Toyota GR Yaris Stage 3 – How to build a 400 HP track beast

ECU and massive power: Time for bioethanol

At this stage, the stock engine ECU is no longer enough. We throw it out and install an advanced Standalone system (MoTeC or Syvecs). Optionally, we add a Flex Fuel kit, allowing you to run safely on bioethanol (E85).

However, the new ECU alone won't conjure power out of thin air – we need to upgrade the hardware:

• Cams and springs: If they weren't installed earlier, we fit stiffer valve springs and throw in highly aggressive Kelford Type B camshafts.
• The result?: On E85 fuel with this spec, we can easily approach the 400 HP mark.
• The magic of Standalone: Power isn't everything. A professional ECU unlocks aggressive and precise differential control. Additionally, we gain a proper, motorsport-grade Launch Control and an Anti-Lag System (ALS) that brutally maintains boost pressure.

Suspension without compromises

Since the car accelerates like a rocket, it must also stick to the tarmac perfectly. Stock or slightly lowered suspension will simply give up here.

• Top-tier suspension: We change the entire setup. From the more reasonable (but still brilliant) options, we recommend KW V4 or Öhlins Road & Track. If the budget allows going all out, we aim for the highest motorsport tier: Intrax or Reiger.
• Top Mounts: While upgrading the suspension, we install motorsport top mounts. They allow for an increased caster angle, which drastically improves stability and steering precision.

Eliminating potential problems

With 400 HP and hard track driving, the Yaris's factory weaknesses start to show. We need to take care of the thermals and drivetrain durability.

• Bulletproof transfer case: The factory transfer gear will be massively overloaded at this power level (especially during Launch Control starts). This is the moment you absolutely need to install our heavy-duty transfer gear set.
• Stiffer gearbox mount: We replace it to improve shifter precision and eliminate unwanted movement of the entire drivetrain.
• Oil cooler: Track temperatures rise in a flash. Our favorite for effectively dropping oil temps is the kit from Forge.
• Closed Air Intake: A closed intake system generally doesn't add horsepower on its own, but in track conditions, it's invaluable – it significantly lowers intake air temperatures.
• Motorsport brake pads: It's worth considering harder compounds, like Ferodo DS UNO, top-tier Endless, or going for totally aggressive and uncompromising CL RC6. With these brakes, you can confidently delay your braking points.

Sequential gearbox

If the budget allows, Stage 3 is the perfect time to finally consider a sequential gearbox (e.g., XShift). It's an element that radically changes the character of the whole car. Shifting gears becomes brutal, mechanical, and lightning-fast, and the car sounds and behaves like a purebred WRC rally car.

Summary

Stage 3 from 4motors is a package for those who take no prisoners on the track. It’s an investment that turns a great hot hatch into a ruthless, competition-winning tool. You get massive power, brilliant traction, and a bulletproof drivetrain that will handle any road.