Maestro Tuning Community Project
I've been thinking of starting a "community project" where we can all work towards a functional custom tune for the 2.0T B7. The other main goal is to provide an environment where everyone can learn about Maestro while seeing the effects of different maps being changed.
I am learning as well here so cut me some slack lol.
If anyone can add to this post to make it better, let me know. Also, feel free to share your knowledge. I know there are smarter people on here that know more than someone else.
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Term definitions
Injector Constant - This is your injector scaling. Usually, you will lower this value if you install larger injectors. A lower value essentially decreases the duration the injectors are open for any given time. A higher number, the longer the duration. This effectively changes how much fuel is delivered at every injector pulsewidth at any situation.
Block 032 - If you monitor this block, you will get two important values: "Short term fuel trims" and "long term fuel trims"
Short Term Fuel Trim - This is how much compensation the ecu is doing at idle and low load to maintain the desired Lambda (Air-Fuel ratio). Negative values are removing fuel; positive values are adding fuel.
Long Term Fuel Trim - This is the same as above but excluding idle. Basically partial throttle and wide open throttle.
Fuel Rail Pressure - This is the pressure your fuel rail runs at. X axis is engine load and Y axis is RPM. The Values inside the cells are MPa. 13 MPa = 130bar. You are limited how high you can go by your PRV. The standard stage 2 file has a max MPa of 13. Don't exceed that unless you have an upgraded PRV. Increasing the pressure at any cell will increase potential fueling for that condition the cell is for. (increases injector flow capability at the given RPM the cell is for)
Injection Correction - This directly affects your Pulsewidth (duration the injector is open) for a specific RPM and requested millisecond injector pulse. higher values add fuel; lower values remove fuel. Think of this like injector constant but more precise.
Maximum VE - This table relates to the maximum amount of airflow your ECU expects to see at a given RPM. Although this table does not actually directly control anything, other maps are calculated from this table, so it is in your best interest to get this table right. In the center white column, you will have values that relate to expected airflow. 100 = ~10 psi. In other words, 100 is ~ 690 millibar before adding 1000 millibar for sea level pressure; 1690 millibar. This is NOT exact, but a good starting point to get you going. The engine sees airflow in millibar, not PSI. Get comfortable with millibar. You will be using it to tune this table.
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Injector Constant.
There are ONLY three situations where you will be touching injector constant.
1. You have upgraded your injectors
2. You are changing fuel types
3. You have tried every other method to get LTFT values within 5% and haven't been able to.
For this example, I will be tuning to get e85 running on a Ko3 stage 2 file.
I will be working with the standard Eurodyne Stage 2 file and making my own modifications to support E85.
IF you have a K04, No way you can run e85 without RS4 Injectors. e85 is already demanding on the stock injectors on a K03..
I road tune, and I feel that most of you will as well. I have broken down basic steps on how I got my file to where it’s at. Tuning to e85 is actually pretty easy. you will be mostly messing with injector constant
The easiest method I have found getting e85 running pretty quickly and safely is first fill up your tank to a 25/75 percent e85 to gas mix for start. You could go right to a 50% mix, but as a beginner, you don't want to make mistakes in your calculations on your first flash going that high e85 content. 25% is real safe but still needs a slight modification in settings to get it safe as before.
Open up maestro and find your own Eurodyne file. The setting we will look at this time is the one called "Injector Constant". The value here should be 0.033320 (If you are using a stock injector file). The value here is states how much your injector flows. Since E85 requires more fuel by volume to deliver the same amount of power, we have to make the ECU "think" we have a smaller injector than we actually have. If we do this, the ECU will increase the duration the injector stays open in an effort to give the same amount of fueling as before. We will ADD a percentage value to the base injector value of 0.033320 relative to the amount of e85 we have in the tank. HIGHER values mean you have a "smaller injector".
For example, let's say you ran 100% e85. You will need about 30% more fuel than gasoline to make the same power. Therefore, you will use this equation: 0.033320*1.30. The final injector constant for running full e85 would be 0.043316. However, I have found that the stock injectors cannot reliably run 100% e85 without causing fueling issues. You can’t increase injector constant forever. The injector cannot open for longer than the time it takes for the piston to compress the potential gas and air mix. You will go into limp mode if too high duty cycle. Because of this, I recommend running a maximum of 50% e85 with a recommended mix of 25%.
Let's go back to the 25/75 mix we did earlier. Since we have a 25% mix, we will be using a multiplication value that is 25% of 30%. Basically the equation is: 0.033320*1.075=0.035819. This means that for any given situation, the ECU will be keeping the injector open 7.5% longer.
Now, save the file and flash it. (Make sure you are using your own stage two file, not mine). After that's done, go ahead and start the car and go for a drive. Drive around for 15 minutes. No need to go WOT. You are just letting the gas mix and allowing the ECU to do a little self learning. After this period, pull over to the side of the road, leave the car on and open up Maestroflash. Navigate to the diagnostics area and click on get controller info then measuring blocks. Then search for Block 032. You will see your STFT to the left and LTFT to the right. The stock stage 2 (in my case) Eurodyne file is pretty decent so you won't be worrying about the STFT. What to look at is the LTFT value. I've already explained what this value is so what you will need to know now is that this value tells you how much percent you are off from 0. A Value of 10.2 means the ECU is having to add 10.2% more fuel to keep at a proper air to fuel ratio. A Negative value is the opposite and is taking away fuel. You want both the STFT and LTFT to have a value between -5 to +5.
Let's say our current injector constant is 0.03998 and after we logged block 32, we find we have a LTFT value of -8.7. We load up our file that we were working on into Maestro and we remove 8.7% from the injector constant. after doing so, injector constant is now 0.03998/1.087= 0.03678. Flash, start the car and drive for another 15 minutes and see what the LTFT are. You may or may not need to repeat the steps outlined above to get you between the recommended values.
