Differential and transmission cooler kits

The SST gearbox is often cited as the Achilles' heel of the Mitsubishi Lancer Evo X, especially under hard driving on fast roads or track days. High transmission fluid temperatures can trigger failsafe mode, reducing performance and often bringing a session to a premature end.

Well-engineered off-the-shelf options were scarce, so HEL built a direct-fit SST transmission oil cooler kit intended to noticeably lift cooling capacity while keeping full OEM function.

Like HEL's other direct-fit cooling kits, the Evo X was 3D-scanned for accurate fitment and airflow management. Custom aluminium brackets were produced to swap out the OEM cooler mount, while still working with the factory air ducting, so airflow reaches where it's needed.

The kit centres on a Swedish-made Setrab Series 6 ProLine unit with a 25-row core, chosen to cope with sustained high-load use. Its larger core adds capacity and surface area, keeping transmission temperatures in check over extended driving while maintaining good flow.

HEL states it track-tested this setup with Evo specialists Auto Torque over full test days, without overheating or driveline issues, a result the standard cooler could not match.

The kit includes preassembled HEL braided hoses, anodised fittings in aluminium, and the hardware needed for fitting. It suits any SST-equipped Evo X driven hard on road or track, adding meaningful transmission oil cooling capacity.

Kit Contents

• Setrab Series 6 ProLine oil cooler, 25-row core, for the SST transmission

• Custom aluminium mounting brackets that keep the factory air ducting in place

• Preassembled HEL braided hoses fitted with anodised aluminium fittings

• CNC-machined fittings and adapters

• Mounting hardware in stainless steel

• Fitting instructions

During hard driving, including track days and some fast road use, the rear differential on a GR Yaris can run excessively hot. HEL developed this kit on its own test vehicle specifically to address that issue.

This kit fits pre-facelift GR Yaris models only. Facelift versions have an extra water tank fitted in the boot, home to the added oil pump, which changes compatibility.

When the differential oil reaches 82°C, an electric oil pump fitted in the boot switches on, circulating oil through a cooler mounted underneath the car to maximise airflow exposure.

A Setrab oil cooler, a design with a long motorsport track record, brings the differential oil down to a suitable operating temperature. Controlled cooling helps extend the working life of both the differential and its oil.

This kit also calls for roughly 450ml of extra oil, nearly double the standard fill, which lengthens the interval between differential services and assists with temperature control.

Fitting difficulty is rated 4.5 out of 5, so having an experienced specialist carry out installation is recommended.

Kit Contents

• High-flow electric oil pump (Marco)

• Custom HEL aluminium bracket for mounting the pump

• Setrab Series 1 ProLine oil cooler, 10-row core

• Custom HEL aluminium bracket for mounting the oil cooler

• HEL braided hoses, preassembled with anodised aluminium fittings, plus a high-temperature heat sleeve where needed

• Preassembled wiring harness including a fused relay

• Thermostat switch rated at 82°C (179.6°F)

• Complete mounting hardware, including aluminium hose separators and adapters

• Fitting instructions

During hard driving, including track days and some fast road use, the rear differential on a GR Yaris can run excessively hot. HEL developed this kit on its own test vehicle specifically to address that issue.

This kit is designed for Gen 2 GR Yaris models only, which come with an extra water tank fitted in the boot.

When the differential oil reaches 82°C, an electric oil pump fitted in the boot switches on, circulating oil through a cooler mounted underneath the car to maximise airflow exposure.

A Setrab oil cooler, a design with a long motorsport track record, brings the differential oil down to a suitable operating temperature. Controlled cooling helps extend the working life of both the differential and its oil.

This kit also calls for roughly 450ml of extra oil, nearly double the standard fill, which lengthens the interval between differential services and assists with temperature control.

Fitting difficulty is rated 4.5 out of 5, so having an experienced specialist carry out installation is recommended.

Kit Contents

• High-flow electric oil pump (Marco)

• Custom HEL aluminium bracket for mounting the pump

• Custom HEL aluminium bracket for relocating the water tank

• Water tank

• Setrab Series 1 ProLine oil cooler, 10-row core

• Custom HEL aluminium bracket for mounting the oil cooler

• HEL braided hoses, preassembled with anodised aluminium fittings, plus a high-temperature heat sleeve where needed

• Preassembled wiring harness including a fused relay

• Thermostat switch rated at 82°C (179.6°F)

• Complete mounting hardware, including aluminium hose separators and adapters

• Fitting instructions