From the January 1988 issue of Car and Driver.
The traditional wind-in-the-face sports car came perilously close to extinction during the seventies, the victim of an unusual combination of forces. Horsepower and performance were sapped by the exigencies of two energy crises and tightening emissions regulations. A shrinking economy reduced the demand for two-seaters and other cars of questionable practicality. Finally, a general falling-out-of-love with the automobile helped to sweep convertibles of all types from the American market.
Fortunately, all of these trends have reversed. Power and performance are at all-time highs, two-seaters are common again, and convertibles are enjoying a remarkable resurgence. Still, the traditional top-down, two-seat sports car has been slow to bounce back. It’s true that convertible editions of the big-gun Chevrolet Corvette, the gold-plated Porsche 911, and the low-volume TVR 280i have been available for several years, but they’re all priced beyond the reach of most buyers. Except for the Panther Kallista, no affordable top-down sportster has come to market within the past decade.
Until now, that is. Mazda has rectified the situation at last with a new convertible version of its RX-7. It’s only fitting that the RX-7 convertible should herald the return of the affordable topless sports car, for it was the RX-7 coupe that, ten years ago, ushered in the modern era of the affordable closed sports car. And just as that machine turned thousands of buyers on to the pleasures of sporty automotion, the new convertible, priced at $20,500, should go far to acquaint the newest generation of sporty drivers with the joys of motoring in close communion with the elements.
If you are unfamiliar with those joys, take it from us that there are few experiences more pleasurable than driving a low-slung open car on a warm, beautiful, sunny day. And to those who remember the roadsters of decades past, we can assure you that the sensation of motion and the exposure to the environment are just as satisfying in the RX-7 convertible as they were in an MG TC in the forties. The rest of the driving experience, of course, is far better.
Mazda designed the second-generation RX-7 with a convertible in mind right from the start. Instead of being a cut-and-chopped version of the RX-7 coupe, the new convertible is built on its own assembly line and incorporates all the necessary strengthening modifications from the ground up. To make up for the lost structural benefits of a fixed roof, the convertible’s front crossmember, door pillars, rear side frames, and central tunnel are reinforced with additional plates and stiffeners. The side sills are stamped from thicker steel, the A-pillars are made with a larger section, and an additional crossmember is added in the rear to stiffen the suspension area.
In the interest of both structural integrity and noise isolation, Mazda has given the RX-7 convertible an unusual top design. The top looks like a standard ragtop at first glance, but it consists of two distinct parts. The flat roof above the passengers is a rigid panel made from sheet molding compound, a fiberglass material. The rear portion of the top is a more or less conventional fabric-over-folding-frame structure; a welcome departure from convention is a glass rear window, complete with a defroster. The dual-top design allows the overhead panel to be removed to create a targa effect.
Another innovation on the RX-7 convertible is a device Mazda calls a “windblocker.” Looking something like an oversize sun visor, it’s a nicely finished, 12-by-43-inch hinged plastic panel located behind the seats. When the top is down, raising the windblocker extends it several inches above the beltline; in this position it deflects much of the turbulent airflow that would otherwise curl over the windshield and strike the passengers from the rear. Mazda claims that, at 60 mph, the windblocker reduces the velocity of air past the driver’s right ear from more than 15 to about 3 mph. Of course, if one prefers the full hurricane effect, the windblocker can be folded down.
The unusual top design and windblocker turn the RX-7 into a satisfying convertible. Lowering the top is relatively simple, because its two portions are connected so that they move as a single unit. First you unlatch two hooks that clamp the flat panel to the windshield header. (These latches are normally hidden by folding cover panels.) Then you turn a knob on the instrument binnacle to activate the two electric motors that retract the top. The rear portion drops into place behind the seats automatically, but you have to undo a catch to allow the rigid part of the roof to fold down and into the storage cavity. The final step is to cover the folded top with an old-fashioned, snap-on tonneau; this is the least sophisticated aspect of the design, but at least it’s tailored well enough so that pulling it into place never becomes a tug of war.
With the top down, body shake is minimal on good roads. There is no discernible bending and little torsional twisting. On very rough roads, the cowl does quiver noticeably when the two ends of the car are twisted in opposite directions, but the RX-7 keeps its tires nicely planted.
The windblocker also works as promised. When both it and the windows are raised, the interior is a comfortable cocoon of reasonably still air, with none of the gale-force winds that make conversation and climate control difficult. Mazda hopes that this feature will extend the appeal of the RX-7 convertible into climates where warm days are in the minority. On a fiftyish fall Michigan day, we had little trouble keeping the cockpit warm.
For even more weather protection, one can drive with the rear portion of the top erected and the overhead panel removed. In this targa configuration, the RX-7’s cockpit is as calm as that of a coupe with an open sunroof. Removing the rigid panel is a bit of a chore, however. First you must fully retract the entire top; then you have to manipulate two sets of latches and covers to detach the fairly heavy panel. Once removed, the panel stows flat in the bottom of the trunk (where, fortunately, it doesn’t take up much of the limited luggage space).
