Introduction to Tuning

Transcription

1 1 Introduction to Tuning As technology has advanced with the automotive industry, the electronics have as well. The ECU within vehicles have become more advanced each year adding more sensors to efficiently control the engine s operation, making numerous calculations and split-second adjustments to ensure the engine runs safely. The most common controls of the ECU have been igniton timing, and Air-Fuel Ratio (AFR for short), in recent years controls such as boost control, valve timing, and electronic throttle control (known as Drive By Wire or DBW) have been introduced. Automotive performance tuning is focused on achieve optimal engine efficiency, regardless if the vehicle is used for racing applications or daily driven applications. No matter what application, power output and engine response is the ultimate goal while retaining an engine s reliability and fuel economy. Vehicle performance has widely been marketed as simply replacing OEM parts with aftermarket parts which promise an increase in power output. As a consumer you must remember that automotive performance is a very large industry, as well as a hobby. Many performance enthusiasts are quick to purchase these items such as intakes, exhaust systems, or even a turbocharger. Performance gains are not limited to just installing aftermarket parts on your vehicle, unfortunately this is where many performance enthusiasts leave off. The problem with installing these parts is that many people do not re-calibrate their vehicle s ECU to accommodate the changes in the engine s efficiency that these parts make. A good example of this is an intake system, this allows a less restricted volume of air to flow into the engine, if the AFR is not calibrated for the additional air flow the engine will likely run lean. This lean condition will limit the performance capabilities of that specific modification, and your engine may actually make less power than its OEM configuration. An un-tuned ECU will generally give less performance and your vehicle s driveabiliy may be affected. There are several options for vehicle tuning on the market today, depending on your specific vehicle there may be limited options available. Many tuners use piggy-back engine management systems as they are inexpensive, and are essentially a quick fix for tuning solutions. The piggy-back units simply wire into your vehicle s ECU wiring to intercept various signals and change the signal values so the vehicle can be tuned. Another option on the market are standalone engine management systems, these are generally for more experience performance enthusiasts. These engine mangament systems are more complex than the piggy-back units, offer full control of your engine, and are generally the most expensive tuning option. Mitsubishi and Subaru owners have one option that is almost equal to that of a standalone engine management system, this is the software known as EcuFlash. This software allows you complete control or all your engine s various settings. EcuFlash is an open source software that many developers have collaborated on over the years and is a free software that you can download. The website OpenEcu.org is filled with a plethora of ECU tuning information, latest EcuFlash version downloads, and an online forum community where you can talk with other EcuFlash tuners and developers.depending on the vehicle, some have had more development than others. The Mitsubishi Evolution platform has been thoroughly developed for this software, while others such as the Eclipse have not received as much development yet. The potential is all there, and is slowly being developed into other platforms the way it has been developed on the Evolution. This is a very inexpensive method of tuning for these platforms which is why it is so widely used. Whether you are reading this to perform tuning on an un-modified vehicle or a highly modified vehicle both will benefit from being properly tuned. Tuning is one of the most beneficial skills to understand with today s electronically controlled vehicles. The factory implements a very basic tune for their production vehicles, while still meeting strict emission standards each year. Consider it this way, the factory s tune is like a cookie cutter; it is the same from production vehicle #1 to #999,999 of the same model. Though your vehicle may seem to run just fine without any modifications done to the engine, there is still more potential that can be gained from a simple tuning session. The factory generally sets ignition timing very conservatively without reaching the full potential for each engine offered, and the AFR is focused on fuel economy and emission standards rather than overall performance. On an un-modified production vehicle, tuning these two parameters alone can still improve the drivability, and fuel economy of the vehicle. BlackHeart Motors (BHM) has documented this with an un-modified Mitsubishi Evo X GSR model, which we know Mitsubishi has poured their heart and soul into that specific platform. The factory tune settings were fair for the average commuter, but we still logged several instances of knock in the upper RPM ranges. We made several adjustments to the factory tune on the Evo X and the overall feel and drivability of the vehicle was noticeably improved. This is proves that even the top of the line production performance inspired vehicles can benefit from tuning. Tuning takes time, so you need to make the time to learn about the tuning process in order to make it beneficial to you. This is not something you can simply pick up, read, and go out and start tuning within an hour or two. You will likely become frustrated at some point throughout all of this, take a break and come back to it again later when you feel refreshed, avoid getting discouraged. There is a lot of information about tuning that a person has to learn, so do not expect to understand everything immediately. It is important to understand all of the information you can since tuning is very detail oriented, one

