Racechrono - Analysis and Review

Hi guys.

I thought I would post up my analysis and review after my first outing with Racechrono.

In this first use I wanted to test it for laptime accuracy and also evaluate it for its lap comparison feature. At this track day (Wakefield Park in Australia), we were able to use the tracks own official Dorian timing system which is accurate to one thousandth of a second. I was using Racechrono on a Nokia N73 with a very cheap Holux M1000 (AUS$65) which is a MTK based 1hz bluetooth receiver. I should also mention I was not very organised so did not mount the receiver on the windscreen or outside the car on the rear window like I had planned so it was in the centre compartment, so not ideal. Anyway here are the results.

Official Natsoft___Racechrono
Dorian Timer

*:**.*** (in lap)__1:47.586
*:**.*** (in lap)__1:54.674

So there you go, all are within 0.2 and 10 out of the 13 are within 0.1. I did three more sessions but they turned off the official timing, damn. Best lap for the day was a 1:11.46.


  • edited September 2007
    Here are some analysing screens:


    Here is a look at my fastest lap of the day. Notice how I have put in split points around the track (mainly at corners) to see what splits I was doing and also what speeds around the corners.


    Here is a screenshot of the comparison feature. Here I am comparing my fastest lap (1:11.460) with one where I was behind a slow car (1:15.128) so had to follow till the straight. You can see quite clearly from the graph where the time was lost.


    Here is a couple of video's so you can see what the track is like.

    1. VIDEO 1
    2. VIDEO 2
    3. VIDEO 3

    Thankyou for this outstanding program AOL!!
  • edited September 2007
    Thanks for the great review and videos! Also great driving and your car seems FUN. Can I use the lap time comparison in some future "marketing" material? It's always nice to see comparison against "real" (not GPS based) timing systems!

    Your GPS data looks to be good despite the receiver installation location, since the lap times are matched, and the plotted route looks OK. Usually it's very important to install the receiver near to the windscreen's lower part, or maybe even outside the car if possible. This improves the route graph and lap time accuracy. In some tracks it's challenging to get proper GPS data in all parts of the track, even if you install the GPS to the best place.

    The next version of RaceChrono, version 0.40, will display your apex and straight speeds in similar fashion to the current sector times display. This way you'll get your corner speeds automatically, and no need for the extra sector/split lines.
  • Yes AOL you are welcome to use any of my data for marketing material. My email is john_hazza@hotmail.com, just email me if you want anything more. Next time I go back, I will install the receiver on the roof and try and grab some more comparisons.

    Can't wait for version 0.40.
  • edited October 2007
    Here is mine on the weekend at Winton Raceway.
    I use similar transponder as Hazza vs Racechrono. I have a iBlue 1Hz one. I think I set the trap exactly where the transponder reads.

    1:48.5960 1:49.92
    1:44.2430 1:44.27 +0.03
    1:42.9630 1:43.02 +0.04
    1:42.9620 1:42.89 -0.07
    1:44.6630 1:44.72 +0.06

    1:42.7650 1:42.74 -0.02
    1:42.2340 1:42.25 +0.02
    1:42.1560 1:42.16 +0.01
    2:17.9680 2:16.76

    This is my theory. The faster I go the more accurate this thing is. Haha. It is well within 0.1 sec of the actual time. You have to be happy with that. It really depends where you set the trap too. I have AIMS timer at the same time and they are not 100% accurate and go within 0.03 sometimes. I will put the phone up the dash from now on. I am sold.

    Keep up the good work
  • edited February 2008
    Hi all,

    I just had a track day at the newly surfaced Wakefield Park. We had official timing, the same Natsoft timing as Hazza. Was stocked to get into 1:17's but this is a newly surfaced track so not sure if it was the track or my driving.

    Here's some stuff.

    258642713_3aybF-L.jpg 258642722_6g8pJ-L.jpg
    258642736_DLuP2-L.jpg 258642745_Hevrc-L.jpg

    Natsoft times for the sessions can be found here,

    Session 1

    38 Paul Flood - 1:31.7620 - 1:21.2180 - 1:19.5560 - 1:20.1450 - 1:20.6200 -
    1:19.4960 - 1:20.5710 - 1:28.0690


    Session 3

    38 Paul Flood - 1:28.5270 - 1:18.3490 - 1:17.8000 - 1:18.0200


    Some funny differences in times between RC and the tracks natsoft.
  • edited February 2008
    Hi Paul, thanks for the great stuff!

    I'll try to explain some of the things that might puzzle you and other users when comparing to official timing systems. Also notice the first lap by the official timing is not counted by RaceChrono in your example.

    The "slow lap" inaccuracy is because the start/finish line is a bit misplaced (maybe the first lap missing is because of this). Many people have compared RaceChrono against official systems, and many of them has had inaccurate "slow laps", but very accurate "fast laps". When you drive over the over a misplaced start/finish line twice (start and end of lap) at considerably varying speeds, you will get inaccurate time.

    Why does it happen only on slow laps? It's because you start your "cooling down" lap driving fast and finish it driving slowly, and start your "warming up" lap slowly and finish it driving quickly. So if your RaceChrono start/finish line is misplaced after the real timing line, your warming up laps will be too quick, and cooling down laps will be too slow in RaceChrono timing. And wise versa if your start/finish line is misplaced before the actual timing line.

    And why are not fast laps affected? Because you drive as fast as you can both times over the start/finish line, and there's not enough difference to make your time inaccurate!

    The smaller infrequent inaccuracies (~0.3s) can be caused by small "movement" of the positioning, which happens unavoidably atleast once per session.

    Here's the same laps as in your post, but compared next to each other:

    official vs. racechrono
    1:20.6200 1:20.7 under 0.1s
    1:19.4960 1:19.4 under 0.1s
    1:20.5710 1:20.6 under 0.1s
    1:28.0690 1:26.6 slow lap, misplaced finish line causes big difference

    official vs. racechrono
    1:18.3490 1:18.6 0.25s, could be GPS movement
    1:17.8000 1:17.8 under 0.1s
    1:18.0200 1:18.0 under 0.1s

    If you like you can send me the complete log files from your memory card, and the timing sheets to tracks(at)racechrono.com. I can use those to move the finish line to accurately match the official timing! Also if you allow this, I could use the comparison in my manual and marketing material. :-)

  • Hi there,

    I too have noticed on Wakefield Park that my fast laps were on the mark (1:12.1) compared to the XT Racing lap timer I had on board too, but my slower cool down laps were off by approximately 2 seconds. I don't have any hard numbers handy but I used the track profile that I downloaded from this website (rather than made my own) so there is a possibility that the traps are indeed in the wrong location as aol has mentioned. Im also assuming the above people are using the same profile. Time for someone to reupload a proper profile!
  • edited March 2008
    If you send the NMEA file for your session (*-nmea.txt under \RaceChrono\Sessions\) to tracks(at)racechrono.com with all of the XT Racing times written down, I can move it for you. The right position for finish line can be found when the cooling/warming lap times even out with the official times.
  • Hello,

    I wanted to say how impressed I am with RaceChrono after using it for the first time yesterday. It worked straight away on a pre-downloaded circuit, bluetooth gps receiver - no fiddling, no hassles as I have experienced with other products.

    It really is first class and I would like to thank you for providing a great piece of software that I hope will help improve my driving in the future !! Keep up the great work.
  • Great to hear that! Remember to advertise RaceChrono to your friends as well!
  • Already have !!
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