Recommendations

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Tuning since 2012

2004-2020 STI

The first thing I always have my customers by for an STI or EJ related platform AFR gauge. If you care about your motor, you’ll pay attention AFR well get more into that below, though the Sti comes with a factory AFR gauge it is inaccurate over a few psi boost due to exhaust pressure rising in the sensor, not being calibrated for high-pressure of the headers. It reads accurately in vacuum, but in boost it’s numbers are not to be trusted. Second, you will need a air oil separator to remove excess pressure from the crank case as the OEM STI rises over five psi in the crank case when adding power or more boost this five psi, crank case pressure rises. You need to evacuate the pressure and that is exactly what their oil separator does as well as keep oil from entering your intake. Oil will lower the octane of your fuel and cause knock. if you wish to keep the factory downpipe, an external wastegate will be very beneficial. A downpipe will increase flow from the turbo letting exhaust pressure out. And allowing more air to enter the engine. This will achieve a quicker spool with more torque. Once you have a good air, oil, separator and AFR gauge an upgraded fuel system with a flex kit would be next best mod for power this will also require a AEM 340 fuel pump or larger, this is also suggested with any mods. A intake is helpful but not necessary until over 400whp the stock turbo will not max out the stock intake.

if you want more than the basic build I would suggest a BCP X500 + or X500R because they both up to a factory car with no other modifications, and clear, the OEM Tgv’s, unlike most other aftermarket turbo’s. The R is capable of over 500whp and the + will get you to it. For these turbos, you will need to either injector dynamics 1300 cc or 1700 cc injectors. A dual fuel pump hanger is recommended but not required. The x500 turbos can outflow a single Aem 340 fuel pump. You can use stock fuel rails though upgrading is not a bad idea. At this point, you will need an intake and either a upgraded top mount intercooler or a front mount intercooler as well as a fuel pressure regulator because the OEM Sti regulator for 2008 and up is not suitable for larger injectors you may have heard of the Sti stumble, and it is referring to the fuel Pulse that goes through the fuel lines Due to the design of the OEM regulator.

08+ STI/WRX EJ25 Stumble

When upgrading intake, downpipe, injectors or turbo you will likely notice a hesitation between 2-3k Rpm's, this is referred to as the 08+ stumble. the cause for this is the oem fuel pressure regulator. The fuel injectors opening and closing creates a pulse or turbulence in the fuel that causes fuel to stall in the fuel lines, so when the injector opens there's a momentary hesitation, this is fixed but a upgraded fuel pressure regulator and is suggested on all 08+ ej

Air Fuel Ratios

AFR are important to engine health

Learning these values can save your engine one day

AFR main purpose is thermal efficiency as you will generally make withing 10% of power from 14.7 to 10.2, the richer the afr the higher cooling effects, however running too rich can raise EGT. For most turbo cars on pump gas the target at full boost is around 11.7 to 10.8, anything past 12.6 is considered over fueling and turbo cars require over fueling in boost to keep the cylinder from overheating causing per-ignition and detonation.

The most important thing to remember is that at full boost you should see an AFR near 11.7 or lower depending on fuel, higher AFR at full boost can cause damage. 91-93 pump gas 11.0 at full boost is prefered

Air Fuel Ratio, or AFR is referring to the amount of unburnt fuel in the exhaust. A complete burn is called Stoichiometric, for pump gas this is 14.7 or 1.0 Lambda. You will see this AFR at idle cruise and low loads. Since most cars use a pump gas conversion no matter what the fuel if reading in afr it will display a value of stoichiometric as 14.7 and full power afr between 12-10.8.

Overrun Fuel Cut Off

Upon decelerating the ECU will turn off the fuel injectors or reduce the duty cycle to 0%. This results in pure oxygen passing through the engine and you will see AFR values of 18-22+ until the rpm where fueling is restored this is normal and for fuel efficiency.

Fuels like Ethanol or E85 have a greater cooling effect and prefer a leaner afr, near 12:1 Gasoline AFR conversion, or .82 Lambda. At 85% Ethanol or Alcohol using the Alcohol conversion that's a AFR of 8:1 or a stoich of 9.7:1 this large quantity of fuel is in part why ethanol can run leaner as well as a lower in cylinder and exhaust gas temperature.

