Recommended GPS lap timer?

I'm looking for recommendations for a GPS-based lap timer. Suggestions? 

This past weekend, I went out to High Plains Raceway and was using the Track Addict app for my iPhone. I've used it previously without much of an issue... but this weekend, my last session didn't seem to register, or at least not the full track. It registered my "Out-Lap", but all subsequent runs were listed under my "In-lap", with no differentiation between them and it didn't register my position on a decent portion of the track. To be fair, the app warned me that signal was poor; which makes me wonder if that was the issue? 

Either way, I'm considering picking up a GPS-based device (vs cell phone signal) to avoid issues in the future. Recommendations? 

I'm pretty new at this as well and am curious to see what the veterans have to say. That said, the two I'm considering now are Harry's Laptimer and RaceChrono.

More to your point, I've been considering buying a XGPS160 to supplement my phone's questionable GPS capabilities and actually allow me to get some better data but not have to puchase a whole new set of kit beyond my phone. I'd be curious if anybody can attest to how much better the apps work with that in use.

I run one of the accessory GPS pucks (like an XGPS160 or even that model I don't remember) on my dashboard, that is Bluetooth connected to my Phone and run Harry's.  It refreshes at 10 Hz, verses the Iphone's 1 HZ. Think about how far your car travels in a second at speed, or how far around a corner 1 second duration is.  Getting that data 10 times a second provides a lot better resolution.  I think it has a battery, but I leave it connected to a 12V to USB charger, that has a hardwired switch next to the camera and fan over-ride switch.

I've been using Harry's Lap Timer. It worked great standalone with my iPhones. I added an OBDLINK MX+ and it was better. Then I added the Dual XGPS 150A which updates at 5hz. Unfortunately Harry's has an issue where it can't sync the external GPS and OBDII data correctly and the OBDII data drops in and out on the video. I've checked on the HLT forum and it seems like he hasn't figured out how to fix it yet. The last time I ran I just left the external GPS in the box. 

If any of you have a better solution I'd love to hear about it. 

Our non-OBDII race car has two.

An old AIM Solo and one I made.

If you don't care about datalogging OBDII stuff you might be able to find an old Solo used for cheap.

I'm a fan of jumping right in to an AIM Solo or Apex Pro or something that is actually logging data and giving you some sort of predictive lap time/light/coaching. You may not think you need those capabilities, but having the ability to compare data to friends and other drivers is a massive learning tool. You can not only see that you're slower, but how and why. Do you really need to work on braking? Is your corner exit losing you 3mph of straight speed? The actual lap time is only a very small part of what you can learn about yourself. 

Aim Solo/Solo2

it's the easy button..

I also understand ApexPro is about the same but have no direct experience myself.

I decided to I ditch Harry's Lap Timer and tried out RaceChrono. I didn't seem to have the same problems with the OBDII data dropping in and out like Harry's did. I did have one session where the OBDII never connected to the app though. I figured out that I needed to go the BT menu on my phone and make sure that the GPS and OBDII connected BEFORE I started the app. Then everything worked fine.

AIM Solo is the next level after cheapish apps

Some reading from your friends at GRM that might help: How To Demystify Data Acquisition.

any other phone better than the Iphone's 1 HZ. GPS

mazdeuce - Seth said:

I'm a fan of jumping right in to an AIM Solo or Apex Pro or something that is actually logging data and giving you some sort of predictive lap time/light/coaching. You may not think you need those capabilities, but having the ability to compare data to friends and other drivers is a massive learning tool. You can not only see that you're slower, but how and why. Do you really need to work on braking? Is your corner exit losing you 3mph of straight speed? The actual lap time is only a very small part of what you can learn about yourself. 

I agree.  There's a lot you can learn from looking at a speed trace, even without datalogging things like TPS, brake pressure, and steering angle.  The phone-based apps, IME, don't have the resolution necessary to do this.

AIM Solo is where I'd go.  Used solo 1, new solo 2, either is fine.  Solo 2 DL is the next level beyond that and is great, but also a big step up in price.

The new Garmin Catalyst is pretty cool too, but another jump in price.  I'm not talking about the "you could go faster next time" psuedo-advice it gives (I actually haven't tried that feature, but I'm highly dubious it's much use).  It integrates a camera though, and the analysis software has that well integrated so that you can do things like jump from turn 3 on one lap to turn 3 on the next lap easily.

codrus (Forum Supporter) said:

I agree.  There's a lot you can learn from looking at a speed trace, even without datalogging things like TPS, brake pressure, and steering angle.  The phone-based apps, IME, don't have the resolution necessary to do this.

The apps themselves have enough resolution, just not the phone gps in most cases. 1hz isn't enough, 5-10hz isn't ideal but is enough to be useful. Agree that just speed, acceleration, and line are plenty of data. I'm on the third year with the current autocross car and I still haven't gotten around to getting the obd data receiver set up.