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.

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

• 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.

• 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.

• 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