2015+ WRX Fa20Dit

For a Fa20Dit WRX I suggest the following:
Ethanol! These cars respond extremely well to E50 or a fuel mixture of 50% ethanol and 50% pump gas. A Flex-Fuel kit, or E50 Tune on average will make 50-100 horsepower more! That means a stock 2015+ WRX on E50 can make a

320+whp or as much power as a full bolt on WRX, or STI on pump gas, with only a Tune, Flex-Fuel kit, and/or AEM 340 fuel pump. A in tank fuel pump is the only required part to run ethanol, a HPFP will allow for slight more power but will not make any more on its own. I suggest a Catted J Pipe & TMIC or FMIC will help with intake temps.

Pure E85 will not work due to the design of direct injection. With direct injection you only have a small window of time to fuel. the only time DI systems can fuel is between the time the intake valve closes and the spark plug fires during the compression stroke, if you are using E85 the car requires 43% more fuel than pump gas. This ends up taking so long to spray the required amount of fuel that you end up spraying fuel while the spark plug Is firing, this ends up not giving the required fuel needed for a safe controlled combustion, since it’s not running out of fuel in the same way a port injection car will, it not rise in afr as the car is leaning out, it will simply breakup, buck and misfire, this is dangerous and the only way to run full e85 is with port injection or methanol injection, m5 is a great power adder

With Ecutek multiple maps are can be chosen on the fly via cruise controller

Rolling anti lag

boost off the line launch control with true anti lag

Don't forget to get a walnut blast every 30K miles

Do not remove any emissions related devices. I will not tune catless vehicles, or delete emissions related ecu fault codes.

GT86/GR86

The GT86 is a great chassis, unfortunately it feels very sluggish from the factory. The best and most noticeable mod for the non turbo Fa20dit is once again Ethanol! You will notice a night and day difference. A Flex-Fuel kit or E85 and E50 Map settings programed via the cruise controller stalk will be the most noticeable difference besides going forced induction. A full bolt on GT86 will make the similar power to a Bone stock GT86 on E85

For the GT86 only a tune is needed to run E85 the stock fuel system has more than enough to run E85+ but a E85 safe pump is never a bad idea

With EcuTek's Race Rom features from PROecu

Multiple maps can be programmed into one tune

1 to 4 Maps can be selected via the cruise controller.

This can be done with the engine running .

To convert to E85 or E54 from Pump gas, simply run your gas tank empty or until at least the low gas light comes on, then fill the tank with completely with E85 or E54. Once full start the car let it run for a moment until you hear the idle change, then pull the cruise stalk towards you, and select the map mode for E85 or E54. If you DO NOT have a flex fuel sensor you can still run E85 or E54 but you will need to test the fuel to verify the mixtures before you fill. If you have a preferred station and no flex sensor, your car can be tuned for that mixture of Ethanol specifically.

TURBO SUPERCHARGER

When boosting a GT86 its import to get a good tune, these cars are designed without a turbo in mind. Since the GT86 uses a direct and port injection system designed for only vacuum, and having no boost reference will not add the required fuel for boost. To correctly increase fueling you need a larger than oem Map sensor the go to for the 86 platform is the omni 3 bar

A catch can is important to keep oil from ent the intake manifold and going through the combustion chamber, this is a must on all turbo cars that see abuse

If you get larger injectors, though most kits do not require them you will it is suggested to go with 700cc vs 1050+ as larger injectors do not flow well as low loads and idle, the ratio between DI and Port is generally under 50%

Why boost leaks are bad

Boost leaks can happen to anyone, but not a lot of people fully understand what’s going on. Yes, you lose boost but if you have a high Flowing turbo you may still hit the same psi, but your turbo is going to work harder now in order for that to happen you have to have more exhaust gas pressure so by having a boost leak this raises exhaust manifold, pressure racing exhaust gas manifold pressure can push more back pressure. This will cause More blow by or higher crank case press than normal leading to more stress on your engine.