How-To

HOW-TO

Last Updated 22 May 2008

944 S2 AIR FILTER ELEMENT REPLACEMENT

Pictures TBD

The air box and filter element for the 944 S2 are located up under the front header panel. This is an ideal location for collecting large amounts of cool intake air, but a lousy place to place the air box for easy access. Replacement of the filter really isn't that difficult, it just requires the proper tools. Here's the procedure:

	Turn on the headlights to pop them into the up position, then switch to parking lights while you complete the procedure.
	Remove the rubber seal directly in front of each headlight. Slide it back and forth a bit as you pull towards the rear.
	Two 8 mm nuts will now be exposed under each seal. Carefully remove these and the large washers. Don't drop them under the headlight!
	Remove the 10 mm hex head screws, one on each side. These are hidden in the outermost, front corner and screw into the fender area. You'll need a 1/4 socket and extension to get into the cramped space. A 10 mm 1/4" drive swivel socket works great.
	Look towards the center of the car through the opening by the headlight. Remove the two Phillips head screws, one on each side (if present). These are a bit difficult to see and to remove and even more difficult to replace, so don't be surprised if the screws are missing.
	Remove the four Phillips head screws at the top, rear of the panel.
	Carefully slide the panel straight forward and remove from the vehicle. You may want to run a strip of masking tape along the front edge of the panel on the flexible bumper cover to prevent it from accidentally getting scratched.

The air box will now be exposed. If you are fitting a standard replacement paper element all you need to do is snap open and unlatch the three spring clamps. The front of the air box and the filter element can now be removed. Check the air box for debris and cleanliness, fit the replacement filter, and re-install everything.

Note: if you are fitting the K&N filter element (info here), you may want to remove the air box completely to replace the element. The K&N "frame" is more flexible than the stock element, which makes it harder to guarantee the element is properly positioned. To remove the air box, simply loosen the hose clamp and remove the 10 mm bolts.

If you examine the design of the air box and filter element you'll see the factory designed it for failsafe operation. Under normal operation only about half of the filter element has significant air flow through it. Eventually, that section of the filter will have a higher pressure drop than the less contaminated section of the filter and more air will flow through the cleaner end of the filter. Therefore, you really get two filters in one. Somehow, I think the factory realized a lot of S2 owners would neglect replacing the filter element so they designed it to last a long time.

For another write-up (with pictures), visit Jim Griffin's 944 S2 air box modification page... info here.

AIRBAG STEERING WHEEL DELETION

Pictures TBD

PCNA sells a brochure entitled Service Information Technik, Airbag- System, part number WKD-497-121. It presents a nice overview of the airbag system, but don't expect to find too much technical information. I did find it helpful in understanding the basic operation of the airbag system however. The cost was less than $10.

STEERING WHEEL REMOVAL

To prevent inadvertent discharge of the airbag during removal, the negative terminal of the battery must be disconnected for a minimum of 20 minutes to allow the firing capacitor in the controller to discharge.

The airbag is attached to the steering wheel with two self-locking Torx T30 screws. If these screws have never been removed they will be difficult to remove. If possible, use a socket driver and ratchet instead of a screw driver.

Disconnect the red electrical connector by pulling it straight out. Once the connector is removed from the rear of the airbag the electrical contacts in the airbag short together to prevent accidental discharge from static electricity.

As a safety precaution, store the airbag with the front face pointing up or away from any solid surface. In the unlikely event of an accidental discharge you don't want the airbag flying across the room!

The steering wheel is attached with a 24 mm nut (M16x1.5, 45Nm or 33 ft-lb). Remove it, the steering wheel, the plastic steering column cover, and the rotary controller for the horn & airbag. This will expose the multi-function switch.

MULTI-FUNCTION SWITCH

When I started this project I was told the steering column multi-function switch (i.e., turn signal, wiper and cruise control) must be replaced with the non airbag model and the matching steering column cover in order to retain a functioning horn. I purchased these parts new at a cost of nearly $150. When I tried to install these pieces I found the new switch wasn't compatible with the cover because it didn't have the proper mounting holes! A defective part? Perhaps. At any rate it went back to the dealer.

So... back to the Airbag-System manual. Hmmm. The 911 and the 928 appear to use the same multi-function switch for both airbag and non airbag steering wheels. The only difference looked like the addition of a little horn contact in place of the rotary airbag controller. After inspection of my multi-function switch it looked like this same part would also work on the 944. I snapped in part 928-652-104-00 (about $4) and had the equivalent of the non airbag setup. Disclaimer: while this horn contact worked great in my 1990 S2 and my son's 1989 turbo, I've been told that not all model year cars have the proper little hour-glass shaped cutout in the multi-function switch faceplate... so be sure to check. Note: to remove the multi-function switch you'll need an 8mm 1/4 drive socket and at least a 3" extension to reach the steering column attachment bolt.

