Re: Semi-Fogg'ed? (long) (archive)

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In Reply to: Semi-Fogg'ed? (long) posted by Peter D on August 20, 2000 at 20:26:46:

I got the parts to Fogg my '97 Z3 1.9l. Took out all those plumbing peices, amazed at how many bends and connectors are in there. When the decisive moment arrived, I paused. If I screw up cutting the hole in the air intake box, then its going to cost a bunch to get a new one. [Pausing seemed warranted also since I suffer from that 'Get a BIGGER hammer' disease.] Looking at the peices I realized the biggest constriction was just outside the box, in a 90 degree bend; there the diameter of the air channel is down below 2 inches. The flexible tubing upstream of that is a good 3 inches, as is the hole in the box. Since the cross section scales as the square of the diameter going from less than 2 inches to 3 inches is goodly gain, though not 4 inches. So, I attached the flexible tubing to the box with duct tape (keeping all adhesive surfaces on the outside since I don't know what volatiles that gives off). Ran the tube down behind the foglight.

Perhaps it is delusion, but I think the engine pulls stronger in the higher RPM band. The air temp readout does respond faster to changes in outside air. What the heck -- I was so pleased I did the same to my '97 318i which also seems more responsive (though I know downstream retrictions may make this futile).

OK, Shawn and others, what did I mess up? Should this have any appreciable payoff? Anybody come up with a more permanent method of attachment than duct tape?

I'm semi-fogged too. What I did was :
1) remove the horn-shaped piece
2) realise that the hose was very nearly the same diameter as the hole in the airbox
3) cut 4 slots across the mouth of the hose, just so it can be compressed slightly in diameter
4) poke the hose into the airbox. It gave a satisfying 'click' and locked into place.

I also had hesitations about the cutting - this way I can put it back to stock quite easily,
and I have a noticeable improvement in performance.

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