Ford Focus ST250 Induction Kits & Intake Upgrades

Ford Focus ST250 Induction Kit Buying Guide

What is the best induction kit for a Focus ST250?

For most Focus ST250 owners, our best all-round recommendation is the AIRTEC Stage 2 induction kit .

It offers the best balance of price, construction quality, airflow, induction noise and suitability for future modifications. It can be used on a standard car, Stage 1, Stage 2 or hybrid-turbo build without needing to replace it again as the car progresses.

In real-world use, the main differences between the full intake kits are appearance, sound, price and construction rather than a dramatic difference in power.

Is the AIRTEC Stage 2 induction kit the best-value option?

Yes. The AIRTEC Stage 2 intake is our preferred option for customers who want a complete intake system without paying extra purely for larger-diameter pipework or engine-bay appearance.

It replaces the restrictive factory airbox and intake pipework through to the turbo, producing significantly more induction and turbocharger noise.

It provides everything required for standard-turbo Stage 1 and Stage 2 cars, while retaining enough airflow capacity for the majority of hybrid-turbo builds.

What is different about the WP-R 3.5-inch induction kit?

The Wayside Performance WP-R 3.5-inch induction kit is the premium option in the range.

Its oversized 3.5-inch pipework creates a much more substantial appearance in the engine bay. The system is hand TIG welded, providing excellent fabrication quality and a high-end finish.

The kit replaces the intake tract all the way from the air filter to the turbocharger. The larger pipework also resonates the turbo and induction sounds more strongly, making it particularly suitable for owners who want maximum noise and visual impact.

The important point is that the 3.5-inch diameter does not produce a noticeable improvement in power or throttle response compared with the other well-designed full intake kits.

Choose the WP-R kit for its fabrication, appearance and sound rather than expecting a substantial power advantage over the AIRTEC, Forge or Wisbech systems.

Is the WP-R intake suitable for standard and tuned cars?

Yes. The WP-R kit can be fitted to standard, Stage 1, Stage 2 and hybrid-turbo cars.

It is not necessary to wait until the car has an upgraded turbo. However, on a standard-turbo car, the purchase decision will normally be based on its appearance, construction and induction sound rather than a requirement for additional airflow.

How do the Forge induction kits compare?

The Forge Motorsport systems offer excellent build quality and similar real-world performance to the AIRTEC intake.

There are two separate versions because Ford changed the induction sensor arrangement during production:

• Forge induction kit for pre-2015 cars with the earlier bolt-on induction sensor.
• Forge induction kit for 2015-on cars with the later twist-type induction sensor.

Check the sensor fitted beside the original airbox before ordering. Do not rely solely on the registration year, as cars registered close to a production change can sometimes differ from what is expected.

Is the Wisbech Engineering intake a good option?

The Wisbech Engineering induction kit is another complete intake option offering strong airflow, increased turbo noise and suitable capacity for standard and modified cars.

Its real-world performance is similar to the other complete systems. The decision between Wisbech, AIRTEC and Forge will normally come down to price, availability, appearance and the customer's preferred manufacturer.

Is the Genuine Ford Focus RS airbox a performance upgrade?

Yes. The Genuine Ford Focus RS airbox is a useful upgrade for Focus ST250 owners who want improved airflow without the volume of an open-cone intake.

It retains an OEM appearance and is considerably quieter than the complete open-filter systems, although it still provides slightly more induction and turbo noise than the standard ST250 airbox.

Pairing the RS airbox with a suitable performance panel filter creates a strong road-car setup for owners who prefer a subtle, factory-style installation.

Which intake is best for Stage 1, Stage 2 or a hybrid turbo?

All of the complete intake kits in this collection provide sufficient airflow for standard, Stage 1, Stage 2 and typical hybrid-turbo ST250 builds.

• Standard car: Genuine Ford RS airbox for a quieter OEM-style result, or AIRTEC Stage 2 for maximum induction sound and future upgrade potential.
• Stage 1: AIRTEC, Forge, Wisbech or WP-R. Choose according to budget, appearance and sound.
• Stage 2: AIRTEC Stage 2 remains our best-value recommendation, although all complete systems perform similarly.
• Hybrid turbo: Any of the complete intake systems can be used. The WP-R provides the most imposing engine-bay appearance, but its larger diameter does not automatically produce more power.

How much power does an induction kit add?

On a tuned Focus ST250, a complete intake system will typically contribute approximately 5–10 bhp compared with the standard intake.

The exact result varies between cars and depends on the ECU calibration, turbocharger, intercooler, exhaust system and existing condition of the vehicle.

An intake should therefore be viewed as one supporting part of a complete tuning package rather than a standalone modification guaranteed to produce an exact figure.

Is a remap required after fitting an intake?

No. A remap is not normally required simply to fit one of these intake systems, provided the correct kit and induction sensor arrangement are used.

The vehicle can be driven safely with the intake fitted before tuning. However, an ECU calibration is recommended to obtain the greatest performance benefit from the improved airflow, particularly when the intake is combined with an intercooler, exhaust or other Stage 2 modifications.

How much extra noise will an open-cone intake produce?

Open-cone systems produce a substantial increase in turbocharger, airflow and recirculation noise.

The turbo can be heard spooling more clearly under acceleration, followed by more noticeable airflow and recirculation sounds when the throttle closes.

The WP-R 3.5-inch pipework resonates these sounds particularly strongly. Customers wanting a quieter result should choose the Genuine Ford RS airbox and a panel filter.

Do open-cone intakes suffer from heat soak?

In our dyno testing, these intake systems have completed repeated back-to-back runs without a noticeable performance reduction caused by the open-cone filter or intake air temperature.

When performance begins to fall during repeated runs, the intercooler and charge-air temperature are normally the limiting factors rather than the induction kit.

A suitable upgraded intercooler is therefore more important for maintaining consistent power on a Stage 2 or hard-driven ST250.

Is the standard crossover pipe restrictive?

The original crossover pipe is not severely restrictive, but its shape narrows and flattens slightly across the top of the engine.

Replacing the complete intake tract removes this compromise and ensures the system has consistent pipework from the filter through to the turbocharger.

For this reason, we generally recommend buying a complete intake system rather than changing only the filter or airbox when maximum performance and induction noise are the priority.

Are the induction kits difficult to install?

AIRTEC, Forge and Wisbech induction kits are straightforward DIY installations for someone with basic mechanical knowledge and suitable tools.

The WP-R 3.5-inch system is also designed as a direct-fit kit, although its larger pipework makes the engine bay considerably tighter. Allow additional time to position the pipes, hoses and clamps correctly without creating contact with nearby components.

Before completing the installation:

• Confirm that the correct induction-sensor version has been supplied.
• Make sure the sensor is fitted in the correct orientation.
• Check that every silicone hose is fully seated.
• Tighten all hose clamps evenly.
• Ensure the pipework cannot rub against the engine, bodywork or wiring.
• Recheck the installation after the first few heat cycles.

Do the filters require maintenance?

Inspect and clean the air filter approximately every one to two years, depending on mileage, weather conditions and how dirty the filter becomes.

Cars regularly driven on dusty roads may require more frequent inspection. Always use the cleaning method specified by the filter manufacturer, as some filters are designed to run dry while others require a specific filter treatment.

Do not apply universal filter oil or cleaning chemicals unless the instructions for that exact filter specify them.