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thanks and a question

turboguzziturboguzzi
edited March 2011 in Older versions of RaceChrono
First time user of the SW. running it with a nokia BT GPS dongle and everything considered, really really neat. My girlfriend is happy not having to stand stopwatch in hand in the cold, i get laps and splits, neat, Thanks a lot!

only weird thing is that analyzing my first race results from Vallelunga in rome, The speed graph seems WAY off.... there's just no way that some third gear turs show as only 50 kmh, ditto for main straight. by gear's/RPM calculation 9500 is 220-225 kmh, graph shows 180...

Any idea as to why this big gap? it's a good 25% off.

Other than that, really nice!

Comments

  • aol_of_RaceChronoaol_of_RaceChrono
    It the problem consistent or just couple corners now and then? If it's consistent lap-to-lap, I'd say it's the harsh reality of having a GPS data...
  • andylaurenceandylaurence
    If you're getting an actual 225kph at Vallelunga, then you have a very, very fast car. The longest straight I can see is ~730 metres. That's similar to the distance from Camp to Quarry at Castle Combe. In my Golf GTi, I hit 106mph down that straight with ~150bhp to play with. In my race car with a dry power/weight of ~400bhp/ton, I'm at more like 130mph. To put a further 10mph on top of that to make 225kph, that's stonking horsepower. If your car has number plates, I suspect you've found the harsh reality of the speeds you're actually doing.
  • AdamwAdamw
    Andy, I suspect since his/her username is "turboguzzi", that the vehicle is actually a turbocharged motorcycle so the suggested speeds may be believable.
    I think the Nokia GPS with only a 1hz update rate and SiRF Star III chipset is probably the most likely cause of the inaccuracies if in fact there are any.
  • aol_of_RaceChronoaol_of_RaceChrono
    The 1 Hz is still once per second. It may explain part of the main straight speed loss (just before braking), but not the corner speeds.
  • turboguzziturboguzzi
    thanks guys

    i race a vintage kawasaki 750 that's been dynoed 90 rwhp, weights 165 kgs, so together with my 85kg is about 360 hp/ton.

    in any case, spent some more time now with the graphs, as well as with the gearing calculator and looks like i was checking with the wrong final ratio. seems now like i was hitting more like 190 km/h before the brake marker while with the right gearing i should be getting 200km/h, guess that a 10% mistake in the revcounter is reasonable, and in any case not easy to read it when you are bent over the bike at full speed.

    so mistery sorted, sort off....

    thanks you all
    TG
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