Disclaimer: I have used the method outlined below successfully to tune my car. I am an amateur and not a professional. If you use this method then you accept full responsibility for whatever damage you do to your car. If you are concerned about voided warranty and damage to your car, you are better off leaving your car without any modifications to the ECU.

I am writing this essay because I often see a lot of request from Evo owners on how to begin tuning, what equipment is needed for accurate tuning, what approach should I take to tuning, etc….

Aside from the equipment and approach, the two most important elements to have are PASSION and TIME. If you want to learn how to tune an Evo simply to make money out of tuning, then IMO you will suck at it. Passion should come first and making money out of tuning is a distant second. If you do not enjoy tuning, then do not do it. You will end up very frustrated and maybe mess up your Evo.

The second important element to learning how to tune is TIME. You must read a lot and test a lot. The most important place to visit and read is the Ecuflash forum on Evom. This is the hub for Ecuflash tuning. I spend hours reading posts from knowledgeable people like MalibuJack, mrfred, razolab, tephra, jcsbanks, touring bubble, etc…. Some of the stuff that I read is highly technical to me. I get confused, so I read and re-read and read again. Sometimes I read threads three to four times before the concepts sink in. I get very frustrated at times since I do not have a technical background. Don’t be afraid to ask questions. The folks on that forum are very helpful. If you are polite and have done your reading prior to asking your question, then they will help you. Other places to visit include aktivematrix (MalibuJack’s website) and NorCal Evo.

When you first start reading you will be confused. The learning curve is steep and the task seems daunting. There is simply too much to read. Some of the posts are top notch and some are pure crap. You will have to figure out which posts to believe in. Use the above mentioned posters’ names as your guide. But do NOT give up, persevere. You CAN do it. It is NOT hard to tune your own Evo. It is not black magic or rocket science. Some pro-tuners want you to think it is, so you will not do it on your own. I was in your shoes once. I thought that tuning was some voodoo/rocket science affair. I too trusted a pro-tuner, only to discover that the pro-tuner I trusted had serious shortcomings. So I took a vow to learn how to do this and never to go to a pro-tuner again.

If you have PASSION and TIME, then the next step is to get the best possible equipment that you can afford. So what will you need?

1. Laptop: You must have a laptop. Modern tuning is all about computers. W/O a laptop, it is very hard to tune accurately with consistent repetitive results. There are many cheap used laptops on ebay. Make sure that you get one that is powerful enough for your tuning needs. I also recommend that you get a small laptop with a small screen. Mine is bulky and has a 14.xx inch screen. I am now in the market for a very small 7 inch mobile computer.

2. Logging hardware: You will need a logging/flashing hardware cable. The one that all of us currently use is the Tactrix Cable (http://www.tactrix.com). You can either get a universal cable or an Evo specific cable. The former will work on Evo and non-Evo vehicles, the latter will only work on Evos. I have one of each. One stays in my Evo and the other stays in my tuning kit.

3. Wideband O2 meter (WBO2): Do not attempt to tune your Evo if you do not have a WBO2 meter. Do not use the narrowband O2 sensor on the Evo to tune the car. The NBO2 was not intended for tuning purposes. It is used for emissions and it is only accurate under stoichometeric conditions and even then it is barely accurate. Tuning with a NBO2 was used back in the DSM days when WBO2 were very expensive and no one could afford them. Today, you can get a WBO2 meter for as little as $180. I use Innovate products. I have an LM-1/LM-A2 with two XD-1 gauges. One gauge reads AFR and the other gauge reads boost. The cost was $750. It was worth every penny. I have had zero problems with this kit.

4. Logging Software: The most widely used logging software is Evoscan (http://www.limitless.co.nz/EvoScan). It uses the tactrix cable to log data from your ECU port. It also allows you to integrate data from your WBO2 with the data from your ECU port. It costs $25. It is a one time fee that entitles you to later updates of the software. It is very user friendly and easy to set-up. If you want free software, then try Mitsulogger from the aktivematrix web site.

5. Tuning Software: The tuning software is known as Ecuflash. It is for free and you can download it from http://www.openecu.org. Be aware that some recent versions of the software have bugs in them and might not work on your lap top. I am still using version 1.29a because I do not want to deal with the possible bugs in later versions.

