Demonstrating the Value of an Engine Tune in Modern Turbocharged Cars

It should come as no surprise that turbocharged cars generally benefit from bolt-on modifications better than their naturally aspirated counterparts. The most common recipe for turbo cars is a larger exhaust and intake. While those two modifications sound like no brainers, it's actually the engine tune that should be dialed in first and foremost to maximize the factory hardware and get the most from aftermarket parts that may be added later.

To demonstrate the value of an engine tune, we’ll look at one of the hottest cars of the year: the 2016 Ford Focus RS. Out of the box, Ford rates the 2.3 liter turbo engine at 350 horsepower. That’s at the engine crank, mind you. Tuners don’t measure at the crank. They measure where the power meets the road – at the wheels.

Recently, Stratified Auto, a Canadian tuner shop located just outside of Vancouver, took to work on the Ford Focus RS to show the world how important the engine tune really is. To do this, the Focus RS was strapped to a Mustang dynamometer (better known as a dyno) to measure and display a readable baseline of torque and horsepower. Then, a conservative off-the-shelf tune via Cobb’s Accessport handheld tuner was installed and measured, followed by Stratified’s own custom tune. The chart below shows all three runs. Stock is red. Cobb in green. Custom tune in blue.

Ford Focus RS engine tune dyno graph

It’s probably time for a disclaimer because I know what you’re thinking. We have zero affiliation with the tuner. This article is to inform our readers what is possible with a bit of tuning to modern day turbocharged cars. Your results may vary. Back to the interesting stuff.

From this we can see that a custom tune can net substantial gains. We display the full graph so that readers don’t get caught up in the peak gain values. Look at the curves. The 2.3 liter engine can produce more horsepower at 4,300 RPM than it did anywhere near redline with the stock tune. The largest gap under the curve is between 4,000 RPM and 5,000 RPM where we see roughly 25 more horsepower.

Horsepower is great but torque is what we feel. Looking at the tuned torque curve, we see a massive gain of 40 to 50 from 3,000 RPM to damn near 5,000 RPM. That’s the meat of the power band, right there. With a big fat powerband like this, there’s rarely the need to downshift. Besides, this is the number that’ll make your passenger’s eyeballs grow large.

Saving the best part for last. With this mod, there are no bloody knuckles. You won’t even have to open your toolbox.

Being that we’ve opened Pandora’s box, you’ll undoubtedly opt for more power. The reason we suggest the engine tune first is to maximize the capability of the hardware already in hand. Tossing on an exhaust on a Focus RS off the showroom floor would add some noise and some minimal power gains. But not any more. Now that the engine tune has been optimized, tossing on that exhaust will net a sizable increase. In the case of the Focus RS, swapping out the catback for a 3″ unit resulted in a gain of just about 20 horsepower and torque, pushing the 2.3 liter engine’s to-the-ground output over 400 pounds feet of torque and just shy of 350 horsepower.

"Ford

What about the downpipe, you say? That was the next part they installed. In short, Ford’s design of the high flow catalytic converter proved to be VERY good. Gains were minimal but there is more to the story when the Waste Gate Duty Cycle is inspected. With the downpipe and catback (called a turbo back exhaust system), the waste gate is actually working less than it was with only the catback. What that means is that additional boost could be added to make even more power.

In this case, the tuner opted not to due to the knock limit of the fuel and the efficiency of the intercooler to keep charge temperatures down and in check.

Lessons were learned in this exercise. The big take away is just how well modern day ECUs are able to control the engine and how important an engine tune is to extract the most power possible. Years ago, ECUs were sluggish and couldn’t adapt fast enough. Increased boost often resulted in uncontrollable boost, sometimes leading to excessively lean conditions and damaged motors. Not any more.

What a great time to be an enthusiast!  Keep an eye out on RFD for some upcoming Mountune-equipped Focus RS goodness!