From the launch of the original MX-5 in 1989, Mazda’s biggest-selling sports car has delivered the right balance between power and weight. It’s never been a car that chased outright performance at the expense of affordability and handling balance. Through all four-generations, the MX-5’s engines have complimented the chassis with a positive throttle response and an eager to rev character.
Thanks to bespoke versions of Mazda’s petrol Skyactiv-G powertrains, these winning ingredients are more clearly displayed than ever before. Customers in the UK can choose between two proven normally aspirated direct-injection engines – the 1.5-litre Skyactiv-G or the 2.0-litre Skyactiv-G, both mated to Mazda’s crisp shifting Skyactiv-MT six-speed manual gearbox, which has been adapted for the MX-5’s classic front mid-engine, rear-wheel drive layout. As before, exclusive to the RF there’s also the option for the 2.0-litre car to be mated to a six-speed automatic.
Significant powertrain improvements and the fact that both engines are homologated according to the requirements of WLTP test cycle to achieve Euro Stage6d emission compliance, means that more than ever the MX-5 perfectly balances performance, sporting character and efficiency. The 1.5-litre Skyactiv-G engine achieves 44.8mpg on a WLTP Combined cycle and the higher-powered 2.0-litre Skyactiv-G engine with manual with manual transmission delivers 40.9mpg on a WLTP Combined cycle.
Most of the components of the smaller 1.5-litre Skyactiv-G were modified for the MX-5’s requirements of increased output, reduced weight and improved packaging. To ensure the 1.5-litre engine delivers the precise and immediate throttle response expected by sports car owners, Mazda’s engineers changed the cam timing and rotating parts to raise the redline, adding a custom steel crankshaft to support the revised engine’s higher and free-revving nature. With a 132ps output - compared with a 120ps maximum output in the last-generation Mazda3 - the MX-5 version of the 1.5-litre Skyactiv-G also has more power. Even better, the redline remains at 7,500rpm, while torque increased from 150 to 152Nm.
However, it’s the 2.0-litre Skyactiv-G that had the biggest upgrade, compared to its launch configuration in 2015. The more powerful, high revving, acoustically tuned version of this engine has seen improvements to every aspect of Mazda’s Skyactiv engine technology. Maximum engine speed has been raised from 6,800rpm to 7,500rpm, while horsepower has increased from 160 to 184ps with torque going up from 200 to 205Nm at 4,000rpm.
The result is 0-62mph performance has improved by 0.6 of a second to 6.8 seconds with the manual gearbox, while the automatic is 7.9seconds. In addition, tuning of the main silencer delivers a cleaner more powerful engine note. Even better, thanks to Mazda’s i-ELOOP kinetic recovery and i-stop stop-start technology on 2.0-litre models, the 184ps version has lower CO2 than the outgoing 160ps car.
Comprehensive improvements to the 2.0-litre Skyactiv-G see the response time of the intake valve and throttle shortened to improve engine the initial engine reaction to accelerator pedal application. Air flow has been improved with larger throttle and air intake ports, while exhaust gas losses were reduced by a high-lift exhaust camshaft and lighter exhaust valves – overall there has been a 30 per cent reduction in pumping loss.
In line with Mazda’s Gram Strategy of efficiency and performance through lightness, the 2.0-litre Skyactiv-G continues to benefit from reduced internal mass and friction. Compared with previous generations, piston weight has reduced by 27grams, the connecting-rod is 41grams lighter and low-tension asymmetrical barrel piston rings and optimally distributed crankshaft counterbalance weights all considerably reduce weight and friction. Combustion has also been improved with lower air intake temperatures, while high-diffusion atomisation injectors increase torque and power by expanding fuel vaporisation.
The importance of the engines aural performance hasn’t been ignored either, as the low-inertia, dual-mass flywheel combines with the sharper engine responsiveness to deliver a crisper engine note, while the main silencer has been tuned to deliver a more muscular and linear sound throughout the rev range.
Both the engines in the 2021 Mazda MX-5 feature attractive die-cast aluminium head covers that are reminiscent of the original MX-5 and weigh the same as a plastic cover. Another example of the all-encompassing focus of Mazda’s engineers is the small and light radiator, which features air ducts and flaps to regulate air pressure from the fan to enhance cooling efficiency. And as one of several measures to optimise weight distribution within the engine compartment, the radiator remains to be positioned close to the car’s centre of gravity. In addition, Mazda’s 4-2-1 exhaust manifold is a Skyactiv mainstay feature that has been redesigned for the MX-5’s rear-wheel-drive layout and tuned to deliver a pleasing exhaust note, at the same time as maintaining its core efficiency benefits.
The Mazda MX-5 also enjoys the perfect transmission – the much celebrated Skyactiv-MT six-speed manual. When experienced in other Mazda models this gearbox has won praise from customers and journalists alike for its ‘MX-5 like’ shifting action. Now thanks to a version of the Skyactiv-MT unit specially developed for the MX-5, things have come full circle. Modified to take into account the MX-5’s front mid-engine, rear drive layout, changes include a simplified linkage to reduce sliding resistance in the gearbox without undermining the crisp shift action. The end result is the same 40mm shift stroke action common to the MX-5 since day one and a smooth, slick and light gear change that seems to draw the lever into the right position. Even better, the Skyactiv-MT is 7kg lighter than the six-speed gearbox in the outgoing third-generation MX-5.
Other transmission highlights include a direct-drive sixth gear that lowers the final gear ratio to raise real-world fuel economy by reducing resistance. The 2.0-litre Mazda MX-5 also has an ultra-compact limited-slip differential. Mazda MX-5 RF’s fitted with the six-speed automatic gearbox benefit from improved shift timing. With bespoke engines and a tailored transmission, the Mazda MX-5 continues to use Mazda’s award-winning Skyactiv technology to deliver a benchmark sports car drivetrain that stays true to the MX-5’s mechanical heritage.