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Road based MAF calibration

Practical Reflash Tuning

Discussion and questions related to the course Reflashing


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Assuming I have Cylair filtering and anticipation as well as LTFT disabled, good injector data, and reliable fuel pressure information I have assumed on long level roadways I could get the MAF pretty close.

Should I use Pedal only or can cruise control also be used to make slow measured 1mph progress working through histogram as RPM and Load change? I have been using a period histogram.

Currently My trims are pretty good however my IPC wheel torque errors are very large. This leads me to believe there is something off in the calibration. So I guess I need to find my mapped point and see why the Torque table believes I should have 300-400 ft lbs at idle?

This Whipple calibration has fooled me from the start. The more I learn and look at different logs the more confused I become due to the fact it does not appear to follow conventional wisdom and instead seems to be a synchronized harmony of scaled values and tables that dont make much sense.

What exactly are you trying to do? Can you give more context?

base Whipple cal with injector upgrade and long tubes.

If injector data is inputted correctly - trims are off especially under idle / vacuum. there is no leak anywhere. tested twice with smoke machine. Trims remove 20-30 percent of the fuel. a test with a flat 20 percent reduction to MAF period cleaned it up in cruise but then car ran 20 percent or more lean under boost. Obviously cant accept that.

If MAF is calibrated with proper injector data Cylair-VE tables and torque model is off. cruising is actually ok but transients surge and under boost the MAF period values from original cal are ok. the areas in which the MAF period was modified show large IPC torque errors, which suggest to me I would have my work cut out for me trying to re-calibrate 15 mapped points for ve and torque tables.

I am thinking now that there is something scaled in the calibration as this original Cal / OS was released for the 5.0. The 5.0 has a inferred fuel pressure model. The GT350 has a dual pump setup with PWM routines that are driven from the fuel pressure sensor on the rail. The calibration when used on the 5.0 behaves more or less as expected. I have talked to several folks that gave up trying to calibrate the OS for the 350.

I think that may be why the Whipple Cal/OS is so off, I do not think the calibration itself is using real-time fuel pressure and instead they used inj data scaling to offset the difference between real / inferred fuel pressure. I have also noticed this cal has a set value of 55psi as "differential fuel pressure" but the value never changes and looks hard coded.

I think I may just go back to a NA GT350 OS and modify it for higher load.

Appreciate any input.