Driving the rotary-engined Mazda classic racers

Everyone goes on about how rotary-engined cars sound. Some suggest they’re as angry and piercing as a woodmill bandsaw, others that they’re shriller and more irritating than a mosquito in your inner ear. No one ever mentions the smell.

At this stage, Oz Clarke would probably start harping on about pungent bouquets of this and syrupy aromas of that, but what we’re dealing with here is the afterburnings of petrol and oil, so wine phraseology isn’t really appropriate. You know Castrol R, though? It’s like that, but instead of the rich, earthy tones, we have darker, more subversive nasal textures, combined with the sweeter high notes of what appears to be ski wax, if that’s of any help to you.

To be precise, we have Redline 50W race oil combined with Castrol two-stroke oil in a one ounce per gallon high-octane ratio. It has a tang. And rotary engines famously burn a lot of fuel and oil. Sitting on the pit wall at Laguna Seca as five of them chew on their fluids, ingesting, digesting and expelling, it’s not only my nose that’s being assailed. You can feel the oiliness in the air, taste it, breathe it. It’s cloying, lingers and wafts around. If I could pinch the air and rub it between my thumb and forefinger, it would be like, oh I don’t know, treacle maybe – slick, with a hint of stickiness.

Photography: Rowan Horncastle

This feature was originally published in issue 283 of Top Gear magazine.

These are Mazda's rotary racers. They’re raucous and they smell. The cars you see here are by no means a complete back catalogue, but they span 20 years of rotary racing, from 1973 to 1992, from 198bhp to 725bhp, and since Mazda has recently unveiled the rotary-powered RX-Vision concept – which looks like a hard sell in the era of electro-hydrogen – it is at least worth considering the case for the defence.

Especially when the evidence looks so compelling. You can see the 787B, can’t you? It’s there, third one back. I could, and I couldn’t wait. The sister car to the 1991 Le Mans-winner, it finished eighth that day. But then someone forgot to slide one of the pins that hold the carbon rear clamshell in properly and on its installation lap, the rear clam took flight. No one panicked, because hey, these were only cars. It could be repaired.

Unusual. But, then, this wasn’t a normal event. This was Mazda USA bringing out its old cars to be driven because, well, they need to be driven. How refreshing. No nannying, no lap restrictions, just five cars (OK, now four) parked in a pit lane, an unlimited-noise day and instructions to go and drive them. I was almost beside myself.

Mazda did not invent the rotary engine, but it was the company’s salvation. Back in the Fifties and Sixties, Japan realised that the home market was not big enough to support the 12–15 domestic car companies – it was export or die. The plan was to fold companies in together, and Mazda was due to become part of Toyota. Mazda didn’t like this, but was told it could remain independent if it had an appealing enough future plan. So Mazda contacted NSU in Germany and acquired the automotive rights for the rotary engine for the Asia Pacific region. And that’s the start, the point of differentiation.

The Cosmo came first, in 1967, and soon after, Mazda realised that the rotary’s compact dimensions and good power density made it suitable for racing. If you’re not familiar with rotary engines, imagine a triangle spinning inside an oval housing. The points of the triangle never leave the walls as it rotates eccentrically around, so it creates chambers that expand and shrink. Pop the fuel and spark in at the right point and you have a three-phase version of suck, squeeze, bang, blow.

They’re renowned for their humming smoothness, but no one appears to have reminded the RX-2 of this. It’s the first port of call for obvious reasons: it’s the oldest, the slowest, surely the friendliest. It has a spindly roll cage and dinky little pedals in the footwell, it starts with a key, has a cabin barer than the inside of a rusty oil drum and has none of the Dale Earnhardt attitude that oozes from the fattened panels of the MX-6 and RX-7. The RX-2 was developed to go racing in the burgeoning IMSA saloon series, and in 1973 this car scored one of Mazda’s first ever rotary race wins.

I twist the key. It barks triumphantly to life, the noise harsh, angry, entirely at odds with the car’s demeanour. This is 198bhp that clearly feels the need to be heard. It trembles down the pit lane. There’s a hairpin before you join the track so I dab the brakes. Hmm, must’ve hit the clutch by mistake. I look into the footwell and reapply (still got time). Oh, really, really nothing. Pulling on a piece of string would be more effective.

But the brakes don’t define the car, the engine does. I just can’t reconcile the way this car looks with the way it sounds. The noise, an angry, rough chainsaw howl, full of fury, is emphatically at odds with the neat, trim body styling. And the way it revs – it’s too frantic, I want to tell it to calm down, frightened that it’s about to do itself an injury as it homes in on 8,500rpm. Things this old aren’t meant to be so hectic and frenetic.

