{"id":498664,"date":"2020-03-17T15:57:04","date_gmt":"2020-03-17T22:57:04","guid":{"rendered":"https:\/\/sportscardigest.com\/\/?p=104116"},"modified":"2024-12-27T12:59:28","modified_gmt":"2024-12-27T12:59:28","slug":"rods-rotary-rally-rocket-1985-mazda-rx7","status":"publish","type":"post","link":"https:\/\/www.supercars.net\/blog\/rods-rotary-rally-rocket-1985-mazda-rx7\/","title":{"rendered":"1985 Mazda RX7 – Rod’s Rotary Rally Rocket"},"content":{"rendered":"

\"\"<\/a>When Rod Millen hit the starter on his custom-designed and built four-wheel drive, four-rotor 1985 Mazda RX7 the explosion made photographer Dennis Fregger and I jump. It shattered the morning quiet, and flushed the birds out of the bushes a hundred yards away. The sound of an unfettered rotary engine at full song is like nothing I had ever heard before.<\/p>\n

I climb over the side bar of the roll cage and settle into the seat, which is comfortable and form fitting. In fact, Millen says, \u201cThat car is like a comfortable old shoe to me.\u201d The custom built dash is all business, with big, easy-to-read, no nonsense Stewart Warner gauges. The tachometer is turned in such a way that Rod can easily see it to keep the engine in its optimum rpm range.<\/p>\n

Taking the wheel of Rod Millen\u2019s championship RX7 is a bit like picking up Eric Clapton\u2019s guitar. Yes, I can pick it up, and even strum a few cords, but play it like Clapton?\u2014not a chance. Likewise, I can sort of drive Rod Millen\u2019s rally car, but \u00a0. . . you get the picture.<\/p>\n

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Photo: Dennis Fregger<\/figcaption><\/figure>\n

The transmission is a full synchromesh five-speed so shifting is easy, if a little imprecise. The clutch is firm but easy to depress. As it warms, the engine settles into that peculiar rump-rump-rump sound that is typical of rotary engines.<\/p>\n

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Rod Millen<\/figcaption><\/figure>\n

Rod\u2019s RX7 is equipped with four-wheel drive and the overall gearing is quite low, but it is designed to yield a maximum speed of 104 miles per hour. Millen points out that from the start line, you need to take off in two-wheel drive in order to preserve the front wheel drive train, and then shift into four-wheel drive once you\u2019re rolling. The engine revs instantly at the blip of the throttle, up to the start of its optimum rpm range at about 10,400 rpm, but effortlessly screams its defiance at 16,000 rpm plus.<\/p>\n

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In fact, Millen says that when racing you don\u2019t want the engine to drop below 6,500 pm, and that it doesn\u2019t make much power below 10,400 rpm. Rotary engines also run optimally on 98 octane pump gas thanks to the engine\u2019s unique design, and there is no practical way to go beyond about 9:1 compression.<\/p>\n

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The rotary, or Wankel engine concept, was not new when Felix Wankel first put together a working model for German automaker NSU in 1954, and then developed prototypes for testing in 1957. After that, in 1961, Japanese automaker Mazda teamed up with NSU to develop the Wankel rotary engine for production. It then debuted in Japanese production cars in the nineteen sixties.<\/p>\n

Rotary engines have the advantage of being simple, light and compact, yet able to produce prodigious power. There is no cam, and there are no pushrods, rocker arms or valves to complicate things, and there are no pistons and connecting rods with their characteristic monkey motion to convert up and down effort into rotary motion. This makes them nearly ideal for performance purposes.<\/p>\n