K&N were good when cars had pancake filter housings and they increased filtration area by about 10x while still sucking from the warm engine bay...
Fast forward 15-20 years to today, and forced air intakes are common place, and filter areas are optimum for the CFM the engine needs to make power.
No longer is power 'given up' when the race for every last gram of power and efficiency is scavenged for where possible. If making a filter housing bigger could add the power K&N often claim, the OEM's would!
They are still great though, where they were always great, on thinks like Dakar racers where they can clean the filters on the fly quickly and easily, where paper ones just clog quickly in such conditions, and may not clean easily either!
Imo, K&N and the like still flogging their filters is a hang over from the day when road cars DID benefit from having them. It's just not the case today so we are sold snake oil instead for most road stuff!
For K&N to do a better job considering what their unit prices are on even the £200-£500 stuff (so possibly £20-£50 to make), vs what the OEM's can do for a similar cost, it just doesn't add up that K&N can do something better for less money than the OEM's do.
Dave
