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2015 Ford Fiesta ST R&D Introduction

Erik Blume  September 17 2019


With the amount of success we have had with our 2015 Ford Mustang Ecoboost product line, we knew that sticking to the Ford Ecoboost platform was a must when we decided to pick up another vehicle for R&D. Our choice was the 2015 Ford Fiesta ST. With a 1.6L turbocharged powerplant, aggressive styling, Cobb support, and a "cult" following, the choice was easy. The order was placed with Inver Grove Ford, and the car was in our hands 2 days later. 

First step was to inspect the stock spark plugs, drain the factory Ford oil , and get a good overall look at what we were working with. The reason for checking the plugs is because of my experience with the stock spark plugs in the Ecoboost Mustang. The gaps were inconsistent and the ceramic was stress cracked after just a few miles. The gaps alone made for odd ignition corrections from the ECU and the ceramic being cracked could of potentially caused engine failure if it wasn't caught.  I made a thread over on which you can check out here that has some good technical info regarding the plugs.


Luckily the factory plugs in the Fiesta were in good shape and pretty consistent at .030, .030, .028, .030. I choose to upgrade to NGK "6510" LTR7IX-11's gapped at .028" which has worked out well for me in the Mustang on all fuels. (93oct, E30, and RG Concentrate).


With the spark plugs swapped it was time to get the oil out of the car. Again, this change is from my personal experience with the Mustang. The factory oil shouldn't be kept in the car for longer than 400-500 miles. It breaks down very easily and after 400 miles it shares the same viscosity as water, and this is no good for your engine. I choose to run Rotella T6 and after a couple thousand of miles I swap it out for Motul X-cess 5w40. Pair it with a high quality oil filter like a WIX (#51348) and you are good to go!


As mentioned above one of the reasons chose the Fiesta ST was that Cobb already had Accessport support for the vehicle. I have been tuning with the Cobb ProTuner software for a couple years now and it is easily the best calibration software I have used to date for a stock ECU car. Not to mention it is the best hand-held tuner on the market, but we will get more into that later. I dropped an email over to our Account Rep at Cobb and let him know what we were up to and they 2-day aired a box of goodies. One of the many packages we will be receiving from Cobb during this project.


Now that we have the proper tool (Accessport) to get baseline data from the Fiesta ST in completely stock form, it was time to move onto the dyno. What we were looking for was to collect as much data as possible before we started R&D. Here is a quick list of what I collected:

  • Ambient Air Temperature
  • Intake Air Temperature
  • Charge Air Temperature
  • Coolant Temperature
  • Oil Temperature (It is inferred from other readings but will give us something to compare to later)
  • Air/Fuel Ratio
  • Ignition Timing
  • Boost Level

These parameters will allow me to document how each product we produce is or isn't an upgrade over the stock unit. This is key in our development as we won't produce a product without any significant benefits for the end user. So let's see what this little 1.6L EcoBoost is putting out in 100% factory form.


189.20whp / 213.07wtq. Pretty stout for such a small lightweight hatchback, but there is a lot of room to improve here, even in with the factory hardware. Next step was to see how Cobb's Stage 1 rearranged the power and torque lines and lay it over the factory power dyno results.


+23whp / +40wtq @ 3,000rpms. Peak power stays roughly the same because the turbo is just too small to produce any more power with the factory hardware. However the peak torque gains and the overall gain between 2,000 - 4,000rpms are clear and you can definitely feel it on the street.20150702_191411

The Cobb Accessport proves itself again to be the best first upgrade you can make, and it will continue to support all future upgrades as well. As we progress through this project, the next update will show the full potential of the Cobb Accessport with our Protuning on 100% stock hardware!


Within the next few days I will be sharing results from my custom tuning versus Stock and Cobb's OTS Stage 1 map. We also have a Kompact BOV and Internal Wastegate that Turbosmart sent over to us for some testing. The materials we need for our first line of products (Intake, Downpipe, Exhaust) are en route and should be here this week as well. Expect some huge updates within the next week, and we hope you are excited as we are to dive into development!

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1 comment

  • Rod Mommaerts: November 10, 2015

    Let me know when you get around to making a BIR capable rear wing and front Splitter for it as nperhaps a rear defuser ;) lol

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