Just messing with commanded fuel ratios.
This graph is interesting and shows max economy at 15.4:1 AFR. Right where I normally run for light load.
As I usually run quite lean I have been trying semi closed loop out. It seems much more responsive. I'm not sure if this is due to bank to bank variation or due to the slightly reduced power from the leaner mix. However after over 33,000 log frames tracking bank to bank fueling the average from both banks is identical. Pre heads, cam and SVO 30's I had around 2-3% variance. So perhaps the injectors were a bit out of whack stock.
I will try near to stoich for a while as I like to responsiveness off idle off the richer mix. I will also reassess using the alpha-n fueling for low throttle and map points as it also seems much nicer response wise.
Ive also ordered a Road Runner pcm. This will allow me to make on the fly changes to the pcm even while driving. This is so I can minimise Dyno time. Basically no need to shutdown and flash updates. Should be cool. It will also help to dial in idle issues as you can make adjustments as the engine is running.
By the way, Ive logged 0.87g/cyl recently. Im still hoping to break the 0.90g/cyl level with some more tuning.
Ok after some testing running close to stoich is much better for power.
I logged O2 mv and the following diagram shows the results in Open Loop. Basically the O2 voltage switches as though its fueled in Closed Loop. This is at idle so only a couple of cells. But hopefully I can get the same affect over the rest of the range. Who needs O2 sensors and a MAF!
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