Throttle position calibration

[gplracerx]

Every time I start the car, the throttle position reads very high until I've applied full throttle in Grand Prix edition v17.0.5. Doesn't this information get saved somewhere? I don't remember it being a problem with version 16.

I'm having other problems too, but I haven't downloaded the crash logs yet. It looks like there may be a problem with using the VBOX Sport with the BT1 OBDII dongle.

[Harry]

On the throttle: no change between version here. LapTimer does not store the max value across sessions. I will consider this for the future. When driving tracks you should have floored your accelerator at least once when you hit the start / finish line, so I hope it is not too critical

On VBOX Sport+GoPoint - that's the combination I usually test. Please let me know what the problem is.

- Harry

[gplracerx]

When driving tracks you should have floored your accelerator at least once when you hit the start / finish line, so I hope it is not too critical

Two problems, I'm autocrossing, not lapping and generally you can't floor the throttle off the starting line on a standing start without way too much wheel spin. Second, my car has throttle by wire, no throttle cable, so even if the pedal is on the floor, the actual throttle opening may not be 100%.

The other problem is crashes, loss of communication and obviously flawed data. I'll bundle up the files and start a topic on that.

[gplracerx]

I'm still having problems with the throttle opening data. I don't think it's calibration either. I get frequent spikes to over 200% throttle. RPM and wheel speed data look good, so primary communication to the BT1 seems to be OK. The gear reading is a little flaky too, but that's less important. I don't think it's a problem car issue as it used to work just fine with a KIWI wi-fi OBDII and an older version of HLT. Is throttle position being extrapolated? If so, you should really but an upper limit of 100% on the extrapolation.

[Harry]

Will cap it to 100% in the next version.

- Harry

[gplracerx]

I'm not sure the problem is just extrapolation. Should I send you a GPS Buddy log file?

[Harry]

Not necessary. Since version 17.0.6 I have limited extrapolation to 8 seconds by the way. This will still generate values > 100%, but it gets limited...

- Harry

[gplracerx]

Eight seconds seems like forever. At an autocross, I'm frequently on and off the throttle several times over that length of time. 17.0.6 isn't doing a very good job with RPM either. See the attached plot comparing GPS speed and RPM. I'm always in second gear after 0.7 seconds. Needless to say, the throttle plot is much, much worse. I think it's interesting that the throttle never gets above 2.55 at any time. I can normalize the plot to the maximum reading, but it still only vaguely corresponds to reality. Is this problem made worse by the high data rate of the VBOX Sport?

July 21 2013 Run 4 GPS Speed and RPM.png (37.9 KiB) Viewed 4872 times

[gplracerx]

Here's the throttle and rpm graph:

July 21 2013 Run 4 Throttle and RPM.png (55.72 KiB) Viewed 4871 times

I think I'm going to try the KIWI Wi-Fi Saturday and see if that makes a difference.

Why extrapolate at all? Are there really up to 8 seconds between good readings from the OBDII when it's updating at 5 Hz? Or do you only get one PID every update?

[gplracerx]

Probably not the right place to put this, but I'm also only getting an effective 10 Hz data rate from the VBOX Sport in the .csv output file, 599 data points in 62.77 seconds.