This data has been compiled from several posts to the list. I wish I could take credit for the extremely useful information found below; however, I just put it in the easy-to-digest form. Thanks to all of the DSM-gurus that have defined these terms. In a few instances, two or more folks provided such good descriptions, that I included more than one paragraph.
A computer-controlled system that can "sense", in a braking situation, when one or more wheels have stopped turning, yet the vehicle is still moving. The computer will then quickly release and re-apply the brakes repeatedly, thus giving the driver more control of the vehicle.
A full-time four-wheel drive system that, on the Diamond-Star cars, is accomplished via a torque-splitting center differential that divides the torque between the front and rear differentials. See also: FWD, RWD.
A system that actively turns the rear wheels (usually no where nearly as much as the front wheels) in the same direction as the front wheels to aid in high-speed cornering and to improve the overall "feel" of the car. The Mitsubishi Galant VR-4 and 3000GT VR-4(Stealth R/T) have AWS systems.
The engine has two camshafts that are above the head. These engines do not have push rods, etc., that are typical of non OHC engines (e.g. typical chevy 350). Some DSM cars are equipped with a 2.0 L DOHC engine. Some people call it DOH "Cam", but if you think about it, there are two Cam *shafts*, each having many lobes (cams) - unless you have a 1-cylinder engine. See also: SOHC.
A joint effort by Mitsubishi (three diamonds) and the Chrysler Corporation (penta-star) to build some of the most incredible automobiles in the world. The vehicles were produced with the names Eagle Talon, Mitsubishi Eclipse, and Plymouth Laser. DSM cars are assembled in Normal, Illinois. The '94-and-up Mitsubishi Galant is also assembled at the DSM plant in IL; previous Galant's were assembled in Japan. The Eclipse and Galant (since '89) share the same platform.
The computer that monitors and controls the various engine parameters.
Usually refers to a gauge that displays the temperature perceived by a sensor that is mounted on the outside of an exhaust manifold/header/etc.
An emission-control system that directs some exhaust gases back into the intake manifold to reduce the formation of nitrous-oxide (NOx) pollutants. EGRs typically operate off manifold vacuum, and therefore only operate in the off-idle state up to WOT.
This device is a basic closed-loop process controller. Its operation is very similar to an electronic cruise control device. You input a desired boost level, and it monitors the actual realtime boost pressure. It then adjusts wastegate opening to maintain a stable boost pressure (supposedly) as engine load and RPM changes. Without a closed-loop control that incorporates an integral correction factor, boost pressure will always vary *somewhat* depending upon engine load and speed. The EVC isn't perfectly "tuned" for all possible engine/turbo configurations, and it is prone to under/over correction at times. The wastegate control is achieved by modulating a solenoid that regulates the amount of air that reaches (and thereby opens) the wastegate.
The control module in the cockpit has controls that allow you to set one of four different boost levels - Off, Low, High and Manual. The Manual control has an adjustable-as-you-drive control for boost levels. The Low and High are small pots in the back of the control unit that you set once and leave.
In In Diamond Star applications, this comes with the PFC. In most cases, it appears that you can't buy it separately. The operating principle of the device is that of a frequency limiter. It is connected to the output of the Air-Mass sensor pin 2 on turbo TLE's - pin 1 on Galant VR-4's). The output frequency from the FCD tracks the input frequency until it reaches the limit setting... the output frequency then stays the same even if the input frequency (coming from the AMS) continues to increase. By fooling the ECU into believing that Mass Airflow never exceeds a predetermined amount, fuel cutoff is avoided. Unfortunately, fooling the ECU into believing the engine is consuming less air than it really is, results in a leaned-out mixture once limiting has begun. Because the turbo DSM's are set up to run quite rich on the top end, no harm is done expect possibly in extreme circumstances.
(NOTE: Other "hacks" have been discovered that will serve the same basic purpose: Removing the lower honeycomb section, enlarging the lower AMS inlet, and adding resistors/pots to the baro sensor and thermistor circuits are all somewhat effective techniques.)
The engine and transmission of a vehicle transfer the power to the ground via the front wheels. In certain high-performance vehicles, FWD also causes condition called Torque Steer, where the vehicle tends to pull in one direction when the driver mashes on the throttle. See also: AWD, RWD.
A special differential that limits the amount of slip (spinning) that will occur on a wheel that has no traction before the other wheel (with traction) begins to move. On the AWD DSMs, the LSD unit is a viscous coupler that will shift the torque to the wheel that has traction. Available only on the rear axle of AWD DSMs (was not available for Galant VR-4). None of the DSMs have front LSD units; they were determined to be unnecessary.
The device used to measure volume of air being consumed by the engine. DSM cars use a specific type of sensor called a "Karman Vortex airflow sensor". The upper inlet of the sensor has an obstruction in the airflow path that generates a constant stream of vortices (think of them as miniature tornadoes) directly behind the obstruction. The velocity of the incoming airflow determines rate at which these vortices are spun off. By placing an ultrasonic speaker and microphone across the stream of vortices, their rate can be counted. (the vortices spin off in alternating directions and thereby produce a alternating FM shift of the received signal from the speaker) In addition to measuring incoming airflow velocity, the mass airflow sensor unit also measures air temperature and the local barometric pressure in order to provide the ECU all the data it needs to do a true determination of the MASS of the air that the engine is consuming.
