Q&A Forum
I've talked to Jostein about this before but I reckon it would be best practise to start a topic so others can read, share and comment if they experience the same issues.
Regularly when I do a power sweep with new retardation run, sometimes the graph won't include the retardation data, sometimes it will, but the max numbers only display the max whp readings. Then after applying a bit of smoothing to part of the graph all of a sudden it does display the correct numbers.
When saving the .csv and loading it later on it will always display the correct numbers. As I'm always tuning in front of my customers, and they often only look at max number, I have to explain to them it's a fault in my dyno which gets quite annoying.
I've added a pictures of the graph, so you can see what I mean.
Regards,
Arthur
Just noticed the picture isn't clear enough to read, basically the max numbers display 179,54 bhp and 194,60nm, while the graph actually shows 199bhp and 220nm +-
edit: cannot attach logs, will send them to you @admin
i dont get what you means exactly, i see 2 different graphs. weird thing is you get retardation run every pull, never had problems with that, are you finish manually the dynorun?
@tuttur, I see the xxx_1 graph is about 200HP according to the graph, but the max number only shows 179 in the table. When you enable wheel HP, is that max 179? Thanks if you can send me a .log file, the csv file and the config file and I can take a look. I realize the table is always correct correctly whenever you read the stored file, but non-the-less maybe it can guide the troubleshooting.
I'll update the software on yourdyno first, as I haven't for a while, maybe that will clear the problem 🙂
Will get back on the subject coming friday
Dyno'd a car on friday which gave the same problems. Uploaded FW and SW after that and haven't had any problems anymore 🙂
I’m having the same issue... and also another issue where my torque is reading innacurate(too high) and my wheel hp is about where it should be. Changing moi does nothing but move both hp and torque numbers up and down at the same rate... I’m stumped
@jrracefab, indeed changing MOI is will change both torque and HP. Torque = MOI * angular acceleration and HP = Torque * RPM (times some factor).
If Wheel HP is where it should be but Wheel torque too high, then check your gear ratio and check your Pulses per Rev in the RPM setup (common mistake).
I double checked my teeth count and it’s accurate at 60 teeth. I calibrated the gear ratio by rpm of tachometer in the car. Set rpm set point to 2000, brought the car up to 2000 rpm in fourth gear and set
the ratio. It came out to 1.55 for gear ratio in use.
OK, that sounds good. One way to check if the settings on RPM is correct is to enable the Speed plugin. Set the circumference of the drum and double check that the speed shown in the gauge is the same as the speed in the speedo.
Should I experiment with different ratios? The fourth gear ratio of the civic I have on the dyno is like 0.967 or something close to that.should I be putting that ratio in manually..?
@jrracefab, no, you enter the gear ratio manually only be done if you know the ratio, which is typically only on engine dynos and sometimes on hub dynos.
Using Tacho or OBD2 is the most practical with a roller based dyno.
Also make sure to only choose 1 load cell is you only have 1 load cell and set RPM2 to Not Used if you don't use it.
With correct gear ratio and correct number of teeth, then RPM of the roller will be correct, and torque/hp can be calculated. They will follow each other correctly. They (both) may still be too high or too low if the Moment of Inertia is wrong for example, or if the load cell is not calibrated.