Search Entire Site
call toll free
888 581-1035
The HOT Spot Menu Top KO Show Cars
KO Show CarsCustomer Cars
Video Clips
Tech Articles
Enthusiasts Events
Other Hot Links

The HOT Spot Menu Bottom

lowest price guarantee

The HOT Spot - Tech Articles - BMW Superchargers and Turbochargers 101
  KO Performance Technical Articles and How-To Archive

BMW Superchargers and Turbochargers 101
For E36 and E46 BMW owners.

Posted on: 12/17/04
Written by: Jim Nolden
KO Sales Manager, BMW Car Club of America (BMWCCA) Member Club #280717, Track enthusiast, and driver and owner of the
KO 97 E36 M3 Supercharged Saloon Track Car
Contact the author - Email:


To many people, the 3 series E36 and E46 BMWs are some of the best cars available on the market. There is a reason these cars have been included in many publications among the best cars you can buy, and why so many competitors have been chasing BMW to come up with something equal to the 3 series in craftsmanship, quality, and performance.

As good as the 3 series BMWs are, a common question among enthusiasts is, "How can I improve my car even more?"

There are many ways to improve the 3 series BMW. Some people chose to improve the suspension, while others add a cold air intake and exhaust components… But to make a dramatic change that will take your 3 series BMW to Supercar Status, and performance the likes of cars that cost two to three times as much money, like Porsches and Ferraris, forced induction is the clear choice.

Forced induction can be broken down into two categories.

The first category is Turbocharging. Tubocharging makes efficient use of the exhaust gases of the car and sends them through a turbocharger which is typically connected to the exhaust manifold of the car. This gives a level of positive boost that inducts more air into the intake manifold of the car. This condition is called boost, or forced induction. Since the motor is an air pump it can generate more power by inducting forced air into the manifold of the car resulting in a higher level of efficiency in the motor and the ability to produce more horsepower.

The second form of forced induction is Supercharging. Superchargers create additional power not from exhaust gases, but rather from boosted intake charges. The intake air is fed through what is essentially an air compressor that takes the intake air and compresses and accelerates it by means of a supercharger. The supercharger isn't driven or powered off of exhaust gases like a turbocharger, but is instead powered by a belt driven by the crank pulley of the car. The crank pulley turns the supercharger so the power is linear with the revolutions of the motor. You will not experience "turbo lag" with a supercharger since it doesn't take time to spool up, but rather builds power as the revolutions of the car increase.

Which is better?

The answer really comes down to a matter of choice, personal preference, and goals for the performance of the car. Let's take a closer look at features and benefits of each…


Turbochargers are capable of producing more horsepower than superchargers in almost every circumstance. They also are capable of producing more torque than most superchargers.

You may be saying to yourself, "So if they can produce more horsepower and torque why doesn't everybody choose a turbocharger?" Well, in a word, money. Turbochargers cost much more in most cases. But for the person looking to really make big horsepower, turbochargers are the way to go. Turbochargers cost more because they have more parts and are more complicated than superchargers, thus requiring more design work for a more complicated system. They also are far more difficult to install than a supercharger and require an intercooler. Turbochargers also generally require that the car's compression be lowered to operate the engine at a safe level.

Tuning can be adjusted far more easily with turbochargers since boost levels can be controlled by electronics and aren't dependent on the revs that the car is running at. Therefore advanced tuning can be accomplished by turning up the boost level and doing additional software tuning. This can also require additional hardware such as larger intercoolers, beefed up internal components and larger injectors. To really build up a huge horsepower car, the turbo has the most expandable capabilities.

