Engine

Inside Mazda

October 7, 2016

All‑new CX‑9 features new SKYACTIV‑G 2.5 L, Direct‑injection, Turbo‑charged Engine.

As far as Mazda’s concerned, All-new means All‑new. And the new three-row, mid-sized crossover SUV designed with North American needs in mind – Mazda’s CX‑9– received a new power plant to accompany its multiple, next-generation provision of advanced features.

As far as Mazda’s concerned, All-new means All-new. And the new three-row, mid-sized crossover SUV designed with North American needs in mind – Mazda’s CX-9 – received a new power plant to accompany its multiple, next-generation provision of advanced features. The All-new SKYACTIV-G 2.5 T engine provides impressive low to mid-range torque against a backdrop of real-world fuel economy. This 2.5 L, direct-injection, turbo-charged gasoline engine reflects the same SKYACTIV Technology which has given birth to a new breed of driver-friendly amenities which combine the need for dynamic performance together with responsible fuel economy. A distant cousin to the naturally-aspirated SKYACTIV-G 2.5, first featured in the Mazda6, the SKYACTIV-G 2.5 T represents the first turbo-charged unit of its kind, providing excellent response devoid of turbo lag, together with linear and powerful acceleration in the low to mid-range where CX-9 drivers spend the majority of their time.1,2

This new engine provides maximum torque of 310 ft-lb, comparing favourably with a naturally-aspirated 4L gas engine.

Traditionally, turbo-charged engines have under-performed in overall dynamic performance at low rpm ranges, including turbo lag and disappointing real-world fuel economy. This new SKYACTIV-G 2.5 T overcomes these shortcomings with its Dynamic Pressure Turbo – a world-first design that varies the degree of exhaust pulsation depending upon engine speed plus a cooled exhaust recirculation system (EGR) that allows the engine to maintain the ideal air-fuel ratio (λ=1) over a wider range of engine output.3

Mazda’s successful evolution of its SKYACTIV engines provides maximum driving pleasure and outstanding environmental performance through arriving at ideal levels of combustion for both demands.

SKYACTIV-G 2.5 T Features:

High compression ratio
Mazda engineers have achieved a compression ratio of 10.5:1 – one of the highest ever for any turbocharged engine with an 89-mm bore size that runs on regular gasoline.4

Dynamic Pressure Turbo
SKYACTIV-G 2.5 T is the world's first turbo-charged engine with the ability to change the degree of exhaust pulsation depending on engine speed. At low rpms (below 1,620 rpm), the volume of the exhaust ports is reduced by closing a series of valves located just ahead of the turbine that drives the turbo-charger. This reduces interference between exhaust pulses while maximizing the energy of each pulse, obtaining a high turbine driving force. At higher rpms, there is sufficient energy in the exhaust flow and the valves open, allowing the turbine to be driven by a steady flow of exhaust gases as in a traditional turbo-charger. Whereas existing variable turbo-chargers adjust the speed or direction of exhaust gas flowing into the turbine, Dynamic Pressure Turbo is a unique technology that varies the degree of exhaust pulsation.

Cooled Exhaust Gas Recirculation (EGR)
This system takes some of the inert exhaust gas that results from the combustion process and reduces its temperature by passing it through a cooler before introducing it back into the engine's air intake. This lowers the temperature of combustion in the engine, preventing knocking while expanding the range in which the engine can maintain an ideal air-fuel ratio, reducing the need to retard ignition timing.

Inherits SKYACTIV-G principals of efficient combustion
SKYACTIV-G 2.5 T is based on the naturally aspirated SKYACTIV-G 2.5 and features the same bore, stroke and bore pitch. Parts of the fuel system, such as the fuel pump and fuel injection system are also shared, helping SKYACTIV-G 2.5 T to achieve the highly efficient combustion for which SKYACTIV-G engines are known.

SKYACTIV-G 2.5 T Specifications (Based on in-house measurements)
• Inline 4-cylinder 2.5-L direct-injection, turbo-charged gasoline engine
• Displacement: 2488 cc
• Bore x Stoke: 89.0mm x 100.0 mm
• Compression Ratio: 10.5:1
• Maximum Output (net): 227HP (169kW) /5,000rpm5
• Maximum torque (net): 310ft-lb (420Nm) /2,000rpm

  • Legal
    • 1 A delay in acceleration response common in turbocharged engines due to the time required for the compressor to take effect.

      2 Below 3000 rpm. Based on Mazda's in-house investigations.

      3 The ratio of air to fuel that provides exactly enough oxygen to burn all of the fuel present. For gasoline the ratio is 14.7:1.

      4 As of November 2015. Based on Mazda's in-house investigation.

      5 When using AKI 87 regular gasoline. Maximum output with AKI 93 premium gasoline is 250HP (186kW) /5,000rpm.