2022 Subraru BRZ Build

Stratified’s 2022 Subaru BRZ development car.

The Car: 2022 Subaru BRZ base model was purchased brand new in late 2021.

Why This Car?

When the Subaru BRZ, Scion FRS/Toyota 86 came out in 2013 it started a new class of its own. The formula was an inexpensive, lightweight, 2-door, 2+2 rear-wheel drive sports car. No other car was able to capture all of these ingredients. There were affordable American 2-door sports cars but they were very large and heavy. There were lightweight, rear-wheel drive European coupes, but they were expensive. There were lightweight, inexpensive Japanese cars, but they were front-wheel drive or 2-seaters. The partnership of Subaru and Toyota that developed the BRZ/FRS/86 platform had met all the criteria of something special… but a lot of people were asking for more power.

Obviously, the platform was here to stay and only got better with subsequent generations. The new 2022 car answered the call for more power with a larger displacement 2.4L flat-4 which sported a 25-30hp increase from the older 2.0L flat-4. The BRZ was always a good handling car but Subaru/Toyota also improved upon that with an even lower centre of gravity and near 50/50 weight distribution. That being said there is always room for improvement… and this is where we come in.

First Impressions:

We first got this car in late 2021 and drove it around in its stock form and since tuning did not become available until late 2022, we tested quite a few parts to observe their impact and set our expectations up for when tuning would be available.

Overall the car is a true driver’s car. It has everything you need and nothing you don’t. You simply get in, start the car and drive. It’s actually quite a refreshing experience in comparison to all the bits, bobs, and gizmos on every other car these days.

We documented a lot of our findings – what works and what doesn’t in a an extensive video series. It all starts with a comparison to the Gen 1 car …

 

The Vision:

This car has one main purpose, it is a track car that you have the ability to daily drive. With a few simple modifications, we will be able to stay competitive in this car within the sport 4 class and pit it up against our new Mk8 GTI which is also going to remain in the sport 4 class for  2023. We will soon be upgrading the wheels and tire combo on the car, as well as adding some camber plates, an upgraded radiator, as well as trackpads.

Baseline Power Figures:

The car when completely stock made approximately 206 HP and 170 LB-FT of torque to the wheels. There is less of a torque dip than the gen 1 car had and the car holds it well throughout the pull.

November 25, 2021:

Here we explore the first mods we did to the car adding some camber and doing an alignment.

December 4, 2021:

Here we explore the difference headers make on the Gen2 car and answer the question do UEL (unequal length) headers make more power?

December 8, 2021:

Our first time taking the car to the track, it was cold but we wanted to see what this baby could do.

December 15, 2021:

Here we take a step backwards and put the Gen2 header on the Gen1 car to see the improvements made specifically to the header on the newer model.

December 24, 2021:

After analyzing the 2.4 headers on the Gen1 car we decided to test some aftermarket equal-length and un-equal-length headers on the Gen2 car.

January 15, 2022:

Here we test out the effects of a cat-back exhaust on the car. As well as testing out a prototype intake we printed on our 3d printer.

November 21, 2022:

Finally, about a year after getting the car, we have tuning support for the Gen2 car and are able to really see what power can be added.

**tuning support also available for the Gen1 car

We start off with a fresh oil change, add a mid-pipe to see what a full exhaust and tuning on this car to see what power it is capable of on 93 pump gas as well as E30.

Dyno Results:

As you can see there was some power to be made with tuning. It wasn’t nearly as much power as a forced induction car but certainly an improvement.

November 29, 2022:

In this video, we explore the restrictions on the OEM intake system, if an aftermarket filter helps, and how much loss there is from the carbon filter.

January 27, 2023:

After the last video testing filters, K&N saw that and decided to send us a K&N intake to test not just their filter but the intake as well. We explore how a cold air intake makes power and test K&N’s guarantee that this intake will for sure make more horsepower.

