woody6244

I have an android and tried cms lap timer pro. Have not been able to over lay runs in analysis trouble closing app. Is there better apps?

lefrog

RaceChrono for Android.
More info on the setup at http://www.frogracing.us/technology/telemetry

383

I just downloaded that one after my last AX. Have yet to use it.
you coming to a Thompson event this year?
http://www.cartct.com/cart-schedule/

lefrog

I didn't know about these events. How is the Thompson AutoX course?
I will certainly do track days at Thompson this year but why not some autoX, it's only 1H30 from home!

jwebsta32

Harrys lap timer for me

383

The AX area is a bit smaller than projected but its new and smooth/grippy
I like it

383

Can the GPS from the OBDII be used with my bluetooth OBD plug?

lefrog

There is no GPS through OBD2. You can use an external Bluetooth GPS rather than the phone GPS, that is much more accurate.
You now have 2 Bluetooth devices, your ODB2 for rpm/speed/throttle position and your GPS for location/speed. You can also use the gyro in the phone for the Gs but it's pretty inaccurate even if the phone is properly hooked up in the car.

froggy47

What do you add for better g's reading? Accelerometer?

lefrog

I use the data from the GPS (rated up to 4g on the Qstarz 1000) but I never found the data to be useful. Most phones don't support more than 2g in hardware but the phone would have to be laying perfectly flat to get usable data.
The most accurate would be able to tap into the car sensors but these are not accessible by obd2.

As the number of channels you can sample per second is limited (you cannot get obd2 channels in parallel but just one at a time), you have to make choices and limit yourself to only the data you really need so that you can get a decent update rate. If I'm focused on performance data, I get rpm/throttle position only from odb2. Speed/location comes from the GPS.
In RallyX I also collect the speed from odb2 to compare with the GPS speed to evaluate the amount of wheel spin.
If I want temps I just use Torque Pro and forget about perf data. Note that you cannot run simultaneously multiple apps sharing the same obd2 or external GPS.

talon95

dl1

edit: damn thing keeps making it lowercase

froggy47

New to this data aquisition deal, I did not know most of what you describe above, thanks.

Rob31

Do I need a external blue tooth with this ? If so what do I need ?

lefrog

Whatever software you use, the phone GPS is only 1Hz, meaning only 1 location update per second. The time accuracy for your runs will be 1 second at best and most of the speed/lines will be too approximate to be useful at an AutoX. It can give you a ballpark at the track but not much more.

An external GPS will works between 5Hz and 10Hz, giving you between .100 and .200s accuracy on your times and 5 to 10 location updates per second which is going to be much better so compare lines between runs. Most software/phones have a hard time handling more than a 5Hz signal on Bluetooth so even if you have a 10Hz GPS, your phone/lap recording software might not be able to record everything. Check beforehand, a 5Hz GPS might be enough!

lefrog

It's an amazing tool to understand where you can really improve.
Here is a video showing how to use GPS telemetry (without OBD2 as the C4 didn't have OBD2):

Here is another one in the WRX at a Rallycross this winter with GPS + OBD2 (jump to 3m15s to see the comparison of data with RaceChrono):

Crepitus

Thanks for the info! What package will do this^? Like Foggy I am clueless about this stuff. Really appreciate the help on this thread. I need a cheep simple system that I can use on short ovals. Lap to lap comparisons would be huge. I think the G force graph would help a lot in finding spots where their is a little speed left on the table. and the vid to compare lap to lap and maby segment speed would really be interesting. I run in a traveling series, anything to help quickly refine lines and alternate lines on different tracks would help a lot. i dont have OBDx.

Thanks
Dave

btw I checked out the phone app site, looks like the Garmen BT GPS recever is a must for a phone based system.

lefrog

If you want lap-to-lap comparison on the spot directly on the phone or tablet, use RaceChrono on Android (it's free). If you don't have an Android phone, just get a cheap Wifi tablet (you can get a Samsung Galaxy Tab 3 for $100 refurbished on eBay). In all cases, you will need an external Bluetooth GPS. The QStarz 818XT is about $85 on Amazon and works great with good battery life (a charge will last you a day of racing).

Here is my Galaxy Tab 3 setup in the WRX:


In the Vette, I removed the radio and put the tablet there instead (pics to come soon).

There is nothing automated for the video, it takes a lot of time to synchronize the data with the video and cannot be realistically be done on the spot with what's available today. But the GPS will give you lines and speed on the phone, which is really the most important for you.

froggy47

I have android phone and Harry's Lap Timer. Harry (the actual programmer) suggested qstarz 818xt or Dual xgps 160. He said the Dual was a little more fresher design.

For obd 2 Harry said any ECM 327 based dongle "should" work, but some are good and some are crap.

I am still refining the info I can gather online & guys I know using for these hardware additions.

Any input is appreciated.

Not a national trophy level driver so cost/ease of use are important.

Crepitus

RaceChrono on Android (it's free). Samsung Galaxy Tab 3 (I like the big display. Would use one for a dash board if I knew how). QStarz 818XT is about $85 on Amazon Im on it, Thank you very much.
Is there any way my Chief can watch in real time? Maby wireless router and wifi to a laptop in the pits?

383

I wonder how that tab would fit in place of the c6 nav.......
That's gonna happen to my next car for sure!