MK8 Fiesta ST Tuning Guide | Stage 1 & 2 | 1.5 EcoBoost | Wayside Performance
The MK8 Fiesta ST moved from the MK7's 1.6-litre four-cylinder to a smaller 1.5-litre three-cylinder EcoBoost engine.
On paper it sounds like a downgrade, but in practice it's anything but — the 1.5 three-pot is a brilliant engine that responds incredibly well to tuning and actually makes more power than the MK7 did from the factory.
The big talking point with the MK8 is the GPF (Gasoline Particulate Filter).
This is fitted to all MK8 STs as part of Euro 6 emissions compliance and sits in the exhaust system after the catalytic converter. It's the main reason the MK8 sounds so muted compared to the MK7.
However, from a power perspective, the GPF is actually far less restrictive than most people think — Revo's own extensive dyno testing showed less than a 4% difference in peak power with the GPF removed, and only through a limited part of the rev range. We have also done extensive GPF testing on other models and had similar results.
The bigger restriction on this exhaust is actually in the manifold and turbine housing design.
So while some owners choose to remove the GPF for sound reasons, it's not something you need to do for performance — and it's worth knowing that GPF removal is not road-legal and will cause an MOT failure.
We've tuned a large number of MK8 Fiesta STs on our in-house 4WD DynoDynamics rolling road here in Coventry and know these engines well.
This guide walks you through every stage, the parts you need, the power you can realistically expect, and the things to watch out for along the way.
All power figures in this guide are based on real results from our own dyno — not manufacturer claims. For optimal results, 99 RON fuel is required.
Stock Where you're starting from
Ford rates the MK8 Fiesta ST at 200hp, and on our dyno that's exactly what we see from healthy standard cars.
The 1.5 three-cylinder is actually a characterful little engine with a surprisingly punchy low-end and a willingness to rev that makes it great fun in standard form. But there's a lot more to come.
Stage 1 — Remap Only The best place to start
A Stage 1 remap is the single best modification you can do to a MK8 Fiesta ST. With no hardware changes at all, a custom remap on our rolling road will take the car from 200hp to 240–250hp with 255–265ft/lb of torque. That's a serious jump from a software-only change, and it completely transforms the way the car drives — the mid-range pull is noticeably stronger and the throttle response is much sharper.
No hardware modifications are required for Stage 1, but the car does benefit from a performance intake kit at this stage.
It won't add huge numbers on its own, but it gives the turbo a bit more to work with and improves throttle response. You also get a much more satisfying induction sound, which is a big part of the appeal on these cars.
Stage 2 — Intake + Exhaust + Intercooler Maxing out the stock turbo
Stage 2 is where we push the stock turbo to its limit with bolt-on hardware modifications and a custom tune to match.
The combination of an uprated intercooler, performance intake, and a less restrictive exhaust gives the engine everything it needs to breathe properly and the results on the dyno speak for themselves.
For the exhaust, a sports cat downpipe is our primary recommendation — it replaces the restrictive standard catalytic converter with a higher-flow unit, improving exhaust gas flow where it matters most (close to the turbo) while keeping the car road-legal and MOT-compliant. This is where the biggest gains come from on the exhaust side of things.
Some owners opt for a full 3" turbo-back exhaust which also removes the GPF — this does give you significant sound upgrade as well as slightly more power.
As mentioned above, the GPF itself isn't particularly restrictive on this engine, so the turbo-back is really for those who want the full exhaust experience. GPF removal is not road-legal and is sold for motorsport / off-road use only.
The stock intercooler on the MK8 heat-soaks quickly, so an uprated front-mount intercooler is essential at this stage to keep intake temperatures consistent and repeatable.
- Performance intake kit
- Sports cat downpipe (turbo-back exhaust optional for sound)
- Uprated front-mount intercooler
- Custom Stage 2 dyno tune
The MK8 and MK8.5 use different exhaust valve motors, so Cobra Sport make separate turbo-back systems for each. Make sure you select the correct version for your car.
Supporting Modifications Reliability & chassis
Lower Torque Mount — The standard lower torque mount on the MK8 is a known weak point and can fail under increased power. An uprated torque mount reduces engine movement, sharpens throttle response, and protects against premature failure. Note that there are two different versions depending on your car's model year — make sure you select the correct one.
Oil Cooler Kit — The 1.5 EcoBoost can run hot under sustained hard use, and oil temperatures on track can climb quickly. An oil cooler kit keeps oil temps in check and is a worthwhile investment for anyone doing regular track days or spirited driving, especially once tuned.
Oil Catch Can — A catch can intercepts oil vapour from the PCV system before it reaches the intake, keeping the intake tract and intercooler cleaner over time. A good preventative modification on any direct-injection turbocharged engine.
Lowering Springs — A set of H&R lowering springs will tighten up the handling and give the car a much better stance. The 35mm drop reduces body roll and improves turn-in over the stock ride height, and helps the car put the extra power down more effectively.
Complete the Look Styling upgrades
Once the performance is sorted, it's worth finishing the car off with some styling upgrades to match. We stock a full range of splitters, side skirts, spoiler extensions, and diffusers for the MK8 Fiesta ST — all designed to give the car a more aggressive look without going over the top.
Browse all MK8 Fiesta ST Styling Parts →
Quick Reference Power by stage
| Stage | Mods Required | Power | Torque |
|---|---|---|---|
| Stock | None | ~200hp | — |
| Stage 1 | Remap only (intake recommended) | 240–250hp | 255–265ft/lb |
| Stage 2 | Intake + sports cat + intercooler + remap | 260–270hp | 280–300ft/lb |
All figures based on real dyno results at Wayside Performance, Coventry. Individual results may vary depending on the condition of the car, fuel quality, and ambient conditions. 99 RON fuel required.
Ready to Get Started?
Whether you're after a simple Stage 1 remap or planning a full Stage 2 build, we'd love to help. All of our tuning is completely custom and carried out on our in-house 4WD rolling road in Coventry — no generic off-the-shelf maps. Every car gets a before and after dyno printout.
Got questions? Drop us a message on the live chat or email us at Support@Wayside-Performance.co.uk
