Comparing acceleration runs

[pentoman]

I have a DL1 and hope to use it to compare acceleration runs; hopefully to approximately confirm the effects of changes to engine tuning.

What would be the best way to do this?

The method I use now is tedious and time consuming:
I load an acceleration run, then trim the start off so the run begins exactly when the acceleration begins. Then I save the trimmed run.
I do this again for every run.
Then I load every trimmed run into the software together and hopefully they all line up correctly to make a nice graph for comparison like this:



But the problem is that the trimming task is time consuming to get each run to line up on the X-axis of the graph correctly. If you don't trim each run then the acceleration runs aren't lined up on the X-axis and you get a pointless graph.

Perhaps there's some way to shift the runs along the X-axis??

Thanks and cheers for the otherwise excellent softare!

[jlucas]

Check out Results -> Performance Calculations.

It's a table based method, not graphical.

[Turby]

... and tabular method don't provide any indication as to WHY some runs are quicker / slower than others eg shift times, more revs at start etc

[RTUSA]

Try selecting "Multiple X Axis" under Data Options > X axis configuration.

You can then plug in different start and finish times for each run graph. Still a bit fiddly but much easier than trimming. Keep the total time graphed (ie Max - Min) the same on each to keep scaling the same.

Cheers,

[pentoman]

Thanks RTUSA I'll check that out.

The graphical representation is a little more interesting to look at than the tabular version, and you can see gearchanges etc. I just realised I could copy the table into Excel and producing a graph that way... should be another quick and easy way.

[ssharkey]

Check out Results -> Performance Calculations.

It's a table based method, not graphical.

Has anyone found the performance table at all satisfactory? I'm guessing that to actually get it to make sense you have to drive for the table - whenever I take a look at this table the performance of the car ALWAYS looks distinctly average. I know I can modify the triggers but I can't seem to get a satisfactory "catch all"setting - I sometimes wish I'd not sold on the AP22 when I got the DL1!

[pentoman]

I do find that setting the triggers can be a bit of work and it can feel like you're fudging the initial launch (if it's standing start run), but it's not bad and it's probably unrealistic to expect it to perfectly calibrate itself.

If anyone's interested here are my runs - complete with some strange deceleration values. I've been using the logger on my road car (Cossie Merc) to learn to get to grips with it. I rebuilt the engine as the compression was low, and according to the logger shaved 1.5s off the 0-100mph time:

Before:




After Rebuild, 2 different runs
1

2


Which says good things considering I didn't really know what I was doing when I started the rebuild! However some of the data is a bit strange - 70 -> 10 mph in 0.23s for example? Not unless I hit a wall!

[tristancliffe]

When I use this, I make sure I only select the data I want to look at. So I select from the start of the race, JUST before I start accelerating, until I brake/lift for the first corner.

It's pretty good, but because you can vary so much from the configuration I don't know what to believe. It can easily change from 3.5 to 5 seconds for 0-60.

Interesting addition - a car is considered well balanced and well geared if the 0-60 time is half the 0-90 time. I note the Merc is