Plagued by chirps, bongs and beeps while you drive?
You must be motoring without a seat-belt, advancing with door/boot/bonnet/tailgate ajar, reversing (just how unaware do you have to be not to know that?), about to collide with somebody in your blind spot or witnessing some imminent mechanical catastrophe.
But if you heard a buzzer in the 1978 Mazda RX-7, it was for a rather more exciting reason – you were 500rpm away from striking the 7000rpm redline of its rotary engine, whose smooth-spinning hum sounded bound for a rev limit a good 2000rpm beyond that. And back in 1978, most engines reaching that velocity were a few reciprocations away from punching hot ‘n mauled componentry around your engine bay.
The Mazda needed a limiter because its rotary motor really could spin too close to the sun, wearing out the critical tips of its twin rotors in short order - hence the buzzer’s rude interruption.
There was little else rude about this car though, even if a glance at its specification suggested yet another in a long line of disappointing Mazda rotaries – they included saloons, the RX-3 and RX-4 coupes and in the US, even a pick-up - in which the engine’s charm was burdened with outweighing the sizeable disappointments to be uncovered elsewhere.
These included vague steering, mallet-in-mid-air handling and a ride more startling than a small-hours phone-call. The RX-7 appeared to offer more of the same with its recirculating ball steering gear, which usually guaranteed direction changing of maritime character, a live rear axle and drum back brakes.
But this time, Mazda had developed its hardware to excellent effect, starting with the fine decision to shift the compact little Wankel motor almost 10 inches further back than it sat in an RX-3, to produce a front-midships layout and 50:50 chassis balance, while the rear tyres hung on for longer because the axle was strapped down with four links and a Panhard rod, its coil springs located as far outboard as possible. Though not for that long, sometimes tenuous road holding was a major part of the original RX-7’s charm.
In the wet, it could have used another buzzer to announce the back-end’s imminent relinquishing of grip, which came entertainingly early and not a lot later on a sunny day. So you needed the Mazda’s quick steering to catch its drifts, and the snap-finger quick gear change to make the best of its limited torque, and not a whole lot of horsepower at just 100bhp.
Still, the RX-7 didn’t weigh much, allowing it a brisk 8.5sec sprint to 60mph, and after a few years it would weigh even less as corrosion nibbled at its rear arches, sills and the odd hidden seam. Rot, the rotary’s thirst and its occasionally troubled high mileage reliability has culled RX-7s to the point of shocking rarity, which will get me hunting for one a little harder.
As the classics market goes today, good value is still to be found. Currently, a 1985 example with 74,500 miles is available for £7000, but you can pay a lot more for mintier ones.
In America, plenty are out there, which is reassuring, though most are convertibles. Early example coupes are to be found for around US$5000.
Reasons to want one: Sharp ‘70s looks, the rotary’s hum, easy drift action
Why you’ll run a mile: It’s thirstier than a marathon runner, rust gets ‘em - and watch out for that buzzer.