KPower: Calculation Accuracy and Precision

Hi everyone,

"I bought a diagnostic adapter with the 409.1 and Kpower software two weeks ago because I was tired of the unreliable products you find on eBay (which don't work with VAGCheck and newer control units)."

I've previously done performance measurements using the VAGCOM 311 cheap adapter and the "Whoopies P*****er" software, always getting results around 135 hp and 280 Nm. With a friend's car (a Fabia 1.4), I got readings of 78 hp and 125 Nm.

Now, using Kpower and VAGCOM 409.1, my car achieves approximately 111 kW and 320 Nm of torque, while my friend's car has 69 kW and 144 Nm.

I'm now curious about where this large difference comes from, or what tolerance is allowed with this calculation.

My car.
Seat Leon 1M - Vehicle weight of 1600 kg including occupants and accessories, measured on a truck scale (accuracy +/- 25 kg).
with a 1.9 TDI engine (standard output: 81 kW / 235 Nm, chipped to 103 kW / 280 Nm).
Sequential tire fitting.

My friend's car.
Skoda Fabia - 1425 kg
with a 1.4 16V engine (series, 75 horsepower, torque unknown).

I either used the existing *.pom files directly or re-imported the LOG files and also performed new measurements. The calculated values were obtained from three different paths, and an average was then computed (the deviation between the individual paths is less than 3%).

greetings

Hi,

The calculations are also performed using acceleration, but in a completely different way. Could you please post your log files so we can see what's going on?

Regarding the data:
- Seat Leon: Curb weight 1334 kg.
http://www.alle-autos-in.de/seat/seat_leon_19_tdi_stella_ktc1284.shtml

- Fabia: 75 horsepower, 126 Nm of torque, curb weight 1135 kg.
http://www.alle-autos-in.de/skoda/skoda_fabia_14_16v_classic_ktb1315.shtml#Motor
http://www.alle-autos-in.de/skoda/skoda_fabia_14_16v_classic_ktc1315.shtml

You specified weights of 1600 kg for the Leon and 1425 kg for the Fabia.
So, either you had the 'Fat Boys' on the scale in your trunk, or your scale isn't that great...
The differences in weight directly affect the result. So, if the Leon actually weighs only 1500 kg instead of 1600 kg, you get 111 kW * (15/16) = 104 kW. Assuming a realistic weight of 1300 kg for the Fabia: 69 kW * (1300 / 1425) = 62.9 kW (85 hp).

How much did your measurements diverge from each other? Calculating the average is usually unnecessary if the data acquisition is accurate.
The differences observed in the individual measurements are typically within the range of 1-2%.

Best regards, Rainer.

Okay, regarding the weight, I didn't mention the unladen weight either.
To the Leon ->
Equipment model: Sport.
Vehicle registration document 1314 KG.
Fuel: approximately 50 kg (full tank).
Passenger weight 160KG <<-- the FatBoy is sitting at the controls .
Approximate weight of items in the car: 100 kg (includes radio, speakers, subwoofer, amplifier, laptop, GPS, climate control system, and floor mats).

It weighs 1624 kg according to the scale, but I only went on a different scale, and it showed just over 1600 kg (which should be accurate; it's a large platform that you drive onto, I don't know if you know what I mean; it's mainly used in agriculture).

The Fabia is secondary for now, and I only included it for comparison purposes.

The difference of 3% in the individual calculations is due to the fact that I had different test tracks and also different weather conditions, and no track near us is perfectly straight over such a long distance.

Here's the log file that produces the best power curve; here, the performance is also slightly higher, at 115 kW / 340 Nm. It was recorded near the Main-Danube Canal.

My question about the difference in measurements concerned Woopsies P... versus Kpower, as there are extremely large differences with my car. I haven't even had my car on a dynamometer once, so I don't have any reference values. And of course, whether the calculated power output is close to reality.

