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The decision of which engine management system to use can be a complex, overwhelming decision to make for the first time for enthusiasts or even an experienced tuner. In essence an engine management system controls the precise amount of fuel and ignition timing to an engine in all operating conditions. It is with this precise control that you can make performance modifications to an engine such as increased compression, larger camshafts, higher flowing intake and exhaust systems, as well as nitrous and boost and retain fuel economy, drivability and power. The main aspects to consider when choosing an engine management system are what features you find necessary for your particular application. Not all engine management systems have the same features, and some are better suited to street cars, while some towards race cars. The most distinguishing features that you’ll find that separate the higher end engine management systems are on board data logging, integrated wideband oxygen sensors, configurable software for cam and crank sensors, multiple ignition outputs, staged fuel injection control and boost solenoid control (PWM control). Below is a chart showing the engine management systems and the features that each one has/does not have that Evans Tuning recommends, sells, tunes, and has personally used in our own street and race cars.
So what engine management do we think you should use?
Without knowing the details each and every set-up, it is difficult to make a suggestion; however, a few generalizations can be made. Starting with the basic daily driver application whether its turbo, supercharger, nitrous or all motor on a budget, systems like Neptune and Hondata S100/S200 are excellent choices. They all retain the OEM Honda ecu, which gives unsurpassed reliability which is essential for a vehicle that is needed for every day driving. These systems do not offer end user tuning (dealer/tuner only), and are intended for the enthusiast that just wants to have their car tuned so that they can simply drive and enjoy it. Next, the Neptune RTP and Hondata s300 systems are geared more towards the users that want data logging and the ability to make changes (end user tunable). These systems still retain the OEM Honda ecu, and are great choices for daily drivers, and even the cars that go to test and tune nights. Finally, for drag race applications we suggest systems such as AEM EMS and FAST XFI. These systems offer the ability to data log many essential parameters related to a race engine, as well as the ability to configure a much more accurate cam and crank signals to the ecu (Hall Effect). In high power drag race applications the increased accuracy of these signals gives much more reliable engine operation at high engine rpms and boost.
Why is data logging so important?
Data logging is essentially the ability to view the major parameters that relate to engine operation. Some of these parameters are engine rpm, coolant/air temperature, engine load (psi), air/fuel, injector duty cycle, throttle position, vehicle speed, etc. All of these parameters can help you get the maximum performance for a given application, as well as be vital in trouble shooting issues that arise. At the drag strip data logging is invaluable, as it lets you see exactly what happened during a run. Data logging can show something as simple as boost leak, being to rich/lean, or not being full throttle which can have a huge impact on mph and e.t. Data logging gives you the ability to compare runs, and make changes to the tune or other settings based on results. You can achieve much greater results in much shorter time when having as much information as possible on engine/car performance.
What are some important parameters to data log for engine performance and reliability?
Some of the most important parameters to data log for engine performance and reliability are fuel pressure, oil pressure, air/fuel, exhaust gas temperature, engine knock and exhaust backpressure. Each of these parameters gives vital information on what is happening with an engine, and will help tremendously with trouble shooting and ensuring consistent, reliable engine performance.
Fuel pressure shows you the pressure that the fuel system is operating at. In a turbo application you need the fuel pressure to rise at a 1:1 ratio with intake manifold pressure. If this does not occur, either you will prematurely use all available flow from the fuel injector or cause the engine to “lean out” and not operate at the desired air/fuel ratio. Monitoring fuel pressure can also help diagnose potential fuel pump, regulator or filter failure, as well as wideband sensor failure.
Oil pressure shows you the pressure that the engine is operating at. If the engine is low on oil pressure, damage to the bearings and other essential components can quickly occur. Monitoring this parameter will ensure the oiling system is functioning properly.
Air/Fuel shows you the amount of air to parts fuel in the exhaust stream. This is essential for optimal performance, as well as keeping engine combustion temperatures within safe levels. Too rich of an air/fuel mixture engine performance suffers, and ignition misfiring can occur. Too lean of an air/fuel mixture engine damage can occur.
Exhaust gas temperature shows you temperature at which the engine combustion is occurring at. Exhaust gas temperature (EGT) sensor probes are typically placed about 1-2” from cylinder head on exhaust gas manifold runner. Monitoring each cylinder EGTs allows for the ability to “even out” all the cylinders so that all are burning evenly. This greatly increases engine reliability. Monitoring EGTs can also show when detonation occurs, due to the sharp rise in cylinder pressure and drop in exhaust temperature during detonation.
Engine knock shows when detonation is occurring. This is vital in engine reliability and performance. Detonation can melt pistons, tear head gaskets and even ruin rod bearings. Monitoring individual cylinder EGTs can tell you which specific cylinder is detonating when knock is detected.
Exhaust back pressure shows the amount of pressure in the exhaust manifold. Exhaust pressure is a critical parameter, as it can give insight into engine efficiency, turbine efficiency, wastegate efficiency and overall engine performance. If a particular exhaust manifold and turbo are not making power, typically backpressure will indicate if the combination is working correctly together. A 1:1 ratio between exhaust pressure and intake pressure is optimal, but is not always achieved. If monitoring backpressure on a log manifold and equal length, you will see a much lower backpressure amount on the equal length manifold which typically indicates an increase in power.
AEM EMS and FAST XFI allow for data logging all of these parameters. While purchasing all of the sensors to monitor these parameters can be costly, it’s well worth the investment. You’ll have the knowledge that the engine is/is not performing safely and optimally. Systems such as S300, K-PRO, and NepTune RTP allow for one or two inputs such as a/f or fuel pressure to be monitored. They are not geared towards a high performance race engine application.
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