UPDATE Jan 02 2010: I am such a goof, lol. I just figured out comparing Injector ms to Wideband and subtract the time it takes for the RPMS to cycle from injector firing to exhaust valve open gives me the time it takes for exhaust gasses to travel from exhaust valve to Wideband. The Mass out is equal to the Mass in always, it is the volume that changes due to heat differences. All of this can be calculated easily in an excel table and thus, allows me to pinpoint the most likely wideband reading to the originating event time. It won't be a perfect calculation but it will be far better then simply sliding wideband readings back a cell or two. Since Exhaust Flow Velocity will surely speed up at WOT. PSI of exhaust is already determined per intake psi.
This will be a huge project but should it work out well the benfits for tuning would be profound, in my opinion. Anything done mathematically with a "good" formula which works will benefit.
Should all work out I'll post up the spreadsheet.
EDIT: Anyone?! Even just a simple velocity at a specific rpm such as idle. Even just a hint...lol
I'm trying to figure out a formula to calculate the speed of exhaust gasses.
I have a formula which calculates velocities of a given gas. But I need to find out how to calculate exhaust gas CFM from Airflow lb/min, Wideband AFR and possibly EGT.
Would anyone happen to know if there is a standard in the auto industry regarding exhaust gas speeds throught the manifolds, downpipe, ect?
Maybe even calculating cylinder pressures at exhaust valve open after combustion. Knowing the airflow in and area of combustion chamber at exhaust valve open, knowing the pressure could give me something to get a CFM of exhaust flow.
Maybe I am making much harder then it has to be. Can anyone chime in?
I wish to use this data in excel to match precise oxygen sensor measurements back to the combustion event that was responsible for it. Basically offsetting the O2's to match engine operation as if there was no distance from exhaust valve to oxygen sensors. Hopefully I can find usefull data to better fine tune my PCM.