April 23, 2023:

Our search for HP on the car continues as we test out more headers on the car. We look at headers from Tomei, JDL, Ace, Borla. We also take a look at a potential problem with the FA24 that could lead to oil starvation in this video as well as install an oil pan baffle while we are at it.

July 10, 2023:

We continue our Gen2 BRZ build journey and turn the focus on suspension. We wanted to find the best suspension combo that would keep this car class legal in Sport 4 for time attack. That meant sway bars, camber plates, springs, and shocks. No coilovers. Did we find a good combo? Watch to find out.

Focus RS Power and Turbo Upgrade Considerations

Some things to consider when upgrading your Focus RS’ turbo and shooting for higher power numbers:

  • The OEM turbo will sit between 350-375whp (to the wheels) on most cars with high quality 93 octane pump gas.

Focus RS Pump Gas Dyno

  • The OEM turbo when paired with E30 fueling or WMI will allow up to low 400whp level.

Focus RS WMI Dyno

  • At the 400-410whp level the OEM fuel system starts to reached its maximum flow capacity and an upgrade is recommended.
  • With a larger turbo such as the NX2 on a stock motor, you will reach around 380-400whp on pump gas before reaching the knock limit.
  • Adding ethanol will allow significantly more power on this turbo but you will need additional fuel system upgrades such as aux fuel to support this.

STRATIFIED X4tra Fuel System - EcoBoost 2.0L/2.3L

  • Once you have addressed the turbo and fueling then you can push power on the stock motor beyond 500whp with something like an NX2 turbo.

Precision Bolt-on Turbo w/ Custom Tune

  • Keeping power levels in the 425-450whp will extend the life of an OEM motor. You can achieve more power but the more torque the rods experience the fewer cycles they will last.
  • At power levels exceeding 450whp supporting modifications on top of the usual flow bolt-ons (intercooler, exhaust, intake) will be needed such as a clutch and a 3.5 or 4 bar TIP sensor.
  • Keep in mind that larger turbos do have a bit of a spool penalty with the NX2 spooling a couple hundred RPM later.

Considering the overall performance per dollar equation, the stock turbo with something like E30 or WMI tuned correctly is a great stock motor option. The NX2 or other turbo upgrades (there are higher performing, pricier options as well) make sense when you can run that high octane fuel AND have a fuel system upgrade.

For more power on pump gas than around 400whp, a better flowing motor is needed and that means cams. We were able to achieve 500whp on pump gas on a built motor with an externally gated 3076 turbo with upgraded cams.

Once the motor is built and fuel system upgraded you can of course push higher with higher octane fuels.

A final note – consider the use of the car. If you want a fun street machine you can pile on the power with just the aforementioned upgrades. However if you want the RS to last on a road course with significantly higher power levels you will want to address engine cooling, the RDU, brakes, suspension and of course tires. So build for your purpose and enjoy the journey!

Happy Tuning!

The Stratified Team

MK7 GTI/R Fueling: How it Works and How to Upgrade

The OEM fuel system of the MK7 becomes a limiting factor as you increase the power level of the cars. Choosing the best solution for your needs is important and the MK7 GTI and R are fortunate enough to have lots of solutions available. So let’s go over how the OEM system works, when you will need to upgrade, and how to choose the best solution for your application.

Please keep in mind that throughout this article the power numbers are in reference to our Mustang Dyno. Power output on different dynamometers may vary. Here’s a video of how a Golf R performs on our Mustang.

mk7-golf-rTo start let’s look into how the OEM MK7 fuel system works. First of all it must be understood that the car injects fuel that is proportional to the amount of air entering the engine in order to achieve a correct air-fuel ratio. The more power you make, the more air enters the motor.

In order to know how much fuel to inject, the ECU needs to know how much air is being consumed by the motor. The more power you make, the more fuel the engine will be consuming to achieve that power output.

