Unlock Your Engine’s Hidden Horsepower

race car


Many vehicle manufacturers are ultra conservative when it comes to programming engine control units (ECU), also known as the engine control module or the engine control computer at the factory. They’re not going to program the control module so that the vehicle runs at its maximum power capabilities, in part because they’re concerned with things like the vehicle warranty, emissions, and fuel economy. Their conservative settings, however, leave you with a vehicle that isn’t producing as much power as it could. How frustrating is that? Is there a DIY engine tuning solution? Quite a few, actually.

ECU unlocking software

A lot of you are probably thinking, “ECU chip tuner” or “reflash” right about now. Reprogramming the engine control computer seems to be the common wisdom when it comes to increasing horsepower. For the uninitiated, an ECU basically controls how the engine goes about its business of producing and delivering power, including air/fuel ratio, ignition timing, idle speed, valve timing, and RPMs.

Back in the day, if you wanted to do some car tuning and change the ECU’s parameters, you had to actually change computer chips, physically swapping them out with newer chips that had software featuring the performance parameters you wanted. Today, one can install new software that changes the ECU’s operating parameters simply by plugging into the OBDII port. Boom. A few keystrokes later and you just raised the rev limit, governed top speed, and tuned the air-to-fuel ratio.

Replacing an engine control computer

What about switching out the engine control computer entirely with a new one instead of just reprogramming it? Is a new control module an option? A couple people, including Ethan Campbell, a Roanoke, Virginia-based tuner toying with a ‘96 Miata, have mentioned the MegaSquirt PNP ECU (MSPNP2) as one possibility for completely replacing the stock engine control computer. Campbell’s winter project is taking an engine with a VVT head from a ’99 Miata and installing it into his ’96 and adding a MegaSquirt ECU. MegaSquirt describes the product as taking “over the functions the stock ECU provides, like fuel control, ignition control, and various other outputs, and lets you adjust these yourself by connecting a laptop to the MSPNP2.”


Another car-tuning option to increase engine performance is Accesstuner from Cobb. The manufacturer describes the software as allowing “the user to get into the heart of the OEM ECU and create custom calibrations for vehicles equipped with virtually any performance modification. The end result is a tune that is custom tailored to the vehicle’s unique modifications, producing maximum power gains while maintaining the drive-ability and sophistication inherent in the OEM ECU.”


What about turbocharging as a car-tuning option? I know that turbocharging a non-turbo car is a viable option for increasing horsepower, but it’s also one that’s accompanied by a whole host of other considerations, including boost level, compression ratios and avoiding knock, that have to be planned for to avoid engine damage when turbocharging. There’s even the option of adding a Nitrous Oxide System (NOS).

If you have DIY engine tuning solutions to share, leave us a comment.

What Is ECU Tuning?

Josh adjusting ECU in car

When car manufacturers install an engine into a new vehicle, they have no idea where the buyer will live or the conditions under which he or she will be driving. So, they install a “one-size-fits-all” engine and overall system that meets today’s emissions standards.

Enter Engine Control Unit (ECU) tuning.

So what exactly is engine tuning and why is it important? Good question! To find out more about ECU tuning, we contacted Josh Dankel, an ECU engineer at Cobb Tuning. Josh explains the situation further. “Let’s say that you live in the mountains,” he says. “Your OEM vehicle isn’t tuned for that type of driving. And, even if you had a car tuned for the mountains, so that you could squeeze the most power possible out of the engine, it wouldn’t be efficient when you were traveling through sea-level land. What works in 100 degree weather in Florida, as another example, wouldn’t work as well in another climate.”

The advent of the ECU

Until the 1950s, nobody gave much thought to the pollution caused by early automobiles. But some experts began to suspect that the smog in Los Angeles might be caused, at least in part, by vehicle emissions. It took nearly two decades for an official Congressional response. Finally, in 1970, Congress passed the Clean Air Act that set tailpipe emissions standards.

In response, manufacturers installed microprocessors to help control emissions. This was the advent of the “car computer.” There’s more than one car computer in a modern vehicle, but the most powerful one is typically the ECU. Like any other computer, the ECU contains settings that can be tweaked for smoother operation, better fuel efficiency, and more horsepower.

ECU tuning - computer screen

ECU tuning, with a caution

“You can definitely cause your car to run more efficiently and get better mileage by using ECU tuning software,” says Dankel. Then he qualifies, “What often happens though is that, as you squeeze more power out of your engine, you also begin to have more fun with your gas pedal. If so, then you won’t get more fuel efficiency by tuning.”

But ECU tuning combined with healthy driving habits can result in a more efficient driving, especially in relation to stop-and-go driving.

At Cobb Tuning, Josh works on a product, called ACCESSPORT, which provides up to 100 different tuning settings for different occasions.

“Let’s say that you always use 93 octane fuel at home,” he says as just one example. “If you go on a road trip and can only get 87 or 89 octane, you can switch to a different tuning to squeeze the most power out of your engine.”

Engine tuning for performance is often accompanied by additional upgrades, such as installation of a freer flowing exhaust. In turbocharged cars such as the 2006-07 Subaru WRX, Cobb recorded a 24% increase in horsepower.

Have you tried tuning your ECU? If so, what are the best ECU tuning strategies that you’ve discovered?