sorry that was my friend that was making fun of me cuz i just got my filter and was happywhat do you mean by diagnostic test. i didn't know they had one that tests hp
If the old one was ****,and backed up,you could get six from it...i always figured the very most 3Hp..but put on some flowmasters,now we are talkingI hate to burst your bubble, but a K&N on a stock Vulcan will not produce more that a 1 HP gain, and even that is a serious over estimate. Will a K&N get you a 6 HP gain on a 800 HP BBC or 460 Ford or 426 Hemi..... yes. Will it gain 6 HP on a 155 HP Vulcan..... no way.
Where did you get the 6 HP number from????? Did you have the car dynoed before / after the K&N install under otherwise identical conditions???
Was your old air filter totally plugged with dirt?