speed density vs. Alpha

[sc91183]

I finally have my 1983 Porsche 911SC up and running via Megasquirt II version 3.0. I am running rich at idle so I am going to start tuning this afternoon. I am currently running a MAP from another Porsche owner that was designed for Alpha should I stay in Alpha mode and do my tuning or is there a advantage to speed density? I have a vacuum line running to the ECU and I have ITB throttle bodies. I currently have a solid stable idle but she's rich. I do have a wideband O2 sensor.

[whittlebeast]

If you are starting from scratch, always start with Speed Density. Never start with someone elses map unless you experanced at setting up fuel injection systems and understand what every cell is realy doing. Use mostly MAPDot as a basis for AE triggering. As a hint on setting up ITBs on the ve table set up the VE table with about 1/2 of the rows covering between 80 and 100 kpa (assuming you are near sea level) as that is where most of the action will most likely be happening.

AW

[sc91183]

Well I switched to speed density and fooled around with warmup enrichment and then did some idle speed adjustments. My air fuel ratio at idle is around 14.9 and she seems to run pretty good, off idle has a few soft spots but I'll continue to adjust it.