Below is an image showing the MK7 with both the port and direct injection systems in place. In Europe the MK7 GTI/R has both port (blue) and direct injection (red) while in North America the car only came with direct injection. Port injection can be added to North American cars – but more on that later.

mk7-intake-manifold-edit-2To measure air entering the motor, the MK7 GTI/R use a speed density (pressure) style control system that does NOT contain a MAF sensor. Some of you may be familiar with these and the main difference is that when you use a MAF, you measure airflow directly while when you use pressure, you need to translate that pressure reading into aiflow.

In order to do this the ECU primarily relies on 2 intake pressure sensors, one pre-throttle (PUT) and one post throttle in the manifold (MAP). Along with compensations for air temperature and barometric pressure these pressure readings then go into a volumetric efficiency model to determine how much fuel is required to meet the target Air/Fuel ratio (AFR).

mk7-airflow-diagram-overview-2

Further to this, the car has an OEM wideband O2 feecback sensor and the ECU constantly adjusts the fueling (under part throttle as well as wide open) to reach the desired AFR. All in all, this is a fast and modern ECU and it controls fueling very well under all conditions.

wideband-sensor-diagramOn the delivery side on North American GTIs and Rs, we have 3 main components: Low pressure fuel pump (LPFP) (in the tank), high pressure pump driven by the exhaust camshaft (HPFP) and the high pressure DI injectors spraying right inside the combustion chamber. Under high load/boost the MK7 injects fuel with a pressure of around 2900psi.

mk7-fuel-system-overview

OEM Fuel System Limitations

As we talk about fuel system limitations keep a few things in mind:

1. Pump gas without ethanol or other alcohol added to the fuel gives you the most headroom in terms of how much mass the fuel system can deliver. However the engine will experience knock the earliest using this type of fuel limiting the power by reaching the knock limit. Running E30 fuel requires around 10% more fuel volume to be injected and running full E85 requires around 30% more fuel volume to be injected compared to ethanol free gas. As you raise the knock limit using ethanol blended fuels allowing you to add knock-free power, you run out of fuel system headroom. You can run a little leaner without knock on ethanol blended fuels that can recover some the fueling headroom – however on a Golf R with the IS38 or an upgraded turbo you will often run out of headroom on the stock system.

2. Ambient temperatures have a big effect on turbocharger efficiency and fuel requirements. A car will require significantly more fuel running the same boost in freezing weather than it will in the heat of summer. If we want a reliable setup, consider the requirements during both winter and summer and build your system for the peak demand you will experience.

OEM LPFP: Starting with the first component in the fuel delivery line we have the Low Pressure Fuel Pump (LPFP) – This in-tank transfer pump is controlled electronically by the OEM ECU via the tune. The OEM LPFP on the MK7 can provide fuel for up to around 400 WHP for the GTI and R.

oem-lpfp-pic

OEM HPFP: The line from the LPFP feeds into the inlet of the HPFP (High Pressure Fuel Pump). The HPFP is driven by the exhaust camshaft of the engine and pressure is controlled via a solenoid. A four-point cam lobe on the camshaft drives the HPFP. As the engine RPM increases, the HPFP’s ability to pump a greater volume of fuel per unit of time also increases. Because of this we see the HPFP start to suffer at peak torque. You can tell the OEM HPFP is struggling if you see pressure drops under high boost and this usually happens around 380-400 WTQ.

OEM DI Injectors: The high-pressure fuel is delivered to the high-pressure fuel injectors These injectors sit on the intake side of the engine under the intake manifold. These injectors are pulsed for a maximum of half the engine cycle (so only around 50% duty cycle) because you can’t inject during the power and exhaust strokes unlike a port injected car. The fuel injector pulse windows shrinks as the engine speed increases and if the HPFP pressure drops, they have to open for longer still to compensate for the lower pressure. Because of this you can see OEM injectors become limited at both peak torque (due to the HPFP dropping pressure) and peak horsepower in the upper RPM due to the limited opening time. They too generally run out of headroom around 400WHP and 400WTQ.

