Articles

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. […]

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 […]

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. […]

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 […]

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 […]

Roll sensitivity describes how far the car will roll given a certain cornering force applied. Depending on the direction of the calculation, any number of the variables in this can be solved with a combination of knowns and assumptions. This can help not only calculate load on a given tire or suspension point, but allow […]

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 […]

A leak down Test can be performed on a warm engine. The appropriate leak down testing apparatus will be required, along with a good air compressor. You should not have a cylinder leakage of more than 10% in any cylinder for a fresh/healthy motor. You should also not have more than 5% variance between any […]

Compression Tests should be performed on a warm engine, with the fuel pump fuse/relay unplugged (and the fuel rail drained/depressurized), and the throttle should be held fully open while testing. These pressure values will be less at higher elevations, and can be lower on engines with more mileage. Aggressive cams or cam timing will also […]

Before you have us tune your car, there are a number of important things to verify. If there is a “small problem” that is unknown before the dyno session, it can nullify The pre-dyno check list is similar to the pre-track check list: – Test the intake system for leaks – Check, clean, or replace […]

Materials can deform both elastically (returning to its original shape and structure) and plastically (permanently changed in shape, structure, or both). Every material under any sort of load (lets consider a fastener in tension) is deformed elastically, even if it is such a small amount that it’s impossible to notice. The strain (deformation, elongation in […]