Free shipping on all
orders over $149

Big Turbo Upgrade - The Ultimate Focus ST Mod Blog Feature
JP Alonso

By: JP Alonso on September 28th, 2017

Print/Save as PDF

Big Turbo Upgrade - The Ultimate Focus ST Mod

Ford Focus ST

Ever wondered if the hype is real? Here's your answer. Hell yes. Be careful though, if you take the plunge on a big turbo, prepare to never be satisfied with a stock turbo car ever again. It just won't be the same. The experience of a hard wide open throttle pull, holding 22psi, or more, all the way to 7,000 glorious rpm makes you mad that Ford gave you such a puny hair dryer of a turbo now that you know what boost can really feel like.

Why do you think we do this for a living? It's addicting and exhilarating, to say the least. You'll find yourself wanting to go for a drive at odd times, maybe even enjoying the drive to work in the morning when the air is cool and crisp, leaving early because you're taking the long way.

A bigger turbo is more than a turbo though, it's a commitment. It's not cheap and it needs supporting modifications and tuning. It's not hard to do, but it's not foolproof. We had one of the very first Focus ST's with a bigger turbo once ATP Turbo released their Garrett based bolt-on kits. We're super thankful for companies like this that make it so easy to go bolt on some big power. We want to pay it forward and try to help you understand what's involved and what turbo fits best for you.

Big Turbo Upgrade - The Ultimate Focus ST Mod (10).jpg

Download our Turbo Kit Buyer's Guide for the Focus ST right here.

Preparing for Big Power

The difference between a stock turbo and a big turbo is significant. The amount of air being forced into the engine takes a huge leap. This requires more support from the surrounding components to perform and if they aren't up to snuff, it might be harmful or limit your power and efficiency. Here are the minimum supporting modifications we suggest to make a big turbo kit work properly.

ECU Tuner and Custom Calibration

The only thing I'm going to tell you is you need it. You cannot put a bigger turbo on without it. Plain and simple. You probably already knew that, but some people ask.

Intercooler and Downpipe

I listed both of these parts at once because they are equally important. Turbos need as little exhaust restriction after the turbo as possible to make good power. Not relieving exhaust pressure well enough can raise your EGTs (exhaust gas temperature), prevent you from running higher timing, and ultimately leaves power and efficiency on the table. The downpipe is the first one in line responsible for clearing out that pressure and gas. It must be free flowing.

On the intake side, nothing is more important than the intercooler. The temperature of the air coming out of turbo is mind blowing. Without being cooled down, your engine would suffer severely. Any intercooler helps cool down the air, but some don't do it well enough. The stock intercooler doesn't work great on the stock setup, so how would it ever work on a big turbo? It doesn't. You need a core that has more volume, denser fin structure, and quality construction.


The intake system in the Focus ST is about as long as an intake gets.  The longer it is, the harder the turbo has to work to ingest air.  There is actually pressure loss (of the atmospheric air) occurring in the intake system before it sees the compressor blades.  The longer and more restrictive it is, the more pressure loss.  In a perfect world, you would put a velocity stack right on the end of the turbo compressor and call it good.  That's obviously not realistic for this car but putting a smooth flowing, larger diameter tube on the intake system will help the turbo breathe better.

Cat-Back Exhaust

Some will argue this isn't a huge necessity but in reality, it is.  Just like I was describing before about the downpipe, the same applies with the exhaust.  It's only a 2.0 liter engine but a bigger turbo is easily forcing up to twice the amount of air through the engine at any given point, or more, when compared to the stock turbo car.  That means there is an equal amount more exhaust being generated.  All that pressure needs to be released to make efficient power.  A catback exhaust might not have as big of an effect on a stock turbo car, but on a big turbo setup, you're leaving a lot of power on the table without upgrading it.

Choosing the Turbo

Okay, let's get to the good stuff.  There are MANY options.  I'll break down the most popular ones and the ones I think make the most sense for the ST.  I'll also share some differences in the options for these turbos, mainly turbine housing sizes.

