1986-1991 Mazda RX-7 Series 4-5 - Buyer Guide

By: Cliff Chambers, Photography by: Unique Cars Archives/Mazda

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While the early RX-7 versions of this iconic rotary are expensive, this series is affordable for now

 

Mazda RX-7 Series 4-5

Mazda’s original RX-7 changed the rules governing Japanese sports car design, then in 1986 took its challenge to the depths of Europe. It was aimed in particular at Porsche, whose 944 bore a remarkable resemblance to Mazda’s second-generation RX-7. The 944 had appeared in 1982, just as Mazda’s stylists would have been inking the outline for an RX-7 to replace the one that had been doing outstanding business since 1978. And anyway what would be wrong with making your Gen. 2 RX-7 look just like the classy, front-engined Porsche?

The new car’s wheelbase and overall dimensions were closen to match those of the S3 RX-7 but the shape of the new car was totally different. Despite looking more substantial the  Series 4 actually dropped 10kg while replacing the earlier model’s live axle with an independent rear end and DTSS (Dynamic Tracking Suspension System).

All-disc brakes were standard, the alloy wheels expanded from 14 to 15 inches and VR-rated tyres were fitted.

| 2020 Market Review: Mazda RX-7 Series 1-5

Switching to Mazda’s 13B rotary engine delivered a 22 percent torque boost, with 182Nm arriving at 3000rpm. The new car also ran cooler and offered better economy. Fuel injection became standard and incorporated two-stage fuel delivery with a microprocessor. The vibration and resonance issues that plagued early rotaries were reduced by introduction of revised engine mounts.

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Power from the basic engine climbed to a respectable 110kW but to challenge that pesky Porsche and rivals like Mitsubishi’s Starion, the RX-7 needed turbo intervention.

June 1986 saw a turbocharged RX-7 arrive in Australia, with a 32 percent power boost to 146kW and a huge jump in peak torque. Acceleration was noticeably improved, with the 0-100km/h dropping below 8 seconds.

Four-speed automatic cars came with a slightly lower (4.1:1) final-drive ratio than the five-speed manual but low-speed acceleration was still sluggish.  

| Read next: 1983 Mazda RX-7 Racer

Australian-market Series 4s came in the equivalent of Limited trim, meaning air-conditioning as standard, central locking, power windows and an electric sliding sunroof.

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Those features were retained into 1989 when the Series 5 RX-7 appeared. Despite slow sales of non-turbo cars, Mazda still didn’t drop the basic model. However the majority of Series 5s in the used market will be turbocharged.

The most contentious issue when discussing rotary-engined cars is fuel consumption. In contemporary tests, S4s with all their factory-fresh components recorded 15-16L/100km and that will still be typical for a suburban-driven Turbo.

History counts for plenty when deciding which turbo-engined RX-7 to buy and prices have climbed steeply during recent years. Quality Series 4s have hit $20,000 but newer S5s remain inexplicably cheaper. From Japan as low volume imports come a few open-top cars priced at similar money to coupe equivalents. Buying a quality car with lots of history and scrupulous service records will prove worthy in the long term.

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VALUE RANGE Mazda RX7 (S4 Turbo Coupe)

Fair: $6000
Good: $13,000
Excellent: $20,000
(Note: exceptional cars will demand more)

BUYER CHECKLIST

Body & chassis

For a long time these RX-7s weren’t valuable and shoddy repairs with cheap repaints and slap-dash rust protection were regrettably common. Now that people are paying upwards of $20,000 for excellent cars insurers can also choose to repair rather than write off good cars following quite serious crashes. Look, with the car on a hoist, for transverse welds to the floor pan and signs of filler where the windscreen joins the turret. Worn or damaged hatch seals allow water and exhaust fumes to enter through the boot area and must be replaced. Hatch supporting struts are frequently weak and generic replacements should be available locally. If not USA suppliers have them for A$70 per pair plus freight.

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Engine & transmission

The days of endemic rotary unreliability are long gone, but you can still break one if you try. Running excessive boost, the wrong lubricants and even fuel-system cleaners can do serious damage, however an engine rebuild costs $4000-5500. Check the mirrors while test driving for smoke from the exhaust; blue for burning engine oil, white is from the turbocharger. Check that wiring and rubber components that sit close to the turbocharger or exhaust pipes have heat shields. Mazda was at one point quoting over $5000 to replace an exhaust system, so cars with non-genuine components are probably common. The clutch in turbo cars is vulnerable to abuse and fitting a heavy-duty unit just means transferring the stress to something more expensive like the differential.

Suspension & brakes

Standard suspension settings are biased towards a comfortable ride rather than pin-sharp handling. However, owners who fit heavier springs and sway bars may have dialled out too much of the comfort. Large-diameter wheels with low-profile tyres lose the ability of the tyre walls to help with damping and send bigger road shocks into the cabin. The rear suspension is complex and needs to be professionally checked for worn components and correct alignment. Series 4 and 5 RX7s brake better than earlier cars and can be improved further with after-market rotors and pads. Quality sets of both range from $1200 to more than $2000.

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Interior & electrical

RX7s used good quality trim materials but 25 years of Australian summers will see a lot of plastic parts looking washed out, cracking and perhaps crumbling. Seats sag and dash-pads crack and replacements, judging by the number of web-site ‘wanted’ ads for them, are not easy to find. Test the sunroof and inspect the hood-lining for signs that water has been sneaking past the seals. Also check the electric windows on both sides, looking for scratches on the glass signifying the mechanism is out of kilter. Make sure that the headlights pop up quickly and remain that way while the engine is running.

1986-1991 Mazda RX-7 Series 4-5 specs

Number built: 272,027
Body: all-steel, integrated body/chassis two-door coupe & convertible
Engine: 1308cc twin-rotor with fuel injection and optional turbocharger
Power & torque: 146kW @ 6500rpm, 265Nm @ 3500rpm (S5 Turbo)
Performance: 0-100km/h: 7.7 seconds, 0-400 metres 15.4 seconds (S5 Turbo) Transmission: 5 speed manual, 4 speed automatic independent with semi-trailing control arms, coil springs, struts, anti-roll bar (r)
Brakes: disc (f) disc (r) with power assistance
Tyres: 205/55VR16 radial

 

From Unique Cars #442, July 2020

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