2 2 mistake could be the difference between a running or damaged engine. You need to have a passion for performance to keep you motivated throughout tuning. Many established tuners would like you to believe that tuning requires some sort of college degree; this is far from the truth. Unfortunately, this is what keeps these tuners in business, and also what prevents many from learning the dark arts of tuning. The majority of people bring their vehicle to a tuner, entrusting them to tune the vehicle. If you do not know, or understand the process you have no way to know for sure if what is being tuned is correct, or even to the full potential. BHM once believed that an established tuner was tuning one of our vehicles effectively, only to discover many key items were improperly adjusted, or simply just ignored. The only way we discovered this was by data logging; if you have no way to data log you really have no way to check if your tuner is doing what you pay them to do. This is how BHM started out with tuning, and the continuous lack of results from other tuners has solidified our reputation for tuning services. As an enthusiast first, and a business second, this is why we have vowed to continue educating others about tuning. We started out like any other performance enthusiast, and this goes to show you that with the time and passion, you too can be achieving exceptional results with tuning. Disclaimer: BlackHeart Motors (BHM) is not liable for any damage that may occur from any use of the information contained within this handbook. The end user (you), assume all risk and responsibility of the tuning performed on your vehicle. It is highly advised that you take your time to completely read and understand each section before tuning your vehicle. If you are not confident with tuning your own vehicle, do not attempt to tune your vehicle as you may cause serious damage. Be aware that tuning can void any existing factory warranty. Vehicle Maintenance Before you begin any sort tuning you need to ensure the vehicle is safely ready. You need to check that all fluids are in good condition, and filled to appropriate levels. If your vehicle is in need of an oil change, do not put it off until later. Bad oil can result in engine damage, especially under harsh driving conditions which are to be expected during your course of tuning the vehicle. Engine coolant is another item that needs to be checked, you do not want to have an overheated engine as this can also lead to severe damage. Be sure you check all four wheels for any damage that may be present, also be sure all lug nuts are torqued to appropriate specifications. All four tires should be in good condition with no signs of bulges, bald spots, or cords showing. Your brake system should also be checked for good operation. If you have not given your vehicle a thorough tune-up recently, now is the best time to do so. Simply put, your vehicle needs to be in its best health possible, maintenance should never be overlooked.

3 3 Understanding the Combustion Process The ideal combustion process would have an AFR value of roughly 12.5:1 to achieve maximum power output of the fuel (excluding E85). With outdated engine designs on some vehicles, and fuel quality not always optimal, this can be difficult to achieve for those running high boost pressures without a water or methanol injection system. As your intake and exhaust valves close, the spark plug fires to ignite the fuel. The leaner your AFR values, the faster the fuel burns (up to 12.5:1, beyond that fuel burns slower). A stock vehicle usually has potential to run a leaner AFR, but with less timing advance. Once your spark plug has ignited the fuel, it burns evenly across the combustion chamber. Imagine dropping a rock in water and seeing the ripples move outward from where the rock was dropped. Your fuel should all be burned with no remaining air-fuel mixture once the combustion process has finished. If this does not occur, it generally means the AFR is too lean. The reality here is that your combustion process does not always happen in the ideal process as outlined above. There will be times where your fuel will pre-detonate, or spontaneously combust after the spark plug is fired, but before the flame front reaches the air-fuel mixture. This is what is commonly known as knock. This occurs when there is too much pressure, and too much heat within the combustion chamber combined with improper octane in the fuel to resist pre-detonation. The higher the octane level of your fuel, the less likely it will pre-detonate under high boost pressures and heat conditions. When a knock occurs it is basically a sharp pressure spike that is outside of normal operating conditions of the combustion process. This pressure spike creates a force within the combustion chamber that causes a resistance on the pistons in reaction to the force generated by the knock. When this occurs your Knock Sensor sends a signal to the ECU where it determines if it is engine knock. If the ECU determines it is engine knock, the ECU retards the timing in order to prevent further pre-detonation, or knock. It is important to remember that the Knock Sensor is a reactive component, it will only adjust timing after it encounters engine knock, not before. If your Knock Sensor fails or you do not address existing knock issues engine damage can occur. Things such as broken spark plugs, valves, pistons, and rings, are possible due to the pressure exerted from excessive engine knock. Pistons will show excessive engine knock because it is abrasive to the crown surface and they will appear as though they have been through a sandblaster due to the small pits on the surface. Excessive knock will also shorten the life of your connecting rod bearings due to the continuous force being exerted on the pistons; this ultimately leads to a distinctive rod knock noise from the engine. All of this information is for your benefit, and to understand how damaging knock can be if left unchecked, or becomes excessive. Almost all vehicles will register knock, the amount and consistency of the knock varies. Provided engine knock is occasional and moderate the vehicle will run for a long time, just not as efficiently as if there were no knock.

4 4 Equipment Required We need to go over what equipment is necessary to effectively perform your tuning. Modern vehicles have computers integrated into almost every aspect of the vehicle all the way down to tire pressure monitor systems. As such, you will need to have a laptop that is up to date (something manufactured within the last five years at least), and powerful enough to accommodate your requirements. Some tuners prefer large screen laptops (14 or larger screens), while some prefer smaller screens found commonly on Netbooks. There are pros and cons to both, find out which one fits your needs and preferences best. The laptop needs to have at least one USB port in order to connect to the required Tactrix cable. In addition to having an adequate computer, you will need to obtain the data logging and tuning software. The most commonly used data logging software is called EvoScan; this is a very powerful and thorough data logging software that will monitor every sensor on the engine. Your tuning software is called EcuFlash and can be downloaded for free online from openecu.org. With your computer chosen and the necessary software installed you need to purchase your Tactrix cable. As of this writing the current cable being used is the Tactrix 2.0 cable. This version replaced the previous 1.3 cable which was unable to work with the newer vehicles that operate on CAN protocol instead of OBD-II. One item that should never be overlooked is a wideband O2 sensor. Your vehicle s OEM O2 sensor is a narrowband sensor and is only accurate under stoichiometric (14.7:1 AFR) conditions and is primarily for emissions. Tuning with the narrowband O2 sensor will result in improper AFR readings, and poor tuning results. There are many wideband O2 sensors offered currently, find one fits your needs, as well as your budget. When installing your wideband O2 sensor it is important not to install this sensor behind the catalytic converter. Installing the sensor in this location can yield inconsistent readings. Also be sure the sensor is mounted in the 3 o clock or 9 o clock positions to give an equal reading of your exhaust gasses as they pass by the sensor. Positioning the sensor as suggested also reduces the risk of condensation build up on the sensor which will damage it. The most useful item to have with your tuning equipment is a notebook strictly for your own tuning log. Making notes throughout your tuning will greatly aid in finding what works and what doesn t, then easily resolving the problems. This one tool will become your bible for tuning information, and ultimately one of your best educational tools.

