Is Mazda Reviving the Rotary Engine?

17 Dec 2019 by Lisa Simm

Mazda has been teasing us for some time that they are bringing back their unique, high-revving, noise-box of an engine.

Although, it’s not in the way die-hard petrol heads have been hoping for… or is it?

What is a rotary engine? – A brief history

The Wankel rotary engine (quiet at the back) was first developed in 1954 by German engineer, Felix Heinrich Wankel (stop it…). His goal was to create an internal combustion engine that would not create strong vibrations like a traditional piston engine.

A rotary engine is essentially made up of an oval chamber with a spinning rotor inside, moving off-centre on an axle. The rotor is in the shape of a rounded triangle to create the three separate sections necessary for a combustion engine: compression, ignition and exhaust. Whereas, a traditional piston engine has a round combustion chamber with a piston that moves up and down to allow for the fuel and oxygen to mix, ignite and exhaust.

Rotary advantages:

  • It only has two moving parts.
  • Vibrations can be practically eliminated.
  • Smooth power delivery and much higher revolutions per minute (revs) can be produced.

Rotary Disadvantages:

  • Usually less torque than piston engines.
  • Engine’s ignition section is impractically shaped, causing poor fuel efficiency.
  • Uses large quantities of oil in the chamber, leading to poor emissions.

The first-ever production car to be fitted with a rotary engine was the 1964 two-seater NSU Wankel Spider. Weighing just 700kg with a 498cc single-rotor Wankel engine, the NSU had just 50bhp. With a 0-60mph time of a lengthy 15.7 seconds, the NSU certainly didn’t cause a stir.


Following this, the Europeans could never seem to get the rotary right, from the dismal Citroen M35 to the outright incredible Mercedes-Benz C111 V1 that could achieve 162mph (in 1969!), but was never put into production. Mercedes only ever made 15 and each is now worth well over £5M, even though only one of those actually has an engine!

Mercedes C111

Mazda’s Rotary Legacy

The Mazda Cosmo – An icon of Japan.

Mazda became the first, and only sustainable, mass-producers of rotary-powered cars in 1967, when it unveiled the breathtaking Mazda Cosmo. Powered by a twin-rotor 982cc engine, the Cosmo produced 110hp, delivered to the back tyres – resulting in a top speed of 115mph. A true icon of the decade, the Cosmo was named and styled to remind consumers of the space-race. The Cosmo is now considered a piece of art by many and has been known to sell for over £700,000.

Mazda Cosmo

The Mazda R100 – The Cosmo’s sensible sibling.

Following the love Mazda received from the Cosmo, they had essentially created their own market and, wanting to sell their new rotary engines to this wider audience, Mazda created the R100 (named the ‘Familia in Japan). Immensely popular on home-turf due to reduced taxes on the rotary engine, the 982cc engine produced a modest 67bhp and quickly became a common sight on the roads of Tokyo.

Mazda r100 rotary

The Mazda RX-7 – A JDM rotary legend.

The head-turning, wallet-emptying, noise machine that every petrolhead drools over. The RX-7, arguably Mazda’s greatest car, quickly made a name for itself. Three generations from 1978 to 1991 were meticulously developed by Mazda, resulting in a refined two-seater sports car, that made incredible noise whilst ripping up the tarmac beneath it. Mazda’s bestselling car – the MX-5 – owes a lot of it’s styling to the RX-7.

After becoming so popular in Japan’s car scene (and thanks to a certain movie franchise), many RX-7s have been extensively modified to produce more power and slide around corners. Due to the unique rotary 13B twin-turbo engine, the RX-7 makes the perfect platform for a drift car.

Rotary rx7

The Mazda 787B – Japan wins Le Mans.

After seeing what the rotary platform could do, Mazda decided to take it racing.

The winning car (no.55) began the race in 19th position, and 24 hours later became the first-ever car to win Le Mans without a piston engine. Remarkably reliable, the 787B had no faults other than a blown headlight bulb and a rear wheel bearing; meanwhile, many competitors were forced off the podium due to mechanical issues.

They came, they won, they left. Since 1991 Mazda has never entered Le Mans again – I wonder, was it not wanting to encourage other manufacturers to develop rotary engines, or to ensure the 787B maintained its legendary status.

