Rev matching and gear info

[drematic]

My car automatically matches revs on downshifts (paddles & dual clutch transmission), which does seem to confuse LapTimer when it computes gears. For a brief moment, it usually ends up one gear lower than selected, then bounces back up. For example, when shifting from 4th into 3rd, it shows 4-2-3.

So far I have been cleaning up the data manually, but it would be nice if LapTimer caught this automatically, since these jumpy "shifts" happen within one second, which would be unlikely in any normal shifting scenario.

[Harry]

LapTimer can not calculate the correct gear when the clutch is pressed (no defined relation between engine and vehicle speed). This situation can lead to undefined gear displays. This will exactly not happen for a dual clutch system. So either the gear ratios are not set up correctly, or the transmission ECU sends rpm updates out of sync... You may re-check the former in your vehicle's details view.

Adding some low pass filter to get rid of short time changes is certainly possible, I can add this to feature requests.

Harry

[drematic]

LapTimer can not calculate the correct gear when the clutch is pressed (no defined relation between engine and vehicle speed). This situation can lead to undefined gear displays. This will exactly not happen for a dual clutch system. So either the gear ratios are not set up correctly, or the transmission ECU sends rpm updates out of sync... You may re-check the former in your vehicle's details view.

Adding some low pass filter to get rid of short time changes is certainly possible, I can add this to feature requests.

Harry

A low pass filter may help. Thanks!

The gear ratios were correctly set up per manufacturer's specs.

Here's a snippet of consecutive samples from the exported data to illustrate the problem. The car is automatically blipping the throttle during the shift and OBD briefly reports significantly higher RPM with the wheel speed unchanged:

Code: Select all

RPM       Wheel Speed    Gear
------------------------------
5003	   50.331066      3
7807	   42.874612      1
8372	   42.874612      1
6292	   42.874612      2

[gplracerx]

Two thousand rpm higher than needed seems a lot for rev matching, unless that's an artifact of the HLT OBDII data interpolation algorithm. It would be nice if you had video of the tachometer to see if the revs really were going that high.

[drematic]

Yeah, you could probably call it more blipping than rev matching.

The car redlines at 8500 and the blips are quite aggressive, so I am inclined to believe the source data. At any rate, it's happening at all other downshifts with about the same ~2000 RPM above-target blip, so I don't think it's an RPM interpolation issue. The tachometer doesn't move fast enough to show the full extent of the blip.