I’m no stickler, but ‘telemetry’ is not the right word for collecting data from a simulated car. I’m not holding my breath about a change in nomenclature, but I’ll just note quietly, that the true meaning of the term ‘telemetry’ is something like “far off + measure.”  True if applied to a real racecar, but not when your computer is measuring the bits flying around on the same processor. But that’s enough on that – I’ll use ‘telemetry’ for expediency.

There is a great value in using telemetry in iRacing to understand several things. First, how the car behaves in relation to other cars offered on the service; second, how changes to the car setup can affect that behavior; third – and most critically – what you are doing right and wrong in driving the car on the selected track.

As for what kind of telemetry to use, there are several options, and I will discuss a few which are available. First, are the built-in features of the sim. Many will dispute this and argue that the speed and rpm displays do not constitute telemetry, but take away these elements from a real-life driver or sim-racer and you will quickly realize the importance of some instrumentation feedback, be it from the gauges, or the special information boxes on the screen. In addition, these displays can be used in conjunction with replays to get an understanding of how the car responds to inputs at various parts of the track. Along with that goes the tire temperature, pressure and wear statistics which you can make use of to learn about what the car is doing.

But enough on the obvious telemetry. The bigger feedback opportunity comes from utilities which ‘talk’ to the sim and provide extra data to the user. This feature will likely be built-in at some point in the near future, but until then there are two great alternatives you must try.

First is the so-called ‘Telemetry Heads-up Display’ or ‘THUD’ for short, which was developed by Stephane Turpin and works on Windows XP, Vista and Windows 7, in both 32 and 64 bit versions. Stephane’s .dll file, when put into the iRacing root directory, provides on-screen data for the driver including: split times, best lap in session, optimal lap (adding up your best sector times), as well as a delta display which shows your differential compared to your best recorded lap, a digital tachometer, a configurable shift-light, a lap counter, a clock, and a new beta feature showing slip angle/oversteer.

THUD provides iRacers with real time telemetry

THUD provides iRacers with real time telemetry

All of these are real-time displays while driving, but the utility also saves files from your session with the data from your best lap (used in future sessions as the baseline for the delta time), and also your best laptime and best sector times. There is also an option to export the sector and best lap times to a .csv file for easier compiling of data in a spreadsheet or database. The THUD utility is very configurable by simple editing of an associated .ini file, or you could also download Claude Leclerc’s THUD Editor to help to set the location of the data on the screen real-estate. Remember also that any function can be removed from display easily, and the whole THUD display can be switched off with a simple keystroke.

Much of the basic functionality is available for free, but the advanced functions will only work if it is registered (send a private message to Stephane, and have an iRacing gift certificate code ready – you decide the amount). Registering was pretty simple and painless, and the token amount was well worth it compared to the amount of usefulness of the utility. Highly recommended!

The last option I will discuss is a program called ‘vbox’ released by Martine Wedlake, the output from which can be uploaded with a telemetry viewer developed for a real-life telemetry datalogger, called ‘Driftbox’ – marketed toward the drifting crowd obviously. Should the output from the Driftbox program not be to your liking, you can export the data to be used in a spreadsheet. This is where the telemetry can really be used to its fullest extent. The resulting dataset includes: location on the track, distance, time, speed, direction, yaw, slip, lateral acceleration, longitudinal acceleration, turn radius, rpm, and the inputs: throttle, brake, gear, and steering angle. The program defaults to 10 Hz (collects all data 10 times per second), but can be adjusted up to the 60Hz ceiling (the rate at which data is calculated and generated within the sim). Keep in mind that 60 Hz results in an enormous amount of data during even a short session on the track. I typically run it at 30 Hz and limit the runs to 3-5 laps so that the file size is manageable.

