Iphone GPS Laptimers

What apps have you tried for lap timing at track days? What are your impressions? Which one is the best?

For example:

GPS Laptimer

Harry's Laptimer is/was the best of them.

I don't use a laptimer on my iPod, but I have been known to make use of an accelerometer app from time to time, just for fun and to see what kind of G's I can manage on highway on/off ramps granted, I've got an iTouch rather than an iPhone, so I don't have GPS capability, just an internal accelerometer, so GPS lap timers are kinda out for me

I have Harry's Lap timer BUTT have not used it yet (track specific).

Will have full report in June.

David zip code: EIEIO

I used Harry's laptimer when I was at Sebring. It seemed to work pretty well, the times were very close to someone who had me on a stopwatch.

That said you need to make sure you get a good, clear view of the sky for a good GPS fix. What worked best for me was wrapping the phone in small towel and stuffing it in the space between the glass sunroof and the sliding shade part.

Also be warned it kills the battery pretty quick, be sure to bring a car charger or someone other method to recharge the phone during the day.

i wonder what Apple thinks when they get the stored GPS and accelerometer data from people that use their products in race vehicles.