5 5 Data Logging You will need to get your laptop and Tactrix cable connected to the vehicle in order to data log. The basic principle of logging is to be in 3 rd gear and make Wide Open Throttle (WOT) pulls from RPM all the way to your vehicles redline (varies by vehicle and engine specifications). You will need to make several of these pulls to get consistent data, generally 3-4 pulls will be sufficient, but sometimes 5-6 may be required. This should be done on a flat surface and be consistent for each log session to give accurate results in your data. In order to achieve the best information you want to log essential vehicle parameters such as Air-Fuel Ratio (AFR), Ignition Timing, Load, Throttle Position Sensor (TPS), Engine RPM, Knock Sum, Coolant Temperature, Intake Air Temperature (IAT), Injector Pulse Width, Injector Duty Cycle, and if applicable, Boost Pressure.

6 6 With several key parameters to monitor, you need to understand what each of these data items means. If you are logging all of the data above, but are not sure what any of it corresponds too than you will likely not achieve optimal tuning results. We will go through each of the above data points and explain what each of them means so that you can be confident in understanding the values they represent. There are other data items that you will be monitoring as you progress in your tuning, but these are the basic essentials for starting the process. Air-Fuel Ratio (AFR) Represents the parts of air mixed with fuel. For example, a 13:1 AFR means that 13 parts of air are being mixed with 1 part of fuel. When the vehicle is idling or at cruising speed the AFR is usually around :1 (This value is known as stoichiometric). The 14.7:1 AFR produces fewer emissions. Ignition Timing Correct ignition timing is critical for engine performance. Ignition timing affects power, fuel economy and reliability. In your ignition maps you will see various numbers shown, the higher the number means timing is advanced; negative numbers represent timing is retarded. (Example: 23* means spark plug will fire 23* before your piston reaches Top Dead Center. A value of -10* means your spark plug will fire 10* after your piston has reached Top Dead Center. Load This value represents how much demand is being placed on the engine to make power. Generally under hard acceleration, or WOT pulls during your data logging it will be common to see this value reach 100% on a naturally aspirated engine, and exceed 100% on a turbo-charged. Throttle Position Sensor (TPS) The sensor located on your engine s throttle body that detects how far open, or closed the butterfly plate is. This is generally represented in a percentage value, under WOT you will usually see a value of 95%-100% shown. Engine RPM This represents the number of crankshaft revolutions per minute your engine is making. This is a key data point to monitor in order to make proper adjustments based on engine speed and engine load. Knock Sum This will tell you if there is any engine knock being detected through your engine s knock sensor. Most vehicles can register 5-10 counts of knock; most tuners do their best to minimize the knock to no more than 2-3. The closer you can get to 0 instances of knock the more efficient your engine will be. Coolant Temperature This is good information to monitor because you can see if your engine is operating at higher than normal temperatures. Also it is beneficial to find your engine s normal operating temperature range before beginning any tuning. A cold engine, or over heated engine is not ideal for optimal tuning results. Intake Air Temperature (IAT) This represents the temperature of the incoming air your engine is breathing. Colder air temperatures are best as the air is denser, high intake air temps can reduce the amount of air the engine takes in, and also drastically reduces engine performance. Injector Pulse Width The duration of your fuel injector being open and is related to the amount of fuel demand required by the engine. Injector Duty Cycle This is measured in a percentage and represents the amount of time your injectors are open and delivering fuel. This value should never exceed 80% to maintain the life of your injectors. Boost Pressure This is simply showing you how much air pressure above your atmospheric pressure is being forced into your engine.

7 7 Introduction to EcuFlash Software This is a very powerful and thoroughly developed software that has become widely established for the tuning of Mitsubishi and Subaru vehicles. This software has a wide variety of parameters that can be adjusted within your vehicle s ECU, depending on how thorough the definition file is. When you read the term definition file, this refers to an XML formatted file that EcuFlash uses to configure all of the data from your ECU (known as a ROM file), and then display it within EcuFlash. The Mitsubishi Evolution platform generally has well developed definition files available, if you are tuning a Mitsubishi Eclipse, or Galant platform chances are the definition files may not be as developed, or even created currently. The development of definition files takes a great deal of skill, and patience to configure properly. Using an improperly configured definition file will result in your ECU s data being displayed incorrectly. You will need to download the EcuFlash software and then launch the installer application for the software. You can choose a specific folder on your computer that you want this to be installed in, or let it be installed to the default location within your Program Files folder. Once the installation has finished, go to the specific directory on your computer where the software was installed and open the EcuFlash folder. To make it easy, make a shortcut of the EcuFlash.exe file and place it on your desktop. All of your definition files will be stored within the rommetadata folder. This folder holds sub-folders of Mitsubishi & Subaru, within these sub-folders are model specific subfolders. If you are tuning an Evolution, Eclipse, or Galant, your definition file should be stored in the appropriate folder so that EcuFlash has access to the information it needs. You should never have any duplicate definitions on your computer as this can cause errors.

