The all-new 2024 CX-90 has made its debut and showcases the brand’s first new front-engine rear-drive biased chassis architecture in decades. Under the hood are also a number of buzz worthy new powertrains, a pair of inline turbocharged sixes paired with a mild hybrid system and a turbocharged four-cylinder plug-in hybrid.
Our CX-90 Turbo S tester featured the top dog 3.3-liter turbocharged inline six with 340 horsepower and 369 pound feet of torque when it’s running on premium unleaded. It can run on regular unleaded fuel but horsepower drops to 319.
Getting to actually see it and the engine bay’s vital organs requires the removal of multiple layers of cover panels. Once free and clear we can see this new gem. The inline six is the first from the brand and we’re told their most powerful production engine ever. It’s mated to an 8-speed automatic transmission that features a powerful electric motor between in and the engine. In lieu of a torque converter, a set of electronically controlled clutches manage all of the power transfer.
The hybrid battery itself is located under the vehicle specifically under the area of the driver seat. The power converter and control unit for the hybrid system is mounted next to and on top of the automatic transmission. Thus, all of the 48V wiring is packaged away from the engine compartment.
While not a full hybrid like most, this system provides boost power to the engine at slow speeds and facilitates a smoother start up with the idle start stop system. It can also provide regenerative braking to recharge the battery as you go.
The engine itself features most of the latest technological features we expect, dual overhead cams with variable timing, 4-valves per cylinder and direct fuel injection. Being an inline six inherently brings a higher level of refinement and internal balanced physics than a V6 engine and thus is much smoother and has a much more pleasurable sound.
Following the airflow, the intake charge begins at the front of the engine bay and travels into the air filter box mounted at the driver side. It then travels through an intake tube around the back of the engine and into the turbocharger.
From there it travels up and over the engine to the driver side and through an air-to-water inter-cooler and a composite plastic intake plenum. From there it makes its way into the cylinders. On top of the engine you can see most of the spark plug coil packs but the rear most is obscured.
Spent combustion gases then exit into the turbocharger which mounts direct to the head with an integral exhaust manifold. It has an electronically controlled waste-gate and the main catalyst is mounted directly to it – hence all of the heat shielding. You can also notice it features a cooled EGR loop system at the driver side, always note this will be hot after the engine has been running.
When it comes to servicing the engine you will need to remove a number of the engine’s covers and access panels to reach all of its fluids. The engine oil filler cap and dipstick can be found at the top of the engine.
The main coolant reservoir is located at the front passenger side over the wheel well, next to it is the windshield washer fluid noted by the blue cap. The air filter is mounted at the front driver side of the engine compartment and can be easily replaced without tools.
The main 12-volt battery is mounted at the passenger side firewall, seen and accessed with the cover removed. On the opposite side you will also need to remove the access cover to get to the brake fluid reservoir which sits on an electronically controlled brake motor unit.
Looking around the engine compartment, a few items of note. The Mazda CX-90 uses cast aluminum shock towers for extra strength and light weighting. They are braced to the firewall bulkhead with substantial steel outriggers. Looking ahead to the front, you can see the electric cooling fan. Always keep hands clear even when engine is turned off.