Management Systems: What you should know
Posted: Tue May 05, 2009 12:03 pm
This thread will try to answer all your questions regarding locally produced management systems, as well as some OEM ones.
This is a collaborative effort, so keep checking back, as the information will be updated/corrected regularly.
If there's anything you want to add/change/correct, please add it to the thread!
First, let's tackle a few general issues:
1. An aftermarket management system, on it's own, is not necessarily a performance enhancer. If your existing system manages the fuelling/timing properly, then you won't see much of an increase if any at all.
2. The choice of system can't be made alone. You need to consult your tuner. Every single tuner out there, will have a personal preference of system. Go chat to him, find out which system he prefers, then decide. Keep in mind that your choice could possibly limit the amount of places that will tune your car.
3. Understand the following: A bad tuner will cost you a motor. Regardless of the system, if it's not set up properly, it will melt. And this is not limited to aftermarket systems... It goes for anything. Engines work best at certain Air/Fuel ratios, and you need to make sure that your engine runs as close to this as possible.
4. Understand your needs vs the system's capabilities. There's no need to spend silly money on a R20k Motec system with everything from knock-sensing to WB Lambda, if you're converting a stock 1.8 carb to injection.
Now, just for interest sake, let's quickly touch on the differences between a carb and injection setup. This is not an in-depth discussion, it's a very broad overview.
Typically, in a carb motor, you have a fuel tank, a carburettor, and a pipe between them. The carburettor draws in air when you open the butterfly, which causes a venturi effect over a jet, that draws in the required amount fuel. Fuel pressure is normally quite low. Then, you have a distributor that distributes spark between the cylinders, causing the explosion. Exactly when it fires, happens in a variety of ways, which is not in the scope of this post.
In a fuel injected motor, things are slightly different. First, the fuel pressure is higher. It runs into a fuel rail, building up pressure behind the fuel pressure regulator, and then returns to the tank on a second line as soon as the pressure limit of the regulator is breached. This is why we need to change tanks when converting to fuel injection. So, now your fuel rail has fuel, and we're good to go. Next, you open the throttle... A few things happen; your management gets one, or many, signals from various places, saying that we are now drawing in air. It then uses the stored map (as well as sensors, depending on the system) to determine how much fuel must go in to run the motor, and triggers (pulses) the electronic injectors.
Common sensors are Manifold Absolute Pressure (MAP), Mass Air Flow (MAF) and Throttle Position Sensor (TPS). But there any many more, like Lambda (measures the Air/Fuel ratio), knock sensing, etc.
Ignition on a fuel injected motor is much the same, except you can modify the exact amount of timing you want, at a certain point in the map. Here we can get very technical though (but we won't), because unlike a carburettor motor, there's a variety of ways in which the engine determines the "Base line ignition", from which the values are modified. Chief among these, are Crank Angle Sensors, Cam Angle sensors and Hall Senders or Generators. The latter is shared with most carburettor motors, for the record.
So, let's sum up what we have here:
For an injected motor to run, you need a management system, injectors, fuel rail, spark plugs, a way of telling the management how much fuel to add, a way of telling the management what the current and requested timing value is, and some sensors to tell it what's happening. Those are the most basic requirements, in short.
Let's start the fun
The system that I use is the Perfect Power PRS2.
Pro's
* Cheap system that's well supported by the makers.
* Easy to install, if you have a basic understanding of management systems.
* Reads MAP, TPS, Lambda, Temperature
* Can read 4 window Hall Generator or 60-2 Crank Angle Sensor.
* Has plenty ignition drivers (can run multiple spark systems)
* Has plenty injection drivers. Can run Full Sequential, Batched, or all of them together.
* Depending on the version, has plenty external drivers. Can be used to trigger VTek, NOS, Meth Injection, Shift Lights, anything you want, depending on an input from either TPS, RPM, MAP, etc.
* It has compensation maps, based on Temperature and MAP, meaning you can set the cold-start conditions, or compensate for boost, altitude, etc.
* Can run a PWM controller like the N75 to control boost.
* Has Narrow-Band Lambda compensation. Will correct the fuelling automatically.
* Has motor-protect functions based on Temperature, MAP.
* Full TPS calibration.
* Can have 2 maps, and switch them on the go. Handy for having maps with different rev limiters, or different timing curves when you change to race-fuel, etc.
Con's
* Not many tuners can/will tune it. You're very limited.
* After buying the system, you will need to spend a bit more money on sensors.