8 8 At this point open your EcuFlash program from the shortcut you created. As you can see this software is very straight forward and user friendly. You will see the folder icon which is what you will click on to open any existing ROM files on your computer. The ROM files can be stored in any folder on your computer that you specify, You can change the default directory that EcuFlash looks in when you click the folder icon. Go to the File tab, select Options, then under Directories select Rom File Directory and set it to your desired fold. The disk icon is what you will click on to save your work once you star making your tuning adjustments. Next to the disk icon you will see 4 different circuit type icons, each one of these has specific features. The first one is the Read feature which will basically download all of your ECU s files to EcuFlash. The second icon is the Write feature, this will write all of the file information back to your vehicle s ECU. The third icon is the Test Write feature which will write all of the file information back to your ECU as a test; this will not actually write the information to the ECU. Last is the Compare to ECU feature which will compare the ROM file you are working on to the one that is on your ECU. This feature does not write any information to the ECU. In order to view all of the defined parameters of your ECU you will need to change the user level within EcuFlash. This is done by simply going to the File menu and selection Option. Once you have done this you will get a pop up window that looks like the one shown here. From here you want to click on User Level, and then select Developer. Once this has been done, click the red X and you will now see every setting within your ECU that has been defined on any ROM file that you view. Keep in mind that not all ROM files are completely defined, not ever ROM file will have all of the same information displayed.

9 9 When you start to view the various tables within EcuFlash you will notice they have a color theme. This can be changed to a variety of options that are preset within the EcuFlash software. Under the File tab, select Options, and under Appearance you will see Default Color Map. Select this item and it will give you a list, as well as a preview of that specific color map s appearance. This is very useful to quickly see where your maps are beginning their transition. These default color maps can be altered to your own desire by opening the.map file in notepad. The information is organized in columns by the three primary colors (Red, Yellow, and Blue). With EcuFlash installed, and understanding some of the key features it is time to connect to your ECU. Open EcuFlash on your computer, connect your Tactrix cable to the OBD port and reflash connector (reflash connector is not used on CAN equipped vehicles), then connect the Tactrix cable to your laptop. Once you connect the Tactrix cable to your laptop for the first time you will get a prompt to install the OpenPort driver software for the cable. Click next and follow the prompts so the drivers are installed. Once this has finished your Tactrix cable will now work with your computer. With EcuFlash open and the cable connected, turn the ignition key to the ON position (Engine should not be running), you will want to select Read ECU in EcuFlash. This will give you a pop up window to select your vehicle s model year. Select the model year of your vehicle (if you have done any ECU swaps or conversions be sure to select the correct model year of the ECU being used). After selecting the vehicle model year, click OK and EcuFlash will begin its process of reading your vehicle s ECU. Do not do anything else during this process to avoid any errors while reading the ECU. Once this process has finished, EcuFlash will give you another pop up window to notify you the process is finished, click OK and turn the ignition key to the Off position.

10 10 At this stage in reading your ECU, if you do not currently have a working definition for your ECU, EcuFlash will give you another pop up window like the one shown below. Do not select Next unless you are able to make your own definition files. This is something more advanced than the average user s capabilities. In order to view or edit any of the ECU information you need to have a matching definition file for your vehicle. Each vehicle has a unique identification number that corresponds to the appropriate definition file. Your ECU uses a binary file (known as the ROM file), the definition file (an XML format) defines each table within the ECU so that EcuFlash can properly display the information you just read from the ECU. Do not edit any table with an improper definition file as it can cause ECU failure, or engine damage. If you need a definition file for your ECU check online with forum communities specific to your vehicle, or also check OpenEcu.org as well. It is important that you save this file before doing anything else. This file needs to remain stock and un-altered as it will be a backup file. Some vehicles are equipped with an immobilizer system which is part of a factory security system. It is important that you write down the immobilizer code from your ECU in your notebook for future reference. Not having this code later may prevent you from starting your vehicle or doing any tuning. If you wish to disable the immobilizer, enter the code FFFF which is a command to disable the immobilizer function. With your ECU file saved, you can now open the file in EcuFlash and begin editing the necessary tables. Before making any adjustments, familiarize yourself with all of the parameters displayed and understand what the tables represent. Next you will want to open your log files in EvoScan to see what your logging information is telling you about the engine s performance. Do not any adjustments to any of these tables; each adjustment needs to be made in small increments to really fine tune the engine to reach its full potential.

11 11 Ignition Tuning Low Octane Ignition Map When knock is detected by the ECU your ignition timing is retarded by a pre-determined value depending on the knock count and operating conditions when knock is encountered. When knock is encountered, and continues the ECU will interpolate between the Low Octane and High Octane ignition maps. It is important to note that the ECU supposedly never operates 100% of the time on the Low Octane maps. Once knock is no longer detected the ECU will go back to running your ignition timing only on the settings within the High Octane map. In a turbocharged application your ECU will reduce the maximum boost pressure if the ECU has a boost cut feature (discussed more in Tuning Boost Pressure section of this handbook).

