Archive | Technical Information

Heat, Energy, and Temperature

Defining terminology: The total of all energy in an object is its internal energy. Heat is not the energy the body contains but the energy transferred from one body to another. We can make clear distinctions between temperature, heat, and internal energy. Temperature is a measure of the average kinetic energy of the individual molecules. […]

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Launch Control, antilag, and rev limiters

rev limiters, launch control, and antilag, are all different things. Antilag is typically accomplished via combustion continuing into the exhaust manifold to spin the turbocharger, but without accelerating the engine. This can be at light part throttle or zero throttle by the driver, but the system will hang the throttle open slightly (or slightly more […]

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Differentials

The purpose of the differential is to allow two wheels to turn at different speeds while coupled to one shaft. With the two sides coupled and no speed differential possible, as in a “locked” or “spool” or “welded” differential, the drive power when turning is substantially higher as slip is required on one side or the other. […]

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Throttle Mapping on DBW cars

In modern cars, there is no longer a “throttle cable” linking the throttle pedal to the throttle bodies. Now we have a throttle pedal that is a sensor/input to the ECU, and the ECU controls the throttle bodies. This is known as “drive by wire”. This has a number of advantages. One of the biggest […]

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Vehicle Road Testing – Part 2

In part 1 of this article, we discussed the principles for gathering coast down data. There are a number of things that can be determined from that data. We can calculate the aerodynamic drag and rolling resistance components of the total drag. The large component at high speed will be aero drag. It will vary […]

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Vehicle Road Testing – Part 1

Enhancing the performance of a vehicle isn’t always limited to making more power. Often more speed can be found by using less power to push the car through the air or along the ground. The best way to evaluate the effect of a change on a car is via controlled testing. We will need to […]

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Trouble Codes OBD1

Trouble codes on your OBD1 BMW

If your BMW was manufactured between the late 1980’s and 1995, you should be able to pull diagnostic codes out of the car via the check engine light. To read these codes, turn the key to position two (run), but do not start the engine. Within 3 seconds of turning the key to position 2, you will […]

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Boost Controllers

The primary control of boost in a turbocharged system will be the wastegate. The purpose of the wastegate is to bypass the turbochargers turbine, reducing its ability to make boost. (For more information on how the turbocharger works, see our article on turbochargers.) The wastegate will have a pre-set spring pressure. This can be adjusted […]

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Engine Calibration and your BMW

If you own a BMW manufactured after the 1970’s, there is some sort of computer controlling the fuel delivery to the engine. By the 1980’s all of the BMW cars in the US had some sort of fuel and spark control based on a piece of electronics. This computer would use various load inputs, such […]

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