the end of injection occurs during an open intake valve & overlap, you've got all that unburnt fuel possibly reacting in the exhaust manifold or otherwise skewing the wideband as I said.
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