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Below you can see the value at 7,000 Hz has been reduced to 1,157.8. At this point, you would continue to make further adjustments using the data you obtained for the values from 5,800 Hz up through the maximum value you can log.

1966 Chevy C10 engine swap - Page 3

swapping in GM's LS3 for more power and fuel efficiency

At higher engine speeds and loads, you may require a wideband O2 sensor to accurately determine the actual air-fuel ratio. The commanded air-fuel ratio is shown in the data logs, but the factory O2 sensors cannot show rich mixtures accurately below approximately 13.5:1, so a wideband O2 may become necessary. This is no big deal though, for if you get a hold of the HP Tuners MPVI GM Pro kit, you can connect up to 4 analog inputs to the interface and the data from those inputs can be logged along with the factory parameters obtained through the OBD II port. It doesn't get much easier than that.

To recap, remember to get your engine up to normal operating temperature, make sure the engine oil is up to temp as well, and then prepare the VCM Scanner for data logging. Activate the logger by clicking on the Record icon and then go for a short drive. Log a solid acceleration run that'll run the engine up to redline in 3rd or 4th gear if possible, and then save the data. Next, use the LTFT corrections to create a list of corrections for the MAF Frequency data points (every 500 Hz point up from idle works well). Once you've completed adjusting each of these points, interpolate the values in between to smooth out the MAF curve. AND DON'T FORGET TO MAKE CERTAIN THAT THE VALUES FOR 5,800 HZ MATCH IN BOTH THE LOW-SPEED & HIGH-SPEED TABLES!! Once you've obtained your new MAF curve, program the PCM and perform another test run to verify your work. It's not at all uncommon to need 2, or in some cases, 3 sets of adjustments to fine-tune your MAF curve. You should be able to get the total correction to within +/-5%. If this is the case, you've managed to do the job well and can get to enjoying your sweet new swap! MET

In this case, we select the cell at 7,000 Hz (shown having a value of 1,244.9) and then we enter "0.93" in the adjust-by box to multiply the value in the cell and thus reduce it by roughly 7%. Easy stuff.