Nissan 370Z Forum - View Single Post

Unclemeaty · 02-08-2011, 08:23 AM

*TIP* Press the 'spacebar' when in real-time tuning to get your 'ghost' tracer going; similar to an Apexi PowerFC standalone. its a quick way to data-observe what values the ECU was hitting during short operation.

So far its going pretty well for self-street tuning. The first thing I found (also mildly documented in Osiris User Guide) was that the ecu was running just barely off the right side of the ignition timing map. I'm sure that when this happens the ECU just provides the last row/column values as thats what most ECUs/standalone's do. The problem with that is you lose precise control of what the ECU is doing at the given engine demand. The ignition map axis peaks at 19.97, but after a few datalogs and traces I found the scheduled fuel was hitting about 3/4 a point higher (About 20.8ish) . The adjustment for this is a little un-obvious because the setting is actually under the fuel table static settings. Raising the value from 19.97 to 21 not only adjusted the Ignition table axis, it allowed the ECU to stay on the target values. I doubt this created any performance gain.

Im not an idiot, but I cant seem to understand why the A/F Correction figures are seemingly not working as I would have expected them to on this setup. At idle and low throttle, I see the correction vary from ~85-105... As soon as I got any higher than about 1/2 throttle the correction stays flat at 100 and does not change at all. Unfortunately this means I cannot tell if the ECU is adding or subtracting fuel out from the main fuel maps; and I seriously doubt that it's so perfectly configured from the factory that it doesnt need closed loop to hit the A/F targets. I also changed the A/F targets to suit. Does anybody see this on their setup?

02-08-2011, 08:23 AM	#26 (permalink)
Unclemeaty Base Member Join Date: Aug 2010 Location: Atlanta Posts: 203 Drives: 150cc Scooter Rep Power: 14	TIP Press the 'spacebar' when in real-time tuning to get your 'ghost' tracer going; similar to an Apexi PowerFC standalone. its a quick way to data-observe what values the ECU was hitting during short operation. So far its going pretty well for self-street tuning. The first thing I found (also mildly documented in Osiris User Guide) was that the ecu was running just barely off the right side of the ignition timing map. I'm sure that when this happens the ECU just provides the last row/column values as thats what most ECUs/standalone's do. The problem with that is you lose precise control of what the ECU is doing at the given engine demand. The ignition map axis peaks at 19.97, but after a few datalogs and traces I found the scheduled fuel was hitting about 3/4 a point higher (About 20.8ish) . The adjustment for this is a little un-obvious because the setting is actually under the fuel table static settings. Raising the value from 19.97 to 21 not only adjusted the Ignition table axis, it allowed the ECU to stay on the target values. I doubt this created any performance gain. Im not an idiot, but I cant seem to understand why the A/F Correction figures are seemingly not working as I would have expected them to on this setup. At idle and low throttle, I see the correction vary from ~85-105... As soon as I got any higher than about 1/2 throttle the correction stays flat at 100 and does not change at all. Unfortunately this means I cannot tell if the ECU is adding or subtracting fuel out from the main fuel maps; and I seriously doubt that it's so perfectly configured from the factory that it doesnt need closed loop to hit the A/F targets. I also changed the A/F targets to suit. Does anybody see this on their setup? Last edited by Unclemeaty; 02-08-2011 at 08:56 AM.