I've been busy for a while checking out the different options to replace the standard airfilter. There is a lot of choice and a lot of junk. Finally the best option seems to be a BMC airfilter:

Ofcourse I didn't only want to replace the airfilter, but also the tube that connects it to the throttle valve. This is a bit of a strange tube, flattend and it has two channels inside. This has probably been done to allow for enough space to the bonnet when the engine is placed in the frontside of a vehicle.

It was tricky to find a good replacement pipe and a way to fit the connectors for the two hoses. Finally I found a couple of aluminium connectors, some Samco and BMC subing and a bit of PVC pipe. Originally I was looking for an aluminium pipe, which I did find in the right diameter.

All parts in a row:

In the end the aluminium pipe wasn't strong enough. So I ended up wit the PVC one (steel would have been another option, but I found that too heavy).

Ofcourse all of the components had to be made to fit the car. So first got out some of the tools and the original pipe from the car.

Trim the new pipe to size. Then drill a hole on the left side for the air temperature sensor. The two connections for the hoses where screwed and glued into place with two component glue. That turned out to make a very good connection.

To place the BMC filter (and also removed the original filter) you need to remove the rear wheel and the archliner. Then we had to find a good place to mount the filter on. In the end we found a pretty good spot. The bracket that comes with the filter needed a bit of bending, but the mount works very well.

Then fit the 90 degree tubo to the pipe and connect the rear hose to its connector.

Connect the 90 degree bend to the throttlehousing and see how to pipe ends up.

Connect the 45 degree bend to the pipe and the airfilter.

Now everything seems to be in place, and the final bit of tubing can be connected to the airfilter can scoop up cooler air. The tube goes to the side mesh in the body. The tube and the air filter are at quite a nice angle, so bigger bits will drop out.

In the end I changed the black BMC 90 degree bend for the Samco bend so it looks a bit nicer. The final setup looks like this.

After the filter was on the car I measured the power. With a completely standard engine I could not measure any difference to the stock filter setup.

What did change was the sound the engine makes. I tried the record it. The mp3 sample below was made from the inside of the car. It gives a bit of an idea what kind of sound the engine makes now. By the way, this is with the standard exhaust system on the car.

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