The steering is nearly as vague as the brakes and the gearchange isn’t much better than that, but the chassis is a revelation. Stupidly forgetting about the brakes, I arrive at corners too fast, pitch it in hopefully and discover the RX-2 has the sweetest chassis. It slides merrily around, heeling over, wagging about. A pure momentum car, what I imagine a Lotus Cortina to be like. Magic. Every time I accelerate, a swarm of killer wasps lodges inside my head, and when I lift off, the exhaust explosions shudder straight through the padding-free seat.

If the RX-2 is like this, what devilment is contained inside the MX-6 and RX-7? Mentally, I’ve packaged these two together as hairy-arsed, hairy-handed, just plain hairy. They’re from the heyday of the International Motor Sports Association series, when the likes of Porsche, Ferrari and Audi did battle with Chevy, Dodge, Mercury, Nissan, Pontiac, Mazda and more. This was NASCAR for road courses, and it must have been awesome.

So I’m vaguely underwhelmed to learn that the 1989 MX-6 only has 300bhp. It’s a GTU car, which I’d assumed meant Unlimited, but actually stands for Under 2.5 litres. The 1991 RX-7 is a GTO car (Over 2.5 litres). That has 640bhp. Not underwhelmed by that. Both use the 13B rotary engine, but while the MX-6 has a pair of rotors, the RX-7 is a quad rotor.

But it’s the swollen bodywork, the sheer width, the barging shoulders that give them both attitude and comic relief. Especially the MX-6 with its nipped-in waist and phoney headlights. This was a front-wheel-drive road car converted to rear-drive for racing, with the fuel tank in the middle of the car – a thing that reputedly made it very nicely balanced.

The cabin is pure NASCAR: the seat pinches you under the armpits, so you drive with your elbows flapping like chicken wings, wrestling at the steering and a gearlever which protrudes from the padded blue transmission tunnel like the upturned leg of a Zimmer frame. It’s a dog-leg H-pattern shift and the gearing is long, so all you need is second and third around Laguna Seca. It’s a lovely shift, though: brief and positive.

They’re not wrong about the chassis balance, either. Laguna Seca gives you no time to breathe – the corners pile into each other, even the main straight, due to the super-fast crested kink – yet this strings things together fluently. Yes, there’s more grip than power, but that’s good – it means you don’t panic that you’ve outbraked yourself on the blind approach to the Corkscrew. It works the rears harder than the fronts, and will eventually slip a little sideways, but remarkably for something with tyres like beer barrels and an engine busily yowling its way to 9,200rpm, it’s friendly and manageable when it does so.

I never get to the point where I find the RX-7 friendly or manageable. This is a car you have to take by the scruff and bully around. If you don’t it’ll be lumpy and surly, and even if you do, it’s still bad-tempered, ready to punish you.

The gearbox has no synchromesh, and the lever moves about as far as the paddle you’d pull in a modern racer. It’s a fearsome thing to deal with when you’ve got 640bhp and regularly lock up the back wheels, but when you slot the perfect shift, it feels magic, as instant as a double clutch. The whole car responds positively, diving into corners, storming down the straights. It’s sharper than the MX-6 and holds on so hard. There’s barely any aero, the grip is all mechanical, the noise smoother because of the extra rotors.

But it’s also exhausting. It demands total mental concentration, not just because of the gearbox, but the speeds involved and the hollow banshee howl. It pushes and nips at you, constantly eager to catch you out. So what’s the Daddy going to be like with an extra 85bhp and roughly 200kg less weight? 

Bloody pussycat. I can’t believe how lovely the 1992 RX-792 Prototype racer is to drive. It’s so slick, has such a deft touch, slices lightly where the lesser ones blunder bluntly. It’s wonderful. Even the gearchange is a complete delight.

It came the year after the 787B, Le Mans having banned rotary engines, Mazda not wanting to stop playing just yet. The IMSA GTP (for Prototype) category gave them the stage, but the 792 never quite lit the place up, with a best-ever finish of second. But I’m not going to let the results get in the way of the experience. I’m sitting crammed into the bubble canopy, nose pressed against the goldfish bowl, heels and buttocks scraping the tarmac. The view is mesmerising, the fluency with which it drives unparalleled. It glides where the RX-7 jinks and weaves, forced into the road by the heavy hand of aerodynamics. Where the others go light and vague as you aim for the tree with the ribbon tied around it at the entrance to the Corkscrew, the 792 plants itself. The brakes are astonishing, the steering sweet and light, the gearchange seeming to lead my hand around the gate.