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Discussion Starter #1 (Edited)
I'm very pleasantly surprised to see the ST is very consistent in generating Vdyno logs/graphs. Virtual Dyno if used correctly can be a great tool if the ECU logging can keep up and timing is accurate. In the case of the ST it seems to be. So post up some graphs and let's see how repeatable they are and how they compare to the real dyno. First, follow the instructions below to setup Vdyno correctly. Logs from both the COBB AP and SCT can be used to generate the graphs.

Remember Vdyno just like any dynamometer is used to show you differences in performance from one tune to another or from installing different components. Always keep this and consistency in mind. The more consistent your logging, the more consistent your results. Vdyno uses the rate change of RPM over time to determine the acceleration and calculate power based on vehicle weight, gearing, tire size, and aerodynamic coefficient.

1. Find a flat stretch of non populated (safe!!) road. This road should allow you to run in both directions.

2. When you take your car there keep your running weight consistent. That means no extra stuff in the trunk, passengers, etc. Try to keep fuel levels the same. All these small variables matter.

3. Wind resistance matters. So if it's windy that day, it's not a good idea to take logs for vdyno.

4. Temperature matters. This however can be compensated for while wind can't. Remember though that all turbo cars lose power in the heat. So if you made 240whp in the winter and you added a big intake and are logging in the summer and you lost power, it's not the intake, it's the temperature. So before making tuning or part swaps, take a baseline run on the same day or close to it. Don't compare runs between winter and summer as it will skew results.

5. Logs in 4th gear are probably best in the ST but 3rd is usable if 4th is not safe. The higher the gear, the more load you place on the motor. So the higher the gear the MORE power you will make. Do all pulls in the same gear - whichever is safe for the area you are logging.

6. When taking the log, always start in the same section of road, Always start at the same RPM (2500 RPM is what I recommend) and just punch the throttle straight to the floor. Don't hesitate. Keep it to the floor until redline.

7. Now, this is very important. Take ANOTHER log going the opposite direction on the same stretch of road. Why? Because you want to make sure your measurements are consistent. If they overlay like the one below, you're doing it right . If they don't overlay, the road is not flat, there is wind, or something else is going on and the data can't be trusted. Remember to take at least 2 runs for every change to make sure there is not error in the run or data until you have the process down and can really trust the data.

8. When setting the dyno type, it doesn't matter what you set it to (Dynojet, or a different correction factor) AS LONG as you always set it the same way. The same goes for smoothing. Setting of 3 seems to be optimal. As we see more of these and compare them to actual dynos, we will see what correction factor makes sense on the ST.

9. Remember to estimate the weight inside the car, and to accurately calculate your tire size.

10. Finally, Vdyno updates frequently and some versions have calculated power differently. Make sure you are comparing logs using the same version of software.

That's pretty much it. If you're lucky to live in an area that has some flat rural roads with little traffic, you can take some very repeatable logs and results and use Vdyno just as you would a regular dyno. Look at the back to back runs taken below in opposite directions on the same road with the same tune and on the same day.

More importantly - remember to be SAFE!!

The runs below were taken today in 40F weather in our ST that is stock aside from tuning changes. The numbers themselves seem a little optimistic (but then again it was cold). The consistency of back to back runs here is what makes me believe this to be a very good tool for the ST as the ECU data reporting rate is quite fast. To setup the logs to show up in Vdyno, see the instructions here:

http://www.focusst.org/forum/data-logs/16438-how-take-post-datalogs-forum-read-last-post-thread.html

Focus ST Vdyno.jpg

To add the Boost and AFR columns correctly, make the following setting changes in Virtual Dyno.

1. Go to File -> Options
2. Select the Columns and Profiles Tab
3. Check the boxes next to AFR and Boost.
4. In the text box next to AFR enter the exact column name in your logs for AFR. For the COBB AP it is Actual AFR (AFR)
5. Do the same for the Boost text box.

Vdyno AFR and Boost.png

Now boost and AFR will show correctly.
 

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I tried to use vitual dyno but the graph is always high at the beginning I don't know why

vdyno st.jpg
 

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I have SAE correction enabled so that I could enter the proper weather. My car is stock other than FSWerks 91 tune. These were 3 consecutive pulls.

Virtual Dyno 1.jpg
 

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Discussion Starter #13
These were taken with V2 AP. Why do you ask?
I've noticed that the faster logging speed of the V3 sometimes makes the logs less consistent on the MazdaSpeed3 with the slower logging ECU and was wondering if the same was the case here. Your Vdyno looked a little shakier - it was likely the smoothing factor or road surface.
 

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I've noticed that the faster logging speed of the V3 sometimes makes the logs less consistent on the MazdaSpeed3 with the slower logging ECU and was wondering if the same was the case here. Your Vdyno looked a little shakier - it was likely the smoothing factor or road surface.
Ah, okay. Yes, I only had the smoothing factor set to 1 and not 3.
 

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Freek, do you have any ethanol blend VD plots?
 

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Discussion Starter #17

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@rader1; here is an e30 tune that I did back in the fall. This particular car has a significant pressure drop across the core so it can't hold as much boost up top as other ST's I've tuned. Still pretty awesome though for a k03 turbo car :)
e85 mix ST.PNG
 

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I'll have to give this a try. I might roll across a set of scales and get an exact weight.
 

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@rader1; here is an e30 tune that I did back in the fall. This particular car has a significant pressure drop across the core so it can't hold as much boost up top as other ST's I've tuned. Still pretty awesome though for a k03 turbo car :)
Sweet!
 
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