here is the link to an excel sheet detailing my A/F.
run 1 was with 50psi fuel
run 2 and 3 were 2nd gear 44psi
run4 was 3rd gear. 44 psi note the range where the mixture was closest to optimal is where my dyno torque maxxed. dynoing in second is useless.
this is with factory tune and 24# EV-6 injectors.
the MAF sample tube is totally modified and has a small tip in lean condition at lower fuel pressures. i would have to remove it and disassemble for oictures, but i altered the sample inlet to outlet ratios. i am probably going to modify it more. the inlet is .655" and the outlet is .800". I radiused the inlet to produce more velocity to the MAF sensor and reduce turbulence. i also cut a fillet .025" at the exit of the oulet to provide more surface area and increased vacuum signal.
i have been modifying MAF sensors since i put this motor and watching ECM response. you ask why? i have no idea why. i guess it's my curiosity, and my own desire to produce a result in a way others won't try. obviously i misses a little.
there is a factor i hadn't planned on that i can fix. first my dynamic decisions.
using 24# injectors and the PPIII was impossible.
my first try was to experiment with stock MAF rear cover plate. i measured and produced my own plate to begin experimenting with outlet surface area and the MAf's response. i found the MAf to be responsive for closed loop operation, but non reponsive for open loop operation regardless of fuel pressure. it ran rich at any rpm and caused closed loop hunting by the ECM. rich/lean/rich/lean in a never ending cycle. it also left tip-in leanout that was unacceptable. also it caused fuel loadup in the exhaust under open loop WOT operation. i found the stock MAF unworkable for open and closed loop.
enter C&L. they design sample tubes for various injector sizes. mine is for 30#. it is useless for 24#. i experimented with restrictions at first. i attempted to lower high signal responses by inserting orifices into the exit stream at the oulet. i tried various shapes and openings with no good results. so i switched to exit surface area and contour. the problem is velocity across the sensor at a variety of WOT rpms. when i increased the exit surface it caused an over sensitivity. so i needed to carefully open the inlet until tip-in alleviated just the smallest amount
to be continued....
run 1 was with 50psi fuel
run 2 and 3 were 2nd gear 44psi
run4 was 3rd gear. 44 psi note the range where the mixture was closest to optimal is where my dyno torque maxxed. dynoing in second is useless.
this is with factory tune and 24# EV-6 injectors.
the MAF sample tube is totally modified and has a small tip in lean condition at lower fuel pressures. i would have to remove it and disassemble for oictures, but i altered the sample inlet to outlet ratios. i am probably going to modify it more. the inlet is .655" and the outlet is .800". I radiused the inlet to produce more velocity to the MAF sensor and reduce turbulence. i also cut a fillet .025" at the exit of the oulet to provide more surface area and increased vacuum signal.
i have been modifying MAF sensors since i put this motor and watching ECM response. you ask why? i have no idea why. i guess it's my curiosity, and my own desire to produce a result in a way others won't try. obviously i misses a little.
there is a factor i hadn't planned on that i can fix. first my dynamic decisions.
using 24# injectors and the PPIII was impossible.
my first try was to experiment with stock MAF rear cover plate. i measured and produced my own plate to begin experimenting with outlet surface area and the MAf's response. i found the MAf to be responsive for closed loop operation, but non reponsive for open loop operation regardless of fuel pressure. it ran rich at any rpm and caused closed loop hunting by the ECM. rich/lean/rich/lean in a never ending cycle. it also left tip-in leanout that was unacceptable. also it caused fuel loadup in the exhaust under open loop WOT operation. i found the stock MAF unworkable for open and closed loop.
enter C&L. they design sample tubes for various injector sizes. mine is for 30#. it is useless for 24#. i experimented with restrictions at first. i attempted to lower high signal responses by inserting orifices into the exit stream at the oulet. i tried various shapes and openings with no good results. so i switched to exit surface area and contour. the problem is velocity across the sensor at a variety of WOT rpms. when i increased the exit surface it caused an over sensitivity. so i needed to carefully open the inlet until tip-in alleviated just the smallest amount
to be continued....