So now that you have all the equipment and tools, what do you do next?

First, you must install the WBO2 properly on your Evo. DO NOT install the WBO2 sensor behind the Catalytic Converter. That will give you erroneous AFR readings. The best position to place the sensor is in the down pipe 2 inches before the flange in the three o’clock position on the passenger side. Do not place the sensor in any position below three o’clock. You do not want condensation to form on the sensor and destroy the sensor.

Second, you have to go out and log data from your Evo. You must log, log, and log some more. Since I live in an urban area, flat freeway on ramp work great for me. Log in 3rd gear. Do WOT runs from 2500 rpm all the way to 7500 rpm. Only log the essential data with Evoscan. Logging all the data from your ECU will slow your logger down. The essentials include: AFR, timing, 2 byte load or loadcalc, TPS, RPM, Knock, boost (if possible), coolant temp, IAT, injector pulse width, and injector duty cycle. You must study and understand what the data means.

Third, download the rom image from your ECU using the tactrix cable and Ecuflash. Save the image to your lap top. Make sure the you write the immobilizer code in your rom on a piece of paper and save it. Understand what the tables in the rom mean. Do not touch them or modify them until you understand what they mean.

Fourth, now that you have read a whole ton and logged your Evo, you can proceed to modify the tables in your rom. The most important advice I could give you is to work INCREMENTALLY. Make small changes to the tables. For example, in the high octane fuel table lean out the map by making changes of no more than 0.3-0.4 target AFR. Do not go too aggressive in your changes. Another important piece of advice is to make the changes SMOOTH between cells. Recently, I saw a map that had the target AFR jump from 10.9, to 9.4 in two adjacent cells in the fuel map. This same map had a timing jump from 9* to 13* from 6500 to 7000 rpm. . The lack of smoothness in the map transition will more than likely trigger knock. A 4* jump from one load cell to the next will more than likely trigger knock on 91 octane gas.

So which part of the rom do I start tweaking first?

A. Timing

Generally, speaking Evos with a stock rom tend to have a lot of timing advance. Timing advance refers to the degrees that the spark plug is fired prior to the piston reaching Top Dead Center (BTDC). The higher the timing number in the load cell that the car hits during WOT operation, the earlier the spark plug is fired. The lower the timing number in the load cell during WOT, the sooner the spark plug is fired. In the timing map image below, I indicated the load cells that a tuned TBE Evo will hit during WOT operation in 3rd or 4th gear. If you look at load cells 220-260 @ 3500 rpm you will see 3, 3 and 2. These numbers tell us that the spark plug will fire between 3-2* BTDC. As the rpm increases so does the timing advance. Why? well the engine has faster speeds and the spark plug must be fired earlier or else there would not be enough time to complete the burn of the air/fuel mixture. So in load cell 220/240 @ 7000 rpm the map indicates 10-9* BTDC. These cells are usually the cells that a tuned Evo 9 will hit during WOT operation in a 3rd or 4th gear log.

The Evo was designed by Mitsubishi to run on 93 octane gas, but in CA we not only have 91 octane gas, but our 91 octane gas is of very poor quality. Almost all of the stock rom evos that I have logged had 6-7 counts of knock in the 5500+ rpm region. My stock evo 9 had 6 counts of knock beginning @ 5000 rpm and continued with 4 counts of knock all the way to redline. This is a bone stock Evo 9.

So my first approach when tuning is to eliminate the knock. This means that you must retard the timing numbers in the high octane ignition map(s) especially in the higher rpms. An Evo 8 has one high octane ignition map while an Evo 9 has 3 high octane ignition maps. So why does the 9 have three? It is theorized that because of the mivec map on the Evo 9, Mitsubish introduced 3 maps. It is believed that the Evo 9 ECU interpolates between the three maps. Unfortunately, most tuners do not know how the interpolation works. It is believed that the Evo 9 ECU uses map #2 80-90% of the time and on occasion uses maps number 1 and number 3. Since our state of knowledge about interpolation is limited, most tuned maps that I have seen make the three high octane ignition maps the same. This gives you a consistent and repetitive timing curve. If you only tweak map number 2, then you might get inconsistent timing. I have seen WOT logs with timing increasing and then decreasing even w/o knock, rather than gradually increasing as the rpms increase. The usual culprit is that the DIY tuner forgot to make all three timing maps the same.

