AWay

I've done some browsing, poured over the section in the PCM manual and still can't quite grasp how to properly use this Sport Chrono as a lap timer. I was wondering if anyone could list the process in simple enough terms for my feeble mind.

I'm particularly interested in how to record a trip/lap distance, save it, and then have the car properly time/record my laps. I'm hoping it's more than just a gimmick and I'll be able to obtain some relatively accurate times during an HPDE.

I greatly appreciate any assistance with it.

No HTwo O

From a timing device standpoint, your are unfortuantely correct.

Most of the Chrono functions are control with the staulk on the left side.

AWay

Yes, I've played with the start/stop/interval etc on the stalk but wasn't sure how to have it record a distance/lap and then time that lap repeatedly. (ie: lapping)

Surely you wouldn't have to activate the stalk every lap would you? I understood it was able to automatically record your laps each time you travel the recorded distance.

AWay

Anyone?

I played around with it further this weekend. Still confused.

zanwar

You have to manually bump the stalk each time you want to start a new lap. It doesn't start the new lap automatically.

If you have a recent iPhone, you could buy "Harry's Lap Timer" from the app store. It uses GPS to time and record your laps. It works quite well. If you don't have a convenient mount for your phone, buy some velcro and stick the phone to the dash or the inside of the windscreen when you get to the track.

Nugget

No, that is exactly what you have to do. It's not useful for timing at at HPDE, imho.

FrankyV

I wouldn't have a problem hitting the stalk once to mark a lap, but my recollection is you have to move it twice, which makes it almost totally useless for timing consecutive laps. Any system that would not require you to mark a lap manually would have to be GPS enabled or utilize a track side beacon. However if you can master the too complicated lap marking dance, the circle graphics that show you current lap compared to your fastest and bar graph of the whole session are kind of cool.

Nugget

Yeah, you're right, you have to double-tap the stalk each lap. Harry's Lap Timer and an iPhone is a much better solution that's actually even cooler than the SC's display stuff.

I've got a Traqmate, myself, but that or a RaceKeeper is going to cost $1-$2K which is hard to justify for most casual DE participants.

AWay

Perhaps I misunderstood the manual but it seemed like the system is or should be able to record a distance that you manually mark the first time around. So start the timer at the line, record the distance around the track (say a 1.6 mile lap), then stop again at the finish. Then the next time you start the timer it will know you're driving that 1.6 mile loop and automatically record each lap as you cross that distance.

Should be no need for GPS or beacons to record time/distance.

FrankyV

I guess it is possible to calculate the lap based on distance alone, but wonder if that would be accurate due to variations in your actual lap distance due to variations in your line. To use the extreme example, what about a lap where you have spun out? At any rate, the system does not do that to my knowledge.

Nugget

The sport chrono does not work this. Furthermore, I doubt this approach is even possible. Depending on the line you drive the distance of a single lap can vary by tens of feet. Even if your line precision is perfect a lap with passing and a lap without passing would be sufficiently different lengths to invalidate any distance-based timing system. Just taking the high line vs. the low line on the front straight at TWS adds about 60 feet to your lap distance.

zanwar

I seem to remember you don't have to hit the stalk twice to begin a new lap. You select sports display mode on the trip computer and use the stalk to start timing. Then you push down on the stalk to select some kind of intermediate timing option and you push the stalk forward once to time each lap. At the end of your session you select the stop timing option.

ADias

Note: this applies to PCM3.

You start the timer with the OBC stalk on the left. When you arrive to the destination you use the stalk to stop it. It does not give 1/100s precision but you may not need that. Last week on the track I saw a team manager timing a car with a regular stop watch... same difference.

On '09 and later cars you can also download a digital file (to a USB stick via the USB port) of the recorded timed event with speed, acceleration, and other param info.

AWay

I'm familiar with the interval timing you refer to. I could handle pushing the stalk forward at the finish line each lap to mark the split time. And then I assume all the splits will be shown at the end? Definitely worth a try.

gstahl

Seems this might be more useful. I use a GPS on my mountain bike and with various software can do ride comparisons. Even with GPS of, there is usually enough data to find the "laps". One could just turn the system on, log the data, download it and (if the software was there) manually add the laps as needed by looking at the data. Sure you will not be super accuracy, I suspect it is not worse than GPS which has significant probable error in the position. In any case it could give you terminal speeds and corner speeds most likely.

Just some ideas.