Doing the Dyno
From PerfExpert website:
Quote:
For reliable test results:
- Always launch the car from the same mark on the road
- Always WOT at the same mark on the road
- Take measurements at the same direction of travel
- Be sure to follow the PerfExpert basic measurement procedures (phone calibration performed, impeccable phone fixation, little wind, free road, lift windows...)
- If the car remained parked in a while then drive a few minutes at medium speed to cool the engine bay in order to always make the measurements under similar engine bay temperature conditions
- For each setup (plenum or open stacks), perform at least two measurements having less than 2% deviation to confirm their reliability. Indeed non-repeatable measurements (differences of more than 2%) reflect a poor phone fixation or poor conditions (road, wind...)
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The first most important thing to take care is mounting the cell phone on the car. The mount should hold the cell phone firmly and there should be no vibrations. This is very important as any vibration in the phone will affect accelerometer data and hence the final result. Here is a picture of how I mounted the phone on my car.
This picture is just for reference. I did not do the dyno run on this road
Once the phone is mounted firmly, open the App, select the car, and a screen with option to do a dyno or a timed run shows up.
Selecting the dyno walks you through four more steps
- Select the configuration. Each car can have multiple configurations (like Stock, Stage 1 remap, Stage 1 remap v2 etc.)
- Select gear to run the dyno and minimum rev to start the log
- Setup additional weight like weight of passengers, luggage and tank capacity
- Weather data – we can either enter this manually or the app gets this from some weather website. During one of the runs I did for Jetta, I found this to have wrong temperature and I entered temperature manually from the temperature displayed on the MID.
Screen shots of the complete dyno run.
Select test mode.
Select tuning setup.
Select gear and minimum rev.
Additional Weights.
Weather data.
Once all the configuration is entered, the dyno screen shows up. Press the start button.
The App shows wait.
Important Note: The car should be in absolute stand still till the status changes to “Go”. Do not let the car creep forward when it says “Wait”.
Go.
Once the App shows "Go" Engage first gear and once on the move, go to second gear and go WOT (wide open throttle) by flooring the accelerator pedal. Once the RPM builds to red line release the throttle, slow down and stop. The app finishes the dyno and displays the summary of dyno result with peak power and torque numbers and asks if you want to discard or accept. Once you accept, the dyno results are displayed.
Dyno results page
Touch the graph in the results page to open the detailed graph.
Move your finger over the graph to see the data points.
Very Important Notes: - Safety is paramount.
- Do not do this test on a road that has traffic. Do this on a straight road which is totally devoid of traffic.
- While doing the run, do not look at the phone screen, but only the road
Clicking on the "Share" icon provides options to create an image of the test and share it using email, WhatsApp etc, or to share a web link of the results, or to export the data.
Below is the image that was created and emailed.
Below is the web link the App created for the test.
https://network.perfexpert-app.com/results/K6VpvUUuSH
Selecting "Data" creates a text file. As I could not attach the text file here, I opened it in Excel and saved as Excel spreadsheet. Attached below.
Jetta 2.0 TDI DSG - 2017.02.17 - 04.21.23.xls Problems Faced and Solutions:
While testing the App, I faced two issues.
Auto Upshift Issue
The app requires the full run to be performed in one gear without upshifting. I used the manual mode in both the Jetta and the GT TSi to perform the dyno runs. Though in manual mode, the DSG upshifts when the RPM hits redline. When I first performed the test on my Jetta, I always went to this threshold and the DSG used to upshift to third gear. Below is the resulting graph.
It took me a few trials before I was able to let go the accelerator in time to avoid the upshift.
Wrong Gear Ratio
When I first did the dyno on the Jetta, I had used the Gear ratio of 3.04 which was listed as the Final II gear ratio in the specifications. Following was the dyno result with this ratio.
The torque was shown as 417Nm, which is not possible. Jetta is rated at a torque of 320Nm. TBHPian kat found the mistake. He rightly pointed out that the gear ratio was 4.12, not 3.04. Then I did some reading and found that the DSG6 has two final gear ratios. Final I which is 4.12 is for gears 1, 2, 3 and 4. Final II which is 3.04 is for gears 5 and 6.
The app allows to edit the parameters of a dyno run even after the dyno is completed. Once I updated the final gear ratio to 4.12, the result was accurate as expected.
![PerfExpert App - The Poor Man's Dyno-correct-gear-ratio.png](https://www.team-bhp.com/forum/attachments/technical-stuff/1610461d1689706204t-perfexpert-app-poor-mans-dyno-correct-gear-ratio.png)