hutch wrote:Geez I felt pretty proud of myself for gluing some pieces of wood together this weekendThis part confused me until I did some reading up on how o2 sensors get their reference oxygen and now I think I understand it a little better. I guess now I am still confused, just in a different way, but how is this not a bigger problem with all FI cars? Is it because factory ECU's usually ignore the narrowband o2 sensor when at WOT to get high boost levels? Is this more of an issue that mostly pops up when tuning with a wideband?squaab99t wrote:In order for the readings to be accurate for a force inducted engine the exhaust pressure reading needs to be obtained and factored in with the AEM Wideband arrangement.
Gluing wood together in a ice cold garage is no easy task.
To be honest that was the first time I have formed tubing like that. Keeping in your mind's eye the shape and were you want to end up. And being careful you don't fold over and crimp the stuff in the process.
I too have been wondering what the need was to have a back pressure input on a force induction engine? Besides to sell you another $250 worth of hardware. We ran the big block n/a without this input, but again the absolute pressure did not change much, it any.
Did some surfing and found info on various forums on setting up engine dyno cells.
Seems that the Bosch or NTK WB sensors are affected by pressure deltas above and below standard atmospheric pressures. Graphically depicted in this screenshot. This is based upon the technical data on the Bosch sensor itself.
I have a feeling it has to do with the Perfect Gas Law. PV = nrT
Now this author used elevation as the variable to cause delta P. IMO (guess), Forced induction would be a bigger factor as the boost pressure simply does not get absorbed in the combustion process. Remember these sensors are in each primary prior to the turbo.
I think you are onto something with the OEMs and ignoring the AFR. It simply goes to the map and grabs a correct value per the predetermined map based upon the the engine development program. Most likely conservatively rich and listening for knock.
Next step is to wire in the AEM module and have it feed the analog inputs to the ECU. It will be interesting to see the amount of each runner is getting compared to it neighbors. I have a feeling cylinder 4 is getting totally robbed relative to the others.