Off the showroom floor – well, used car showroom floor, to be honest – project Habanero hatch has been a joy to drive. And, unless you’ve been hiding under a virtual rock for the last two years, Ford’s Fiesta ST has pretty much won the internet and the B-segment hot hatch crowd’s hearts, alike. That being said, we won’t bore you with anymore overzealous praising or biased fanboy-isms. Bottom line: we have one, and with 24,000-odd miles on the clock, it was time to tear into the virgin underpinnings and welcome more ponies to the stable.

Naysayers, put down your crudely-drawn picket signs. We know that balance, handling, and driver involvement are the heart and soul of the ST, with overall power running a close second. But, when the guys at COBB Tuning start flashing their shiny wares, touting tire-scorching performance gains across the dyno graph, we were sold.

So, we rolled the ST into the Power Automedia shop and strapped it down to our Dynojet chassis dyno to find out what the little car was cranking out in its unmolested state. The first pull netted us a healthy 178.5-horsepower and 222.6-lb/ft of torque to the tires – a solid power number with excellent torque considering the engines extremely modest displacement. We pulled the car once more in the stock configuration and found the dyno graph wanting for a considerable 23 horsepower. On the third pull, another 7 horsepower fell off the board while torque seemed to remain steady.

What happened? Who left the stable gate open? The culprit was, without debate, heat soak.

The factory intercooler is extremely inadequate,” said Braden Bergher of COBB Tuning. “It is slightly more efficient on the road than on the dyno, but it always heat soaks. That means you won’t get the same experience every time you put the pedal down.”




Once the car begins to accumulate heat in the intake tract, the resulting thinner air density costs noticeable power and torque. This was a problem we would remedy later down the line. But, with our baseline dyno complete, next up on the list was to install COBB Tuning’s Stage 1 kit.

The complete air intake system from intercooler to the piping along with the tune round out the Stage 2 modifications. The downpipe and full exhaust will come as part 3.

COBB offers their power-aiding components for the Fiesta ST in three kits. The first of which includes a COBB Accessport (which is at the heart of all three kit tiers), a COBB rear engine mount, and a high-flow drop-in air filter. The rear motor mount (which we will get into more detail on later) helps resist engine movement under hard acceleration and allows the car to put power more effectively to the pavement. It is also a lot easier on the exhaust flex joint on the downpipe. The drop-in air filter also helps get air into the engine more effectively, but the Accessport is the real show winner in the stage one kit.

This handheld tuner is the last you will ever need for your Fiesta ST (though COBB offers tuning solutions for a plethora of other vehicles). The Acessport is update-able and compatible with both Apple and Windows operating systems. It can also be used to install completely custom engine tunes via COBB’s purchasable Accesstuner Race software. Below are the highlights of the system’s capabilities.

  • Change Tunes (performance maps, anti-theft, economy and valet)
  • Read trouble codes
  • Launch Control
  • Flat-Foot Shifting
  • Real-Time Gauge displays
  • Datalogger
  • Performance Calculator (0-60, ¼-mile, Trap Speed)
  • Shift light

Before we hooked our Accessport up to Habanero Hatch and mated it to the vehicle (a function only required on first-use), we updated our firmware via COBB’s downloadable Accessport Manager software. It stores all original ECU data, should an owner wish to restore their vehicle back to an as-factory condition. After the unit was mated, we selected the stage one, 91-octane tune. The Accessport takes only about 2 minutes to change engine maps. With the correct map loaded for our filter and gasoline (93-octane is also an option; but ,depending on your location, it may or may not be available ), we set to work running the car on the dyno once more.




Stage 1 dyno

The Stage One upgrades are simple: A tune, panel filter, and engine mount, which will take about 1.5 hours of your time (total) to install.

Truthfully, we didn’t have very high hopes for the stage one kit, but it surprised us. A filter-only swap tends to produce fairly negligible results (from experiences past) but it was COBB’s rework of the fuel, timing and boost tables, administered via the Accessport, that really made a difference in the car’s performance. Horsepower was up by 5 but it was torque that really showed and improvement, with a bump of 17.3 at peak. Under 400 rpm, all of the dips in the OEM torque curve were filled in and significantly bolstered. The torque improvement reflects what the driver feels in the seat of their pants every time they pull away from a stoplight.

After a simple air filter and tune change, our Stage 1 Fiesta update netted an increase of 5.5 horsepower and 17.3 lb-ft of torque, with the new numbers at 184.1 horsepower and 239.9 lb-ft of torque.

Stage 2 Upgrades

With the stage one test complete, we wheeled the car off of the Dynojet and onto our Bendpak two-post automotive lift. The hydraulic motor whirred as the car was hoisted into the air. It was now time to up the ante by bringing the Habanero Hatch up to spec with a COBB stage two kit.

If you recall, the biggest problem we encountered on stock and stage one dyno tests was heat soak. Not only did it rob power between back-to-back pulls, it also had us sitting around aimlessly, waiting for the car to cool down enough to deliver accurate numbers. To remedy that well-documented problem, COBB includes a substantially larger intercooler in its stage two kits.

Once the headlights were removed, we then began to remove the front bumpers.

