Originally Posted by RichardV6
A GDI owner showed me his similar well thought out new installation yesterday. This consisted of a bespoke air deflector fitted within top of cowl, angled upwards to take cool air from well in front of rad and over the top, as suggested by Cain at Wolf Performance. A broad collector located as high as possible behind and slightly behind rad and attached to 4 inch hose hose picked up this cool flow and fed it to air box, mitigating the heat convection/conduction from rad top tank. Important since he had the now common larger aluminium rad limiting space above.

Developing a viable and improved cold air intake has been on the agenda for some time.

No drilling into, cutting or irreversibly modifying existing components on the car was a prime consideration. Consequently if the mods were of no discernible benefit, all items could be removed and the intake returned to standard.

At speed, a strong flow of cool air enters the cowl grill and this was the favoured entry point. The louvres in the side of the bonnet were considered too small to be effective and fitting a large side intake cowl would involve cutting the bonnet. A low level front entry point was considered impractical due to the inner wing and the steering/suspension components obstructing a smooth duct passage.

A large touring plaque had previously been tied to the cowl front without adverse heating effects, and consequently an aluminium plate has now been fixed in front of the radiator to deflect cool air between the top of the radiator and the underside of the cowl. This cool air will be channelled into a duct leading to the air filter box. The greater the road speed, the greater the air box should become pressurised. So long as there is a fast air flow, the air in the duct should not heat up appreciably from the presence of the radiator and exhaust beneath. It may be necessary to vent the air box, but that is for the future.

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Behind the cowl about 100mm beneath the top of the radiator on each side is an M6 inner wing fixing bolt. These bolts were used to secure aluminium brackets. A close fit to the side of the inner wing and a thin rubber pad acting as gasket prevents bracket rotation about the bolt. The brackets are curved to match the curvature of the inner wing. An aluminium deflector plate was then cut and secured to each bracket via a pair of M5 bolts at each side.


Two types of air duct intake will be assessed. One is a closed end tube with large side holes and the other is a tube cut at an angle to scoop air into the duct. A bespoke U- shaped duct bracket has been fabricated and fixed using the standard fixings. The duct has an aluminium ring at the air box end and is a push fit into both the air box spigot and the U-bracket. Entire duct removal takes no more than a few seconds.

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Currently waiting for the weather to cheer up before road testing and a track day at the end of February should deliver a verdict on these mods.