The Truth about Cell Phones, ECUs and Car Control

It didn’t take long after Brad Kezelowski pulled out his cellphone during the 2-hour-long Daytona red flag for the conspiracy theorists to leap into action.

The argument goes like this:  Cellphones should be banned from the car because a driver could use his specially prepared cellphone to a) change the Engine Control Unit (ECU) and/or b) transmit data from the car back to his crew chief during a race.  We will not address the suggestions that the driver could use the cellphone to talk secretly to the crew chief during a race because anyone who has been in a race car or worn a helmet knows that’s just plain dopey.

Let’s differentiate between telemetry and electronics.  The word telemetry comes from two Greek words:  tele (meaning ‘at a distance’) and metre (meaning ‘to measure’).  Telemetry technically means measuring something (like the speed or acceleration) remotely, but many people use the word to include the ability to send information from the crew to the car.

Let’s start with the assertion that is the easiest to disprove:  you cannot control the ECU remotely.  Some people seems to have problems distinguishing between electronics and telemetry.  Just because something is electronic does not mean it can be communicated with remotely.  I can start my 2010 Fusion from inside the house by pressing a button on its remote.  My 1998 Ranger remote doesn’t even have such a button because the truck lacks the ability to receive instructions from a distance.  An app that sends a signal to a car doesn’t do anything if the car isn’t able to receive and interpret the signal.

The McLaren ECU is built specifically to preclude the ability to change any engine parameter without plugging a computer into the system using wires.  There simply is no way to change the ECU wirelessly.  When NASCAR initiated the switch to EFI, they worked with McLaren from day 1 to develop a system that would minimize any possibility of “cheating”.  If you want to keep someone from stealing something from your car, you can make sure you lock he doors.  The sure way to make sure it doesn’t get stolen from your car is not to leave it in the car.

No major racing series allows teams to talk to the ECU remotely.  Even F1, which used to allow it, realized that fans don’t want to watch engineers race absurdly expensive RC cars.  NASCAR drivers are not controlling their ECUs with their cellphones.

The second argument is a little more subtle because we all know that data can be read from the car during a race.  For the last 10 years, a company called SportVision has provided information to NASCAR’s television broadcasting partners using telemetry.  This information includes the throttle position, brake, rpm, speed and position of each car.  Prior to the introduction of EFI, SportVision got their throttle and rpm data from throttle position and shaft speed sensors in the car.  This year, rpm and throttle data are acquired directly from the ECU (which, incidentally, provides much more accurate data than the sensors did).

The question of intercepting data isn’t new with EFI: The company has been required by NASCAR to keep all data they collect out of the hands of the race teams since the program began.   SportVision encodes the data that is transmitted from each car.  If you were able to intercept the data, it’s not like you could open up the data file in Word and see a line like “4500 rpm, 147.6 mph, 80% throttle”.  It would be a series of ones and zeroes that would take some serious decoding in order to figure out what each piece of data was, much less what it meant.  This makes it difficult for anyone besides SportVision to intercept and make sense of the data.

Let’s assume for a moment, however, that a team did figure out how to intercept and interpret the data (and incidentally, you wouldn’t need the equipment to be insider the car – you could do it from well outside the car).  The SportVision folks told me that the sum total of all the data from the 43 cars competing in each race ends up being about 2 Gigabytes worth.  To set a scale:  One character is a byte and an average word is about 10 bytes.  One page of an encyclopedia is 10,000 bytes or 10 kilobytes.  The 2 Gigabytes of data collected during each race is 2 billion bytes, or 200,000 encyclopedia pages.

Each car provides about 46.5 million bytes of data, which corresponds to 4,650 encyclopedia pages worth of information each race.  For an average three-and-a-half hour race, a single car transmits information at a rate of about 3700 bytes (a third of an encyclopedia page) every second.  Handling this rate of data input and analyzing it in real time is nearly impossible.  In the words of one of the SportVision engineers, “If you find someone who can get the data and analyze it in real time, I want to hire that person!”  SportVision doesn’t even do real-time data analysis because of the huge amount of data coming in.  Even if you were able to intercept and read the data, analyzing all that data and getting something useful out of it (something you could use to make the car better) would be a huge challenge.

For the sake of argument, let’s assume that a team WAS able to intercept, interpret and analyze the data from the car in real time during the race.  What can they do with that information?  If they want to change anything on the ECU, they have to take the car behind the wall.  The time it takes to make the ECU change isn’t going to be offset by the performance advantage you might get from making the change.  The teams get all of the data from the ECU after the race anyway, so there’s absolutely no advantage to capturing it during the race.

Let’s also think about the practical.  If you had invested all this time and expense to develop the software and hardware necessary to intercept and transmit data from the car back to the pit box, don’t you think you’d tell the driver not to pull out his cellphone and make a show of carrying it in the car during a red flag in the most-highly-watched race of the year?

Here’s my biggest concern about cellphones in cars.  If you are going 180 mph and you stop suddenly, anything not secured in the car becomes a projectile with an initial speed of 180 mph.  Putting the phone in your firesuit pocket (yes, firesuits have pockets) is also not advisable:  Do you really want a hard piece of metal and plastic trying to embed itself in your leg? Or elsewhere?

Conclusion:  if you want to argue against cellphones in racecars, the best argument is the 180-mph projectile safety argument.  The drivers are not controlling their cars with their cellphones, they’re not intercepting data and sending it to the crew chief with their cellphones and, even if they were, there isn’t anything useful the crew chief could do with that intercepted data.  So let’s put that theory to bed for good and just enjoy some Bristol racing.




  1. I’m not sure i understand why you’d say the information is coming in too fast to be processed…of course it can be translated and processed…that’s why we see it on TV screen in relative real-time. Could the encryption be broken? (easiest way is just to hire someone who used to work there…Credit Card companies always tell us how secure they are…but we hear all the time how they’ve been hacked) Could it then be turned fed into something that could aid in monitoring the setup (or telling the driver he’s driving 30 ft deeper into the turn than the driver turning the fastest lap) of course it could. Could it be turned around into the dreaded traction control? (no…probably not…too much latency in the data transfer…that would require a cellphone in the car and a wire running to the ECU…the phone is IN the car…it doesn’t need to remote control anything. Do I think anyone is doing it? probably not…it’s not like one team is on a roll like Harry Gant was all those years ago. (well OK.. SHR is on a heck of a roll…but not enough better than the competition as they would be)

    • Bob; Some of the easier data can be processed in real time; however, all the detailed EFI information – the stuff you’d need to learn something about your car – is voluminous. The comment about not processing all the data in real time came directly from SportVision. They give TV the throttle, rpm and location, but they also collect a TON of additional data that they really can’t do anything with until after the race. Thanks for giving me the opportunity to clarify!

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