Here is the timing map that I use on a lot of Evo 9s. Of course, every Evo is different and you will have to tweak this map to fit your need. Keep in mind that this map is set-up with 21-22 psi peak boost (3500-3700 rpm) and the boost holding @ 20.5 psi in the midrange and then tapering to 19 psi by redline. The AFR for this timing is 12-13 during spool-up, 11.6-11.7 during peak and gradually tapering to 11 by redline. It goes without saying, that if you run less boost, and a richer AFR then you can run more timing.



I suggest that you save this map and compare it to the stock map on your rom to see where the changes were made. Generally speaking, I have found that Evo 9s like no more than 2-3* of timing advance @ peak boost/torque (3500-3700 rpm) and no more than 10-11* by redline provided you are running the boost that I mentioned above.

My approach to timing is to follow the MTBT method, i.e., Minimum Timing for Best Torque. Simply stated, the method declares that a tuner should advance timing until advancing the timing no longer yields gain in power/torque or, lacking a dyno, until knock is encountered. On the last Evo 9 that I tuned, 1* beyond 10**at the top end and the car started registering 2-3 counts of knock. So I backed the timing from 11* to 10* and stopped tweaking the timing map.

You will note that in this map, I have also advanced the timing from 5* to 7* in the 0-40 load and 0-1000 rpm cells. Why? Well, according to those in the know this will help smooth the idle even on a stock Evo, but it is usually used on cammed Evos. The load cells from 0-100 and 1500 to 7500 rpm are for cruising. Generally, they are left alone.

B. Mivec Tuning (Evo 9 only)

The Evo 9 has variable cam timing on the intake cam. It varies the cam timing from a value of 0 to a value of 30 in the VVT table. You can input values beyond 30 in the table but nothing really happens. Those who specialize in ECU disassembly on the Evo have not figured out a way to log cam timing. I am pretty sure that in due time they will figure it out. When that happens we can figure out exactly what load cells we are hitting across the rpm range and create far better maps. In the meantime a lot of DIYers have experimented with cam timing and posted their maps and their findings (http://forums.evolutionm.net/showthr...t=mivec+tuning)

All the maps tend to follow a similar pattern: cam timing advance is low in the lower rpm, but as the engine speed increases cam timing is advanced. Cam timing advance reaches its peak around 3500-4000 rpm and then cam timing is gradually brought back close to zero by 6500-7000 rpm.

Most DIY tuners start by using the Evo 9 JDM RS map. That map forms the basis of 90% of Mivec maps that are posted and used in the VVT table. Here is what the map looks like:



Most DIYers change the numbers in the “island” that has 24 in it to 28.8 and save the map and flash it into the ECU. Others change the entire 28.8 numbers to 30, save the map and flash it into their ECU. This is a really good map.

I tinkered with mivec and was able to come up with a map that I really liked. It is a fusion of two maps. The first map was posted in the Mivec Tuning thread on Evom and the second map was created by John Bradley who is the resident mivec guru on Evom. I took the top end (load cell 70 to 300) from one map and fused it with the bottom end from another map. I was very surprised by the increase in low end snappiness of my Evo. The car felt like an NA car. You can put it in high gear at low rpm and simply touch the accelerator and the car goes. I thought it was only in my mind, but when I tested it on other Evos, the impressions of the drivers were the same. Two caveats about this map: First, it will slightly increase your idle by about 100-200 rpm during normal driving. Second, after you hammer on the car for a while, your idle will go up to 1000 rpm. If you can tolerate this, then go ahead and use the map. If you cannot, then use the JDM 9 RS map.



C. Setting the Boost

In SoCal the overwhelming majority of Evo owners use an MBC to control boost. So this is what I will use in this write-up. The more recent use of ECU boost control I will leave for another write-up. The most widely used MBC is the Dejon Tool (DT). It is simple to use, cheap, and effective. Turn the knob counterclockwise and the boost decreases. Turn the knob clockwise and the boost increases. Be very careful though, the DT is very sensitive to even the smallest of adjustments. So make your adjustments about 1/8 of a turn whenever you are increasing the boost.