Quote:

Thursday, September 22, 2005, 15:18:01. 038 906 012 AT, "0000SG 2815". Group A: ,'005,,,,Group B:,'006,,,,Group C:, Not Running "Engine speed, Start Injection Quantity, Actual Start of Injection, Coolant temperature, Speed, Brake pedal, Cruise control, Cruise system," ,TIME,rpm,2*A-3*BTDC,2*A-3*BTDC,*C,TIME, km/h,F/F47/F36 ,Cl/Br/Re/Ac/on/on,0,TIME,,,, MARKER, STAMP, /min, mg/R, °, °C, STAMP, km/h, , , , STAMP, , , , ,0.00,1491,19.8,0.2,89.1,0.32,38.0, 0 0 0, 000000,255.0,,,,, ,0.64,1533,19.8,6.4,89.1,0.96,39.0, 0 0 0, 000000,255.0,,,,, 1.28, 1680, 19.8, 6.2, 89.1, 1.60, 42.0, 0 0 0, 000000, 255.0, , , , , 1.92, 1890, 19.8, 5.7, 89.1, 2.24, 47.0, 0 0 0, 000000, 255.0, , , , , 2.56, 2100, 19.8, 6.4, 89.1, 2.88, 52.0, 0 0 0, 000000, 255.0, , , , , 3.20,2352,19.8,7.0,89.1,3.52,58.0,0,0,0,000000,255.0,,,, 3.84, 2562, 19.8, 7.7, 89.1, 4.16, 64.0, 0 0 0, 000000, 255.0, , , , , 4.48, 2793, 19.8, 8.8, 89.1, 4.80, 69.0, 0, 0, 0, 000000, 255.0, , , , , 5.12,3024,19.8,9.9,89.1,5.44,75.0,0,0,0,000000,255.0,,,,,, 5.76, 3213, 19.8, 11.2, 89.1, 6.10, 80.0, 0 0 0, 000000, 255.0, , , , , 6.42, 3423, 19.8, 12.5, 89.1, 6.74, 85.0, 0 0 0, 000000, 255.0, , , , , 7.06,3612,19.8,13.4,89.1,7.38,90.0, 0 0 0, 000000,255.0,,,,, 7.70, 3780, 19.8, 14.5, 89.1, 8.02, 94.0, 0 0 0, 000000, 255.0, , , , , 8.34, 3927, 19.8, 15.2, 89.1, 8.66, 98.0, 0 0 0, 000000, 255.0, , , , , 8.98, 4074, 19.8, 15.4, 89.1, 9.30, 102.0, 0 0 0, 000000, 255.0, , , , , ,9.62,4221,19.8,15.0,89.1,9.96,105.0, 0 0 0, 000000,255.0,,,,, 10.28,4368,19.8,15.2,89.1,10.60,108.0, 1 0 0, 000000,255.0,,,,, ,10.92,4641,19.8,9.5,89.1,11.24,109.0, 1 0 0, 000000,255.0,,,,, 11.56,3234,19.8,0.0,89.1,11.88,108.0, 1 0 0, 000000,255.0,,,,, 12.20,1806,19.8,0.0,89.1,12.52,107.0, 1 0 0, 000000,255.0,,,,, ,12.84,1029,19.8,1.5,89.1,13.16,106.0, 1 0 0, 000000,255.0,,,,, 13.48, 924, 19.8, 1.3, 89.1, 13.82, 105.0, 1 0 0, 000000, 255.0, , , , , 14.14, 882, 19.8, 1.3, 89.1, 14.46, 104.0, 1 0 0, 000000, 255.0, , , , , 14.78, 882, 19.8, 1.1, 89.1, 15.10, 103.0, 1 0 0, 000000, 255.0, , , , , ,15.42,903,19.8,1.1,89.1,15.73,102.0, 1 0 0, 000000,255.0,,,,, 16.06,903,19.8,0.9,89.1,16.38,100.0, 1 0 0, 000000,255.0,,,,, ,16.70,903,19.8,1.1,89.1,17.04,99.0, 1 0 0, 