Originally Posted by jfsiutza
This would be possible if the cars computer would adjust extremely quickly. the cars computer has to learn new fuel trims and new timing with different spark plugs everytime. so doing it back to back would be pointless and wont have reliable numbers. this is why I've tested a pre-learn stage then later on a learned stage dyno test.
No the ECU as long as you didnt take the batt cable loose can learn the new fuel and timing in mil seconds , there will be little no no fuel changes at all with changing plugs
The only way to do this test properly is
NEW OEM plugs installed on the dyno just like the plugs your testing , just installing a new plug even if it is the same plug thats already in there will make petter HP
Then the other plugs installed and dynoed new
I like the Autolite AR and XP plugs