Before we go further, I want to bring something to your attention that many people are hesitant about when considering a turbo upgrade.  Although you'll lose a little low end punch with these bigger turbos, you'll actually INCREASE the amount of usable range of power.  For example, the stock turbo spools around 2800 rpm but falls off badly around 5500 rpm.  It actually doesn't help you to stay in the throttle past that point.  Let's pretend you lose 800 rpm of low end torque and hit peak boost at 3600 rpm now.  Although you lost 800 rpm of usable boost, you gained as much as 1500 rpm at the top end because you will hold your boost level all the way to 7000 rpm or higher if you are pushing it harder.  That's a net gain of 700 more rpm of usable power, compared to the stock turbo, when you rev to 7000 rpm, just something to consider.

ATP Turbo

ATP was the first to market for a bolt-on big turbo.  The kits are complete and fit really well.  We know because we were one of the first ones to use one on our own Focus ST in the form of a GTX2867.  Since then, the GTX Gen2 turbos have been released and they're very impressive.

The ATP turbo kits fit with the stock style downpipe and the stock style intake system.  It comes with all the oil and coolant lines for the new turbo setup.

Big Turbo Upgrade - The Ultimate Focus ST Mod (8).jpg Big Turbo Upgrade - The Ultimate Focus ST Mod (7).jpg
  • GTX2860R Gen2
    • Before the GTX Gen2 models came out, I would have went straight the 2867.  But with the flow rating increases of the Gen2, a 2860 becomes a real player for a quick spooling turbo that can put out over 450hp!!  If you're looking for about 350-380whp, this is a great choice.  This is about 75-100 more whp than the stock turbo can pump out.
    • Optional turbine housings available.  Smaller housing for quicker spool, larger housing for better top end power.
  • GTX2867R Gen2
    • What was probably the best all around turbo for the ST before the Gen2 came out just got better.  The same spoolup characteristics as before, now with a higher flowing compressor wheel.  What could be better?  This basically means you can push more power than the old GTX version or you can achieve the same amount of power without stressing the turbo as much.  The reason why I'd pick this over the original GTX is because they cost the same.  I don't think there is a reason to get the old one over the new one.
    • Optional turbine housings.  Smaller housing for quicker spool, larger housing for better top end power.
    • 425-450whp capable
  • GTX3076R Gen2
    • There are a handful of turbos you can select in between the 2867 and this.  However, since the 2867 can get you to the fueling limit of the car and then some, this is the next logical step.  It's a 750hp capable turbo that spools like the mid frame turbo that it is.  Plan on seeing full boost in this one by about 3800 rpm depending on your mods.  That's not that slow, especially when you consider what it's capable of.  You don't have to have 600whp for this to make sense, it would be great for 500whp too.  Lower boost will keep the turbo in a more efficient island on the compressor map leaving you with cooler intake temps and a slower spinning turbo to achieve the same boost as a smaller turbo.  
    • No turbine housing options available.  0.74 A/R is the standard size.
    • 600whp capable

Full Race

Full Race Motorsports has been on the EcoBoost bandwagon since day one with multiple Ford platforms.  Knowing they're BorgWarner lovers meant an EFR was on the way as soon as the Focus ST hit the streets.  There are 3 turbo offerings from them, all utilitizing the same supporting components.  They all use the T25 turbine flange and internally wastegated EFR turbos.  Blowoff valves are built in and a new plug-n-play 3 port boost controller is included.  These are more of a true turbo kit where it uses proprietary supporting parts.  The downpipe, intake, adapter elbow, and all hardware are included and are required for fitment of the EFR turbo.  

