Installing in the collector will give an average A/F reading for side of the motor. Typically when installed in the collector you will only get an accurate reading at higher rpm 3-4k plus, due to reversion effects at idle. Installing in header will give accurate reading from idle up, but only for that cylinder.
EGT's are not as accurate for precise tuning as wideband O2 sensors, but are more cost effective for matching cylinder to cylinder performance.
Be sure to click on our banner at the top of the page for ClassRacer member discounts!