K & N Filter Installation
by Richard Poniarski
On Saturday I installed my new Ram-Air K&N setup for the M42. What follows is my experience with installation fun & games and the changes it has made to the car.

Step 1. Removal of the existing air box.
This was pretty easy. You just have to unbolt the two rubber mounts from the side of the airbox. Unclip the four clips on the airbox that you use to install a new standard filter. The bottom assembly just pulls out complete with snorkel. You then undo the four bolts that attach the top of the airbox to the air flow meter. Then voila, a nude air flow meter sits before you and the old airbox sits somewhere else.  

Step 2. Installing the Brackets
First up was setting up three brackets that attach together and then to the side of the air flow meter to steady it now that the airbox has gone. One bracket attaches to a stud on the rail below where the old airbox was. This is an L shaped doovy. Next bracket (a twisty little fellow) attaches to the rear airbox mount using the existing rubber mount. You are then supposed to bolt these brackets together. Problem 1 has now arisen. These two brackets may as well have been at opposite ends of the car the chance they had of connecting. Hmmm, make a note, pick up another bracket to join these two together when I inevitably have to go to the hardware store. But continue on in case some other problems arise. The third bracket works nicely and will attach to the air flow meter (AFM) with the supplied bolt and connects to the L shaped braket OK. Whoops, hold on, the supplied bolt is about quarter of an inch too long for the air flow meter. OK, I found a nut that I could use to fix this.  

Step 3. Attach the polished aluminium tubing to the AFM
OK, partial brackets installed awaiting parts. Now, connect the lovely polished aluminium tubing to the AFM. This is done by just slipping it onto the AFM using the protruding four bolts and tightening with newly provided bolts and washers. Is it? Is it really? Well, it doesn't fit. It nearly fits though, one of the holes is out about a couple of mm. OK, better drill out the offending hole slightly. But I don't have a drill, the one I normally borrow has been lent to somebody else. Well, its about time I bought my own anyway. Note to pick up a drill and appropriate drill bits from the hardware store. This is now getting expensive.

Step 4. The hardware store
After checking that everything else fits I popped down to the hardware store in another car and picked up a drill, appropriate drill bits and a bracket. About time I got a drill. Bad side effect of this is I can feel impending home projects being organised by wife. Sure enough, wife says "ooh, a drill now you can remount the bathroom mirror....."

Step 5. The installation
OK, hole redrilled. Perfect fit. Bolt aluminium tubing on using existing gasket. Perfect snug fit.... now. Assemble brackets. Everything now nice and secure though a bit Heath Robinson. Attach K&N cone filter to yellow plastic mount and tighten clamp. Attach yellow tubing to aluminium tubing and secure two clamps, one on yellow mount side, one on aluminium tubing side. One dose of the essence of terror, two doses of sinister salts, forget the tincture of tenderness. It's alive! Oooh, it does look good. The K&N is perfectly positioned where the snorkel for the cold air intake was. Very nice. Very 'European Car'.    

So what's it like??
Off I go for a drive. No change in sound on a light throttle. OK, things are warm lets have some fun. Yes, it feels a bit free-er. Seems to go a little better. Nothing dramatic but a less constrained feeling. Seems to work well with my RD chip & exhaust, and it will probably improve as the ECU learns. Seems to have improved torque down low and feels smoother over 4000rpm. Should have G-Teched it but I ran out of time.   Now, the sound, just great, there's a sort of slight turbo like swooshing on the transition from light throttle to more throttle and then that lovely marbles in a box induction roar that I love. Not as exciting as the symphony of the M3 Evo but a huge improvement over standard. Yes, a great addition, wide smile registered.   After checking the installation after my drive, I think I'll definately do the heat/fan shield thing soon as it gets pretty damn hot under there - and it's still Winter. It would be interesting to get one of those cheap thermometers and check the temp at idle and at speed to see the impact of the outside air flow. This would also be very useful when designing the heat/fan shield. I think I'll do this. They're only $20 or so. Pales into insignificance when you consider how much this has now cost me, what with initial cost, postage, duty, sales tax, unexpected installation costs....


http://www.318ti.org/notebook/KNfilter/
September 17, 1999