12 12 Ignition Tuning High Octane Ignition Map The High Octane map is essentially your ECU s primary ignition setting. This map is where you will make your initial ignition timing adjustments to achieve optimal ignition timing without registering excessive knock counts. Remember that when knock is continuously encountered your ECU goes back and forth between the Low and High Octane maps until knock is no longer present. The more you can get your High Octane map dialed in for timing, the less likely your ECU will need to interpolate between the Low and High Octane maps. When you have eliminated knock from happening, this enables stable operating conditions. From here you are able to focus on increasing power output with higher boost levels, or other engine modifications.

13 13 Ignition Tuning - Knock Ignition timing should be the first item to deal with in tuning as to resolve any existing issues with knock. A stock vehicle has a lot of timing advance which usually generates moderate knock counts and is something that can be corrected. As we know from the combustion process, knock causes sharp pressure spikes within the cylinders. If this is not resolved, engine longevity and performance is reduced. The way we deal with knock is to retard the ignition timing in the specific area of the table until no knock is registered. During your data logging sessions it will show you where knock is being registered, and how many counts. EvoScan tells you that this parameter can vary from 0-50 counts of knock. When tuning your vehicle it is strongly advised that you tune your ignition timing, fuel, and boost pressure (if applicable), without registering more than 1-2 counts of knock. For every 3 counts of knock your timing is retarded 1 degree (there will be instances where 1 count of knock will pull 1* of timing), this is an important note to remember later as it will assist you in tuning the ignition timing tables. Knock that is consistently in the same spot on your log files is something that needs to be addressed first as it has the potential to cause long term damage to the engine. If you have one or two spots in your log files with occasional knock, not always in the same spot, or same count, this is an occasional knock that you do not need to be concerned about. In the example image to the right you can see that there were 13 counts of knock registered. We know that 3 counts will retard timing 1 degree, so the timing here was retarded at least 4 degrees from the value set in the ignition map. Since the Knock Sensor is a reactive sensor, timing was not retarded until after this was registered. With a timing advance of 18 degrees, we need to retard the timing to 14 degrees and make another logging session to see if knock is still present. Once you have resolved any knock, it is time to start tuning the rest of your ignition table. You can focus with certain areas of your ignition map where knock is registering as a starting point, and then go through the rest of the ignition map. One method that has shown optimal results is called Minimum Timing for Best Torque (MTBT). This method states that you should advance timing until it no longer gains power or torque, or without a dyno, until knock is encountered. It is important to note that the MTBT method only applies to octane fuel. If you run E85 fuel you can advance timing without registering any knock and cause serious engine damage. In turbo-charged applications keep in mind your AFR can also play a role in your timing adjustments. If you are running less boost pressure and a richer AFR you can safely run more timing.

14 14 Tuning your Boost Pressure If you are tuning a naturally-aspirated engine skip this section. Most forced induction owners use a Manual Boost Controller (MBC), to control their boost pressure. It is important to make your adjustments about 1/8 of a turn whenever you are increasing the boost pressure. Do not rely on your boost gauge for accurate readings as many mechanical boost gauges are not completely accurate. You will see this within your log files that your gauge may be 1-2psi off from what is actually being registered by the engine. In order to properly log your boost pressures it may require the installation of a Manifold Absolute Pressure (MAP) sensor and calibrating it based on atmospheric pressure specific to your elevation (this depends on vehicle application as some are capable of logging boost pressure from the OEM MAP sensor). The MAP sensor converts the air pressure into a 0-5 volt signal that is able to be monitored on EvoScan. Based on the calibration you set for your specific MAP sensor, this signal is translated directly into PSI in your log files. Many tuners have used the GM 3 Bar MAP sensor as it is widely available and easy to set. Most manufacturers should be able to provide you with the necessary calibration data needed, however the GM 3 BAR sensor calibration is as follows; Boost Pressure Voltage If your vehicle s ECU is equipped with a boost limit feature, it is important to understand what this feature is. Once the ECU reads a load value below the specific cell value, it will begin injecting fuel once again. The ECU uses the calibrated output from your MAF to determine the Air Flow. Though this feature is most commonly known as Boost Limit, it is actually an Air Flow Limit. Under no circumstance should you remove this feature on octane fuel. You can raise this limit slightly higher if necessary, but do not set this to maximum setting to avoid engine damage. The boost limit is a safety feature for the engine to prevent overboost conditions. This means if your vehicle hits a load cell in excess of 260% for 1 second, the boost limit takes over and cuts fuel to protect the engine.

