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Performance Testing - differences with Performance Box software.

Andy_CaseyAndy_Casey
edited July 2009 in Older versions of RaceChrono
Hi all, not been on here for a while... Firstly, thanks aol so much for adding the user defined performance testing to v1.3, I use it for 0-60 (new addition) and 30-60mph (custom addition) performance tests so I can monitor results on the fly.

Another interesting point is that you can change the type of performance test for the data in the session properties and it re-calcualtes the times for that new test, anther really useful feature, means that you can get 0-60 from 1/4 mile data etc.

One thing that I have noticed, I used to use the Performance Box software to analyse the exports, it's a lot simpler than getting stuck into Excel! I have noticed some discrepancies tho between the Performance Box calculations and the RCv1.3. The 30-60 times are identical, all good, however, the 0-60 times differ buy up to 0.2s, I'm using a BT818x. Here's a list of results for my Audi S2:-

RC_____PB
5.26s__5.19s
5.22s__5.15s
5.14s__4.98s
5.41s__5.25s
5.19s__5.15s
5.40s__5.20s

Must be a difference in choosing the start point? Interesting tho...

Comments

  • andylaurenceandylaurence
    Is this consistent with all speed tests starting from rest and not an issue with speed tests with a rolling start? I suspect, given that it differs by up to 0.2s that it's down to where RC and PB Tools decide when the acceleration started and your GPS has a resolution of 0.2s. Probably, PB Tools decides the run starts when the first data point showing an acceleration is noted, whereas RC does some maths to determine where in the gap between the two data points the acceleration started.
  • Andy_CaseyAndy_Casey
    I have only notived a difference on starionary starts for the 2 sets of data that I have looked at. I was not been able compare before as I wanted 0-60mph and previous RC 'only' had 0-100kph. Thus I either used the PB software or I used Excel to sort a start point.

    As above, I am in agreement that the difference is down to the method that the software uses to determine the start point for each test. The worst case difference above is 0.2s in 5.3 (avg), thus a 4% difference. I guess that as long as you compare the same results (RC or PB) then any gains, losses or differences will be apparent (I've removed 5% weight from the car so am looking for small differences).

    As the PB times are shorter, I can only assume that it calculates the acceleration slope using later data points than RC and thus the steeper slope intercepts the zero speed axis later as the acceleration slope is steeper at that point.

    Would be nice to have an accelerometer to remove some of the guess work, shame that the GPS unit doesn't have one in it, neither does the phone.

    Just though it was worth mentioning in case people compared PB figures with RC or vice versa. What you can do is to open old data and change the performance testing critera on that data (as stated above) and RC should calcualte times from previous runs :-D
  • Andy_CaseyAndy_Casey
    Just checked and you can reverse engineer any saved session by cahnging to performance testing and then selecting whichever metric you require... very clever!
  • andrewandrew
    For some reason ive found performance box software rather useless when it comes to lap timing.

    I use RC on my friend's race car and on rc it says that the cars did for example a lap time of 56.8, the time from the offical race timer says 56.7 yet in performance box it says the same lap is in the 61's,can never seem to get it to be the same.
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