Could someone go into the theory behind each of the above. To expand on the question, some run their AFR's starting at say 10:1 at max boost (low in the rpm range) and taper it to say 11.5:1 at redline. Others run it opposite starting at 11:1 and going rich higher in the RPM's. What is the theory behind each of these tuning methodologies and what is each trying to accomplish when timing is entered into the equation?
i dont pretend to know but more fuel - cooling and at WOT the EGT goes up and to cool it you add fuel.
Richest at peak cylinder pressure = at peak tq = lower in the revs (with smaller turbos), then lean out to try and keep cylinder pressure up at the top. Depends on the turbo, with a big enough turbo you flatline it... SS
Ah I gotcha, so it is more a matter of cylinder pressure more than anything? So in theory you would also want to have it at peak advance? Why does Subaru have it the oposite? They go from leaner at lower RPM in the higher boost and richen it up on the top end.
Richen up at the end injects extra fuel to cool down the cylinder. That's important too, but many other tuners lean out toward redline to compensate loss of Volumic efficiency as revs climb up. I picked the later path. Mine runs 10.5 at peak torque area then tapers up to 11.1 @ red line. I need to change my plugs and fine tune little more. (check your pm mike)