Review: Mazda ND MX-5 RF (2017-on)

Overview

Commencing production in October 2016 and released in Australia in January 2017, the Mazda MX-5 RF (Retractable Fastback) was a two-seat convertible with a retractable hardtop roof. Manufactured at Mazda’s Ujina plant in Japan, the rear-wheel drive Mazda MX-5 RF was powered by a 2.0-litre four-cylinder petrol engine that was mated to either a six-speed manual or automatic transmission.

SkyActiv-G engine

For the Mazda MX-5 RF, the 2.0-litre ‘SkyActiv-G’ four-cylinder petrol engine had an aluminium block and cylinder head, double overhead camshafts, four valves per cylinder, electric intake sequential valve timing and oil exhaust sequential valve timing (dual sequential valve timing or ‘dual S-VT’), direct petrol injection, a compression ratio of 13.0:1 and a 6800 rpm redline. Furthermore, the engine requires 95 RON premium unleaded petrol.

The MX-5 RF GT was also fitted with Mazda’s ‘Induction Sound Enhancer’ (ISE) which transmitted induction noise into the cabin via a plastic duct in the dashboard.

SkyActiv-G engine: post-September 2018

From September 2018 deliveries, the following changes were introduced for the 2.0-litre SkyActiv-G engine:

• A larger throttle diameter, ‘common type’ intake ports (previously discrete type), shortened intake manifold length and increased valve diameter. The common type intake ports increased tumble-swirl for faster combustion;
• For the pistons, lower crown height, a reduced skirt area and a 27 gram mass reduction (per piston) to reduce mechanical friction;
• For the connecting rods, newly-developed high-rigidity bolts and ‘optimised’ thickness for a 41 gram mass reduction (per rod);
• New high-diffusion fuel injectors which sprayed fuel over a shorter distance to prevent fuel sticking to the cylinder walls;
• The redline was raised to 7500 rpm (previously 6800 rpm);
• A new control scheme to achieve three-stage, split fuel injection in the engine’s low-rev/high-load operating range;
• A re-balanced crankshaft (still with eight counterweights) which contributed to a ‘minimal’ mass increase;
• For the exhaust valves, increased valve and exhaust port diameters (the latter to suppress exhaust gas separation), increased exhaust valve opening angle and light height, and increased internal diameter for the exhaust manifold. According to Mazda, these changes contributed to a 30 per cent reduction in pumping losses; and,
• For the main silencer, a new inner structure (i.e. new exhaust gas routing and newly-adopted fiberglass materials) to absorb high-frequency sounds.

Beyond these changes, Mazda sought to reduce the lag between pressing the accelerator and engine response – 

• For models with manual transmissions, uneven changes in acceleration – caused by torsion and released in torque-transmitting components – were suppressed using predictive control measures. A dual-mass flywheel was also introduced; and,
• For models with automatic transmissions, acceleration control was improved and the final drive ratio was raised from 3.454 to 3.583 for better synchronisation between the engine and torque converter rotation. Furthermore, shift timing at turn-in and torque control at turn-out were also revised for ‘greater precision in sporty driving situations’.

Dimensions and retractable hardtop

Compared to the Mazda ND MX-5 soft-top , the Mazda MX-5 RF had the same length (3915 mm), width (1735 mm) and wheelbase length (2310 mm), but was 5 mm taller (1235 mm). Significantly, the Mazda MX-5 RF’s power-operated, retractable hardtop consisted of:

• A front roof made from aluminium;
• A middle roof made from steel;
• A rear roof made from Sealed Mould Compound (SMC) plastic; and,
• The rear window glass.

The hardtop could be opened or closed at speeds of up to 10 km/h at the touch of a button in 13 seconds and – when the roof was open – the front and middle sections were stowed with the back window glass in a space behind the seats. Furthermore, the Mazda MX-5 RF has similar boot space (127 litres) to the MX-5 soft-top (130 litres).

The Mazda MX-5 RF featured a sound-absorbing headliner on the inside of the front and middle roof panels and sound insulation around the rear wheel housings to produce ‘a significantly quieter ride’ when the roof was closed. Furthermore, a large acrylic aero board wind blocker reduced air from the rear blowing back into the cabin.

The Mazda MX-5 RF had an unladen mass of 1055 kg and 1080 kg for manual and automatic models, respectively – this corresponded to 47 kg and 49 kg increases relative to the Mazda MX-5 soft-top.

Suspension and steering

The Mazda ND MX-5 RF had double wishbone front suspension and multi-link rear suspension. Furthermore, the Mazda MX-5 RF had dual pinion electric power-assisted steering.

Safety equipment

Standard safety equipment for the Mazda MX-5 RF included dual front airbags, side airbags, ABS, electronic brake force distribution, brake assist, electronic stability control, traction control and front seatbelts with pre-tensioners and load limiters.

As standard, the Mazda MX-5 RF was also fitted with:

• Blind Spot Monitoring (BSM): used a quasi-milliwave radar and operated at speeds in excess of 10 km/h to detect vehicles approaching from behind or in the driver’s blind spot (on either side of the vehicle); and,
• Rear Cross Traffic Alert (RCTA): could warn the driver of approaching traffic when reversing from a parking space by sounding an audible alert and illuminating LED icons in the door mirrors.

From March 2018, the Mazda MX-5 RF GT was equipped with –

• Lane Departure Warning (LDW): used a windscreen mounted camera to monitor the vehicle’s position relative to lane markings. If the driver was about to cross lane markings without the turn indicator having been applied, an audible alert would sound; and,
• Mazda’s ‘Adaptive LED Headlamps’ (ALH): combined ‘Glare-free High Beam’, which controlled the illumination coverage of the high beams to avoid dazzling other drivers, and ‘Wide-range Low Beam’, which expanded the area of illumination.

