Sway Bar Upgrade
My 750iL handles great for a 5000 lb car, but it was known to lean a lot in the corners. After taking my car to the track, I really... Show more wanted to do something to improve the handling and flatten the way it corners. Upgraded sway bars were order. They made a big difference in handling and the car corners much flatter. The real test will come when I head out to the track in the spring.
Here is the original 20.5 mm front bar and the 22 mm �sport� bar that comes on late 740i Sport models. It is a direct swap for the factory bar on any E38 7 Series. The only other parts that are needed are new rubber bushings with 22 mm holes in the middle.
Here is the original 10 mm rear bar and the 13 mm �Eastern European� and �Bad Roads Package� bar, which is not available in the US. If your car has a rear sway bar, the new one is a direct swap. As with the front bar, new bushings with the proper sized holes are needed.
Unfortunately, swapping the front bar is NOT an easy job. It takes most of the day and there are no shortcuts. You need to disconnect much of the lower front suspension, unbolt the steering gear, raise the engine several inches, then unbolt and lower the front subframe.
The rear sway bar is much easier to swap. It can be done in about an hour. It only requires unbolting the sway bar brackets, disconnecting the self leveling sensor attachment, disconnecting the end links, removing one wheel and sliding it out the side.
Sway bars were factory installed in the US on all long wheelbase 740iL and 750iL models with self leveling rear suspensions. They were not installed on other models. The possible exception is short wheelbase 740i Sport models. Many published specs indicate that the sport models have sway bars, but owners of 740i Sport models have indicated that their cars do NOT have rear sway bars.
Here is the bracket that mounts the sway bar to the car�s subframe. This shot was taken with the exhaust system removed from the car. This bracket is normally only visible from getting all of the way under the car and looking up.
This is the subframe mounting bracket viewed from underneath, looking straight up.
Here is the left frame bracket as viewed from the center of the car looking toward the left. The camera position was just below the differential.
This shot shows the position of the rear bar as it crosses behind the differential. There is plenty of clearance behind the differential, but the clearance behind the self leveling sensor and the front of the spare tire well �tub� is quite limited. In this picture, the self leveling sensor is bent slightly out of position and the arm that connects to the sway bar is missing. It was damaged when the floor jack slipped out from under the differential as the car was being jacked up.
Unfortunately, cars without rear sway bars do not have rear sway bar mounting brackets. A number of people without rear sway bars have indicated a desire to install brackets and rear bars on their cars. These photos are included to help identify how the brackets are mounted for the benefit of those that may wish to install their own. This picture shows the distance between the bar and subframe that the lower control arm mounts to.
Subframe mounting bracket.
Lower control arm. On the first picture, the end of the tape measure is at the center of the lower control arm bolt.
Lower control arm bracket from the side. (Sorry about the lack of focus.)
Lower control arm bracket from the top. On the last picture, the end of the tape measure is at the center of the lower control arm bolt.
Please browse to the following pages:
2 In the Beginning
3 From the Front
4 From the Side
5 From the Rear
6 The Interior
7 The Audio Video System
8 Both of My 750iLs
9 May Puget Sound Meet
10 June Puget Sound Meet
11 July Puget Sound Meet
12 Engine and Drivetrain
13 BMW Club Concours d'Elegance
14 BMW Advanced Driver Training
15 BassLink Install
16 Oil Change and Oil Pump Bolt Check
17 Quad Rear Brake Lights
18 Phone Install
20 Strong Strut
21 Eisenmann Exhaust
22 Sway Bar Upgrade Show Less
Page 21Eisenmann ExhaustI had been thinking about an exhaust upgrade for some time. There were two things stopping me. The cost of the exhaust system was o... Show morene. What to do about the cutouts in the bumper valance was the other. Getting rear ended caused me to move forward. In the end I invested close to forty hours on my efforts, but I am extremely pleased with the results. The rear valance is unique in that it looks like a factory installation, even up close.Here is my car after I got rear ended. I was taking up the rear of a Seattle 7s drive. I was at the end of a long line of cars stopped for a red light. You can see the intersection in this picture. All of a sudden I heard and felt a crash as a car hit me from behind. The Toyota Corolla that hit me had a wedge shaped nose, which was nose-diving as the driver slammed on the brakes. It went right under the rear end of my car. Fortunately, none of the drivers in my car experienced the slightest injury, not even sore necks or backs. The driver of the other car had minor abrasions and cuts from his airbag, but