15 15 Tuning your Air-Fuel Ratio (AFR) An important piece of information to remember about AFR values is that gasoline produces the best power at roughly 12.5:1 regardless of turbocharged or naturally-aspirated. Under high boost pressures and lean AFR conditions, 91 octane fuel becomes unstable and can cause knock as well as other problems. Increasing the boost pressure will impact your AFR readings due to the higher load cells the vehicle will be capable of. Mitsubishi designed their fuel maps to become richer as the load increases. The higher the number within your fuel map, the leaner the AFR mixture is, the lower the number the richer it becomes. The factory sets the stock fuel maps to produce the least amount of emissions possible. The AFR value is generally set to 14.7:1 during idle and cruising speeds since vehicles spend 90% of their time within these conditions. It is important to note that an AFR of 14.7:1 does not produce the best fuel economy; an AFR of roughly 15.2:1 will give best fuel economy. The numbers in the fuel maps are not your actual AFR readings. Setting your AFR depends to a large extent on the timing and boost pressure that your car is using. The AFR readings you log with your wideband will be different from those contained within your fuel map. Under no condition should you enter the AFR values that you logged with your wideband into the fuel map. The formula below will show you how to correctly make adjustments to your fuel map to obtain the desired AFR value; Example: Your Actual AFR (AAFR) reads 11.13:1. The fuel map AFR (MAFR) shows 9.7. We want a desired AFR (DAFR) of 11.4:1 in that load cell. What should the new map AFR (NMAFR) be? NMAFR=11.4 X 9.7 / = NMAFR=DAFR X MAFR / AAFR So the number that you should enter in the fuel map in that specific load cell should be 9.9. You can create a template in Microsoft Excel using the above formula. Simply input the numbers and Excel will do the calculation and output the AFR value you need to enter into your fuel map. This will allow you to create a consistent AFR, and reduce a lot of time spent tuning your AFR. Another useful tool to use for tuning your AFR is a program called Virtual Dyno. This software also shows you your AFR readings throughout the RPM range of your WOT pulls. If your AFR line is not smooth and steady, this graph will show you and you can pinpoint areas within your fuel map that need adjustment. The graph below is an example of a tuned fuel map, note how smooth the lines flow across the RPM range (AFR is represented by the solid blue and red lines which are from two separate WOT pulls); Tech AFR Information about Octane Fuel: 6:1 = Rich run limit 9:1 = Low power with black haze 11.5:1 = Rich best torque at WOT 12.5:1 = Safe best power at WOT 13.2:1 = Lean best torque at WOT 14.7:1 = Stoichiometric ideal burn AFR for gasoline 15.5:1 = Lean light load, cruise/part throttle 16.2:1 = Best economy, cruise/part throttle 18:1 = Lean run limit

16 16 Open Loop Tuning Your engine s operating temperature dictates whether the vehicle runs in an Open or Closed Loop setting. The Open Loop operation is when your engine is below the preset temperature level; at this point your ECU does not use the front oxygen sensor to maintain a steady 14.7:1 AFR. When the ECU does not use the data from the front oxygen sensor it simply calculates the AFR based on air-flow data it collects from your Mass Air Flow (MAF) sensor. Closed Loop operation is when your engine temperature has reached the preset value, at which point your ECU begins using the data from the front oxygen sensor to adjust fueling to the desired AFR in your fuel maps. The temperature setting is scaled in degrees Celsius, not Fahrenheit. The table shown has a value of 7 degrees Celsius (approximately 44.6 degrees Fahrenheit) set, this means the vehicle will run in Open Loop until this temperature is reached. Once the engine has warmed up beyond this temperature it will switch to Close Loop operation. Engines with aftermarket camshafts may benefit from adjusting this temperature to degrees Celsius so the ECU can make more consistent fueling during the engine s warm up period. For the fueling to be consistent, your injector scaling and latency must be set correctly (detailed in the Injector & Latency Tuning section of this handbook). In addition to the Open Loop Coolant Temperature table, there are RPM versus Load tables that you can adjust that will force the ECU to run in Open Loop operation during certain RPM ranges based on load. You can adjust the cruising RPM range to obtain optimum fuel economy. To make this adjustment you will need to make a cruising speed log and evaluate what load your ECU registers, and at what RPM range. Once you have logged this information, simply set the value lower in the Open Loop load table in the specific RPM range. Since there are two of these tables (Open Loop Load #1 & Open Loop Load #2), it is currently not known how the two tables are differentiated. It is for that reason that it is best to set both tables to the same values. *Note- When the ECU operates in Open Loop, the Long Term Fuel Trim (LTFT) that is applied during Closed Loop operation is applied to the entire fuel map. This is a good feature of the ECU, but this requires your fuel trims to be dialed in a close to zero as possible.

