Perennial Wankel Woes Holding Up New RX-7

Cammy Corrigan
by Cammy Corrigan
perennial wankel woes holding up new rx 7

A few weeks ago, I wrote about Mazda’s new RX-7, scheduled for release in 2011. Well, that now looks unlikely. In fact, Mazda have put the release date as unknown, ushering the wankel warrior into the dreaded category known as development hell. Autocar reports that the development of Mazda’s new RX-7 is plagued with problems. The RX-8 had problems with fuel economy and high oil consumption and the Mazda engineers are no closer to solving them with the new RX-7. They could solve the problem by adding direct injection, but that’ll drive them into another problem. The DI components would make the RX-7’s engine weigh more than the current 13B motor, an outcome that would be in direct conflict with Mazda’s vision of cutting 100kg from all its cars in the next five years. Other problems, include lack of mid-range torque and trying to get the current engine to reach their target for maximum revs. Couple these problems with Mazda’s sales dropping 19% and the prognosis doesn’t look good.

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  • Matt51 Matt51 on Jan 12, 2010

    A 300 hp Mazda rotary can run reliably all day at 300 hp. Normally a 300 hp piston engine runs very little time at 300 hp. The Mazda rotary has proven itself more reliable than piston engines in small airplanes. If we look at Robinson trying to sell its first turbine helicopter using a 300 hp Allison gas turbine, it would be far more affordable, and just as reliable, using the Mazda rotary. I would love to see a small helicopter manufacturer pair up with Mazda, or see Mazda enter aerospace, as Honda has done.

    • Ccd2 Ccd2 on Jan 13, 2010

      And that may be the future of the wankel IF it has any future at all. Think of it. This is a website for car people. A new wankel based car has the potential to be one of the more interesting car introductions in any year and nobody cares.

  • Matt51 Matt51 on Jan 14, 2010

    Someone is selling two Suzuki Hayabusa engines tied together into a V8 for $30,000. This gives 400 hp at 200 lb weight. 2 hp per lb. My guess is the new Mazda Renesis will match this, because they have new advancements, including the "block" or three side plates, will be made of aluminum instead of cast iron. I would guess the engine alone could be purchased from Mazda for about $10,000. The 300 hp at 200 lb matches the Allison (RR) model 250 gas turbine, but at better fuel economy. Running these 400 hp engines at 300 hp should give good life for flight applications. 300 hp at 200 lb is important, as this is large enough to allow for a safe (1200 lb) helicopter of adequate size. So for the first time, piston and rotary engines now are matching the gas turbine, but at much lower cost. This is going to be revolutionary in terms of low cost flight. There is no such animal as a "low cost gas turbine". Just the difference in cost for the hot section overhaul is going to be astonishing. You could throw away the Mazda engine and put in a new one for $10,000, as opposed to a $200,000 hot section overhaul of a turbine. Another advantage of the Mazda engine is it turns at lower rpm than the gas turbine, so you need less reduction gearing in the helicopter.

  • RotaryMan91 RotaryMan91 on May 16, 2010

    Wow! I can see that there a lot of "non-rotor heads" responding to the possibility of Mazda cancelling the new RX-7. First of all, the rotary's day is not over as far as its ability to perform as well or even better then a piston engine. It is today as good as it has ever been. Yes, there are some problems with getting the emissions correct and fuel mileage right. But, those are problems the Mazda engineers can work out just as they did upon the debut of the RX-7 to America in 1979. The rotary has proven itself a powerhouse in many applications, but specifically on and off of the track. Mazda's rotary has been penalized so many times in racing because they are simply, "too fast for the competition”. But even when adding weight to these rotary cars, they still went out and became the first sport car ever to reach 100 racing victories faster then any other sports car in history. Their endurance is unprecedented. All this racing performance has and continues to translate to its production cars with of course the RX-7 and RX-8. The RX-8 may not have the performance of the beloved RX-7, but it is still no slouch. It is true that we "rotor heads" have long been disappointed with Mazda for not putting the engineering over the years into developing either a very powerful 2 rotor rotary or a 3-rotor rotary. Mazda seems to have gone with light weight and less HP concept in competing with the likes of Datsun/Nissan, Toyota, and Porsche over the years. In racing, the rotaries blew away the aforementioned other cars as well as the ‘American muscle’ with championship after championship. On the street, they were as good or somewhat off their competition except when it came to the 3rd generation RX-7. With 255hp, 0 to 60 in the mid 4 seconds and a top speed of 161mph, every rotor head felt that Mazda might be getting ready to move the RX-7 into the "super sports car" category. But no further development was made due to the public’s lack of interest at the time for not only the 3rd generation RX-7, but sports cars like the Supra, 300ZX and others. The SUV and sports sedan craze was taking over the public interest at the time. The rotary engine is not ready for the "scrap heap" or as one of you put it, retirement to the museum. If you truly knew the history behind this wonderful engine especially in all of its forms (2-rotor, 3-rotor and 4-rotor), a lot of you would change your mines about it. It was Mazda’s 700+hp prototype sports car that was the first Japanese manufacturer to win the infamous 24 hours of Le Mans in 1991 by several laps over the likes of Porsche, Mercedes and Jaguar. Today, it is the RX-8's in GT racing using the 3-rotor engine (410hp)that is once again, has the competition crying foul because the cars are powerful and out handle the others so much better. I would love to see Mazda offer a Special Edition Miata with a 20B rotary, designated MX-5R; with the "R" standing for "rotary". Base hp for a 3-rotor is 310 regular aspirated. Thank God that the Mazda engineers over the years have not been detoured by the nay sayers as I have read here. Chevrolet and Mercedes couldn’t produce a viable rotary engine car. But Mazda did and put it on the map as both a production and racing applications. Remember, that it was the RX-7 that was the first that saved the Mazda Company from bankruptcy. And yes later the Miata did the same thing. But no RX-7 would have originally meant ‘no’ company to create a Miata for a second salvation. I hope Mazda hangs in there and starts an even more serious development into not only the 2-rotor engine, but the 3 and 4 rotors as well; and yes, come out with that 4th generation RX-7 with at least 300hp.

  • Keld Tundraking Keld Tundraking on Aug 28, 2010

    I get the confusion from some people. The MX-5 is such a joy to drive. It begs the question why work so hard on a engine, whos research only benifits one model in your lineup. I have a '88 RX-7 and I love it. It's old, but i love the way it sounds and drives. Some people might just buy em for the fascination in the motor, that's what first drew my interest, plus I just love the 80s sportscar look. I want the rotory to live on, and I think there are two main things mazda needs to do to make it happen. 1. Find another venue to profit off of the tech, a single car model is not going to cut it, especially not now, rotory's are for sportscars, if your thinking practicality and back seats why the hell are you thinking an engine that, if it's lucky gets 18 miles to the gallon. I've read a few articles, and posts about them being used in small aircraft. Sounds like a good place to start. Then your development costs see a larger market of return. 2. Maybe it's cost, trying to keep the price down? Or wieght. But Mazda needs to reunite the rotary and the turbo. The rotary engine was born starving for forced induction. A belt driven supercharger might be better still, alleviating even more of that low end grunt issue. Without it's turbo, the everymans rotary just falls into mediocrity in the current environment of engines, with piston motors seeing the benifits of being researched by every car company and rotaries just having 1.