At this point, you are done with injector constant.
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Maximum VE
Before continuing, it would be a good idea to refer to the term definition above so you can familiarize yourself on Maximum VE. I will be going into more detail here. Before we can get to tuning, I will explain what is Maximum VE in more detail, Setup, and tuning.
What is VE? VE is what is known as Volumetric efficiency. Simply put, This value states how much, in percentage, your cylinders are filled up with air. In a naturally aspirated car, the maximum VE a car would see is around ~100. This means that 100% of the cylinder is being filled with air. Why would it be less than this? That has to do with a lot of things, such as cam design and head design and even your intake. For example, out of the car's cam efficiency range, the cylinders may only get a chance to fill up 75% or so and when on the strongest part of the cam, you may see 100% or even 105% due to an efficient intake manifold design allowing more air than atmospheric pressure to be crammed into the cylinder. Add a turbo to the equation and now we can fill up 200% more air in a cylinder.
When you tune maximum VE, you are telling the engine what is the maximum VE the engine will possibly see at a given RPM. This table is looked up by the ECU before any corrections to related maps are applied. A mis-tuned Maximum VE table can have a few detrimental effects. If if the ECU is expecting 2000 millibar of maximum VE and you can only push 1600, Your ECU will dump too much fuel until it is corrected by the o2 sensor. If your requested airflow is not met, the ECU will try a few tricks to raise boost/airflow such as using the closed loop PID boost system to close the wastegate to increase boost. Relying on Maximum VE to raise boost should NOT be used this way. Doing so will cause the boost to spike slightly right when you finally hit requested boost. Use Boost duty to raise boost. If your actual boost is higher than requested, then the ECU will use tricks to lower boost. Ideally, when finalizing your tune, Boost duty and Maximum VE should be inline.
Now for the setup. There are two ways to do this. Ill start with my prefered method. Use this method if you have a reasonable base spring pressure. Leave your N75 plugged in but disconnect the hoses to it. Connect the boost source directly into the wastegate. Doing this way will bypass the N75 and allow the car not to apply any PID (closed loop) corrections to the wastegate. A spring pressure of 14 PSI should have you see 14 psi max boost. If you are like me and have a base spring pressure of 7.5 psi, then you could use this method or use the second method which is to tune the Boost duty map first until you have your desired PSI reached. (DON'T put a 30 PSI wastegate spring if you don't plan on running 30 PSI). Then move on to tuning Maximum VE or just do both at the same time. You can get real close on a good Maximum VE on your first try using my method.
Open up your base file and navigate to Maximum VE and make sure that no value is less than 160 (~16psi) around where you expect to hit max boost. This assumes a base spring pressure of 14 psi This will ensure us the car wont take measures to lower boost if we hit it. Flash the file if you had to make any changes. There is an example of my horribly calibrated for start:
Get in your car, connect up Maestro and go for a drive. Make sure to drive to operating temp + 25 minutes to get the oil warm. Find a stretch of road, get into 3rd gear, start the log, and from 1000 rpm, smash the throttle and hold it until you hit peak boost and let go and stop the log when safe. It's a good idea to have a friend to tell you if you have serious knock so you can let off the throttle before anything bad happens. You can either look at the laptop for the 14 psi or you will feel it.
Let's take a look at my log:
As you can see, there is a large discrepancy with requested and actual boost. If you look, you will also see a boost spike as well. I had my N75 connected so the ECU was using boost PID to try to increase boost and it overshot when I hit requested boost. This is just one symptom of a miscalibrated Maximum VE map.
Remember the log you took earlier? You will use it to calibrate your Maximum VE table. Guess and check is not the way to do this. Use math. Simple math, but it's the best way to do it. Get your calculator out.
When you look at Maximum VE table in the Maestro file, you will see a RPM with the VE value under it. For example, in my table above, 1000 rpm has a value of 123 and 3000 rpm has a value of 172 and so forth.
Now go back to your log and take a look at those rpms. You will see a discrepancy of requested and actual boost. Divide your actual boost by your requested boost and then multiply by your current Maximum VE value for that RPM. Here is an example at 2750 RPM: 1320/2210*171.988=102.726. This will be your new value for that RPM on the Maximum VE table. Do this for every datapoint on your Maximum VE table using your logs up until your boost levels off. we are tuning only the pre peak boost situation here. Here is an example of what my table looked like following this method. Note that I rounded up to the nearest whole number, but I did this only for simplicity sake.
As you can see, the area before peak boost is very different now. If I were you, you should also change your data points on the blue column to be more concentrated around the areas with the sharper curves on the graph. I didn't do that here but it's best if you did. Let's go do another log. As usual, we are looking only to go WOT until we hit our desired peak boost.
As you can see, the actual and requested boost are very close now. As a positive side effect, the boost does not spike anymore either. This is because the Boost PID system now can properly assume expected airflow. I would have been more closer if I didn't round up. You can do another log and do this log calculation again to hone in even closer IF you want now (or later). Then you can plug in your N75 if you haven't before and cap the Maximum VE at the appropriate value for what PSI you are looking for. In my case, I left it at 172 because i'm looking for 17 PSI. Make sure the boost duty isn't too high or you will still spike past your Maximum VE requested boost pressure. You can then polish your boost duty if nessesary and get everything in line.
You may have to do one or two more full power runs to redline at third gear to get the top rpm Maximum VE spot on.
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Disclaimer: I take no responsibility for any fault or damage caused by reading, downloading or following advice in this thread . No warranties of any kind are given.
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Originally Posted by Fdny5772
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