GT, gone but not
Join Date: Feb 2007
Location: United Kingdom
With an open cone filter you will get heat soak, that is to say, when at a standstill the air in the engine bay will get hotter so when you pull away you are sucking in warm air which means less dense air which means less oxygen to burn which means less performance from a standing start. Once you get moving and the air is cooler it's usually more efficient than the manufacturer standard set up and you should see a slight performance improvement.
Best option if you can is find an airbox that fits the cone inside with about an inch all round, then route some ducting to the front of the car. That way even at standstill you will be sucking in external air which, even on the hottest day, will be cooler than that in the engine bay meaning better performance at all times. However, this is when it's really important not to route the ducting to the underside of the car as it will literally suck up water, whereas a well oiled cone filter may take on some water but it's less likely.
That's basically a very round about way of saying that if you have it low you risk taking on water, if you move it higher you will probably lose some performance from a standing start.
If you do enclose it though you will lose a lot of the induction roar you get from an open cone.
Good luck with the GT, can't wait to get my hands on one!