[FreeBMW.net]

This mod will yeild a slightly louder exhaust note below 3000 rpm which is when the valve would normaly open. This method will not cause a CEL/MIL or be detectable by a scan of the DME/ECU but it can be seen pretty easy if visually inspected.

Needed items: two 3/16th vacum line plugs, one 3/16 vacum line male/male barbed fitting and about 15 mins.

The procedure:

1. Park car on level surface and set parking brake. I also recomend using a wheel chauk to prevent the car from rolling onto you in a freak acident.

2. Crawl under the car right behind the drivers side rear wheel and locate the flapper valve actuator on the left exhuast tip tubing. It will have a black hose with a yellow stripe pluged in to the actuator.

3. Remove the hose from the actuator by pulling and twisting on the hose.

4. On the actuator use one of the 3/16 vacum plugs and plug and cover the nipple you just pulled the hose off of.

5. Put the other vacum plug on one end of the male/male barbed fitting.

6. Use the plugged male/male barbed fitting to plug the open hose you removed from the actuator.

7. Tuck the plugged hose behind the metal bumper support.

8. Start the car and enjoy the new found grumble.


An optional install would be to have the car running while you pull the vacum hose from the actuator. you will hear the flapper open and the new sound. Make sure the car is not in gear so you dont run yourself over and dont let it run too long or the exhasut could get hot.

Pics below....