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If you’re looking for the perfect parade car for Earth Day, Toyota Prius Convertible from NCE is it.

Imagine gliding silently behind the Precision Hemp Weaving Society’s float and just in front of the Marching Compost Band, while the Recycling Queen waves to the crowd. It’s almost too politically correct and too environmentally responsible. It is, however, too perfect.

If you’re a fiend for clean air, then the match between the Toyota Prius and open-air motoring is just what you want. Even better, NSC’s drop-top conversion even works pretty well when you’re not in an Earth Day parade.

Clever in Yet Another Way
As the flagship of Hybrid Synergy Drive, the Toyota Prius represents some pretty clever engineering on the part of Toyota. Yet it’s taken another dimension of cleverness by NSC in California, to transform the five-door Prius hatchback into a four-door convertible.

Al Zadeh, President and chief engineer of NSC has a degree in petroleum engineering from the University of Southern California, but for the last 30 years he’s chosen instead to turn cars, trucks and SUVs into convertibles. Some of the decapitated machinery he’s produced has been dang near brilliant, and his convertible conversion of the Acura NSX is so sweet it’s hard to believe that Honda didn’t intend for the midengine sports car to be built that way. Meanwhile, some of the conversions are just plain bizarre, as he’s built a full-size Chevy Express van convertible that is awkward in ways it would take Isaac Asimov to imagine. But by now, NCE’s Zadeh knows every trick in the beheading book.

We drove NCE’s flip-top Toyota FJ Cruiser last year and found it to be generally sturdy and heinously fun. But the FJ is basically a truck, a body-on-frame vehicle that requires only straightforward reinforcement to retain its structural integrity. The Prius, on the other hand, is a front-wheel-drive package built within a sardine-shape unibody that could implode if not judiciously reinforced once the roof is removed.

Considering how much amperage runs through the Prius, that act of lopping off the roof isn’t something to be done lightly. But cut it Zadeh does, taking the roof off completely from aft of the rear doors right up to the windshield header. He retains the window frames around the side glass, however, and then neatly incorporates a stub of the excised hatchback to form a trunk lid. He also builds up a reinforced hoop out of two sections of 1-by-2-inch steel to brace the sides of the body.

Keeping the window frames intact does mean that there’s a lot of structure visible above the beltline of the Prius even with the top down. But this design also means the windows seal securely, and that means a lot less wind noise when the top is up.

Tops in Tops
While the rage in production convertibles these days is retractable hardtops, Zadeh still has faith in the classic fabric soft top. Not only is it more straightforward to design a soft roof that stacks behind a car’s seats, but also there’s much less in the way of expensive hardware and labor.

The Prius convertible’s power-operated top is a five-bow design that incorporates the windshield-header latches from a Toyota Solaraconvertible. It’s covered in three layers of material — German-made canvas, 0.75 inch of insulating foam and a conventional headliner. The heated rear window comes straight out of an Audi TT.

NCE has done a remarkable job of retaining the original shape of the Prius roof line. At first glance, the NSC Prius might be mistaken for an example of the Toyota hybrid that has been inexplicably “blessed” with some kind of dealer-installed canvas-trimmed landau roof. And don’t think there aren’t Toyota dealers out there selling Priuses so equipped (and perhaps further enhanced with Vogue whitewalls).

Tops in Top-up
Once the top is up, this NCE conversion proves to be a relatively taut and rattle-free Prius. Yes, there’s some cowl shudder when you go over railroad tracks and a slight rustle along the top as the wind travels over it, but it doesn’t feel like the car is about to shake itself apart. Think second-generation Chrysler Sebring convertible, and you’re just about where the NSC Prius is when it comes to top-up structure.

Visibility is compromised somewhat by both the excision of the rear quarter windows normally embedded in the C-pillars of the Prius sedan and the replacement of the rear hatch window with that Audi-sourced porthole. Even so, Zadeh has retained the small window that runs across the Prius’ butt between the upper portion of the taillights, and this makes for better rearward visibility than you might expect.

Because part of NSC’s reinforcement is that hoop made from box-section steel, the rear seat no longer flops forward for additional storage. What’s left is a small-ish trunk, and it gets even small-ishier when the top goes down into it.

Tops in Topless
Press and hold a small button installed just to the left of the steering wheel and the NCE fabric top elegantly folds back in just about 30 seconds. The top takes some wrestling to get under its tonneau cover, but it doesn’t stack very high and looks well finished when it’s down.

Toyota expended a lot of effort to make the current Prius aerodynamically friendly and the car’s large, extravagantly raked windshield does a wonderful job of keeping turbulence out of the convertible’s cockpit when the top is down. This NSC Prius is an exceptionally quiet convertible even when the 1.5-liter internal combustion engine is whirring away. It’s especially quiet for an aftermarket conversion; the lack of wind noise is close to astonishing. Let’s call it “astonishing adjacent.”

But despite NSC-added reinforcement down each rocker panel, the structure does feel more loosey goosey when the Prius’ top is down. Again it’s no worse than in some production convertibles of recent vintage, but it’s no better as well.

NSC claims that its conversion doesn’t add any net weight to the Prius, and during our time with the car it felt as quick and maneuverable as any Prius we’ve ever driven. That means not-that-quick and not-that-nimble, but not-that-bad.

In Character
We have to admit that we failed to arrange a rainstorm (or a car wash) to test the water-tightness of the top, and we didn’t drive the NCE Prius far enough to make any generalizations about the impact of open-air motoring on fuel economy. But it does feel tight and we can’t think of any reason why fuel mileage should suffer terribly.

No one has ever confused the Prius with a car that’s thrilling to drive — at least not in the conventional manner. It’s mild-mannered and ultimately a bit distant in the way it responds to you. Of course it does offer terrific utility and clearly superior fuel economy. If only Prius owners weren’t so smug about the politically correct virtues they presume their cars to have.

It turns out, however, that those virtues match up quite well with a convertible top’s sun-worshipping indulgence. Think of NCE’s Prius as a hybrid with the addition of solar power.

By John Pearley Huffman