Generally speaking, Mass Airflow measurement is more precise than the speed-density system which has been largely replaced in newer automotive designs. Its (MAF) calibration is not affected when mods that change the engines volumetric efficiency are performed.
HKS sells this "piggy-back" computer, and its purpose is to fool the stock ECU into delivering more fuel under certain conditions. It's important to note that this "piggy-back" computer (as they call it) does not exactly work *with* the stock ECU the way that HKS ads might lead you to believe. The PFC doesn't share any data or address lines with the ECU, the only connection it has is thru the lines that originally ran directly to several engine sensors. By altering the signals from these engine sensors, the ECU is "fooled" into delivering an different quantity (usually more) of fuel.
There are limitations with this system, because the factory ECU it still is in final control and has the same limitations.
It should NOT be viewed as a substitute for an self-contained engine computer/control system. A true aftermarket engine control computer will provide vastly greater function and flexibility. The major advantage of the PFC-FCON is that it is fool-proof and very easy to install.
Used to state how fast an object is rotating (e.g. the crankshaft of an internal-combustion engine). The tachometer displays the RPM of the engine of a car.
The engine and transmission of a vehicle transfer the power to the ground via the rear wheels. This method of automobile propulsion is exemplified by the Mustangs and Camaros in your rear-view mirror. See also: FWD, AWD.
An engine with a single camshaft that is mounted over the head. Certain DSM cars are equipped with a 1.8 L SOHC engine. See also: DOHC.
Sometimes referred to as "silent recalls". These are service notices that the automaker sends to the dealers to notify them that certain conditions have been experienced by a significant number of owners. They suggest actions that can be taken to try to solve the problem. These are NOT safety recalls; the dealers are not required to perform the service suggested by the TSB for free (or even at all). If you know of a TSB by number, call dealers in your area to be sure they know what you are talking about, before you just drop off your car for a known (at least to this list) service problem. For the Diamond-Star cars: Mitsubishi and Chrysler Corp. do NOT always issue identical TSB for the same problems; you may have to dig a while to get your problem(s) resolved.
Also called MBC (Mechanical Boost Control) - A fancy name for a simple bleeder valve. A device (air pressure regulator, aquarium valve, ice-maker valve, etc.) that bleeds off a bit of boost pressure that is supposed to be going to the wastegate control valve, thus delaying the opening of the wastegate.
This device allows the removal of the stock air-mass sensor. It simulates the signal that the air-mass sensor normally supplies the computer. It uses standard speed-density measurements to determine (estimate) the air mass being consumed. Speed-density works by factoring together engine RPM and manifold pressure. Barometric pressure and ambient air temperature also also fudged into the final calculation. The calculations are highly dependent on the volumetric efficiency of the motor. For this reason, the VPC needs to be "tuned" differently for engines that have different levels of modifications. Many people report that low speed operation and idle quality is adversely effected. While this is not always the case, it is an indication of the fact that this device isn't a "plug n' play" solution. Once the VPC is tuned to provide a reasonable facsimile of the signals that the stock Airflow Sensor previously provided, the major advantage of the VPC becomes apparent. The elimination of the stock (restrictive) air-mass sensor increases incoming airflow capacity substantially. It is credited with providing very substantial horsepower increases mainly by virtue of the reduced intake restriction. Some advantage is also attributable to the fact that the air-fuel mixture can be easily changed with the front panel controls. Supposedly, the output signals from the VPC are held within a range that won't cause the ECU to fall into a fuel-cutoff mode. (A few people report that fuel cut problems still exist however - despite their best efforts to cure them)
(NOTE: See the section on the PFC. The VPC is completely separate from the stock ECU (engine computer). It doesn't (can't) change it's programming or performance limits in any way. It merely provides the ECU with input signals that are supposed to mimic those normally provided by the original airflow sensor.
It consists of a pressure sensor and a temperature probe that goes into the air-stream right before the throttle-body. There is control unit that has a socketed EPROM that is changed depending on the car, weather the stock injectors are installed, boost levels, etc. The control unit has a interface that plugs into the harness between the stock computer and the wiring harness.
There are two models, the VPC and VPC-II. The II is the newer model that does not have front panel adjustments, just a single 16 position rotary switch. The older model, has three adjustment ranges on the front for different RPM ranges/mixture levels. I am told if you can get the right chip in the VPC-II it's much better than the VPC-I, but the VPC-I is better if the chips maps do not quite match your engine.
Your right foot (with the accelerator pedal beneath it) is firmly planted on the floorboard of the vehicle.
Please mail any corrections/additions to Ron Gregory, firstname.lastname@example.org.
June 29th, 1996