di-injection

How to Upgrade the OEM Fuel System

LPFP Upgrade – With nothing else added this can get you about 20-30 WHP at the top end. The 450 LPH (liter per hour) pumps can supply enough fuel for around 550WHP and most are E85 compatible. If you are looking to push above this there are 525 LPH LPFP as well. Upgrading the LPFP requires tuning changes or running an external controller to prevent the OEM ECU controller from overheating. We recommend tuning for any fuel upgrades with something like a Cobb Accessport and custom tune.

lpfp upgrade

HPFP Upgrade – This upgraded replaces the internals of the HPFP with a larger bore pump. An HPFP upgrade increases the amount of fuel delivered per stroke and can prevent the pressure from dropping at peak torque. A HPFP on its own will give you an extra 20-30 Ft-lbs. of torque headroom in the mid-range and is E85 compatible.

hpfp-upgrade-pictureAfter you have replaced the HPFP and LPFP you have gained the capability to comfortably run E85 fuel on most IS38 bolted cars year-round and have fueling headroom for 420-430 WHP and WTQ.

However – there is a better way!

MPIMulti Port Injection. If your ECU and tuning solution support adding port injectors, you only need to add an MPI kit and an LPFP upgrade for a practically limitless fueling solution.

With some mild modifications to your manifold, adding MPI allows you to add 4 injectors to the manifold of the MK7 GTI and R to provide port injection.

mpi-upgrade

In addition to providing additional fueling, an MPI system will have the added benefit of port cleaning and a low side fuel pressure sensor which allows you to both read how your LPFP is performing in real time and to control the LPFP pressure.

mpi-injector-diagram

How To Choose your Fueling Upgrades:

The stock fuel system of the MK7 will get you up to the 400 WHP and 380-400 WTQ range.

If you are looking to just hit around or just above 400WHP/WTQ range, you can achieve that with just the HPFP upgrade.The HPFP upgrade alone is good to run on E30-E50 IS38 setups year round and full E85 IS20 setups.

HPFP and LPFP upgraded together will be sufficiency for full E85 setups on IS38 cars. 

Beyond that it is recommended to get the MPI kit with an LPFP (You can leave the OEM HPFP in place).

When sizing your MPI port injection kit – 700WHP can be reached with 980cc injectors and up to 1000WHP with the 1300cc injectors.

For the LPFP the 450 LPH LPFP will support up to 550WHP or there is the 525 LPH option if more is needed. Most cars over 600+whp may consider surge tanks and upgraded lines.

mk7-r-engine-with-mpiWe recommend running MPI with an LPFP upgrade if you want to run hybrid or larger turbochargers on E50+ ethanol mixtures. MPI also keeps your intake valves clean AND gives you the low pressure side readings and control over pressure in real time. This makes this setup the most robust and with the most features.

Below we break down the relative power potential of the different permutations.

fueling-upgrades-comparissonBelow you can see an example of a car that is we tuned using the COBB Accessport with a bigger turbo, upgraded low side fuel pump and a MPI kit making 500+whp.

mk7-r-mpi-big-turbo

Hope this helps you choose your fuel modification path and Happy Tuning. Get in touch if you have further questions.

The Stratified Team

*Pictures sourced from Volkswagen Service Training Manual for the 2.0L TSI Engine.

Keeping the Tuned Ecoboost 2.0 Alive (and kicking butt)!

I want to shed some light on the Ecoboost 2.0 piston failures (the most common failure mode) and offer some pointers on keeping the OEM motor happy and living.

Let’s get one thing out of the way first – the weak point in the EB 2.0 is clearly the piston. Failures happen on stock engines, tuned engines – even ones tuned by Ford Performance! We don’t see failures like this in the 1.6 and 2.3 engines and Ford has made a point of reinforcing ringlands on the 2.3 EB. The 2.3 is more likely to toss a rod before a piston falls apart. Every engine has a weak point.

focus-st-failed-pistonNow that this is out of the way – let’s look at what makes the engines fail and how to make it less likely for it to happen to your Ecoboost!

