VINTAGE AUTO RACING ASSOCIATION

Pen Pendleton · Posted: Sun May 11, 2008 10:04 pm Post subject: In-Car Lap Timer Questions

What is the best brand/type of in-car lap timer? Also, I'm unclear about the need for a trackside transmitter – are these necessary for each car, or can a reciever run off of any receiver that someone has trackside?

So is the "Hot Lap" brand the best? I have also seen less expensive units designed for motorcycles - wouldn't those work on an open cockpit car?
I also saw another type of timer used in a Lotus 11 up at Monterey, but I forgot the name.

Also - I don't care about complex data acquisition, I just want lap times, so the simpler (and cheaper) the better.

And - anybody have one for sale?

Thanks!!

Pen
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1972 Elden FF
1974 Dallara/Fiat SR

Alan Berry · Joined: 12 Nov 2007 Posts: 30 Location: Poway, CA

Pen,

If you're using an AMB Transponder and go on mylaps.com you can see every lap you ever run at a race. Even the 2 hour ENDURO at Willow Springs had every lap recorded and I was surprised to see all laps on warm up on Sunday morning recorded. It was weird to see my fastest lap all weekend was in Sunday morning warmup! I love the feature where you can pick any car in your run group and compare all laps for races on charts side by side.

I guess if you were looking to time laps for practicing on non race days then you would need the hot lap system.
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Volvo PV 544 "Swedish Meatball"

Mark Scott · Posted: Mon May 12, 2008 7:37 pm Post subject: Ultra Lap

Ultra Lap timers.

Contact Chad Plavan. he is a VARA member and alos a dsitributor of them.
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Mark Scott
#267 Porsche 911 CP-GT

C.Plavan · Joined: 02 Nov 2007 Posts: 28 Location: Fresno, CA

Pen,
You can just place and order for a Ultralap Reciever. There always seems to be a transmitter out on the track during our race weekends so you really do not need one. I can't remember the last time I had to put a transmitter out on the wall to trigger our times. Many of us have them.

http://www.plavanracing.com/ultralap.htm (They have been recently updated and have a bigger screen now, I'm just too lazy to change the website at the moment) Smile

Shoot me an email if you have any other questions. chad (@) Plavanracing -dot- com
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Thanks,
Chad Plavan
#02 Porsche 911 E CP-GT (2.4L With 60 over)
Documented FIA and IMSA legal through 1972

clayt · Joined: 12 Feb 2008 Posts: 11 Location: Yorba Linda, CA

So, could all you that have transmitters position them strategically around the track so everyone could get split times from several different sections on the same lap?
It would be cool to see increments from several sections rather than only one section at a time...

C.Plavan · Joined: 02 Nov 2007 Posts: 28 Location: Fresno, CA

You could, but have you seen how some VARA drivers drive? We would probably loose a few transmitters a weekend Smile

.
I would just suggest a data logger for that.
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Thanks,
Chad Plavan
#02 Porsche 911 E CP-GT (2.4L With 60 over)
Documented FIA and IMSA legal through 1972

bobwass · Joined: 01 Nov 2007 Posts: 16 Location: Sherman Oaks

i asked a racer friend from the great midwest what he knew about GPS systems and what he was using, here is his response:

I do indeed know more than I ever wanted to about GPS data logging. Basically, there are three options: 1.) the expensive Motec, Stack, etc. type logging systems that cost over $3k; 2.) more consumer/amateur friendly systems made by G2X and Traqmate that go for about $1,000 including in car display; and 3.) DIY setups that use a Bluetooth GPS receiver (available from Amazon.com for about $100) and software running on a Bluetooth enabled PDA (~$150 for the software and $150-$300 for the PDA).

Obviously, option #1 is gross overkill in most situations. Even if you received the components for free, you might never figure out how to use it. Kind of akin to buying a UNIX workstation as your home PC -- not something you would want to do even if you had all the money in the world. OTOH, if you are actually using Motec as your ECU and using a Motec display as your dashboard, then it might make sense for a hobbyist. I would assume this is uncommon in vintage racing.

Option #2 is very popular with DE drivers and club racers. G2X and Traqmate are the dominant systems in this class and are used by tons of people. Most of the GPS data charts that you see on trackpedia.com are G2X. I suspect Traqmate is a bit more popular, but they basically split the market.

For about $1,000, you get four components: 1.) a black box that saves all the data; 2.) a GPS antenna that is about the size of a matchbox (mounts on the roof of the car with a magnet and has a wire that runs to the black box); 3.) a small dashboard/console display similar to a HotLap display that connects with a cable to the black box; and 4.) PC software. You basically mount the black box somewhere in the car (i.e., the roll cage) and either hardwire it or connect it to a cigarette lighter. The GPS antenna goes on the roof of the car or can be placed on the dash or backlight (it just needs a view of the sky). The dashboard display mounts with Velcro or zip ties within sight of the driver.

As you drive, the black box will log your GPS coordinates (i.e., position in space) as captured by the antenna either every 0.2 seconds (5Hz) or 0.1 seconds (10Hz). It also contains accelerometers and logs lateral and longitudinal Gs. Because it captures this information at a regular interval and is very accurate, this is adequate to figure out your speed, segment or lap times, draw traction circles, etc.