Big Turbo Upgrade - The Ultimate Focus ST Mod (9).jpg

  • EFR6258
    • 42-44 lbs/min max airflow, 450 bhp capable
    • Very fast spooling, great for 325-350whp setups
    • Very responsive turbo in between shifts
  • EFR6758
    • 48-49 lbs/min max airflow, 500 bhp capable
    • Very fast spooling, great for 400whp setups
    • Very responsive turbo in between shifts
  • EFR7163
    • 60 lbs/min max airflow, 600 bhp capable
    • Spools fast for how big it is, 500whp capable
    • Very responsive turbo in between shifts


Just like ATP, cp-e bases their kit around a Garrett turbocharger.  However, it's a completely different animal.  cp-e's kit uses the Tial V-Band in/out turbine housing.  This gives you many options for A/R sizing and a 35R size is also available.  This is a very well designed and efficient kit.  All parts come with the kit to make it completely bolt-on.  The cast adapter elbow is a beautiful piece that incorporates an external wastegate design and feeds exhaust gases back through the downpipe for a recirculated design.  This gives you the best boost control while not being too loud and complicated.  From our experience, this is the best overall turbo kit on the market today for the Focus ST.

Big Turbo Upgrade - The Ultimate Focus ST Mod (4).jpg Big Turbo Upgrade - The Ultimate Focus ST Mod (2).jpg
Big Turbo Upgrade - The Ultimate Focus ST Mod (1).jpg Big Turbo Upgrade - The Ultimate Focus ST Mod (3).jpg
  • GTX2867 Gen2
    • A/R options are 0.63 and 0.86.  Use the lower A/R for faster spool and less top end ability.  Use the 0.86 for higher top end flow and power.
    • 450whp capable
    • Tial Stainless Steel V-Band Housing
  • GTX3076 Gen2
    • A/R options are 0.63, 0.82, 1.06.  Lower A/R used for quicker spool, higher A/R used for more top end flow and power.
    • 600whp capable
    • Tial Stainless Steel V-Band Housing
  • GTX3582 Gen2
    • A/R options are 0.63, 0.82, 1.03.  Lower A/R used for quicker spool, higher A/R used for more top end flow and power.
    • 700whp capable
    • Tial Stainless Steel V-Band Housing


The mountune kit is a very simple one that allows you to bolt on a lot more power using an EFR based turbo.  The kit is based on the EFR T25 flanged 6258 and 6758 turbos.  Each of which will provide a large increase in power on your ST.  It features a cast exhaust outlet elbow to mate to the turbo.  It includes a silicone intake pipe to mate with the mountune intake system.  Unless you're going to make your own custom parts to support this kit, you'll need the mountune intake pipe and downpipe, both sold separately.  My favorite part about this kit is the oil and coolant lines.  They are hard piped and pre-bent, just like a factory style system.  This makes fitment spot-on and the user experience will be very good.

Big Turbo Upgrade - The Ultimate Focus ST Mod (5).jpg Big Turbo Upgrade - The Ultimate Focus ST Mod (6).jpg
  •  EFR6258
    • 42-44 lbs/min max airflow, 450 bhp capable
    • Very fast spooling, great for 325-350whp setups
    • Very responsive turbo in between shifts
  • EFR6758
    • 48-49 lbs/min max airflow, 500 bhp capable
    • Very fast spooling, great for 400whp setups
    • Very responsive turbo in between shifts

Bolting up a bigger turbo can be a very rewarding experience on the Focus ST.  Often times, we hear people questioning why they didn't do it sooner.  With the tuning ability of the ECU using a Cobb AccessPort, or similar device, and the aftermarket part support available for the Focus ST, a big turbo is not a large feat anymore.  It's as easy as adding it to the cart, waiting for it to arrive, and taking a weekend to install.  If you think you're ready, go for it and never look back!


About JP Alonso

I'm the founder of Edge Autosport and I remember first getting into cars in high school. I read all the magazines, bought a bunch of technical books, and finally got to start wrenching around the age of 19. I really enjoy modding and being able to live out a passion is truly awesome. I wouldn't change a thing.

  • Connect with JP Alonso