Fuel and Air Fuel Ratios

The car uses full time closed loop fuel control using a wideband O2 sensor. That means it is always adjusting the air fuel ratios  (part throttle and wide open) to match what is being commanded in the tune. Using a speed density strategy (using pressure sensors to infer air mass consumed by the engine) makes the air fuel ratios unaffected by charge air leaks that would throw MAF based cars off. Having looked at 10s of thousands of datalogs from these vehicles, we almost never see them deviate from target air fuel ratios. The only exception is if there is an exhaust leak that draws oxygen into the exhaust stream “fooling” the wideband sensor. If severe enough this will trigger a “lean” running CEL. Check and fix exhaust leaks (and boost leaks for the sake of performance).

Carbon buildup often interfere with injector spray patterns. Cars driven in traffic and idled for long periods of time are more prone to this. Consider an injector cleaning or replacement as the engine gets up in age past 60,000 miles. 

Boost

In terms of boost pressure – the OEM turbochargers have a very weak wastegate spring with a large internal wastegate. This in turn means that boost will taper regardless of what you do electronically with the OEM wastegate actuator. This prevents overspeeding of the turbo and boost is held at peak values for a very short section of the power band (tapering starts just past 4000 RPM and tapers to 13-16psi by redline). The OEM intercooler is not designed for performance and extended high gear, high load conditions will warrant an intercooler upgrade. Changing your wastegate actuator or turbo definitely requires a retune so don’t make these changes without having tuning handled as well.

Spark and Knock

“Normal spark knock” is very well handled with the OEM knock control system. You never see pistons pitted from detonation when taking the engines apart as the ECU if setup correctly is very fast to react and again if setup correctly effective at adjusting for variance in driving conditions and octane levels. The most common spark related issues are spark plugs. Consider them a maintenance item and replace spark plugs every 20,000 miles on a tuned engine. Replace them with a step colder plug gapped at 0.026″. Failing to do so will cause misfires which add to carbon deposits.

How the knock detection system works

If you got this far excellent; I am going to get into the issues that cause these cars to fail as we observed from working with them over the years.

Common Failure Modes and Avoiding Failure

1. LSPI – low speed pre-ignition. The common killer of downsized highly boosted direct injection engines. A concoction of oil blowby, carbon buildup, high torque, oil formulation, injection spray pattern will cause the mixture to pre-ignite and be immediately followed by what is known as super knock. That means that the mixture will ignite well before the spark plug is triggered by the ECU. The chain of events that follow will quickly destroy a piston as the expanding hot combustion event will push down on an upward moving piston. It only has to happen a few times. The most common time this will happen is when you have been cruising on the highway and then punch the throttle or get into boost quickly. Remember the car will build a lot of boost even at part throttle.

The hot engine in combination with a lot of PCV oil flow make the scenario much more likely. This is the reason you often don’t see these engines failing at wide open throttle. During an LSPI event you can get an outright failure or you get a crack that will eventually lead to the failure at what appear odd times. There are many ways to mitigate LSPI but the fundamental reason for it is ingrained in the design of the motor. Things like water-methanol injection, added port injection, carbon cleaning, using high quality oil and changing it often (there are now oil formulations designed to be more pre-ignition resistant) and good intercooling go a long way. This first part comes down to keeping the engine cleaner and cooler.

This engine when tuned will makes the majority of its torque in the lower range of the power band with an OEM turbo. That’s simply a physical fact from the way the engine and turbocharger are designed. This is the operating zone associated with LSPI. Keep this in mind and AVOID getting into boost right away after you have cruised on the highway for some time. Downshift, ease into boost, build it gradually and then get into it. After this initial time easing into it, have a blast going through the gears! I also recommend to avoid loading up the motor in the low RPM range and a high gear in general – downshift if you are under 3000 RPM on the highway and you need to make a pass.

Don’t confuse this with not driving the car hard. Cars that survive the longest are often well exercised. Run it through the gears in boost and allow some of the oil and carbon residues to burn up.

