Mazda MX-5 review – engine and gearbox

Both of the MX-5’s engines are from Mazda’s current selection of Skyactiv units, but they have both been revised for use in the sports car. The old, entry-level Mk3 MX-5 used a 1.8-litre MZR engine, but that has been replaced by a 1.5-litre motor that weighs 14kg less. Compared to this engine’s use elsewhere (it's available in the Mazda 2 supermini), it features revised cam timing, lighter rotating parts, a custom steel crankshaft and new intake and exhaust systems, while retaining the 4-2-1 exhaust manifold.

The 1.5-litre MX-5s dip under the magic ton at 975kg without a driver (2-litre cars weigh an extra 55kg), which helps to offset the rather effete 111lb ft of torque, generated at a lofty 4800rpm. With peak power of 129bhp generated at 7000rpm, it’s obvious that this engine will need to be worked hard. And so it proves, but as long as your performance expectations aren’t set too high it has plenty of appeal, with an effervescent character and a sweeter rasping note than the 2-litre.

The new 2-litre, as mentioned previously, has undergone a substantial update on the previous unit, with a nuanced and technical approach, such as delicate weight savings to the pistons and conrods, revised camshafts, exhaust valves, injectors, throttle valves and a new intake. All of these subtle changes make a huge difference though, with the new engine having more urgency at high revs, even if it still sounds a little coarse at its 7500rpm red line compared with the 1.5-litre motor. When still box-fresh, these engines have a tendency to feel a little tinny and tight, but with miles the engine really loosens up and feels every one of its 181bhp.

53

Both engines share the same six-speed manual transmission, which has a wonderfully short, mechanical action. Directly poking straight out of the transmission, there’s an acute physical connection between the gearbox and your left hand, passing through vibrations and movements as the whole powertrain wobbles on its mountings. A more solid connection would allow the engine to fizzle through the car, but the MX-5 is all about delivering fun without day-to-day compromises. 

In terms of outright performance, the box’s ratios feel better suited to the bigger, torquier 2-litre engine. You spend more time trying to keep the 1.5 near its top end, so you need to get some revs on the board before shifting up – that's no hardship though, and the engine's light, free-revving character and more enthusiastic note suits the car to a tee. You can easily punctuate each downshift with a blip of the throttle thanks to well-spaced pedals, too.

There is an automatic gearbox available, and it comes with steering wheel-mounted paddles, but it is only available on the RF.