So I installed my MBC, how do I set my boost?

Please refrain from using the “eyeball-the-gauge” method to set your boost. Mechanical boost gauges are inaccurate to begin with. I had a Defi D boost gauge that I thought was very accurate. When I logged the boost, the Def D was 1-1.5 psi off. I have logged several Evos that have had their boost set using the “eyeball-the-gauge” method and the result of the log is different than from what the Evo owner told me the boost was set to.

Logging the boost requires installing a MAP sensor and calibrating it properly based on atmospheric conditions in your area. A MAP sensor is usually tapped into the little hose that connects from the intake manifold to the FPR. That is the way it reads pressure. The pressure pulses are translated in the sensor into 0-5 volts signals and sent to a data logger. The data logger takes the signals and based on the calibration data that you supplied translates the voltage into psi.

I use two methods to log boost. The first uses the GM 3 Bar MAP sensor. This sensor is widely available and very easy to set up and use. I bought mine with a pig tail harness for $75. I set it up using the calibration data that was provided by the manufacturer. The calibration data that I enter in my logger (Logworks logs the LM-1/LMA2) is as follows:

PSI---------Volt
-14.7-------0
-8.9--------0.631
-4.4--------1.134
0-----------1.6
20.1-------3.884
29.4-------4.914

The second method to log boost is to use a JDMMAP sensor specifically designed for the Evo. In Japan, the Evo is equipped with a 3 bar MAP sensor that sits atop of the intake manifold. The USDM Evo gets a worthless 1 bar MAP sensor. An enterprising genius on Evom by the name of mrfred figured out how to use the JDMMAP sensor on the USDM Evo. The process involves swapping the sensors and modifying defined tables in the ECU to log the values from the JDMMAP sensor. The same principle that I outlined above applies to the JDMMAP sensor only now you can log the boost directly from the ECU provided you have properly modified your Evoscan xml file to log boost. The whole process is outlined here http://forums.evolutionm.net/showthread.php?t=259595

So what does the boost look like on a stock Evo 9? A bone stock evo 9 should have the following boost profile:



First, the average boost number @ peak is close to the 20.3 psi. 20.3 psi is the spec sheet boost for the Evo 9. Environmental conditions will make the boost vary. I have noticed that logging on a day with high humidity will bring the boost down a bit. Second, the boost tapers like crazy on the Evo 9. By 6500 rpm the boost is below 16 psi. It is a pity that I do not have stock boost logs from my old Evo 8 to compare to my Evo 9.



The above boost chart is what the boost looked like on my Evo 9 after installing a TBE with a HFC. You will note that the boost climbed to an average of 20-21 psi at peak and the boost stayed above 16 psi by redline. Also of note is how the load has climbed from 200 to 220. Generally speaking, the more power the Evo makes the higher the load cells that it will hit.



This is what your boost should look like on 91 octane gas. Your target average boost should be between 21-22 psi for an Evo 9 and less than that for an Evo 8. You will note that the Evo is now hitting higher load cells and can hold higher boost to redline. Unfortunately, if you want your boost to be higher by redline, then your boost will climb higher by 3500+ rpm. On 91 octane, this can become dangerous.

What about the boost limit, aka, boost cut?



The picture above shows the boost limit table and the boost delay table on a stock Evo 9. What does it mean? If your Evo hits a load higher than 255 (approximately 22 psi) for 1 second, then the boost cut will kick in. The higher the rpm goes, the lower the limit. So at 7000 rpm if your EVO hits loads of more than 235 for 1 seocnd, then the boost cut will kick in. This is an excellent safety feature that Mitsubishi engineered into the ECU.

Under no circumstances should you eliminate this safety feature on 91 octane pump gas. When it comes to boost limit, just set the limit slightly higher and please leave the boost delay alone. Setting the boost limit @ 300 or maxing it out to 319 simply removes the safety from your ECU in case of an overboost condition. Here is the way I set the boost limit on an Evo running on 91 octane gas:




To be continued….