So what are the downsides of turbos?
The answer basically comes down to the buyer's limitations of funds. A Stage II Active Autowerke kits run around $11,000. Installation typically runs around $4,000. There are, however, a few other things that some people don't like about turbos. Turbos can have what is called "turbo lag". This is a time delay between when the turbo spools up and actually starts to deliver boost to the car, and when the driver presses the accelerator down. This is usually more noticeable at lower speeds. Smaller turbos will produce less lag time, and less power, while a larger turbo produces more power but more lag. It is a trade off, and tuning can remove a lot of these limitations, but none the less, it is a common knock on turbos. The other consideration is drivability. Turbo power is not linear. It is very much more like an on/off switch. When the turbo starts making boost, power is delivered very quickly. Since it is driven off of the exhaust gases it produces power when the spool up of the turbo has occurred and produces boost very quickly. This results in surges of power and torque in a very quick rush. If you are driving this car on the track this can be a trait you don't necessarily want. Boost coming on at the wrong time can be a dangerous thing on the track or street if in the hands of an inexperienced driver. No one wants to spin out in a turn from an unexpected surge in power at the wrong time.

Just how much horsepower can you produce in a Turbocharged E36 M3? It is possible to reliably build a 600 horsepower car with a turbo. For example, a Stage II Active Autowerke Turbo Kit will produce about 450 horsepower and 369 ft/lbs of torque.

Let's take a look at supercharging...

Supercharging is the second form of forced induction and produces similar results to turbocharging through a method of accelerating intake charges through a compressor or "supercharger". Intake air charges are run through the supercharger which is driven by the crank pulley of the motor. This linear effect drives supercharger revolutions based upon the revs that the car is running at. So acceleration and power will come on in a very smooth linear effect across the entire power band and will reach maximum horsepower as redline approaches. Since the supercharger runs off of the intake charge it is not always necessary for supercharged cars to have an intercooler since the air charge is not from the hot exhaust gases of the car but rather the cooler intake charge from outside air.

Superchargers are far less complicated than turbos, and typically can be bolted on to existing components without doing any internal engine work. They will usually bolt on to existing hardware in the car and require little if any permanent modifications to the car in order for them to function properly. They also don't require all the hardware a turbo needs since they don't use a modified exhaust manifold and don't require the car to have the compression lowered in order to function safely.

Superchargers will produce very good horsepower numbers, and in almost all 3 series BMW applications you will see an additional 100 horsepower, and usually another 40-50 ft/lbs of torque. All of this power will come in to play in the 3k to 4k RPM range on a 3 series BMW. These conditions make a BMW Supercharged 3 series extremely drivable. For street purposes the supercharger is a very fun car to drive. It doesn't have any of the turbo attributes of going from lag to boost quickly. The supercharger is usually very seamless, and feels very much like the car did being normally aspirated (non-boosted / pre forced induction), only with much more power.

So what are the features and benefits of a supercharger?

BMW Superchargers cost far less than turbo kits and can produce similar results although they are not as expandable as a turbo kit for advanced tuning.

They are usually fairly simple to install, and don't require modifications to the motor or require complicated hardware to function properly.

They don't exhibit "turbo lag" and produce very linear smooth power that is easy to control.

There are many choices for a 3 series BMW supercharger vs. available choices in turbos. Many tuners have spent a lot of time and money in developing and improving superchargers for street applications, whereas there are only a very few BMW tuners offering turbo applications.

Now that we have discussed the basic principals of forced induction, lets talk about each of the kits that are out there and find out which kit is the right kit for you!

Superchargers are available in many different types and sizes. For this purpose we will look at the most common kits available for the 3 series BMW.

The first BMW supercharger we will discuss, and also the most common BMW supercharger used is powered by a Vortech blower unit. Vortech is the most common supercharger you will see in most BMW applications. This is the choice of ESS's E36 kits, along with Dinan. Vortech Engineering designs and builds superchargers that don't need to have an intercooler integrated into their systems. Vortech does this by using a very efficient blower that doesn't generate high temperatures that would require an intercooler at 5 to 8 lbs of boost. Vortech kits are also expandable (although Dinan won't ever admit this)! Additional boost can be run in these units with the use of an intercooler or aftercooler for even higher performance levels. KO Performance has engineered, and designed a Stage II Boost Kit for Dinan and ESS Vortech BMW Superchargers that allows for the normal boost levels in a standard Dinan, or ESS kit of 7 psi to safely be increased to 9.5 psi for additional horsepower and torque reaching almost turbo levels!