17 17 Injector Scaling & Latency When you start adding more modifications to your engine such as a turbo, cams, or higher compression you will need to install larger injectors to provide sufficient fuel flow for the engine. Once you have installed larger injectors you need to scale the injectors properly and correct the injector voltage latency settings, without doing this your vehicle will run poorly as it is still registering the original injector sizes and latency settings. This process is very time consuming, and one of the more difficult tasks to deal with in regards to your tuning process. You will spend a lot of time with trial and error until you reach the right settings. Be sure to allow yourself enough time, generally a full day may be used to do this. When you open EcuFlash and open your vehicles ROM file (the file you saved from the beginning), you will want to find the Injector Scaling, and Injector Battery Voltage Latency tables which look like the image to the right. The Injector Scaling table is what the ECU is using for fuel supply calculations. This number is always smaller than your actual injector size. You want to scale your injectors 15%-20% less than the actual injector size being used. Once you have entered this information you will now need to adjust the Injector Battery Voltage Latency settings in order to correctly use the larger injectors. The Injector Battery Voltage Latency table, also referred to as Injector Dead Time, represents the time in milliseconds that it takes to open your injectors directly related to the battery voltage. As you battery voltage decreases the time it takes for the injector to receive the signal to open, and when it actually opens increases. This means you will need to send the signal sooner in order to have the injector open at the correct time. As injector size gets larger the more time is required to open them so you will need to increase the number in the millisecond column accomplish this. Setting your Injector Latency will take time, be patient as skipping this portion will yield poor tuning results. Now that you have scaled your larger injectors and found the correct Latency settings you need to ensure everything is working correctly. The information you need to data log to find out if everything is working is called Fuel Trims. There are two of these that need to be monitored will take a lot of time and you will burn a lot of fuel due to how these items operate. The Long Term Fuel Trim Low (LTFT Low), refers to your idle Fuel Trims. The Long Term Fuel Trim Mid (LTFT Mid), refers to your cruising Fuel Trims. These have a value range of +/-12.5% and you want to get these to read +/-5% or less, the closer to +/-0% you can get the better. If either of these fuel trims register to much positive the ECU begins to add fuel making your AFR rich. If these are too negative, the opposite happens and the ECU removes fuel which makes your AFR lean. Fuel trims cycle approximately every 4 minutes, this means in order to get accurate information you will either need to drive the vehicle, or let it idle for a minimum of 16 minutes. This allows enough time for your fuel trims to cycle enough to see where they are registering. We will start with tuning your LTFT Mid (Cruising Fuel Trim). This fuel trim requires you to drive the vehicle at a steady speed for at least 16 minutes. The speed should be an average cruising speed (60-70mph is sufficient), and held steady so that your information is accurate, any fluctuation in speed may give inaccurate results. If your fuel trim is negative then you need to raise your injector scaling incrementally until you are within +/-5% or less. If your fuel trim is positive, then your injector scaling needs to be lowered to reach appropriate range. Next is your LTFT Low (Idle Fuel Trim). This is much easier to do as you simply need to let the vehicle idle for 16 minutes. As outlined above you want to get this fuel trim as close to +/-5% as possible, with +/-0% being ideal. If your LTFT Low is more positive than your LTFT Mid you will need to increase the latency value. If the LTFT Low is less positive than the LTFT Mid, you need to decrease the latency value. If this occurs you may need to refer back to your injector scaling values. With both your LTFT Low, and LTFT Mid dialed in as close to +/-0% as possible you must go back to your AFR tables in order to correlate to the new injector settings you have entered. Unfortunately you will be tuning your AFR twice if you have followed everything correctly. There is no way to bypass this without achieving optimal tuning results. Refer back to the Tuning your Air-Fuel Ratio (AFR) section from here.

18 18 Mass Air Flow (MAF) Scaling The MAF is your vehicle s primary load sensor. This one sensor is what the ECU uses to calculate the proper amount of fuel and ignition timing required at specific RPM and load ranges within normal operating ranges. The Mitsubishi MAF is a Karman- Vortex design using ultra-sonic sound that outputs an alternating signal equal to the airflow. On the Mitsubishi Evolution platform this airflow signal ranges from a frequency of 30Hz, to 2600Hz with high resolution at lower airflow ranges. The way the MAF works is that it calculates the mass of air entering the engine based on the MAF size, Intake Air Temperature, and Barometric Pressure. From here the engine load is calculated and applied to the fuel and ignition maps. From this stage the ECU determines how much fuel is required for a specific AFR by checking the MAF Smoothing table, Barometric Pressure, Manifold Absolute Pressure, Fuel Map, Injector Scaling & Latencies. Other variables that can be included are Accel Enrichment, Warmup Enrichment, Closed Loop, and Lean Spool (if applicable). Your stock MAF Scaling table has data expressed in g/s in one column and units in the other. The problem with how this information is displayed in EcuFlash is we have no way to compare the airflow information from EcuFlash and EvoScan since EvoScan logs airflow in Hz. Being able to log your airflow in Hz, and going to EcuFlash and seeing the same data displayed makes fueling problems easier to deal with. First, open your ECU s ROM file, and then open the MAF Scaling table. You will not change any of the values within the table, just the way it is expressed or scaled. Right click on edit and select Edit Definition. You will now see the definition table with a top and bottom portion. The top defines the numbers displayed in the right column of the MAF Scaling table. The bottom portion defines the numbers in the left column of the table. You will need to change the scaling in the top portion (named Data Values (2D) MAF Scaling), from Airflow 8 to unit8. Next you need to change the bottom portion (named Y Axis Load ), but you must first make a new definition for this. Click on the Scalings button, and then click the Add button on the bottom. The name should be AirFlowHz so that it is easy to remember. In the ROM to display f(x)= line, change x to x/ In the Display to ROM f(x)= line, change x to / x* Next, change data type from unit8 to unit16. Lastly, change display max from 255 to Click Ok and exit out of the scaling manager. From here you need to change the scaling on the bottom portion (named Y axis load ), from unit16 to AirFlowHz. The numbers in the left column will now represent your airflow in Hz, this will now match the airflow data you log in EvoScan. The numbers in the right column are what you will adjust to fine tune fueling at specific airflow ranges based on the logging information from EvoScan. Here is an example of how it works. You log your LTFT Low, it registers +5%. You then look at your Wideband O2 Feedback (STFT, Short Term Fuel Trim) and it is around +3%. Add the two numbers together and this tells us that you need to increase fueling 8%. Since this example is using idle speed, we look at your log to see what airflow your vehicle idles at (let s say 50 Hz). Next, go to your MAF Scaling table, in the 50 Hz line there is a value of 165 in the right column. The ECU uses a default adder value of 140 built into it, so you will need to add 165 and 140 together; this gives you a number of 305. Since your fueling needs to be increased by 8%, you take 305+8% which equals 329. Now remember, the ECU automatically adds 140 to the original value displayed in the table, so we need to subtract 140 from 329, this gives us a value of 189. This is your new value to enter into the 50 Hz line. This same process can be done with your LTFT Mid as well to really get your fueling dialed in precisely. Once you have adjusted your MAF Scaling table you can view the line graph that is associated with the MAF Scaling table. Click the View tab, and then select View Graph from the menu. You will notice the line does not follow a smooth path as it progresses. Refer back to your notes for specific airflow ranges that you have adjusted and do not alter those adjustments. You will want to smooth out the rest of the settings so that your line graph flows smoothly.