000000,255.0,,,,, 17.36, 903, 19.8, 1.1, 89.1, 17.68, 97.0, 1 0 0, 000000, 255.0, , , , , 17.99,903,19.8,1.1,89.1,18.32,96.0, 1 0 0, 000000,255.0,,,,, 18.64, 903, 19.8, 1.1, 89.1, 18.96, 95.0, 1, 0, 0, 000000, 255.0, , , , , 19.27, 903, 19.8, 1.3, 89.1, 19.59, 94.0, 1 0 0, 000000, 255.0, ,,,, 19.92, 903, 19.8, 1.1, 89.1, 20.24, 92.0, 1 0 0, 000000, 255.0, , , , , 20.55,903,19.8,1.1,89.1,20.90,91.0, 1 0 0, 000000,255.0,,,,, ,21.21,903,19.8,1.1,89.1,21.53,90.0, 1 0 0, 000000,255.0,,,,, ,21.85,903,19.8,1.1,90.0,22.17,89.0, 1 0 0, 000000,255.0,,,,, 22.49,903,19.8,1.1,90.0,22.81,88.0, 1 0 0, 000000,255.0,,,,, 23.13, 903, 19.8, 1.1, 90.0, 23.45, 86.0, 1 0 0, 000000, 255.0, , , , , 23.77, 903, 19.8, 1.1, 90.0, 24.09, 85.0, 1 0 0, 000000, 255.0, , , , , 24.41,903,19.8,1.1,90.0,24.75,84.0, 1 0 0, 000000,255.0,,,,, 25.07,903,19.8,1.1,90.0,25.39,83.0, 1 0 0, 000000,255.0,,,,, 25.71,903,19.8,1.1,90.0,26.03,83.0, 1 0 0, 000000,255.0,,,,, ,26.35,903,19.8,1.3,90.9,26.67,82.0, 1 0 0, 000000,255.0,,,,, 26.99,903,19.8,1.1,90.9,27.31,81.0, 1 0 0, 000000,255.0,,,,, 27.63,903,19.8,1.1,90.9,27.97,80.0, 1 0 0, 000000,255.0,,,,, 28.29,903,19.8,1.1,90.9,28.62,79.0, 1 0 0, 000000,255.0,,,,, 28.95, 903, 19.8, 1.1, 90.9, 29.27, 78.0, 1 0 0, 000000, 255.0, , , , , ,29.59,903,19.8,1.1,90.9,29.91,78.0, 1 0 0, 000000,255.0,,,,, ,30.23,903,19.8,1.1,90.9,30.55,77.0, 1 0 0, 000000,255.0,,,,, ,30.87,903,19.8,1.1,90.9,31.19,76.0, 1 0 0, 000000,255.0,,,,, 31.51,903,19.8,1.1,90.9,31.83,75.0, 1 0 0, 000000,255.0,,,,, 32.15, 903, 19.8, 1.3, 90.9, 32.47, 75.0, 1 0 0, 000000, 255.0, , , , , 32.79, 903, 19.8, 1.3, 90.9, 33.11, 74.0, 1 0 0, 000000, 255.0, , , , , 33.43, 903, 19.8, 1.1, 91.8, 33.75, 73.0, 1 0 0, 000000, 255.0, , , , , 34.07, 903, 19.8, 1.1, 91.8, 34.39, 72.0, 1 0 0, 000000, 255.0, ,,,, 34.71, 903, 19.8, 1.1, 91.8, 35.03, 72.0, 1 0 0, 000000, 255.0, , , , , 35.35, 903, 19.8, 1.1, 91.8, 35.69, 71.0, 1 0 0, 000000, 255.0, ,,,, 36.01,903,19.8,1.3,91.8,36.33,70.0, 1 0 0, 000000,255.0,,,,, 36.65, 903, 19.8, 1.1, 91.8, 36.97, 70.0, 1 0 0, 000000, 255.0, , , , , 37.29, 903, 19.8, 1.1, 91.8, 37.61, 69.0, 1 0 0, 000000, 255.0, ,,,, ,37.93,903,19.8,1.3,91.8,38.25,68.0, 1 0 0, 000000,255.0,,,,, 38.57, 903, 19.8, 1.1, 