DIY: 328i/323i 'Golf Tee' Mod

[sirius600]

Here's a DIY for the Golf Tee Mod that was first posted on my own forum. Original post:
http://www.e36-tech.com/forum/diy-328i-323i-golf-tee-mod-3402.html


Those with a 96-99 328 or 323 i/is may have heard of a 'golf tee' mod for their cars, though were never quite sure what this was referring to. The golf tee mod is a easy, cheap way to add a more aggressive tone to your OBD2 exhaust system that uses a simple golf tee as a vacuum plug.

The 328's and 323's have a dual stage exhaust that is actuated via a vacuum. In the center most tailpipe, you can look in and see a small flap which when working properly will appear closed. It activates once you pass 2500rpm, in which a vacuum is added from a line that runs under the car and to the intake manifold, and forces the flap to open allowing a near straight shot from the cats. The sole purpose of this is to quiet the car down at idle. The illustration below describes the process.



Unplugging this vacuum line will leave the flap open at all times, allowing for a more aggressive exhaust note at idle. The 'golf tee' comes in play as an ideal plug for the loose hose once it is unplugged, as the vacuum for this actuation is sourced from the intake manifold and not only creates the potential for vacuum loss but also makes a good place for insects to crawl into.

Now looking at the picture above, you may think why not just pull out the whole damn thing, part numbers 12 through 17. Well in theory you can, though unplugging the vacuum switch (#16) may throw a check engine light. Also be sure to properly plug the nipple on the intake manifold or else you will have a major vacuum leak.



For this mod you will just need a golf tee, some gloves, and perhaps a zip-tie.

First put the car's e-brake on. Then get on your back under the muffler, and look towards the edge of the rear valance. You will see what looks like a pressure regulator attached to the center most tailpipe. There will be a small rubber hose connected to the unit shown below by the red circle. (the person in these pics used a screw instead of a tee)



Simply pull out this hose, and stick a golf tee into it. Some have considered using a hose clamp or zip-tie to secure the tee in the hose, though ive found the tee to fit snugly enough to be on its own. Once the line is plugged, you will need to secure the loose hose by zip-tieing it to the vacuum fixture coming out of the tailpipe.



With this mod done, the flap in the tailpipe will remain in its default open position at all times.



Take it our for a drive, you will notice i much deeper growl at lower RPM's that was not there previously. Not bad for a mod that costs all of $0.10.

[PHARMDVIPER]

I did mine a while back....it did change the tone a bit especially around idle

gah I really want to put my system-U on

[Meatball546]

I did mine a while back....it did change the tone a bit especially around idle

gah I really want to put my system-U on

Same with me, except I didn't notice much of a change at low engine speeds. All I noticed was the increased off-throttle noise at fuel cut (sounds good to me) and the back firing is a little more noticeable.

If I ever get an exhaust upgrade, I'm definitely going with the System-U! I've listened to a few of the videos, and that's one of the most tasteful, yet aggressive exhaust noises I've ever heard on a six cylinder car.

[cornerpower]

wow...its so nice