nothing serious.The injuries to my car look fairly minor, but they added up to nearly ten thousand dollars, not including another fifteen hundred for a rental car for over a month. The obvious damage was to the left muffler and bumper valance. It also smashed in the spare tire �tub�. This required removing the entire exhaust system and rear suspension and all of the electronics in the trunk so that a new pan could be properly welded in using the same factory seams as when the car was built. There was also a very small wrinkle in the fender just above the left rear wheel. This required a chassis pull, fender repair and repaint of the rear end of the car.Because half of the exhaust behind the rear axle had to be replaced, I decided to go all the way and upgrade it with an Eisenmann exhaust. I also took the opportunity to cut and mold exhaust cutouts in the new bumper valance before it was painted. Here is the car that hit me. As you can see, the damage was extensive. The car had to be towed away and was totaled.Key to my exhaust cutouts was a heat gun, which I used to mold the edges of my cutouts to form a smoothly blended lip on the edge, rather than just a thin edge that I would have got by simply cutting out the shape with a saw or rotary cutting tool. After my old bumper valance was removed from the car, I went to work practicing and developing techniques for shaping the edges. I used a couple pairs of wide jawed vice grip pliers to bend the plastic while I heated the edge with the heat gun. It took a lot of work to find the right amount of material to leave in place and the right technique for bending the plastic.Here is the old valance with all of the test cuts and bends. I got the measurements for the cutouts from a friend�s car that already had a similar Eisenmann exhaust. I marked a centerline and referenced all measurements from there.After I got the general shape of the lips on the cutouts, I used a special plastic filler to blend and shape the edges, as well as provide reinforcement. The filler is called Duramax 4040, which is sold by automotive paint and body supply dealers. It is used to repair urethane bumpers and other materials. A large tube costs about $40.They offer a large gun to simultaneously squeeze out the material, but it was quite expensive, about a hundred dollars. I chose to simply use a long screwdriver to press on each of the plunders individually. It wasn�t at all difficult to measure identical amounts simply by pressing each plunger the same amount.Once the material is mixed like epoxy, it has to be applied within a few minutes before it starts to harden.Here is what the back of the cutouts looked like. I used a special fiberglass reinforcing grid tape underneath the filler, as recommended by the manufacturer. This helps reinforce the corners and prevent cracking. After the filler was fully hardened, I shaped and sanded the surface using regular body finishing techniques to smooth the surface. The body shop that repainted the back end of the car did some final finish sanding before it was painted. Here is the completed bumper wrapped up and in the trunk of my rental car as I brought it to the body shop.Because the Eisenmann exhaust for my car was out of stock and had to be built in Germany and shipped to the US, I had to wait about six weeks for delivery. Once my car was back from the repairs and I had to drive around for almost a month with the cutouts, but no exhaust tips sticking out.Here is the new Eisenmann Exhaust laid out to admire. There are three levels of performance available; sport, high performance and race. I selected the middle option, high performance. There are two types of tips; flat oval and round. I selected flat oval. Unlike most people, I installed the exhaust system myself. The first step was to jack up the car and disconnect all of the exhaust mounting bolts and letting the factory exhaust system hang down. I set the new Eisenmann exhaust on top of the factory exhaust and marked the locations to cut through the original exhaust pipes with a portable grinding wheel. The new exhaust slips over the old pipes and clamps on with heavy duty exhaust clamps. All of the other mounting points utilize the factory mounting points.Here is the new exhaust system installed on the car.Unlike the original Eisenmann exhaust systems, the new models are staggered so that the tips follow the contours of the rear bumper. The cutouts look good from any angle. The black color makes it hard to see the details, but the edges do bend under and form a lip that looks like a factory installation.The new Eisenmann exhaust sounds great and looks great. Please browse to the following pages:1 Introduction2 In the Beginning3 From the Front4 From the Side5 From the Rear6 The Interior7 The Audio Video System8 Both of My 750iLs9 May Puget Sound Meet10 June Puget Sound Meet11 July Puget Sound Meet12 Engine and Drivetrain13 BMW Club Concours d'Elegance14 BMW Advanced Driver Training15 BassLink Install16 Oil Change and Oil Pump Bolt Check17 Quad Rear Brake Lights18 Phone Install19 Jets20 Strong Strut21 Eisenmann Exhaust22 Sway Bar Upgrade Show Less