91.8, 38.89, 67.0, 1 0 0, 000000, 255.0, ,,,, ,39.21,903,19.8,1.1,91.8,39.55,67.0, 1 0 0, 000000,255.0,,,,, 39.87, 903, 19.8, 1.1, 91.8, 40.19, 66.0, 1 0 0, 000000, 255.0, ,,,, 40.51, 903, 19.8, 1.1, 91.8, 40.83, 66.0, 1 0 0, 000000, 255.0, , , , , 41.15, 903, 19.8, 1.1, 91.8, 41.47, 65.0, 1 0 0, 000000, 255.0, ,,,, 41.79, 903, 19.8, 1.1, 91.8, 42.11, 64.0, 1 0 0, 000000, 255.0, , , , , 42.43, 903, 19.8, 1.1, 91.8, 42.77, 64.0, 1 0 0, 000000, 255.0, , , , , 43.11, 903, 19.8, 1.1, 91.8, 43.43, 63.0, 1 0 0, 000000, 255.0, , , , , 43.75, 903, 19.8, 1.1, 91.8, 44.07, 62.0, 1 0 0, 000000, 255.0, , , , , 44.39, 903, 19.8, 1.1, 91.8, 44.71, 62.0, 1 0 0, 000000, 255.0, ,,,, 45.03, 903, 19.8, 1.1, 91.8, 45.35, 61.0, 1 0 0, 000000, 255.0, , , , , 45.67, 903, 19.8, 1.1, 91.8, 45.99, 61.0, 1 0 0, 000000, 255.0, , , , , 46.33, 903, 19.8, 1.1, 91.8, 46.65, 60.0, 1 0 0, 000000,255.0,,,,, 46.99, 903, 19.8, 1.1, 91.8, 47.33, 59.0, 1 0 0, 000000, 255.0, , , , , 47.65, 903, 19.8, 1.1, 91.8, 47.97, 59.0, 1 0 0, 000000, 255.0, , , , , 48.29, 903, 19.8, 1.1, 91.8, 48.61, 58.0, 1 0 0, 000000, 255.0, , , , , 48.93, 903, 19.8, 1.1, 91.8, 49.25, 58.0, 1 0 0, 000000, 255.0, , , , , 49.57, 903, 19.8, 1.1, 90.9, 49.87, 57.0, 1 0 0, 000000, 255.0, , , , , ,50.21,903,19.8,1.1,90.9,50.55,57.0, 1 0 0, 000000,255.0,,,,, 50.87, 903, 19.8, 1.3, 90.9, 51.19, 56.0, 1 0 0, 000000, 255.0, , , , , ,51.51,903,19.8,1.3,90.9,51.83,56.0, 1 0 0, 000000,255.0,,,,, ,52.15,903,19.8,1.1,90.9,52.47,55.0, 1 0 0, 000000,255.0,,,,, ,52.79,903,19.8,1.3,90.9,53.11,54.0, 1 0 0, 000000,255.0,,,,, ,53.43,903,19.8,1.1,90.9,53.77,54.0, 1 0 0, 000000,255.0,,,,, ,54.09,903,19.8,1.1,90.9,54.41,53.0, 1 0 0, 000000,255.0,,,,, ,54.73,903,19.8,1.1,90.9,55.04,53.0, 1 0 0, 000000,255.0,,,,, ,55.36,903,19.8,1.1,90.9,55.69,52.0, 1 0 0, 000000,255.0,,,,, ,56.01,903,19.8,1.1,90.9,56.32,52.0, 1 0 0, 000000,255.0,,,,, ,56.65,903,19.8,1.3,90.9,56.97,51.0, 1 0 0, 000000,255.0,,,,, ,57.29,903,19.8,1.3,90.9,57.63,51.0, 1 0 0, 000000,255.0,,,,, ,57.95,903,19.8,1.3,90.9,58.27,50.0, 1 0 0, 000000,255.0,,,,, ,58.58,903,19.8,1.1,90.9,58.91,50.0, 1 0 0, 000000,255.0,,,,, ,59.23,903,19.8,1.1,90.0,59.54,49.0, 1 0 0, 000000,255.0,,,,, ,59.86,903,19.8,1.1,90.0,60.19,48.0, 