The "FYI" on K&N

[1ptturbo]

quote:Originally posted by Cal Cruzer

Cool! Where can I plug in to get it to tell me how much torque I am producing?

Call DCX

[Dalite]

quote:Originally posted by Cal Cruzer

The PCM is programmed to manage the engine a certain nunber of times per second using data collected from the sensors. It can make as many corrections as needed in each cycle with no problems. It won't do any more or any less. The PCM's primary goal in life it to keep the AF mixture within certain perameters at given RPM, load, boost, temp, etc. If you can get more air into the engine, the PCM can't spit it back out, it has to do what it does to make the AF ratio right. More fuel, air = more power. There is no horsepower meter, torque meter or anything else that the PCM reads and reduces HP if it sees too much. It just tries to keep AF within programmed parameters. Can you get more boost? Great! It knows you need more fuel to keep the AF ratio right, based on sensor data, up the the maximum duty cylce of the injectors. When it can no longer make enough correction is when you go lean and start blowing things up. If the PCM had a HP readout we would not need a dyno, just plug into the PCM and tune. Don't give the PCM credit for more than it can do.

A set of Powertrain Diagnostic Procedures manuals and a service manual would go far in explaining what the PCM does do.

In addition to performing the tasks you describe above as well as any pre 1996 OBDI computer does, there have been other features that have been added in the last 8 years of computer development.

The PCM's Task Manager routines are constantly going in the background. Each monitored sensor has a "cycle" that is determined by mileage, time, or number of cycles without error. Some cycles can take up to 140 miles (by the best computations I can make with the limited amount of info that DCX has released and what I can afford to buy from SAE.). Part of the error correction routines require that data received is verified by repeat readings to eliminate bad data. This redundancy is a standard procedure for all datastream operations used in digital sampling systems in the last 10 years. It is commonly found anywhere from car engines to Cellphone datastream applications. It requires computer overhead.

The air to fuel ratio control of the PCM accounts for a very small percentage of operations. If you take away approximately 95 other individual functions that it is tasked with, A/F moves to the forefront. Unfortunately by that time, the car wouldn't crank, run or be drivable.

Here is a small rundown on the PCM (Only 2 pages from the Service Manual, which is 2078 pages total):

[b]OPERATION
The PCM receives input signals from various switches and sensors that are referred to as PCM Inputs. Based on these inputs, the PCM adjusts various engine, transmission, and vehicle operations through devices that are referred to as PCM Outputs

NOTE: PCM Inputs:

² Air Conditioning Controls
² Ambient Air temperature Sensor
² ASD Sense
² Baro/Tip (Turbo)
² Battery Voltage
² Battery Temperature Sensor
² Brake Switch
² Camshaft Position Sensor
² Clutch Upstop Switch (1.6L)
² Clutch Interlock
² Crankshaft Position Sensor
² Cruise Control Switch
² Electronic Throttle Control (1.6L only)
² Engine Coolant Temperature Sensor
² Fuel Level Sensor (Bus message)
² Ignition Switch
² Intake Air Temperature Sensor
² J1850
² Knock Sensor (1.6, 2.0, 2.4L only)
² Natural Vacuum Leak Detection (NVLD)
² Manifold Absolute Pressure (MAP) Sensor
² Oil Pressure Switch
² Oxygen Sensors
² Pedal Position Sensor (1.6L has 2 sensors)
² Power Steering Pressure Switch
² SCI Receive
² Speed Control Switches
² Throttle Position Sensor (1.6L has 2 TPS Sensors)
² Transmission Control Relay (Switched B+)
² Transmission Input Shaft Speed Sensor
² Transmission Output Shaft Speed Sensor
² Transmission Pressure Switches (L/R, 2/4, OD)
² Transmission Range Sensor (TRS)
² Transmission Oil Temperature Sensor (Integral

[Dalite]

quote:Originally posted by Cal Cruzer

If you can get more air into the engine, the PCM can't spit it back out, it has to do what it does to make the AF ratio right. More fuel, air = more power. There is no horsepower meter, torque meter or anything else that the PCM reads and reduces HP if it sees too much. It just tries to keep AF within programmed parameters. Can you get more boost? Great! It knows you need more fuel to keep the AF ratio right, based on sensor data, up the the maximum duty cylce of the injectors. When it can no longer make enough correction is when you go lean and start blowing things up. If the PCM had a HP readout we would not need a dyno, just plug into the PCM and tune. Don't give the PCM credit for more than it can do.

If you put more air into the turbo than it is designed to receive, it will be vented to atmosphere. This topic has been covered here before, and even confiormed by 3BarBoost, before DCX pulled him from posting.

The Turbo and it's associated PCM management routines takes the extra air produced by the turbo (within it's acceptable limits of input and output, as controlled by the surge and wastegate functions) and controld the mixture.

Any thing falling outside the boundaries is either disregarded or is met by engine derating until data falls back within boundaries.

The most noticable exception to this is using a MBC, which bypasses the systems used for venting excess boost. Also, wastegate spring mods will accomplish the same on the other side of the turbo.

Both of these mods cause extra PCM Overhead; trying to make the system perform as it was designed. Often, a CEL is thrown because the PCM cannot interpret the erroneous data.

When the PCM cannot figure out what is going on, it goes RICH; to prevent engine damage. This is often desctribed as a "limp home' mode of operation.

The concept of "Torque Based Turbo Management" was first introduced in the SAE Engineering Paper, then later brought to the public in an article by Sport Compact Magazine. 3barBoost also confirmed this in forum messages.

Nowhere does it suggest, intimate, hint at or otherwise lead anyone to believe that it does anything else than provide a consistant amount of torque in relationship to the throttle position; no matter what the temperature or atmospheric conditions are.

It does not give a readout of torque; it merely provides a method of assuring torque consistency

This looks like (on the surface) an exceptionally complicated development; rich in technology.

In essence, it is nothin more than a system designed to prevent damage to the axles, transmission, clutch or torque converter.

It is merely a system to prevent shortcomings on the GT design from becoming apparent in operation.