Alright guys and girls, you go to the fleamarket and see this awesome cone air filter. You remove your existing box and flat bed filter and put in the filter you brought at the fleamarket. It sounds cool. It feels faster. You want to show off so you go to the next dyno day. You find out you have 5KW less power!
What your filter is actually doing in this situation is actually sucking in all the hot air from your engine. Bummer! Why do you think there was a plastic box around your filter. Also to make sure the air is being routed from the front of the car directly to the intake.
The only solution here is to create your own performance box around your air filter and to make sure no hot air is coming from the engine close by. You will need a proper induction kit made out for your car or purchase a universal kit that has been tried and tested. You can also use Ram air piping and place it on a bumper duct or where there is the most air pressure to get the most of this system.
Oh and please do not use those Turbo Air Wizard or that thing that plugs into your car battery to create more power. That stuff is rubbish and we refuse to sell it on our stores.