Originally Posted by dyn085
And as an fyi, the K&N intake actually lengthens the intake tract from the MAF sensor on.
Are you only measuring to the MAF? Intake tract length would include the entire length of the tract that generates vacuum, correct? Wouldn't the tract length be measured to the filter on the K&N (where the vacuum chamber effectively ends), and past the filter to the snorkel on the stock intake?
Also, I wouldn't expect the stock box to necessarily gain hp with the lid removed due to filter/elbow restriction, but I wouldn't be surprised if low-RPM torque was reduced by removing the lid. Removing the lid would effectively shorten the intake tract.