2. Another scenario that is hard on the rotating assembly – rods and pistons – is sitting on a rev limiter. Launch Control, Redline Rev Limiter, Flat Foot Shift Limiter all work the same way. The OEM logic for this cycles cylinders on and off to maintain a certain engine speed by shutting off fuel and ignition temporarily on some cylinders. However the acceleration and deceleration of the rotating assembly is hard on the components. This often triggers the knock sensors also indicating the resonance created by this activity (slap and lash) is similar to detonation events and unhealthy for the motor.

Sitting on limiters excessively for public displays is not doing the motor any favors. We offer crackles which are NOT achieved by adding any fuel or energy to the engine. We are careful to implement these in an OEM-like fashion (common in other makes like VW, Porsche, even the Focus RS). Let me be clear, the crackles are NOT an invitation to be abusive to the motor if you want it to last. So, sorry for all those who ask but we don’t and won’t purposefully make the cars shoot flames.

The engines are not inherently weak and we have customers with hundreds of track lapping days on OEM motors making 350-400whp on larger turbochargers. The motors survive. I recommend reading some of the tech literature we have on our site meant to help you, the enthusiast. With an Accessport in your hand you can view and datalog a lot of tuning parameters for yourself including air fuel ratios, boost, knock, charge air temperatures and those articles teach you how to interpret most of these. If you have questions or want us to perform datalog reviews get in touch – we offer these for every car we tune!

Enjoy the cars, tune them well, operate them wisely, and be familiar with these excellent machines, their weak and strong points.

More articles below:

Is your Ecoboost Tune on point? Here’s what to look for

 

 

Subaru WRX FA20 DIT Tuning – Initial Findings

We have been involved with tuning direct injection turbocharged performance engines for over a decade – so naturally it was time apply our knowledge to one of the most iconic sport compact vehicles on the road today: The Subaru WRX.

subaru-wrx-2018-stratified-2

Initial impressions with the car are that unlike some of its competitors it feels very much like a white canvas. There are no sound symposers, pops, burps or fancy torque vectoring differentials. The full time AWD system adds great traction and the low center of gravity of the drivetrain along with suspension tuning make the car feel very stable. A good sign when you plan on adding power.

subaru-wrx-stratified

Out of the box, it is not impressively fast or punchy. This white canvas feel to the car (a bit of a throwback) is excellent in the sense that it gives the enthusiast a lot to build on an individualize. Our plan is to do just that – build on the character of the car and add enjoyment to the driving experience.

Our first modification (after 160 miles of ownership) was a COBB Accessport. This is the tool of choice for the other platforms we calibrate and it is very well featured on the Subaru platform.

subaru-wrx-cobb-accessport-tuned

We dug right in and built our calibration on the otherwise bone stock 2018 WRX. Below you will see a power comparison between Stock, COBB Stg1 91, and the Stratified tune on the same 91 octane fuel.

subaru-wrx-dyno-stratified-vs-cobb-vs-stock

The interesting thing is that stock (as well as with the COBB tune) the car ran so rich that it actually hesitated under wide open throttle operation. The OEM MAF calibration was around 10% rich using our ethanol free fuel. This is something to keep in mind if your fuel has low ethanol content and if you feel hesitations during acceleration – even stock. Leaning the curve slightly as well as adjusting the MAF and utilizing the wideband O2 under WOT are effective ways we used to address these issues.

You can see that the COBB OTS tune is quite conservative picking up power in the midrange with mild boost increases over stock.

Aside from running a leaner (yet still very much safe) air-fuel ratio which improved driveability and response, we found that even on 91 fuel we were able to add repeatable performance and improve response over the COBB OTS Tune. We did this by increasing boost, adjusting timing, refining boost control, and tuning variable valve timing.

Fuel quality plays a large role in limiting performance beyond this point. We will be working with ethanol shortly as well as adding parts to the vehicle. Stay tuned as we continue the journey with the Subaru DIT and provide custom tuning support for the FA20DIT engine.

The Stratified Team