Pay attention to pipe diameter when buying your new system. For example, the optimum exhaust size for a 318is is 2.25 inches, but the M3 uses a 3-inch diameter. This is to achieve the best flow rate versus backpressure. Induction kits can increase power gains across the entire series, but be sure to use a heat shield around an enclosed filter because heat soak will result in power loss.
You can get more power out of smaller engines by simply using a panel filter. Throttle bodies are also important when you’re looking to increase power to any 3 Series. Big bore throttle bodies or individual throttle bodies help deliver more power and a better throttle response to your BMW. Once you’ve finished with your power modifications you should consider a remap completed to fully take advantage of your upgrades.
The remap will ensure that drivability is at its peak and your power is increased as much as possible. Many people with smaller engine BMWs put this off thinking it won’t make much of a difference, but gains are available for all engines. If, after you’ve done this, the power is still not enough, you might want to look into a turbo or supercharger.
Once you’ve amped up your power you can look into styling. This is the most exciting part of a 3 Series project. There are as many parts available so you can literally spend days looking through what is available and planning your custom look. Some of the most popular aftermarket manufacturers include Hartge, AC Schnitzer, and Alpina.
One of the most important choices to make during your upgrade is which wheels to upgrade to. Bimmex recommends lightweight wheels to maximize performance without adding additional weight. This means avoiding replica wheels as they are generally heavier than standard wheels.
Many drivers choose to put 5 Series rims on their 3 Series BMW. If you decide to do this, you will need to use a spigot ring to reduce the center bore size. If you skip this you will experience wheel wobble at higher speeds.
If you’re working on an upgrade or considering starting one, call Bimmex with any questions you have. We are happy to answer your questions and help with installation and parts. We’ve upgraded hundreds of BMWs and enjoy working with drivers to help create ultimate driving machines.