The black box in both G2X and Traqmate have additional inputs (a.k.a., "channels") so that you can add sensors for other data. This other data will also be recorded at the 0.1 second or 0.2 second sampling intervals and paired with the GPS and G data. Generally, these sensors are just potentiometers and the black box is capturing their voltage reading (between 0 and 1 volts), which you will then assign a value to in the PC software (i.e., 0% to 100% for throttle position). This is actually how the sensors in a modern car with fuel injection work. In a car like mine (1987 Porsche), you can skip installing some of the sensors and instead just splice into the wires in the ECU wiring harness. On an OBD2 car you can get a cable that plugs into the OBD2 connector and offers most of this stuff up. The common sensors are RPM, steering wheel position (potentiometer goes on the steering shaft), throttle position, brake pedal pressure, A/F ratio, and shock absorber position/movement. The majority of people don't bother with any of this. I don't know how much more the extra sensors cost, but I would presume that adding RPM, throttle position, and steering wheel position adds something like $500 to the $1,000 starting price tag.

Option #3 is basically Option #2 light, but also portable. The center of the system is a rechargeable bluetooth GPS receiver that is about the size of a box of matches or matchbox/hotwheels car. These things cost about $100, can mount with velcro on the top of the dashboard or backlight, and just receive GPS coordinates and send them out wirelessly via bluetooth every 0.2 or 0.1 seconds. They are basically the same as the GPS antenna from option 2, but are self powered and wireless. They turn on and off automatically, so you only need to turn it on at the start of a weekend and you can then forget it. The main commercial purpose of these is for PDA/Treo based navigation systems for your car.

A bluetooth PDA (palm pilot or microsoft -- they pretty much all come with bluetooth now) can receive the GPS coordinates and save them. There are a couple of shareware programs you can download to do this, but by far the best setup is sold by www.maxqdata.com. This is what I'm using, and I love it. Besides allowing you to see your lap/segment times on the PDA between run groups while you sit in your lawn chair and relax, you can also see your speed at any point on the course on any lap you choose. I think this is more useful than the dash display unit on a G2X or Traqmate. It also imputes Gs. The PDA software has a dash mount mode that shows you lap time, etc. while you're driving if you choose to mount it with velcro, zip ties, or whatever on the dash or console. I've seen several people use plastic vent mounts for the PDA that you can buy for about $10. MaxQdata also comes with laptop software that is pretty comparable to G2X and Traqmate.

To me, the big upside of this setup is that I can easily use it in Skip Barber cars and rentals that don't have laptiming systems. It's also a lot easier to install and remove in my car and less intrusive. All I have to do is put the GPS receiver in the hatch area of my car and flip the switch. For DEs, I I'm happy just carrying the PDA with me and skipping the dash mount. I just shove the PDA in the crack between the passenger seat and center console, and the software automatically starts logging data when the car goes over 20mph. For Skip Barber cars, which somewhat amazingly have no timing system visible to the driver, I'm mounting the PDA to a small block of wood that I can zip tie to the steering wheel so I can see lap times as I drive.

There are a couple of other variations of the MaxQdata setup. They make a black box type gizmo that lets you add something like 6 channels, akin to Traqmate or G2X. They also just introduced an update to the software that allows you to skip the PDA entirely. The GPS receivers also can be purchased with memory that logs all of the GPS coordinates internally, rather than spitting them out in real time via bluetooth. I think these were designed to be carried while hiking or biking so that you can see how far you went after you return. You can now use one of these to simply capture the data as you drive and then upload the data to a laptop. If you aren't interested in the realtime dash display and keep a laptop with you at the track, this might cover all of your needs for only $300.

All of these systems are extremely accurate for timing purposes -- they impute your lap times to within hundreths of a second even though they only sample the data every one or two tenths. They'll never replace AMB transponders, but they're more accurate than a person with a stopwatch, which is adequate for evaluating yourself.

If you are only going to use this in your Alfa, I would be tempted to go for a G2X or Traqmate system. It would cost a bit more than the MaxQdata set up, but you wouldn't have to worry about charging batteries or installing and removing stuff at every event; and you would have pretty easy expansion options. I don't think that capturing shock absorber movement is very important, but throttle position, brake pedal pressure, and RPM might be nice. This is particularly true if you ever work with a coach who will drive your car to give you some baseline data.

All of these systems are easy to integrate with video. Once you've uploaded your data to a laptop or PC, you can use the software from http://www.trackvision.net/ to overlay a little dashboard with your data in the corner of the digital video of your runs. This Trackvision software can import data from MaxQdata, G2X, Traqmate, and the professional grade systems. You basically just synch up the video with the data by marking the point in the video at which the car started to move in the hot pit and the point in the data at which the sped rose above 0mph. The software will then take care of the rest.

C.Plavan · Joined: 02 Nov 2007 Posts: 28 Location: Fresno, CA

I have a traqmate also along with a Ultralap. I really only use the traqmate for the incar video portion (MPH, RPM, Braking)
_________________
Thanks,
Chad Plavan
#02 Porsche 911 E CP-GT (2.4L With 60 over)
Documented FIA and IMSA legal through 1972