The intercooler and larger aluminum piping help keep the intake charge substantially cooler, while removing restriction from the intake tract. In order to install the hard piping and intercooler assembly, the front of the car does need to be removed. However, it is not an intricate process. About 10 bolts, the headlights and several of those pesky Phillips-headed plastic expansion clips are all that require removal to get at the stock intercooler. COBB did an extremely thorough job detailing the process in their instructions.




With the face off the car, the installation of the intercooler and piping is an extremely straightforward affair. Also, the windshield wipers and cowl will need to be removed to allow access to the backside of the engine. Again, this is a very simple procedure, involving only basic hand tools.

Once we finished buttoning up the intercooler, we turned our attention to the intake system. The assembly makes use of the stock, lower air box, which already does a great job of isolating engine bay heat and ducting cool, outside air to the filter. COBB’s system replaces the upper intake pipe, the airbox lid and the previously installed drop-in filter with a higher-flow conical unit.

The upgraded engine mount keeps the engine from coming through the dash on hard shifts.

With the intercooler installed, we finished up the rest of the induction upgrade by installing COBB's cold air intake. This is a straight forward installation that includes an enclosed cold air box to house the conical filter.

Now that the car was up on the lift, we also took the opportunity to install the rear engine mount (included with the stage one kit). Though there was one problem, the car already had one. It turns out our virgin Fiesta ST wasn’t as untouched as we thought.

With the intake and intercooler installed and the tank topped off with 91-octane gasoline. We used our Accessport to reflash the computer with the appropriate stage two tune. As soon as the electronic wizardry was complete, we fired up the car and made three back-to-back pulls; the first of which yielded 195.6 horsepower and 229.3  lb/ft of torque. A solid horsepower improvement over our baseline runs (however, we did lose some torque to the heat of the day). The real triumph here was in the consistency of the power output. Between our three pulls, horsepower never wavered more than 3 percent. In a racing scenario, such as autocross or time attack, this consistency is a key factor to victory. Even for those content to simply tool around with their cars on twisty back-roads, a consistent power production means you can expect the same performance every time you mash the pedal.

Torque was down a little on the intercooler install but peak horsepower continued to climb – an increase of 11.5. This puts our numbers after our Stage 1 and 2 upgrades to 195.6 horsepower and 229.3 lb-ft of torque.




Driving impressions

Driving Impressions with a host of COBB goodies under-hood and an ECU that has had its stacks of zeros and ones substantially rearranged, project Habanero hatch is even more fun to drive. No, it doesn’t feel like a whole new car. The experience is more akin to driving a better version, with factory quality, reliability and attention to detail. Throttle response is crisper; and, thanks to the bolstered torque curve, less throttle tip-in is necessary when pulling away from a stop – the car effortlessly glides up to speed.

Mash the pedal and the power, torque and removed boost restriction in gears one and two are immediately noticeable. We’ve never felt the car to have an issue with torque steer, but the steering wheel more-than-ever saws back and forth in the driver’s hand as the front tires claw at the pavement in a relentless hunt for grip.

In addition to the welcome power gains, there are a few other aspects of the COBB stage two kit worth mentioning. Namely, the launch control and flat-foot shifting features. Launch control is a blast to use and makes getting the car properly motivated off the line significantly easier. The steps to engage the feature are simple: Depress the clutch pedal, select first gear, hold the cruise control cancel button, and pin the throttle. The car will hold 4,000 rpm until you drop the clutch and release the button. One caveat is that the pedal does need to be fully depressed.

“We’ve had a lot of people contact us saying that the launch control feature doesn’t work for them,” says Bergehr. “We’ve found that most of them aren’t pressing the throttle all the way to the floor. With launch control, you’re ‘in it to win’ it, so if you are going to use it, go for it!”

We’ve put a few tanks through the car since installing the COBB components, and while we can’t say it improved our mileage, we can honestly admit it didn’t affect it whatsoever. Habanero hatch commutes roughly 600-miles a week to work and most of its driving is steady-state at 70 mph. Pre-upgrades, it consistently returned between 31-33 mpg, (based on miles traveled divided by fuel used). We did notice that the average mile-per-gallon readout on the dash usually read much higher, (between 34-36 mpg). Our post-install tank came in right around 32 mpg.

If improved MPG is what you are after, and pending you can live with a muted performance potential, the Accessport comes preloaded with an economy tune. Flash that baby onto the car and boost limits drop from 22psi to 6, fuel tables go on a diet and part-throttle timing is increased. We did run a tank through the car on this tune but didn’t see a noticeable difference in our highway-only tank. We suspect that if city driving is a major part of your commute, the lowered boost will net you a more noticeable improvement at the pump –not that many enthusiasts could tolerate such a painful separation from boost for long. Shut up and take our gas money!

At the end of the day, we were pretty impressed by the stage two kit. It delivered everything it promised and the dyno results backed up all of COBB’s claims. However, that doesn’t mean we are finished. We will soon be bringing you a follow-up story where we install the Stage 3 kit, which features a full exhaust, from down-pipe to tail-pipe. Stay tuned for more dyno results, more power, and a whole new sound from our Fiesta ST.