Lee,
when doing my gearbox oil i had a good look around the TME air intake system. I even removed the air box/fuse box to get a better idea of the layout.
My thoughts are as follows:
Standard air box, filter and pipe to turbo doesn't look bad. They are a decent size. Main restriction will be the air flow meter which has a 4mm pitch hex flow lineariser (makes the flow non-turbulent). The trouble is theres not much you can do for this without binning the standard ECU and going for a manifold pressure system to measure (deduce) air flow.
The intake pipe to the air filter has a 3 inch entrance to the air box but due to proximity of inner wing alot of this flow area is lost. This pipe also had a very badly formed entrance by the side of the battery. This entrance had very sharp edges which would be detrimental to flow .The reason I think this is down to the days when I used to do alot of head grinding and was checking the flow through the ports. It was amazing the difference that putting a carburetter intake trumpet over the port entrance even though the port was square and trumpet round. Hence I took off the intake pipe and with my power drill and an arbour smoothed the entrance into this pipe.
In the future I will look at connecting this intake pipe direct to the front aperture to gain some ram effect and cooler air. The potential problem with this is water ingress. To stop this I am thinking of a further air box directly behind the bumper entrance. The air would flow into this tangentially which would fling the heavier water droplets onto the edges of the box where it would run down to the bottom and out of a small hole. The air would then exit out of the top of the air box via a hose (tumble drier type) which would connect either to the intake pipe or directly into filter air box. I shall have a look around a scrappy for a suitable secondary air box, but a montego one may suit. Or it may be possible to weld one up out of bits of pvc drain pipe.
I have ordered a pressure adapator for my multimeter and will check the preesure losses in the system to confirm the above.
A few questions:
1. can you get a performnace element for standard box?
2. how easy is PVC pipe to weld?
Any commnets on this would be welcome.