Please note that the multifunction switch is somewhat adjustable for position on the steering column. In other words, it can be moved in or out slightly after loosening the clamp bolt. You may find it necessary to adjust it's position slightly so the rear of the steering wheel hub will clear the large diameter hole in the plastic faceplate cover... and at the same time put adequate pressure on the horn contact.

So far so good... the only problem is the horn wire for the stock thumb switches goes through a rotary contact device with a separate wiring harness. On the non airbag setup the horn wire harness terminates at pin 71 at the back of the multi-function switch. The new horn contact has this new pin and the existing connector has the provision for it... you just need to find a method to splice in the existing horn wire. I was able to purchase the proper female crimp socket at my local Porsche dealer from their stock of miscellaneous electrical parts. I cut the existing horn wire at the "car side" of the horn connector in the rotary contact harness, and terminated it in this socket, which then clipped into the existing connector holder. One of these days I'll get around to taking some pictures since I'm sure they would help :-)

PASSENGER SIDE AIRBAG & WARNING LIGHTS

At this point the car will run and the passenger side airbag will still be operational. However, the Airbag Indicator, Seat belt, and warning lights will remain lit because the SRS controller will register a fault from the disconnected driver's side airbag.

There are at least two methods that can be used to turn off the warning lights.

METHOD 1: SNIP THE WARNING LIGHT WIRES. The SRS controller is the bright orange module bolted to the underside of the dash in front of the glove box. It connects to the car harness through a round, 7-pin connector. The wire colors and functions are as follows:

1- brown, ground
2- red/black, central electric KL50
3- black/white, central electric N48
4- black /red, supply for DME relay
5- white, buzzer relay, seat belt
6- unused
7- yellow/black, airbag warning lamp

To keep the warning lights from activating, snip wires 5 and 7 on either the car side of the harness or at the controller itself. (Note: the wires directly attached to the controller are different colors). I didn't use this method because I didn't want to cut any wires in the car harness or controller. In any event, if you snip the wires or just leave the warning lights on, you do NOT KNOW THE STATUS OF THE SYSTEM. Therefore, I recommend the passenger side airbag also be removed or disconnected AT THE BAGS to ensure the bag contacts are shorted. This requires pulling the glove box, which is easily removed by taking out the 5 Phillips screws, the glove box light, and the glove box door. Removal of the passenger airbag is a PITA. I left mine intact, but disconnected.

METHOD 2: DISCONNECT THE CONTROLLER. This is the method I used. If you just disconnect the 7-pin connector the car won't start because the controller needs to send a signal to the DME relay via pin 4. This problem can be overcome by jumping pins 3 and 4 together so the relay receives a signal. The easiest method to do this is to use an old controller-side connector half from a bad controller... or the one from your old controller if you don't intend to use it again. This preserves the integrity of the stock wiring.

I suggest cutting all the wires off the back of the old plug except those corresponding to pins 3 and 4, solder or crimp those two wires together, and protect with shrink wrap or other suitable method (I sealed the back of the connector with RTV). Insert the modified plug into the car side connector half and the engine will start and function normally, and the warning lights will be deactivated :-)

I have one reservation about using this method however. In the event of a real crash that would have been sufficient to deploy the airbags, the controller interrupts power to the DME relay. This turns off the engine and fuel pump. By leaving the controller connected and snipping the warning light wires, this feature is retained.

I really love the look and feel of the 3-spoke steering wheel, and the slightly smaller diameter is nice for the added leg room and quicker steering. If you can live (no pun intended) without the airbags, I highly recommend fitting the 968 CS or similar steering wheel if you drive on the track. Take a look here.

Dissclaimer: I do not advocate removing or deactivating the airbags for purely cosmetic reasons. There are valid reasons for removing or deactivating the airbags, such as: track use, equipment age, or protection for short drivers. Weigh the associated risks and make your own informed decision.

	To prevent inadvertent discharge of the airbag during removal, the negative terminal of the battery must be disconnected for a minimum of 20 minutes to allow the firing capacitor in the controller to discharge.
	The airbag is attached to the steering wheel with two self-locking Torx T30 screws. If these screws have never been removed they will be difficult to remove. If possible, use a socket driver and ratchet instead of a screw driver.
	Disconnect the red electrical connector by pulling it straight out. Once the connector is removed from the rear of the airbag the electrical contacts in the airbag short together to prevent accidental discharge from static electricity.
	As a safety precaution, store the airbag with the front face pointing up or away from any solid surface. In the unlikely event of an accidental discharge you don't want the airbag flying across the room!
	The steering wheel is attached with a 24 mm nut (M16x1.5, 45Nm or 33 ft-lb). Remove it, the steering wheel, the plastic steering column cover, and the rotary controller for the horn & airbag. This will expose the multi-function switch.