2015 Ford Focus ST

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Welcome to my 2015 Focus ST build thread!

This page is dedicated to tracking the modification progression of my 2015 Focus ST (FoST) along with performance gains realized.  The Focus ST is an amazing little car!  It comes with the Ford EcoBoost 2.0 liter 4 cylinder direct injection turbo-charged engine.  From the factory, this car puts out 252hp and 270 ft.lbs of torque.  Keep in mind, these numbers are not at the wheels, but measured at the crank, so the actual wheel horsepower (whp) and wheel torque (wtq) will be less.  My FoST came with the full Recaro seats, ST3 and 402a packages.  The car is a perfect commuter to and from work and for longer trips due to the exceptional mpg-to-horsepower ratio!  Although this 4 banger puts out some serious ponies and torque for its size, it does so extremely efficiently.  Since I have had the FoST, I have not averaged below 20mpg on any tank!  Typically, during normal conditions, commuting to and from work, i’ll average closer to 24mpg!  On the highway, cruising, these numbers continue climbing closer to 30mpg!  Simply amazing, in my opinion, for the amount of power it is capable of putting to the road.  Speaking of power, let’s get to the mods!


The car was originally purchased from Wade Ford without any mods, new vehicle.  From there, before modifying anything, I wanted to get a solid baseline on the dyno to see exactly where the car was from a whp and wtq perspective.  It came in @ 219.5 whp & 265.9 wtq on the best run.

Dyno - Stock

Cobb Stage 3 Kit:

One of the main things I wanted to do to the car once I bought it was change out some of the basics, such as intake, exhaust and front-mount inter cooler (FMIC).  The best setup I could find was the stage 3 kit by Cobb Tuning!  This kit had it all, the full turbo-back exhaust with a catted down pipe, intake, FMIC w/ new charged air piping, rear motor mount (RMM) and last but certainly not least, the Cobb AccessPORT v3!  In addition to the Cobb Stage 3, I also added the Turbosmart 50/50 blow off valve (BOV), Cobb symposer delete (which was a fancy little thing Ford added to channel intake air into the cabin to make the car sound more throaty.  Cheesy, so it was blocked off in lieu of actually hearing the real engine!), and Cobb short-shift plate to reduce shifts by 40%.  Cobb really does make top-notch products, perfect fitment and excellent quality, I could not be happier!  After installing these components, I took the car back to the dyno for another run to see performance gains from the additions.  At this point, from a tuning perspective, I just applied the Cobb OTS stage 3 93 octane tune that came with the AccessPORT.  It came in @ 242.9 whp & a whopping 330.3 wtq on the best run.  That is a gain of +11% whp and +24% wtq.  Honestly, I was expecting more from the whp perspective; however, the wtq was off the charts!  Going from 265 to 330 is a HUGE difference on the street!

Dyno - Cobb Stage 3

Stratified E-85 Flash Tune:

Now that Cobb stage 3 has been installed, I wanted to look further into tuning as the OTS tune from Cobb still left a lot to be desired on the whp side of things.  In addition, the OTS tunes have to run super conservative since they are “off the shelf” tunes that have to work & perform in a huge variety of conditions, gas quality & grades, altitudes, etc..  E-85, as you may know, is the fuel that can be used in the Flex Fuel capable vehicles.  The FoST, although not designed to run on 100% E-85, can tolerate E-10 to E-15 all day long, it even says so right on the gas gap.  By introducing a blend of E-85 along with high test 93 octane fuel, you achieve a mix closer to E-30, which has been proven to yield significant performance increases, especially in turbo-charged engines.  By introducing the E-30 mixture, you are effectively increasing your octane level quite a bit beyond 93, allowing for higher boost and more aggressive tuning while still avoiding detonation.  If you would like to learn more on the subject, please visit the forums and research.  I now have applied the Stratified E-85 Flash Tune via the AccessPORT and have done the 3 gallons E-85 and topped it off with 93. This definitely added a good deal of pickup to the car, and the numbers proved it!  Went from 242.9 whp & 330.3 wtq up to 261.9 whp & 349.5 wtq!

Dyno - Cobb Stage 3 + Stratified E-85 Flash Tune

Modification List:

Cobb Intake
Cobb FMIC w/ Charged Pipes
Cobb RMM
Cobb Turbo-Back Exhaust
Cobb Exhaust Hanger Kit
Cobb Short-Shift Plate
Cobb Symposer Delete
Cobb AccessPORT v3
Cobb Shift Knob
Turbosmart 50/50 BOV
Boomba Racing Wing Risers
Mark II Shark Fin Antenna
JSTUNED (93 + E-85)



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Cobb Stage 3 Kit – During Install

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Cobb Stage 3 Kit – Installed

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Boomba Racing Wing Riser Kit

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Front End Fab Work
(FMIC Cobb Branding & Air Dam Modifications)

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Mark II Shark Fin Antenna Installation

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Dyno Run – Stock

Dyno Run – Cobb Stage 3
(Cobb Stage 3 OTS 93 Octane Tune)

Dyno Run – Cobb Stage 3
(Stratified E-85 Flash Tune)

Cobb Turbo-Back Exhaust

Turbosmart 50/50 BOV
(OEM setting, medium firmness)

Boomba Racing Wing Riser Kit

Special Thanks

I wanted to take time to show some gratitude for those who have helped me out during this journey.

First, I want to thank Luis Ricardo Santiago, my Hypermotive parts guy!  Luis is the BEST asset for all your Focus ST parts, upgrades and advice!  He makes it so simple, offers recommendations based on what he and his customer’s have seen, has exceptional prices and makes ordering a breeze with super fast shipments!  Doesn’t get much easier!  He’s tha man!

*To contact Luis, you have two options:  Facebook (Luis Ricardo Santiago)  or  email via:  [email protected]

Second, I want to give a huge thanks to my man Eugene Chou @ KoruWorks of Marietta, GA!  I love working on cars myself, and can do basic bolt-on’s in a garage; however, when doing the full stage 3 kit, not having a floor jack/stands, and wanting the components installed professionally and in a timely fashion, I made the decision to have it installed in a shop as opposed to the weekend warrior approach 🙂  Eugene & team did a phenomenal job on the installation!  I could not be more satisfied with the price and quality of work they provided!!  I ordered the Cobb Stage 3 kit through Eugene, and all other parts through Luis.  Together, they are my dynamic duo for FoST success 🙂

*To contact Eugene Chou, you have three options:  KoruWorks Website,  email via:  [email protected],  telephone via:  678.290.8831

Last, but certainly not least, I want to give a BIG shout out to Brian Tyson from JST Performance!  This guy is the real deal when it comes to everything you expect with a professional E-Tune!  He genuinely cares about your car and applying as much power as he can, safely!  During the tuning process on my ST, he was extremely responsive and provided revisions same-day, unbelievable!  I got both the 93 and E-30 tune from JST.  This was to replace the Cobb OTS 93 tune that came with my AccessPORT and get a little more juice from E-30!  Let’s just say the difference was VERY noticeable in the seat!  I am still waiting on a dyno pull after these tunes as my local dyno shop is closed until further notice, and Brian lives two hours away 🙁  Will post dyno-proven results ASAP.  HIGHLY RECOMMENDED!!

*To contact Brian Tyson, you have four options:  Facebook (Brian Tyson), JST Performance Website, email via:  [email protected], telephone via:  478.290.7953

Stay tuned…(pun intended) 🙂