Toyota GR Yaris Stage 2 by 4motors – LSD, power, and dropping lap times

Power: Now it really moves

Stock output around 260 HP in a lightweight chassis does the job, but to increase performance, we need to give the engine some boost. Before we turn up the pressure, however, we need to take care of breathing and thermals.

• Exhaust and cooling: The foundation is a more efficient intercooler. In the exhaust system, we remove the "ecology" (catalytic converter and GPF). You can opt for just a decat/GPF delete, a dedicated off-the-shelf system, or a custom exhaust welded by us.
• Engine internals: Gen 1 vs Gen 2: In Gen 1 Yaris (pre-facelift), upgrading to stiffer valve springs is necessary at higher power levels. While doing this, it would be a sin not to throw in aggressive Kelford Type A camshafts. In Gen 2 models, the factory has already improved the springs, so you save on this cost.
• EcuTek Tuning: The real magic happens in the software. On stock cams, we achieve a stable 340-350 HP. With Kelford cams, we break the 350-365 HP barrier. Furthermore, EcuTek unlocks purely competitive features: Launch Control (a crucial time-saver off the line), Flat Shift (shifting gears without lifting the throttle), and the ability to switch between 4 different maps on the fly.

Suspension: Scalpel-like precision

In Stage 1, we did the baseline geometry, but at higher speeds and grip levels, we need absolute rigidity and better angles in the rear.

• Hardrace Uniballs: We throw out the stock rubber bushings in the front and rear control arms, replacing them with uniballs. Rubber will always flex and give way in corners. A uniball provides instant, precise feedback from the tire straight to the steering wheel.
• Adjustable rear control arms: What we didn't do in Stage 1, we fix here. We install fully adjustable rear control arms, which finally allow us to set the perfect camber on the rear axle tailored to a specific track.

Traction: A mechanical LSD is a gamechanger

The GR-Four drivetrain is brilliant, but for the car to turn in more aggressively, we need to support the electronics with hard mechanics.

• Cusco LSD: Installing a limited-slip differential is one of the most important mods for an advanced driver. We have three configurations to choose from:
  • 1-Way: locks only under acceleration.
  • 1.5-Way: works under acceleration, and locks more mildly under braking (the most popular choice for the track).
  • 2-Way: locks aggressively under both acceleration and braking.
• The result?: An LSD provides incomparably better control over the car using the throttle – both mid-corner and on exit. The car becomes pleasantly and predictably oversteery. It's much easier to flick the rear out and position the car before the apex.

Summary

The Stage 2 package turns the GR Yaris into a purebred weapon. You get a car capable of securing top spots in competitions and systematically improve on your personal bests. You get massive driving joy from a machine that reacts instantly to every movement of the steering wheel and throttle pedal. It's an uncompromising, street-legal rally car.