Of course, even though the romantic attraction of a convertible is topless motoring, most convertibles are driven most often with their tops raised. In that mode, the RX-7 convertible is outstanding. With the top up, the car is very rigid, with no detectable cowl shake or wiggling on any surface. It’s not quite as solid as an RX-7 coupe, but it compares well with a Corvette coupe, for example. And, as Mazda promises, the solid roof panel helps to minimize air leaks, wind howl, and the general buffeting and floppiness inherent in most fabric tops.
In other respects the convertible is much like the standard RX-7. It has the same suspension, with struts in front and an elaborate semi-trailing-arm arrangement with articulating hubs in the rear. Because the convertible is more than 300 pounds heavier than an equivalent coupe, however, it’s fitted with stiffer springs all around and the larger vented disc brakes from the higher-performance models.
The only powertrain available in the convertible is the 146-hp, normally aspirated two-rotor engine coupled to a five-speed manual transmission. To help the convertible achieve the same EPA fuel-economy ratings as its lighter brethren (17 city, 24 highway), Mazda fits it with a 3.91:1 final drive instead of the 4.10 used on other RX-7s.
Maintaining fuel efficiency is certainly a worthy goal, but in this case it takes a severe toll on performance. Our convertible needed 9.2 seconds to reach 60 mph from rest and 16.9 seconds to cover the standing quarter-mile. The 1986 RX-7 GXL we tested two years ago hit 60 mph in but 7.7 seconds and sprinted through the quarter in 16 seconds flat. The differences are even greater in top gear: the convertible needs more than nineteen seconds to amble from 30 to 50 or from 50 to 70 mph, whereas the earlier car ran both tests in the high-twelve-second range. At least the convertible’s ultimate velocity, aided by a top-up drag coefficient of 0.33, matches the coupe’s 124-mph performance. With the top down, the drag coefficient rises to 0.38, and top speed falls to 118 mph.
The driver can compensate for the performance shortfall to some extent by using the lower gears to stay in the engine’s upper rev range. The rotary spins willingly enough, and staying above 4000 rpm brings the extra benefit of avoiding the annoying throttle dashpot that otherwise makes smooth shifting impossible. Such tactics, of course, cancel out the fuel-efficiency advantage of the taller axle ratio.
Perhaps we wouldn’t miss the power if the RX-7 convertible were a driving dullard. It’s anything but that: the topless model exhibits the same crisp road manners we’ve come to expect from other RX-7s. The suspension keeps body motions under tight control, yet the ride is comfortably supple and the steering is precise and agile. There is plenty of grip available as well, with a peak adhesion of 0.80 g. Stability at the limit is excellent.
The convertible’s standard equipment includes an upgraded sound system, 6.5-inch-wide BBS wheels, and power steering, windows, and mirrors. An options package on our test car included leather seats, a compact-disc player, and dual speakers in each headrest. The sound system produced beautiful music, and the speaker locations made it easy to enjoy whether the top was up or down.
Aside from its disappointing acceleration, we can find little fault with Mazda’s new convertible. It offers all the benefits of open motoring but presents few of the traditional drawbacks. And when its equipment additions are taken into account, it costs only about $3000 more than the RX-7 coupe. That makes the RX-7 convertible the best deal in topless sports cars on the market.
1988 Mazda RX-7 Convertible
Vehicle Type: front-engine, rear-wheel-drive, 2-passenger, 2-door convertible
Base/As Tested: $20,759/$24,018
Options: option package (includes leather seats, compact-disc player, cruise control, tilt steering, headrest speakers), $2400; air conditioning, $859
two-rotor Wankel, aluminum rotor housings, cast-iron end plates, port fuel injection
Displacement: 80 in3, 1308 cm3
Power: 146 hp @ 6500 rpm
Torque: 138 lb-ft @ 3500 rpm
Suspension, F/R: struts/semi-trailing arm
Brakes, F/R: 10.9-in vented disc/10.7-in vented disc
Tires: Bridgestone Potenza RE71
Wheelbase: 95.7 in
Length: 168.9 in
Width: 66.5 in
Height: 49.8 in
Passenger Volume, F: 48 ft3
Trunk Volume: 4 ft3
Curb Weight: 3012 lb
C/D TEST RESULTS
60 mph: 9.2 sec
1/4-Mile: 16.9 sec @ 82 mph
100 mph: 28.9 sec
Top Gear, 30–50 mph: 19.3 sec
Top Gear, 50–70 mph: 19.4 sec
Top Speed: 124 mph
Braking, 70–0 mph: 196 ft
Roadholding, 300-ft Skidpad: 0.80 g
C/D FUEL ECONOMY
Observed: 18 mpg
EPA FUEL ECONOMY
City/Highway: 17/24 mpg
C/D TESTING EXPLAINED
Csaba Csere joined Car and Driver in 1980 and never really left. After serving as Technical Editor and Director, he was Editor-in-Chief from 1993 until his retirement from active duty in 2008. He continues to dabble in automotive journalism and LeMons racing, as well as ministering to his 1965 Jaguar E-type, 2017 Porsche 911, and trio of motorcycles—when not skiing or hiking near his home in Colorado.