Mazda Rotary 787b

The Mazda RX-8 – The end of an era?

Released in 2003, the RX-8 was Mazda’s successor to the RX-7, although the two shared no components. The unique coupe had questionable, quirky design features, such as the backwards opening doors, a strange centre console, and unfortunately, when sold in the UK, a number plate plastered over the grill.

However, the rest was sublime, the 1.3L engine produced 228bhp, was creamy smooth all the way up to 9,000 revs and could storm any B-road. Costing just £22,000 when released, the RX-8 was packed full of tech, and proved to be incredible on both the track and road.

“This car is sensational. Of all the cars I’ve driven this year, I’m pretty sure this one is the best.” – Jeremy Clarkson, 2003.

You could pick up an RX-8 for as little at £500 in 2017, but the values are now quickly appreciating.

A hydrogen-powered rotary engine?!

Mazda saw the future coming, perhaps accelerated by the astonishingly bad fuel economy from the rotary, but in 2003 they developed a bi-fuel version of the RX-8 Wankel engine that could run on both traditional petrol and hydrogen. The car could be switched from petrol to hydrogen from a button in the cabin. Simply-put they just added two extra fuel injectors for the hydrogen. So why did it never catch on?

The 2003 Hydrogen RX-8 was a lot like a traditional RX-8, however, it was less practical, needed filling up twice a day and the boot was filled by the hydrogen tank. But, it proved a concept: a car that produces nothing but water.

This non-production RX-8 could run on either petrol or hydrogen.

Now, Mazda has been very quiet about how they are going to make its cars green, apart from the SKYACTIVE-X engine we’ve seen in the 2019 Mazda 3, as well as the all-new MX-30. But very little has been said about its “rotary range extender” – my main question is, will it be bi-fuel?

If it is, will we see Mazda become the leaders in green-fuel cars and the MX-30 become a conduit to the future progression of such vehicles? The convenience of still being able to use traditional petrol stations, but the option to fill with hydrogen. That would fix all the issues the Toyota Mirai faced – it was a little ahead of its time, the infrastructure to use Hydrogen as a main fuel source is not yet in place, but having the option – that’s what begins to solve the carbon crisis.

Hydrogen can be created from electrolysis, which can use electricity from solar and wind power – this creates a completely carbon-free fuel. As more questions are asked about the eco-credentials of lithium-ion batteries, is Mazda ahead of the trend?

Certain YouTube evidence has given us hope, but the jury still seems to be out for now as to what the Japanese manufacturer’s plans might be.

All the major draw-backs of the Hydrogen RX-8 were caused by a less-than-ideal testbed. A modern SUV chassis would fix these (…an MX-30) and there would be plenty of space to mount a Hydrogen tank.

So, if Mazda creates another rotary engine that runs explicitly on Hydrogen, with the power delivered straight to the wheels, it cuts out the need for electric cars, batteries and charging infrastructure. Essentially solving the impact cars have on climate change. But is it this simple? And will governments be willing to support Hydrogen as a mainstream fuel source? We can only wait and find out.

So is the RX-9 coming?

A few years ago, we saw the “RX vision concept” a supposed rotary-powered sports car, with styling cues that seemed outlandish at the time. However, the all-new Mazda 3 has some suspiciously similar taillights and the headlight-grill combination is steadily becoming Mazda’s signature. Now, this was first shown in 2015, but little information regarding an RX-9 has been squeezed out of Mazda since.

So, will we see the RX-9 as soon as 2020? There is no way of knowing, but we can hope. If it looks as incredible as the 2015 concept, it really will give the 2020 Toyota Supra a run for its money.

The Mazda RX Vision Concept was first shown in 2015.

So far the only confirmation we have had is that there will be an electric all-new MX-30 released in 2020. It has a range of 124 miles. Which begs the question of why the rotary range extender is not inside, is it still being developed? Or have Mazda changed their mind?

Never-the-less, you can get some great deals on new and used Mazda cars here at Stoneacre, we have a range of the all-new Mazda 3 that harnesses the low-emission SKYACTIVE technology that is not only kinder to polar bears, but will also help cut down your fuel bills.

The 2020 all-electric Mazda MX-30.
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