YES OR NO??

Been looking at them for a while, but wanted to get some opinions on them from people with a) a Ford Focus and b) an air induction kit.

I've read they can hammer fuel economy if you have a heavy foot and that they can also damage your engine

Cheers

no all they do is make a noise and lose power as they suck hot air in from under the bonnet even with a cold air feed it requires the car to be moving to get the cold air so at lights etc you just suck hot air stick to the standard set up

Not too sure. Different people have different results. I had an open fine which was all noise, but recently done a DIY job.

Put a K&N panel in the original airbox, sealed it all and then took all the resonator out (below the battery) and ran a cold air feed straight to the passenger fog light. It's all sealed so the air has nowhere to go except the engine.

Once your moving, about 40mph or above, there is a noticeable increase in torque, quite a bit to be honest. The feeling of being nudged back in your seat lasts quite a bit longer if you know what I mean.

But the open cone just converted fuel into noise so don't so that haha

Mine (hybrid K&N Gen 2) works nice and gives bit more turbo/dump valve noise without being OTT (imho)

Much better access to the oil filter and other things too now the airbox has been removed.