The second type of supercharger (blower) is Rotrex. One of the biggest BMW tuning shops in the USA, Active Autowerke, uses the Rotrex blower for its ability to produce more low end torque than Vortech units . Rotrex does this by running at higher rpm's than the Vortech unit. The by-product of this feature though, is higher temperatures. The Rotrex supercharger generates more heat since it runs at higher revs. Active Autowerke properly engineered their system to incorporate an intercooler, and an oil cooler to address the heat issues from the Rotrex blower. The oil cooler helps keep oil temperatures under control for the blower. This supercharger setup actually has its own oil supply that isn't dependent on the engine's motor oil. This results in a kit that doesn't heat the engine oil to an unnecessarily high level due to it serving duel duty as the engine and supercharger oil supply. Active Autowerke kits are not expandable and will not be able to be added on to like a Vortech kit.

The third type of blower in production right now is the ASA blower. ESS (European Supercharging Systems) has begun releasing BMW supercharger kits using ASA blowers. The ASA supercharger has a unique advantage that the Rotrex and Vortech kits don't have. It has a clutch that engages past 1k rpm. The advantage to this is that the supercharger is not being driven and producing heat when the car is idling! The ASA blower runs very similarly to the Vortech kit, in that it doesn't need an intercooler to reliably produce horsepower, and is expandable like the Vortech kit is. Another great feature is the fact that it isn't producing the heat levels the other two types are, because it is not engaged at low RPMs. For the cars that sit in traffic, or are often idling, this is a major advantage for people that do a lot of driving in dense population centers, and other high traffic areas. These blowers are new to the BMW supercharger market, but not to tuning in general, and are very reliable and safe supercharger kits to add to your BMW.

So, now that you know the basics of superchargers and the three types of kits available for BMWs, how do you choose what is right for you? Here are some good questions to ask when considering BMW superchargers for your vehicle.

1. Do I ever want to expand on the horsepower that I will be adding, or is this as far as I want to go?

2. Will this car be driven in hot climates that may require an intercooler and oil cooler?

3. Do I drive a lot in traffic where the heat generated by a supercharger would cause me to heat soak the motor?

4. Do you plan on putting this car on the track where heat would be an additional concern?

The best way to answer those questions is to research as much as you can, and find out the differences between the BMW kits available on the market, or call and speak with one of our qualified Performance Specialists on staff at KO Performance. A KO Performance Specialist can help you get the answers to the questions you have, and make sure you make an educated decision that you know you will be happy with.

You can enjoy some peace of mind in knowing that KO Performance carries only the best BMW performance parts available, and we only supply products that we know work, and are from the best names in the business. The one constant among all these kits is that they are all very good, and you can't really make a bad decision with any of them.

The last bit of advice I can give you is DON'T PAY MORE FOR LESS! Dinan has, for years, dominated the BMW tuning industry with their name and reputation. Unfortunately they also charge a premium for that name and reputation. All of the BMW supercharger kits on the market are built to the same or better standards than Dinan. Many of the other kits are also designed to be expandable as well, to allow for additional tuning. What Dinan won't tell you is that there are other people and companies that have also spent countless hours tuning the 3 series BMW and charge far less for their kits, while producing similar results! Dinan makes great BMW supercharger kits but so do Active Autowerke, and ESS (European Sugercharging Systems). You will find all of their hardware to be first rate and their tuning excellent. Call and find out for yourself before you pay too much for a Dinan kit.


KO Performance offers the BEST PRICES on BMW superchargers and turbochargers GUARANTEED!
Test us on this… you'll be happy you did.

Stay in the loop! Sign up for our free Newsletter and Member Specials emailed to your inbox

Bimmer Magazine May 2006 Featured Article "Hammer of the Gods" unveils KO's E36 M3 Stage III Supercharger Boost Kit!
Bimmer May 2006 Feature "Hammer of the Gods" -
KO's E36 M3 Stage III
Supercharger Kit unveiled to the
public at 400 RWHP! more info...

Our Lowest Price Guarantee | Privacy Policy | Terms & Conditions of Sales, Use, and Disclaimers
© 2001-2013 KO Performance. All Rights Reserved.