8 BMW E9X Weight Reduction Ideas

The E9x 3 Series

The fifth generation of BMW’s legendary 3 Series arrived as a 2005 model year replacement for the popular E46. This new platform had four main body styles, a four-door sedan (the E90), a five “door” station wagon (the E91), a two-door coupe (the E92), and a two-door hardtop convertible (the E93), and collectively these body styles make up what is known to BMW enthusiasts as the E9X platform. The E9x was available with both automatic and manual transmissions, and multiple engine choices were available, including four-cylinder, six-cylinder, and a V8 which was a first for the M3 model. The E9x was in production until 2011 and is still a popular choice for drivers and racers today.

The E9x 3 Series continued BMW’s success in motorsport by becoming a winning platform for racers at all levels of competition. E90 Sedans have won the British and World Touring Car Championship, an E92 M3 won the 24 Hours of the Nurburgring, and they have had lots of success racing in the United States in the IMSA Series. E9x cars make popular choices for track day cars and budget endurance racers today not only because the platform was a winner from the beginning, but because the model has been constantly developed since day one, and many aftermarket parts are available that increase performance and reliability.

E9x BMW came from the factory weighing anywhere from 3,100 to 4,000+ lbs depending on the car’s body style and options, so if you are preparing one for any form of competition, from a local autocross to a twice around the clock endurance race, you will need to shed some weight. Weight reduction can be a simple process on an E9x, and listed below are some of the best BMW E9x components to remove and replace to help you reach your goals.

1. The Trunk 

The easiest place to start shedding a few pounds is in your car’s trunk. For many years a spare tire, jack, and all the tools needed to replace it could be found in a BMW’s trunk from the factory. However, if you are driving your car to an autocross or track day, then you will most likely have a full set of high grip tires and tools in a separate vehicle or trailer.

BMWs will have various trunk panels and liners that only serve an aesthetic purpose, and these can all be easily removed. These may not be as heavy as a spare tire, but they add up to approximately 19 pounds and will not be needed on a competition car, so there is no reason to bring them to the track. While in the trunk, your car’s battery can also be replaced with a lighter-weight performance battery which will be a performance upgrade as well.

2. Rear Seats

On both two-door and four-door E9x models, the rear seat is easy to remove. This is partially because the engineers at BMWs placed an access cover for the fuel pump under the back seat, so it needs to be removed for pump access. This also makes the rear seat easy to reinstall if needed for street use.

With the rear seat removed, it will become easier to remove the various interior panels that cover the seatbelts and rear speakers in coupes, and if you are building a track-only car out of a four-door, removing the rear door panels makes sense too. The combined weight reduction of the rear door panels and rear seats equates to approximately 84 pounds.

3. Sound Deadening

BMWs are known for their perfect blend of performance and comfort, and to provide the most comfortable driving and riding experience for passengers, the factory has installed sound deadening material to eliminate as much road noise as possible. For BMW owners looking for extreme audio upgrades, more of this material is often added, but for any car that is looking to shed a few pounds for the track, as much of this material as possible should be removed along with any stereo system equipment still in the car.

With the trunk panels and interior panels removed, you can now begin to remove the sound deadening material found inside the car's cabin and in the trunk of the car. If you are building a track-only car, it makes sense to remove the carpet, which will give you easier access to all this material. There are a few ways to remove this heavy tar-like substance, but the most popular seems to be using a heat gun, hammer, chisel, and lots of elbow grease, and some even prefer to use dry ice. You will be amazed at just how heavy this stuff is, and removing it is one of the best ways to reduce weight in any BMW. The combined weight of insulation and carpeting is about 56 pounds.

4. Front Seats

All BMW E9x models came from the factory with front seats that are both comfortable and safe, but they are bulky and heavy. The front seats combined weigh approximately 124 pounds. Replacing the front seats with lightweight racing seats is a good idea for several reasons. A quality racing seat will not only way a lot less than a stock seat, but it will also be far safer than the seats that came from the factory and will allow you to utilize a 5-point racing harness instead of a traditional seat belt.

Removing and installing the front seats in an E9x BMW is a task that can be accomplished by any knowledgeable and competent BMW enthusiast, and this will also provide you with the opportunity to remove the carpet beneath them. To make installation even more manageable, a planted seat base can be installed that will allow you to mount sliders for adjustment and the seat of your choice. The best planted seat bases available can be found at Condor Speed Shop and will make the installation of racing seats trouble-free.

5. HVAC System

BMWs are known for their comfort, and the climate control (or HVAC) system plays a significant role in this. There are very few drivers on the road today that would purposely remove a car's air conditioning, but anyone building a race car will want all of the HVAC components removed to reduce weight and to reduce the strain on the engine. All components considered, the removal of the HVAC system equates to about 42 pounds.

If you plan to remove parts of your E9x’s Heating system, you will need to isolate it from your engine's coolant system, and Condor Speed Shop produces high-quality coolant HVAC delete plugs to block off heater hoses from the rest of the cooling system. Condor also makes an aluminum firewall panel and blower delete kit to seal off the cabin from the engine bay once your HVAC components have been removed.

6. Deleting the Sunroof

Finding a BMW without a sunroof is a rare and desirable option, but removing an e9x sunroof to save weight is not out of the question and is even required for many racing series. How you go about deleting your sunroof depends on what you will use your car for. Permanently removing the headliner is a must for a race car, but is not necessary for a car that will only see a few track days a year. Some racers prefer to replace the entire roof clip, which can be expensive, but the best overall option is a sunroof delete panel.

A sunroof delete panel allows you to remove the entire heavy sunroof cassette, and replace it with a single solid panel that fits perfectly and bolts directly into place utilizing stock mounting points. Condor Speed shop offers a bolt-in sunroof delete panel that weighs under six pounds (compared to the 33 pound OEM sunroof card) and will not require any significant modifications.

7. Lightweight Wheels

Aftermarket wheels are an extremely popular upgrade used to save weight on an E9x BMW. There are a lot of aftermarket wheels out there, so it is essential to purchase high-quality wheels from a reputable source. There are a lot of cheap wheels out there, but these are more likely to weigh more than stock wheels and can fail under pressure, making them unsafe for use on a racetrack, so installing quality wheels is very important.

8. Lightweight Panels and Polycarbonate Windows

Anyone building a serious race car will want to shed as much weight as possible and replacing heavy glass windows and body panels with lightweight parts are a must. Almost any panel on an E9x can be replaced with a lighter version, and most will want to start with a lighter hood and trunk. Front fenders and doors are also available but might require more skill to get the fit and finish precisely right.

The windows found on E9x cars are safe but heavy, making polycarbonate window replacements a popular weight-saving upgrade. Polycarbonate windows allow you to remove the heavy glass windows and their bulky mechanisms to save even more weight. Condor Speed Shop offers a polycarbonate window kit for E90 sedans that are a bolt-in replacement weighing only half as much as a stock window setup. They also offer window slider kits that allow for airflow without having to remove a widow. Check out this weight-saving window kit here at:

Less Weight Equals More Speed

Listed above are some of the best weight-reducing ideas for the BMW E9x platform. Everything from removing a few panels in the trunk for a local autocross to replacing heavy glass windows with polycarbonate for an endurance race makes a difference. The combined weight savings of the above equates to about 352 pounds, not including glass window weight. How far you want to go is up to you, but one thing is for sure, the best BMW parts available are found at Condor Speed Shop. Install the best lightweight parts available and hit the track!