Not only will this option allow you to see your G-G plots (showing your cornering and braking ability), but it also allows you to dissect your performance at specific areas of the track so that you can target your analysis to get the best feedback and make informed decisions. Again, this kind of information is easily configured and just as easily viewed, and thus is – again – highly recommended. Do yourself a favor and try it out and see if you can figure out where you are losing time, and what setup or driving line adjustments will provide the best improvements using hard data.

Now how about calling it ‘iMetry?’ How about ‘E-metry?’ No, no. I’ve got it. ‘Simmetry.’ Yep, that’s the ticket.

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I want to acknowledge the great work by Stephane, Claude, and Martine, and also the screeenshot by James Dickens (http://members.iracing.com/iforum/message.jspa?messageID=512508#512508). Great work, guys!

Ray Bryden
September 23rd, 2009 at 3:33 pm

I would like that iRacing would (at least) do some kind of telemetry like Gran Turismo 4 has. And that i could compare the data in my web browser on the main iRacing page.

I might send this proposal to iRacing crew and we will see what they will answer.

Martynas Pranckevicius
September 23rd, 2009 at 3:58 pm

Great article. Would be interesting to know how these programs interface with iRacing, i.e. how they are able to pull the data from it? Is this a complete hack or is there a published API?

John Bell
September 23rd, 2009 at 6:19 pm

John – they extract data from a telemetry API that iRacing prepared for motion simulators. Do a forum search on”API” and you’ll find more information. PM Steve Myers if you’re interested in programming something using the API. It is available I guess but not exactly ‘published’.

Ray Bryden
September 23rd, 2009 at 7:00 pm

Let me give you a testimonial for THUD, and THUD EDITOR.
Simple, Easy , AWESOME, I can’t tell you how much these 2 helped my racing… After a very short and easy install of both (you have to read the README, or you won’t understand what your LOOKNG at), which I’d like to tell you, get the THUD EDITOR, all you have to do is drag and drop…. No numb calculations… what and where you want it on the screen. I noticed a huge drop in my times. And if wondering its not an Arcadi spin. Look at like this, All real world racers have data loggers like MOTEC, and DRIFTBOX. This goes from the smallest to the largest F1 teams….. These and he Vbox is or MOTEC, and THUD really does what your Spotter should be doing to, letting you know your times and how to make up time, Heck you could even use it to save off a bit to save fuel…. Thanks for all your hard work and bringing these tools to us here at iRacing to better our selves and develope or abilities….

Don Caldweel
September 23rd, 2009 at 10:06 pm

great article, tku 😉

Make me happy to see iRacing drivers love my tool 🙂

Stephane Turpin
September 25th, 2009 at 11:45 am

i’d like to see iRacing export telemetry data in the same way they do with the rFactor Data Aquisition Plugin. that way, we would be able to explore that data in motec i2.

September 28th, 2009 at 1:58 am

Nice piece. I could sit down with a beer and debate the the definition of telemetry for a few hours with you 🙂 . I’ve always had it drummed into me telemetry is live data feed, so by definition, a tacho is a form of telemetry. Once it gets saved somewhere (i.e data unit memory card), it’s no longer telemetry (which sounds so evocative) and becomes plain old (don’t I sound drab) data 🙂

Chris Hall
October 1st, 2009 at 2:10 pm

Chris – Hehe… I’d never considered the live vs saved aspect of telemetry. But at what point in time does it lose it’s telemetriness? What do you call the scrolling data charts where the data is a few seconds old – not necessarily saved, but not exactly live either? Quasi-telemetry? Data purgatory? lol

I need another beer! 😀

Ray Bryden
October 6th, 2009 at 3:07 pm

where do you get this file at??

November 30th, 2009 at 11:20 pm

The Thud program has changed due to the restrictions on the latest build, and it was is being re-developed to be in compliance – I haven’t kept up with it to know what the status is – try searching the forums. If you’re speaking about vbox, just go to the iRacing forums and search for ‘vbox’ and it should be one of the first on the list – by Martine Wedlake.

Ray Bryden
December 1st, 2009 at 6:35 pm

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