Tuning EMS, Fuel and Ignition Options

[McMark]

I'm installing the beta KitCarlson FI and I'm turning my attention to tuning. I have access to a wide band O2 sensor setup for tuning in the FI part of the setup, but I'm not exactly sure how to optimize the ignition. My initial assumption is to install an EGT gauge. I would think this coupled with knowing the AFR would clue me into the ignition. There are so many factors I can modify that I'm having trouble keeping it all straight. Help me figure out what I need to do to get it well tuned. (IMG:style_emoticons/default/pray.gif)

[DNHunt]

Markd

I'm gonna be facing this in a month or so. I assume your ignition tuning screen is a grid with MAP vs RPM. Megasquirt is set up with a 12 X 12 grid.

Ignition timing gets a little fuzzy for me because the whole thing is counterintuitative. You probably are more comfortable with it than I am but this is the way I understand it. A vacuum advance unit actually returns the timing to the mechanical curve. Under light load there is a need for more advance because there is less fuel and air and it therefore burns slower. The area below the intial curve is lighter load and should require more advance. Above the curve will be where the engine is under increased load with more fuel and air in the cylinders and faster flame propagation. There should be some retarding of timing. But, this is the area I worry about. I think this is where tuning really comes in.


This is what I'm planning. I'll use the Unilite curve with the grey, grey springs off the Mr Gasket page to establish an initial curve. I'll use 12 degrees at idle with 28 degrees max then pull 4 degrees out by 5000. I think this will be pretty close. I'll advance the timing a little below the curve. Above the curve I'll start with the same figure as the curve for each column (RPM) then very slowly pull a little timing out and watch the temperatures and see how it feels. EGT responds quicker than CHT so I'm gonna install an EGT gauge for tuning and a knock sensor would be nice. When I think it's close I'll take it to a chassis dyno. I THINK THE DYNO IS A MUST.

Hope it goes well for you. Please keep us informed how the tuning goes.

Dave