Absolutely agree. My LS PCM recomendation was due to actually running them. He has a fantasy of lean cruise adding 5-10 mpg in something the weight of his van with the aerodynamic loada of his van. I have run well implemented lean cruise on many of my vehicles for 2 decades now. G20 and Express van both saw about 2-3 mpg improvement on flat, level road at highway speeds. 5-10 mpg is fantasy land even if the engine were moving a slick Corvette or Camaro. My buddies 71 Chevelle saw the biggest improvement I have seen and it was about 4 mpg. It has a 6.0L/4L80E and a 4.10 rear gear so it is singing along at ~2,500 rpm at 70 mph with very little engine load.Originally Posted by dave w
I suggested the 0411 or P59 because it is a far better PCM for what he is attempting to do than a stone age 165 and its matching MAF that even 10-15 years ago was nearly impossible to find a quality MAF sensor replacement for.
Ignition timing and fuel injection timing based off a crank sensor are far more accurate than a distributor. With dual timing maps and inidvidual cylinder retard capability the 0411/P59 results in less wasted torque and fuel. The LS PCMs also offer the ability to alter injection timing with engine temperature which is a big benifit. Can spray the fuel on the back of a closed valve with a cold engine and shift to spray as the exhaust valve closes with a hot engine, minimizing wasted fuel during split overlap. With even a stock L31 I can reduce the pulsewidth for the idle fueling as much 10-15% shifting hot injector timing to spray the fuel with a closed or almost closed exhaust valve. I have also mentioned to the OP that for torque at 1,500 rpm the TPI is actually about the worst single intake for that setup.
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