19 19 Accel Enrichment Tuning This portion of your tuning is related to the amount of fuel that is added when you depress your accelerator pedal quickly. Vehicles that are equipped with big bore throttle bodies, aftermarket intake manifolds, cams, or forced induction can benefit greatly from adjusting this table. With a modified vehicle, an unmodified Accel Enrichment table can give you a brief lean condition when you quickly depress the accelerator pedal. To view the line graph that is associated with his table, simple click the View tab, then select View Graph. The column on the left defines your engine s RPM, and the column on the right defines the percentage of fuel that is added under acceleration. As you can see in the example below, the line graph is not smooth and even dips down at 3250RPM; Ideally you want to have this line graph a smooth flowing line, for unmodified vehicles you will want to maintain the percentage values as close to the original settings as possible. Adjusting this table too much will result in too much fuel being added, making it too rich. Not making enough of an adjustment will result in not enough fuel being added, making it lean. Making the adjustments to this table will take some trial and error to get this setting dialed in based on the modification specific to your vehicle. Once this adjustment has been set appropriately to your vehicle, the acceleration response will be greatly improved. The example Accel Enrichment table below has been smoothed, and adjusted to give you an idea of what it would look like after being adjusted. Notice the dip that appeared in the table above at 3250RPM has been smoothed out, the percentage of fuel being added has also been raised to accommodate minor engine modifications such as a big bore throttle body;

20 20 MIVEC Tuning The term MIVEC stands for Mitsubishi Innovative Valve timing Electronic Control, system. MIVEC is Mitsubishi s brand name of variable valve timing (known as VVT) technology. The technology was developed initially for increasing an engine s performance, but has been developed further for better fuel economy and emissions standards. MIVEC simply varies the timing of the intake and exhaust camshafts to improve the engine s operating efficiency, this translates to better power output over a broad RPM range. Unlike other types of variable valve timing systems, MIVEC improves both the low and high end RPM power ranges. This is done using two different camshaft profiles to favor a low speed mode on the low lift profile, and a high speed mode high lift profile. An easy way to think of MIVEC is installaing aftermarket camshafts into an engine. Generally installing aftermarket camshafts will favor either an increase in low end, or high end power ranges instead of favoring both such as MIVEC. The values in the MIVEC tables are degrees of crankshaft rotation. This means if you set the value to 30, your camshaft timing is 15 degrees. You can advance or retard cam timing enough to increase turbo spool up, and overall engine performance. MIVEC maps tend to follow similar patterns where camshaft timing advance is set to 0 in the idle range, as engine speed increases the camshaft timing is advanced. Camshaft timing advance peaks around RPM, then gradually brought back close to 0 by RPM. This pattern allows for smooth idle as well as reduced emissions. Engine response becomes crisp in the lower RPM range with a progressive camshaft timing advance as RPM and load increases. If the advance is too drastic this causes harsh and jerky engine response, more so during cold or warm-up conditions. This table needs to be tuned per application and driving style of the vehicle, keep in mind adjusting these tables can generate knock so ignition tming needs to be monitored during the tuning of MIVEC tables.

21 21 Map Smoothing The 3D Graph feature in EcuFlash is one of the most valuable features that many simply overlook. To access this feature you will need to open your fuel or ignition map, click the "View" tab at the top of the map window and select "View Graph" (or ALT G for shortcut). You can click on the graph and use your arrow keys to rotate the graph, or click and drag the graph with your mouse. This feature will show you every sharp edge in the map that you will want to smooth out. These sharp edges are drastic changes in your fuel or ignition maps that the ECU needs to make. Remember that the ECU has to make a number of calculations in split seconds, the more drastic the changes from one cell value to the next, the more work you ECU has to do within that short period of time. The less work your ECU has to do, the more efficient it will operate, and the more efficient your tuning will be. The best advice is to minimize the changes from one cell to the next as much as possible, and minimizing the changes as much as possible from the previous cell. Making changes larger than this in some areas can produce instances of knock, lean, or rich fueling conditions. The ECU essentially interpolates the value from one cell to the next meaning it is forced to raise or lower the value between the two cells for that specific load and RPM range. If the values between the two cells have a large numerical gap, the ECU is being forced to do much more work than it needs to. The more you can reduce the ECU jumping back and forth on values from cell to cell the more efficient everything, including your engine, will operate. Map smoothing is not for specific areas of your maps that you are tuning, smoothing out the entire map can greatly improve throttle response, as well as cruising load, or RPM ranges of the maps. Below is an example of a stock/tuned unsmoothed ROM file compared to a stock/tuned smoothed ROM file;