How do you set base running airflow and IAC counts after a cam swap?
HP Academy's approach with HP Tuners:
- Correct fuel and spark first, or the airflow numbers you log won't mean much.
- Raise the idle target to suit the cam (about 800–850 rpm for an aggressive cam).
- Allow more throttle opening: idle "percentage max" is about 2% stock; raise it to 4% or more for aggressive cams.
- Log real airflow: use the VCM Scanner histogram to record mass airflow at idle across the coolant-temperature range, and put those values into base running airflow, adding 1–2 g/s so rpm doesn't drop out.
- Expect big increases: with aggressive cams, minimum airflow in the 600–1,000 rpm range can need up to about 50% more.
Don't drill the throttle plate to add air — adjust it in software. See cam tuning.
Want to do it yourself? See who tunes it, and how to learn.
Confidence: medium — sources disagree or are limited; check the sources below.
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Sources
- LS Tuning For Optimum Performance — LSX Magazine
- LS Idle Tuning Basics With HP Tuners — High Performance Academy