This article is one in a series that have been released in conjunction with Wayne's book, 101 Projects for Your Porsche 911. The book contains 240 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 650+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Porsche 911 owner's collection. See The Official Book Website for more details.
It's almost unbelievable that the early 911s did not ship with a stock front mounted sway bar. The front sway bar is probably the best suspension improvement that you can perform on your 911. The sway bar adds stiffness to the suspension by coupling the spring effects of one side with the other. The sway bar acts as a torsion bar that resists suspension displacement across the width of the car. When one side of the car starts to dip, the sway bar (connected to the other side) acts to pull it back up. Through this coupling effect, the car maintains an increased stiffness and reduces side-to-side sway.
Up until 1973, almost all 911s appear to have shipped from the factory with the mounting tabs for the bulkhead mounted sway bar. In 1974, the sway bar was mounted below the body and integrated into the front suspension (see Pelican Technical Article: Replacement of Sway Bar Bushings and Brackets). Some racers prefer the through-body setup that was used on the early cars. You can install this through-body bar on the later cars with a set of aftermarket mounting brackets.
For 911s with the mounting tabs already installed, the attachment of the sway bar is a snap. For those without these mounting tabs, you will have to drill the holes required for the installation of the aftermarket bracket. You may also have to install the u-tabs onto the a-arms of your car if it didn't come with them installed. Most cars will have a cover attached to the sway bar mount on the inside of the fender. If your car has this cover, then simply remove it and the sway bar installation becomes a bolt-in process.
The first step in installing the sway bar is to obtain all the parts that you need. For this installation, you will need a sway bar kit with drop links, a u-tab mounting kit, the sway bar mounting kit for the bulkhead, and new bushings for both the bar and the drop links. You will also need a 1" hole saw to drill the hole for the sway bar in the bulkhead, if your car doesn't already have this hole.
You can choose to install the stock 19mm Porsche sway bar setup, or you can opt for an aftermarket setup. The stock original Porsche sway bar kits are still available, however, they can be quite expensive. A good aftermarket kit is the Weltmeister sway bar kit. Available in sizes 16 mm , 19 mm, and 22 mm, the right sway bar for your task can easily be fitted to your car. I suggest that you use the stock 19 mm size sway bar if you are planning on driving the car on the street, or the thicker 22 mm if you plan to do some racing. The Weltmeister bars also offer adjustability along the torque-arm of the bar, which means that you can lower or increase the rate of stiffness in only a few minutes.
The first step is to install the u-tab kit on your 911 front suspension arms. Jack up the front of the car and remove both the left and right wheels. Most 911s without sway bars did not come with these tabs installed. Check your a-arms before you order the kit, though, as some did sneak out of the factory with the tabs attached. Drill a hole in the a-arms exactly perpendicular to the top surface of the a-arm. This hole should be located 5 1/8" from the center of the ball joint. Make sure that this distance is equal on both sides of the car. Fasten the u-tab kit to the a-arm using the hardware supplied in the kit. If you have access to a welder, then these tabs can be welded instead of bolted-on.
The next step is to create the holes required for the sway bar to fit through the chassis. It is recommended that you use the improved sway bar mounting bracket available from Weltmeister (part no. SB-1955). This bracket mimics the factory-welded plate that was installed with cars outfitted with factory sway bars. The kit includes a template for drilling the holes in sides of your chassis. Make two photocopies of the template and tape it onto the inside fenders of your car, according to the directions in the kit. There should already be a depression in your chassis where the mount is to be located, so you shouldn't have too much trouble placing it in the correct position.
Drill two of the three small holes that are used to mount the adapter. Once these two holes are drilled, you will want to bolt the adapter plate to the car in order to use it as a template for drilling the remaining holes. For ease of drilling, mount the adapter plate to the outside surface of the fender well. You will have to reach around into the inside of the front trunk of the car in order to fit two bolts into the plate. With the adapter plate mounted to the outside face of the inner fender, you can now use the adapter to guide your drill for the large center hole, and the remaining mounting hole.
Once you have the adapter mounted to the outside of the fender, use the third hole in the adapter plate to guide yourself, and drill through the chassis. Then, using the 1" hole saw, drill the large center hole through the chassis. Repeat the same procedure for the opposite side.
After you have all of the holes drilled, the sway bar can be assembled on the car. File down any of the edges that might stick out of the chassis sheet metal from the holes that you drilled. Make sure that you use new bushings at the mounting points near the fender well, and also use new drop link bushings. Remove the adapter plates from the outside of the fender, and place them on the inside of the car, using some masking tape to temporarily hold them in place. Then insert the sway bar into the chassis. Place the bushings onto the bar, and then attach the outside mounting plates to the sway bar on each side. Finally, bolt the arms to the ends of the sway bar, and attach the drop links to the u-tabs on the a-arms. Make sure that the drop link clears the brake line and the strut before you reattach the wheel.
If you are going to be using your car for racing, then a wise upgrade might be a set of adjustable drop links. These allow you to dial your front suspension for greater balance, or to adjust the sway bar in case the track on which you are racing only banks in one direction.
When you put your car back on the road, you will feel a remarkable difference, particularly when making quick turns. You will wonder why the factory never installed these as stock equipment in the first place.
This photo shows the inside fender well and the stock early 911 sway bar installed. Use a new bushing at the bulkhead, and also new drop link bushings when you are installing the bar. Also make sure that the nearby brake lines and shocks don't have any opportunity to make contact with the sway bar mechanism. Check the bar for clearance both when the car is elevated, and when it's resting on the ground.
This is what the inside of the fender looks opposite to the sway bar mount. The nuts shown here are welded in from the factory. If your car doesn't have this these mounting nuts and bracket already installed, then you will need to install the aftermarket bracket which has these nuts integrated into its construction.
Shown here are the u-tab kit and the aftermarket inner bulkhead mount from Weltmeister. The u-tab kit contains the necessary hardware to mount the tabs to the 911 a-arm. The bulkhead bracket consists of heavy gauge sheet metal with three encapsulated nuts on the rear.
On the left is a picture of a factory 911 a-arm with the u-tab already installed. If your a-arms are missing this u-tab, then you will need to install the kit onto the a-arms, as shown on the right. Install the sway bar into the car first, so that you can double check the location required for the u-tabs. Make sure that they are in the same location on both sides of the car.