Beginners Guide to Tuning

[Gumba]

How to Tune an Evo

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?