but surely a lot of intakes are designed to reduce engine noise as much as possible rather than gain maximum performance ?
Nowadays? You are right.
Unless its a performance derived car designed for that purpose, you can pretty much guarantee that standard induction systems are designed to reduce sound & emissions first and foremost. Thank the U.S (Californian) and Swiss market for that part!
As Javam says: A lot of performance related car manufacurer's go to a lot of trouble and effort to get it right with standard induction... Many mainstream "shopping/ family car manufacturer's don't though, space limitations and the above being the being a prime directive.
The results in the video dont suprise me. That is typical... However....
What does shock me is the lack of run length of the entire intake that they used with the aftermarket induction systems. Heat soak, airflow routing and buffeting all playing their part to make it as bad an effort as possible to get the worse result. But in all fairness, that's exactly what the average "Chav" does when fitting aftermarket induction kits
It wasn't the most "balanced" review I have seen...
A bit more effort and planning would see far better results, but that wasn't the point they were trying to prove, was it?
Am I a fan of after market induction? Yes and no!
If it's to get rid of bad design and build quality like the Alfa airbox lid and the issues it causes for example, then yes.
For the average Nismo/ Evo/ WRX/ GTi, prancing horse etc. then no!.... It was designed right in the first place.
As long as the correct principles and planned route is followed, there is no reason why healthy gains can't be achieved
There is always going to be argument's for and against...
My installation was out of neccessity really and the extortionate cost of O.E replacements!