In September 2018, standard safety technologies for the Mazda MX-5 RF were extended to include:

• Smart City Brake Support (Forward) with pedestrian detection (SCBS F): operating at speeds between 4 km/h and 80 km/h for vehicle detection and 10 km/h to 60 km/h for pedestrian detection, SCBS Forward used a near-infrared sensor that was mounted on the windscreen for ‘precision detection’ of objects up to six metres ahead of the vehicle. When an obstacle was detected and a high risk of collision was assessed, the brakes would be applied automatically to avoid or reduce the severity of the collision (i.e. autonomous emergency braking or AEB); and,
• Traffic Sign Recognition (TSR): used the forward-facing camera to detect speed limit, ‘No Entry’ and ‘Stop’ signs while driving and display them on the Active Driving Display.

From September 2018, the Mazda MX-5 RF GT was further equipped with:

• For SCBS Reverse: operated at speeds between 2 km/h and 8 km/h and used ultrasound sensors in the rear bumper to detect obstacles up to two metres behind the vehicle. Like SCBS F, AEB would be initiated when an obstacle was detected and there was a high risk of a collision; and,
• Driver Attention Alert (DAA): operating at speeds above 65 km/h, the DAA system initially observed driver behaviour – such as steering wheel operation, vehicle speed and lane positioning – for 20 minutes to establish a benchmark. The DAA system then monitored driver behaviour for signs of fatigue and recommended rest breaks if detected. Furthermore, alerts would be issued if the driver had been driving continuously for more than two hours.

Brakes

The Mazda ND MX-5 RF had 280 mm by 22 mm ventilated front brake discs and 280 mm by 9.5 mm solid rear discs.

Euro NCAP testing

In Euro NCAP testing , the Mazda ND MX-5 soft-top received a four star safety rating which included an 84 per cent adult occupant protection rating and an 80 per cent child occupant protection rating. In the frontal offset test, protection of the front passenger and the driver’s thighs and feet were rated as good, though protection of the driver’s head, chest and lower legs was rated as adequate (i.e. a slight risk of serious injury). In the side impact test, chest protection was assessed as adequate; in the more severe pole test, chest protection was rated as marginal.

Features: Mazda MX-5 RF

Standard features for the Mazda MX-5 RF included 7.0J x 17-inch alloy wheels with 205/45 R17 84W tyres, a six speaker sound system with auxiliary inputs (3.5 mm/USB/iPod), Bluetooth mobile phone connectivity and audio streaming, a 4.6-inch full-colour TFT display, black cloth seat trim, air conditioning, cruise control, LED headlights, LED daytime running lights, leather-wrapped steering wheel and gear shift knob, remote central locking, power windows and mirrors, tilt and telescopic steering wheel adjustment, push-button start, tyre pressure monitoring, a trip computer and an immobiliser.

All Mazda MX-5 RF models with manual transmissions were fitted with a limited slip differential as standard.

Features: Mazda MX-5 RF GT

Compared to the Mazda MX-5 RF, the MX-5 RF GT was further equipped with a Bose sound system which had a 203 watt amplifier and nine speakers, Mazda’s ‘MZD Connect’ system with a seven-inch touchscreen, satellite navigation and Internet radio integration, leather seat trim (black or tan), heated front seats, climate control air conditioning, an Adaptive Front-lighting System (AFS), LED daytime running lights, automatic headlights, rain-sensing wipers, proximity key (i.e. keyless entry), heated mirrors and an auto-dimming rear view mirror.

The Mazda MX-5 RF GT was also available with a black painted roof; for these models, premium Nappa leather upholstery was fitted as standard.

2018 Mazda MX-5 RF Limited Edition

The Mazda MX-5 RF Limited Edition was released in Australia in February 2018. Based on the Mazda MX-5 RF GT and solely available with a six-speed manual transmission, changes for the MX-5 RF Limited Edition included:

• 17-inch BBS alloy wheels;
• Four-piston Brembo front brake callipers;
• Brake discs with circular, pillar-shaped cooling fins and ‘European-style’ low-steel brakes pads which provided greater fade resistance;
• A front strut bar which linked the front suspension towners to increase chassis stiffness;
• Bilstein gas-pressurised dampers;
• A Kuroi Sports Pack which added winglets near the front wheel arch openings to direct air away from the wheels; and,
• Recaro front sports seats.

Furthermore, each vehicle was sold with a custom-made Seiko stainless steel Mazda MX-5 sports chronograph. The Mazda MX-5 RF Limited Edition had a drive-away price of $55,790 and Australian deliveries were limited to 110 vehicles.

September 2018 update

In September 2018, the following updates were introduced for the Mazda ND MX-5 RF:

• A rear camera (‘Rear Monitor’) was made standard across the range;
• The steering wheel column gained telescopic adjustment (30 mm);
• The detachable cup holders were made more rigid;
• The seat recline levers gained thicker internal frames ‘to give a more assured feel when operating’;
• Door opening and closing was improved by changing the checker from a three-stage to a two-stage type. The increased distances between the door pause points allowed users to position the doors across a wider range of operation; and,
• The 17-inch alloy wheels for Mazda MX-5 RF had a black metallic finish (previously gun metallic).

Brochure

• Brochure: Mazda ND MX-5 Soft-top and MX-5 RF (December 2016)