The Morning Call and Mcall.com's view

There’s no doubt about it convertibles are fun. Even a routine trip over familiar and unexciting roadways can become an adventure. And depending upon one’s imagination, the open air feeling of a convertible can be compared to piloting a boat or flying an open cockpit biplane.

It could also be a dirty, grimy trip if passing through one of the many construction sites; an odorous one if stuck behind a diesel, or even a discomforting trip beneath the blazing high noon sun. But, what the heck, it’s all part of the convertible experience and those who own convertibles soon learn what to do and what not to do.

The convertible, to be sure, does not appeal to everyone. But for those who want to be a little different and/or want to be seen, a convertible can certainly fill the bill.

One of the latest entries in this class of cars is Mazda which is now offering a convertible in its RX-7 line. And for those who think a convertible is sporty, a convertible sports car is, well, even sportier.

The RX-7 convertible is one sharp looking car with a rather unique top design. Obviously, Mazda just didn’t slap this thing together. When you consider Mazda, for one thing, had to turn a fastback design into a notchback, it is not difficult to see that much effort had to be put into it. But, then, Mazda has always been an innovative car builder so one should expect it to do things up right.

Both the convertible and the fastback share the same styling up to a point behind the doors. That is, a smoothly rounded nose, low hoodline and sharply raked windshield. To accommodate the top mechanism and provide a traditional convertible look, the back end is ”squared off” but in a contemporary aerodynamic fashion. In fact, with the top up, the convertible has a coefficient of drag of 0.33, which is quite low.

With the top up or down, the convertible is attractive. However, the test car with black paint and a black top didn’t really show off the lines as well as one with contrasting colors. Even though this is the worst possible color combination for a convertible – besides not showing a contrast, it turned out to be a ”hot” car with the black just soaking up all that heat – it still turned heads.

Operating the top mechanism is not really that difficult but instructions in the owner’s manual seem to be unnecessarily complicated. Perhaps this can be attributed to Mazda’s lack of experience with convertibles. The top is padded, complete with rear-window defogger, which will provide a quieter and easier to heat or cool interior with the top up. Although not very large, the top is powered. And a somewhat interesting fact is that the top mechanism will not work unless the emergency brake is set.

The rigid front panel of the top is removable from the rest of the top. Take it out, and the RX-7 has a half-open roof, or landau roof, configuration. Almost like removing the panels from the T-roof. Another innovative device is the ”Windblocker,” which Mazda points out is patent pending. This device is a panel behind the seats that prevents air from entering the seating area from the rear of the car. It also reduces wind noise and air disturbance at highway speeds. The Windblocker also held in the cooler air from the air conditioner and made driving more pleasant on those very hot days. By the same token, it should also hold in warm air from the heater when driving with the top down in cooler weather.

Although the convertible top is cleverly done up and innovative, it is not without its trade-off. As with many other convertibles, the RX-7 has a very small trunk and little storage space. In fact, most of the trunk space is taken up by the rather bulky top boot when it is not being used. With the top down, the little bit of storage space behind the seats (when the top is up) is unusable. Who ever claimed that convertibles were the most practical cars in the world.

Once the novelty o f the top wears off, though, there are still plenty of interesting things about the RX-7 convertible. After all, it is an RX-7, one of the most popular sports cars around and the only production car in the world with a rotary engine.

Back in the early 1970s the rotary engine appeared to be the engine of the future and many manufacturers had plans to build them. But it wasn’t to be. Mazda, the first manufacturer to produce rotary engine-powered vehicles in any numbers, had a couple of problems – some through design and some through abuse – and the company almost went out of business. The other manufacturers dropped the rotary like a hot piston.

Obviously the problems couldn’t have been insurmountable since Mazda has had great success in racing with this engine. Mazda ”reintroduced” the rotary with its new RX-7 in 1979 and since that time both have been doing well. But I must admit I am very surprised that no one else brought out a rotary powered car.

Very briefly, a rotary engine differs from a piston engine in that, for one thing, it has no pistons and it has fewer parts. Basically, it consists of a triangular-shaped rotor that spins within an oval-shaped combustion chamber. A spark plug fires a fuel/ air charge which has been brought into the combustion chamber by a port valve arrangement. Outstanding features are its impressive power-to-displacement ratio, light weight and smooth running.

The engine in all RX-7 models, aside from the turbo, is the ”13-B” rotary featuring six-port induction, ”Dynamic Effect Intake” system, electronic fuel-injection and a microprocessor-controlled engine management system. The engine measures only 80 cubic inches or 1.3 liters and is rated at 146 horsepower at 6,500 rpm and 138 foot pounds torque at 3,500 rpm. Quite a fistful of power for its size. (The turbo is even more impressive. With the same 80 cubes it is rated at 182 horsepower at 6,500 rpm and 183-foot pounds torque at 3,500 rpm. The turbo engine, however, is only available in its own special model.)

The test car was quick and responsive but performance is somewhat slower than the fastback version with the same non-turbo rotary and five-speed manual transmission. And this is simply because the convertible weighs 3,003 pounds while the fastback weights 2,625 pounds. So, there’s a lot more going into the convertible than meets the eye. Even so, don’t get the idea that the convertible is slow; it is just slower than the fastback.

Fuel mileage averaged 14 miles per gallon for city driving and 22 mpg over the highway. Not bad not great. On the bright side, unleaded regular can be used.

The RX-7 convertible is perhaps most impressive in handling. But it is a sports car and handling should be taken for granted. But you can still be impressed.

The sophisticated suspension system features modified MacPherson struts with forged aluminum A-shaped lower arms and double construction bushings up front, while the rear has Mazda’s patented ”Dynamic Tracking Suspension System.” The design includes a trailing arm mounted to a crossmember, with a wheel attached to the arm through ”Triaxial Floating Hub,” yet another Mazda patent.

There is a big explanation from Mazda on how all of this works but if you just take it out and wring it out, you will quickly learn all of its good points.

Base price for this car is $24,050 and includes every piece of equipment you can think of with the exception of air conditioning. This does seem somewhat strange and who knows what goes on in those inscrutable Mazda minds. Add the air at $860 and the price is $24,910. As far as can be determined, if a fastback was comparably equipped, the convertible would cost only about $1,300 more, which if you think of it, isn’t bad. However, the initial price is beginning to get up there.

The car is protected by Mazda’s bumper-to-bumper three-year/50,000 mile warranty.