Building a virtual toolbox: Apps and tech for the digital mechanic

Building a virtual toolbox  Apps and tech for the digital mechanicSince cars were invented, people have tried to make them go faster. We’re a long way from the Little Deuce Coupe and its flathead, though. Today’s computerized cars are as much about software as they are about camshafts and engine displacement. The tools of automotive performance are also being digitized.

There’s a host of apps that promise to tell you exactly how much power your car is producing, and how fast it can go. Others reveal what’s going on under the hood. They might be the perfect thing for diagnosing problems, testing modifications, or just figuring out why you got beaten at the stoplight.

Digital Dynos

Typically, when a car company or speed shop wants to find out how much power a car produces, they strap it to a dynamometer. It essentially allows a car to run in place: the wheels spin rollers, which allows technicians to calculate horsepower and torque.

Now, developers are peddling apps that they claim can do the same job. As its name implies, Dynolicious ($13 at the iTunes App Store) turns an iPhone into a dyno. It measures horsepower (or, if you prefer, kilowatts) and uses the phone’s accelerometer to record acceleration times (0 to 60 mph and quarter mile elapsed time) and lateral g.

DynoBox app screenshotAll you have to do is enter your car’s curb weight and drivetrain loss. Be sure to include your weight, and the weight of the fuel (each gallon of gasoline weighs about six pounds). Drivetrain loss should fall between 10 and 30 percent of the car’s factory-rated horsepower.

For ultimate bragging rights, you can upload your times to Facebook and Twitter.

DynoBox ($4.99) is another iOS option. Like Dynolicious, it uses the iPhone’s accelerometer to measure performance. It also measures horsepower, and not torque, along with quarter mile times and lateral g (0 to 60 is not available). It all appears on a less flashy but simple screen with big numbers and a line graph.

One important detail DynoBox’s developers did include is a sensor that tells the user where to mount their device securely. Since these apps use accelerometer data, any excess movement will skew the readings. DynoBox recommends a custom bracket, but at the very least you should put your phone in the cupholder for either app to work.

Android users can use a different method to get their performance data. Car Performance ($4.00 on Google Play) uses a phone’s GPS chip and “complex algorithms” to calculate the important numbers.

This seems like a more indirect way to measure acceleration; that’s what an accelerometer is designed to do, after all. However, Car Performance’s developers say their approach is less complicated, since the phone doesn’t need to be locked in place and no calibration is required.

On the other hand, Car Performance has no horsepower calculator. It does acceleration runs and elapsed times, both at user-programmable intervals (sick of 0 to 60 mph? Try 0 to 72 mph). It also logs deceleration times to measure braking performance.

These apps provide fun ways to enjoy your car (in a safe, legal environment, of course) but without the ability to calculate horsepower and torque, they aren’t really dynamometers.

Virtual Dyno ($1.50 on Google) comes closest to working like an actual dyno. In addition to showing horsepower (both total and with drivetrain loss factored in) and torque, it also calculates compression and the power an engine makes at specific rpm. Like the other apps, Virtual Dyno also calculates 0 to 60 and quarter mile times.

Virtual Dyno uses an algorithm to come up with its figures, so environmental factors like weather and traction aren’t counted. On the flip side, the developers say it’s a great way to “test” parts before you buy them, since the app can simulate how they’ll work.

Virtual Dyno also requires more in-depth knowledge than other apps. You’ll need to know your engine’s bore, stroke, and gasket height, among other things. Fortunately, Virtual Dyno comes preloaded with a menu of engines to get you started.

Reading your car’s mind

A low horsepower reading is a sign of trouble, but not a diagnosis. For that, you’ll need to crack the engine’s computer, commonly referred to as an ECU or Engine Control Unit, and other sensors.

Every new car made since 1996 has an OBD-II (onboard diagnostic-II) connector; mechanics plug specialized devices into this port to diagnose problems and shut off “idiot lights.” Now, there are apps that can download and display OBD-II data.

Rev trouble code screenshotFor iOS users, Rev ($39.99) and DashCommand ($49.99) provide a comprehensive suite of functions. Among other things, Rev can show horsepower, torque, fuel pressure, coolant temperature, and emissions.

DashCommand offers even more options, including trip computer-style fuel economy displays and, for the especially neurotic, the amount of time spent in each gear. All of it is broken up into virtual “gauge” clusters for performance, fuel economy, and engine readouts.

Both apps are pricey, but they provide a lot of data. They can also turn off OBD-II trouble codes (like a check engine light), saving a trip to the dealer. Rev also offers a free Rev Lite version with fewer functions.

There are some cheaper options for Android users. Drive ($3.95) has diagnostic items like engine trouble codes and a transmission temperature gauge, but ti doesn’t have the performance, fuel economy, or dyno features of other apps. Also, it’s only compatible with a limited number of vehicles.

OBDmax (free, but most content requires the $1.00 Extended version) is basically a list of engine toruble codes, including 7,000 generic codes and 3,000 make-specific ones. It will tell you what’s wrong with your engine, but it can’t reset anything.

Torque Pro ($4.95, or get the free Lite version) is probably the best of the Android bunch. It offers horsepower and torque calculations, 0 to 60 mph times, CO2 emissions, and has the ability to reset engine trouble codes. It can also send OBD-II data to a user’s e-mail account, or convert it into an Open Office document.

Regardless of what features they have, all OBD-II apps require a little extra hardware. You’ll need an ELM 327 device, which plugs into the OBD-II port and sends signals to your phone via Bluetooth or Wi-Fi. Prices vary from roughyl $10.00 to $50.00. In December, Mavizon is also launching the Mavia, a device that automatically sends data to the cloud every 30 seconds. It will cost $169, plus a $5-per-month service fee.

Digital mechanics

Fixing a broken car or improving its performance will always require turning wrenches, but tech can help point the aspiring mechanic in the right direction. You may need to invest a little more cash than the average app purchase, but you will be able to get a good idea of what’s going on under the hood, without having to turn a wrench.