1 0 0, 000000,255.0,,,,, ,60.51,903,19.8,1.1,90.0,60.82,48.0, 1 0 0, 000000,255.0,,,,, ,61.15,903,19.8,1.3,90.0,61.49,48.0, 1 0 0, 000000,255.0,,,,, ,61.80,903,19.8,1.3,90.0,62.12,47.0, 1 0 0, 000000,255.0,,,,, ,62.44,903,19.8,1.1,90.0,62.76,47.0, 1 0 0, 000000,255.0,,,,, ,63.08,903,19.8,1.3,90.0,63.40,46.0, 1 0 0, 000000,255.0,,,,, ,63.72,903,19.8,1.1,90.0,64.04,45.0, 1 0 0, 000000,255.0,,,,, ,64.36,903,19.8,1.1,90.0,64.68,45.0, 1 0 0, 000000,255.0,,,,, ,65.00,903,19.8,1.1,90.0,65.34,44.0, 1 0 0, 000000,255.0,,,,, ,65.66,903,19.8,1.1,90.0,65.98,44.0, 1 0 0, 000000,255.0,,,,, ,66.30,903,19.8,1.1,90.0,66.62,44.0, 1 0 0, 000000,255.0,,,,, ,66.94,903,19.8,1.3,90.0,67.26,43.0, 1 0 0, 000000,255.0,,,,, ,67.58,903,19.8,1.1,90.0,67.90,42.0, 1 0 0, 000000,255.0,,,,, ,68.22,903,19.8,1.3,90.0,68.56,42.0, 1 0 0, 000000,255.0,,,,, ,68.88,903,19.8,1.1,90.0,69.20,42.0, 1 0 0, 000000,255.0,,,,, ,69.52,903,19.8,1.3,90.0,69.84,41.0, 1 0 0, 000000,255.0,,,,, ,70.16,903,19.8,1.1,90.0,70.48,40.0, 1 0 0, 000000,255.0,,,,, ,70.80,903,19.8,1.1,90.0,71.12,40.0, 1 0 0, 000000,255.0,,,,, ,71.44,903,19.8,1.1,90.0,71.76,40.0, 1 0 0, 000000,255.0,,,,, ,72.08,903,19.8,1.1,90.0,72.40,39.0, 1 0 0, 000000,255.0,,,,,

Hi,

I've reviewed the log file, and everything seems plausible. If you can rule out the following potential sources of error, then it should be fine.
- Uphill when accelerating, flat surface when coasting?
- Are there any other rims/tires mounted that have a smaller rolling circumference?

You could compare your results by visiting a proper dynamometer with a good fan (otherwise the intake air temperature will rise too much and the power output will suffer). For example, you can find such facilities at organizations like ADAC. While you're there, you can also have them check the speedometer reading to account for any correction factors that might be necessary if you're using different tires.

Best regards, Rainer.

"No, 15-inch standard tires, no downhill slope when accelerating, more like a 1% incline, and when rolling to a stop, meaning that if the calculation is really accurate, the car probably has too much power."

Hi,

Okay, then your car is running really well.

Best regards, Rainer.