How to Get More Power From Your BMW
by IAN WENDT
If you are considering boosting for your BMW, or any bimmer for that matter, there are several things to consider. There are the basic questions like, turbo versus supercharger, which tuner and how much boost to make. But also equally important are issues of how other systems within your BMW will need to be changed to adequately handle all of that increased power. It is rarely the case where you can install a supercharger and you are all set without having to consider these other systems.
I can't address every BMW model in terms of supercharging and turboing, there are too many versions to describe here. However, in general, superchargers result in a slightly less expensive, easier to install kit. They often produce 6-8 lbs of boost and the typical home mechanic can safely install a quality application in 6 hours. Superchargers will typically produce significant horsepower but many suppliers will not produce a impressive amount of low rpm torque. For average driving you will not observe much of a difference until you get to higher RPMs. Turbos result in tremendous power potential, result in a lot of low end torque but can present a time consuming install. For example, in high boost pressure applications you commonly need to lower the compression ratio with either a spacer head gasket or shorter pistons. There are more pieces to a turbo application as well, consisting of items like an intercooler, bypass valve, blow off valve, waste gate, exhaust manifold, larger injectors, etc. The average home mechanic will likely be unable to do this install. A professional mechanic will require 8-12 hours depending on which kit and this can boost the total expense of the project. But, the higher power is worth every penny if it is within your budget.
Stopping: Well, if you build a 400 to 500 horsepower bimmer you had better have 400 to 500 horsepower brakes. Increased power results in higher acceleration, increased speed and much greater stress on your brakes. Typical upgrades include bigger diameter discs, upgraded multi piston calipers, sport brake pads, stainless steel brake lines and performance brake fluid. This should be one of the first things you upgrade after buying a turbo or supercharger.
Drivetrain: If you have a manual transmission, you should seriously consider improving your clutch. The Sachs heavy duty clutch is ideal for mild applications with higher performance kits requiring a UUC, Clutchmaster or similar application. It is best to swap it out now, because your OEM clutch will most likely die very quickly otherwise. This is typically about a six hour job for many technicians.
Cooling System: Horsepower equals heat. Your vehicle's radiator is designed to handle your stock power heat output. If you live in a hot climate, track your car or do a lot of performance driving you need better cooling. Your best bet is to find a larger capacity, performance radiator. Ensure the radiator is flushed and has new fluid. You may also consider engine heat shielding to keep the heat away from your intake and special hoods that have slats in them to allow the heat to get out quickly.
Your Skills: The most crucial thing to upgrade is your driving skill. All of that power may get you in a lot of trouble and you do not want to be hurt or injure anybody else. A great place to start is to look into BMWCCA driving schools. These are expensive and you will really learn a great deal. There are also many other professionally run driving schools around the country that have the ability to teach you how to safely drive your high performance BMW.
Rand Stuck is a BMW certified technician with over 11 years experience working on BMWs and currently manages the BMW parts department for an online parts retailer.