* You need to add one or two 2k2 resistors depending on some sensors. (most 5V TPS's for instance) - This is explained in the manual though, so not much of an issue.
This is a collaborative effort, so keep checking back, as the information will be updated/corrected regularly.
If there's anything you want to add/change/correct, please add it to the thread!
First, let's tackle a few general issues:
1. An aftermarket management system, on it's own, is not necessarily a performance enhancer. If your existing system manages the fuelling/timing properly, then you won't see much of an increase if any at all.
2. The choice of system can't be made alone. You need to consult your tuner. Every single tuner out there, will have a personal preference of system. Go chat to him, find out which system he prefers, then decide. Keep in mind that your choice could possibly limit the amount of places that will tune your car.
3. Understand the following: A bad tuner will cost you a motor. Regardless of the system, if it's not set up properly, it will melt. And this is not limited to aftermarket systems... It goes for anything. Engines work best at certain Air/Fuel ratios, and you need to make sure that your engine runs as close to this as possible.
4. Understand your needs vs the system's capabilities. There's no need to spend silly money on a R20k Motec system with everything from knock-sensing to WB Lambda, if you're converting a stock 1.8 carb to injection.
Now, just for interest sake, let's quickly touch on the differences between a carb and injection setup. This is not an in-depth discussion, it's a very broad overview.
Typically, in a carb motor, you have a fuel tank, a carburettor, and a pipe between them. The carburettor draws in air when you open the butterfly, which causes a venturi effect over a jet, that draws in the required amount fuel. Fuel pressure is normally quite low. Then, you have a distributor that distributes spark between the cylinders, causing the explosion. Exactly when it fires, happens in a variety of ways, which is not in the scope of this post.
In a fuel injected motor, things are slightly different. First, the fuel pressure is higher. It runs into a fuel rail, building up pressure behind the fuel pressure regulator, and then returns to the tank on a second line as soon as the pressure limit of the regulator is breached. This is why we need to change tanks when converting to fuel injection. So, now your fuel rail has fuel, and we're good to go. Next, you open the throttle... A few things happen; your management gets one, or many, signals from various places, saying that we are now drawing in air. It then uses the stored map (as well as sensors, depending on the system) to determine how much fuel must go in to run the motor, and triggers (pulses) the electronic injectors.
Common sensors are Manifold Absolute Pressure (MAP), Mass Air Flow (MAF) and Throttle Position Sensor (TPS). But there any many more, like Lambda (measures the Air/Fuel ratio), knock sensing, etc.
Ignition on a fuel injected motor is much the same, except you can modify the exact amount of timing you want, at a certain point in the map. Here we can get very technical though (but we won't), because unlike a carburettor motor, there's a variety of ways in which the engine determines the "Base line ignition", from which the values are modified. Chief among these, are Crank Angle Sensors, Cam Angle sensors and Hall Senders or Generators. The latter is shared with most carburettor motors, for the record.
So, let's sum up what we have here:
For an injected motor to run, you need a management system, injectors, fuel rail, spark plugs, a way of telling the management how much fuel to add, a way of telling the management what the current and requested timing value is, and some sensors to tell it what's happening. Those are the most basic requirements, in short.
Let's start the fun
The system that I use is the Perfect Power PRS2.
Pro's
* Cheap system that's well supported by the makers.
* Easy to install, if you have a basic understanding of management systems.
* Reads MAP, TPS, Lambda, Temperature
* Can read 4 window Hall Generator or 60-2 Crank Angle Sensor.
* Has plenty ignition drivers (can run multiple spark systems)
* Has plenty injection drivers. Can run Full Sequential, Batched, or all of them together.
* Depending on the version, has plenty external drivers. Can be used to trigger VTek, NOS, Meth Injection, Shift Lights, anything you want, depending on an input from either TPS, RPM, MAP, etc.
* It has compensation maps, based on Temperature and MAP, meaning you can set the cold-start conditions, or compensate for boost, altitude, etc.
* Can run a PWM controller like the N75 to control boost.
* Has Narrow-Band Lambda compensation. Will correct the fuelling automatically.
* Has motor-protect functions based on Temperature, MAP.
* Full TPS calibration.
* Can have 2 maps, and switch them on the go. Handy for having maps with different rev limiters, or different timing curves when you change to race-fuel, etc.
Con's
* Not many tuners can/will tune it. You're very limited.
* After buying the system, you will need to spend a bit more money on sensors.
* You need to add one or two 2k2 resistors depending on some sensors. (most 5V TPS's for instance) - This is explained in the manual though, so not much of an issue.