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I would say the parts industrie would suffer.I think the concept of the engine is sound I am not a engineer but to class this engine as a joke is a bit over the top.Mazda Honda engines are top of reliability so at least they are trying something different .Maybe to do with cost why mazda are not developing this engine more i dont know i would have to talk to one of their engineers .
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>>Mazda Honda engines are top of reliability
That the piston engines maybe - not the rotary ones.
the RX-8 uses fuel and oil like its going out of fashion, in fact its the only car I know of, that is supplied new with 1 litre of oil in the boot (at least it was when I worked with Mazda, can't see its changed)
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The Wankel engine is extemely inefficient-mainly due to it's tortuous inlet and exhaust passages.And before someone claims outstanding performance from a 1300cc. engine,it has a "swept" volume of 3,900cc(3x1,300cc) and whilst the fuel consumption and emissions are inline with an engine of this capacity, the BHP output isn't.
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As a devotee of the Wankel engine (my father had about three NSU Ro80s) and his company trained the main garage mechanic to fix them, I can say without doubt that they are a great idea in principle, but flawed in use. An esoteric option that has certain advantages but also significant disadvantages that in today's world are more important than the advantages.
Therefore, suitable as an interesing USP for a low volume sports car (Rx-8), but not for mainstream production models.
If it was so good, Subaru would make one - and they don't!!
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Biggest advantage of the rotary engine is its relatively compact size which allows a very low centre of gravity, ideal for a sports car such as the Mazda RX8. However it also results in a car which, instead of rewarding its owner with an appealing 6, 8, 10 or 12 cylinder soundtrack, sounds like a vacuum cleaner.
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>>The Wankel engine is a joke
I fully agree, they're a nonsense.
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Even Felix Wankel himself disowned the design variant that went into production.
In his original prototypes, both the rotor AND the main housing rotated around the eccentric shaft, with the drive taken from the housing.
Of course, this created installation & mass-production problems so the rotor housing became static, with the rotor & eccentric shaft making the drive instead.
His comment to NSU was "you have made my race-horse into a cart-horse."
However, he wasn't too proud to bank the patent & licence fees :-)
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The piston engine continues to get better after 100 years of intensive development, and the rate of improvement doesn't seem to be slowing down yet. I wonder where the Wankel engine would be after all this investment/development?
Apart from all the technical stuff the name always created a snigger in my school days. Tee hee....
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If they are as good as claimed, and seal wear problems sotted why have all the RX7s dissapeared?
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For the same reason all the Open Monzas, Ford Capris, and Ford Probes I guess.
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I had a brief passenger ride in one of the last RX-7 twin turbos, rumoured to be producing 280 bhp from its 1.3 litre rotary engine. It was fast, and uncannily smooth, spinning to 8000 RPM with not even the slightest hint of vibration. Sounded dull though - reminded me of an electric motor with a bit of bass.
The real fly in the ointment was fuel economy. Its owner told me that driving "like a nun" in perfect conditions, it would just about do 20 mpg. Throw a bit of traffic and stop/start into the mix and it was mid to high teens. Drive it hard, and you could get a tank average down into single figures. It was fast, but not THAT fast.
I've never seen the point of this engine beyond its novelty value. Apart from its smoothness, it has no real advantage that I can work out. It's torque deficient, thirsty, has question marks over its longevity, and the vast majority of mechanics out there will have no more clue about its inner workings than you or I.
The engine is the only reason I wouldn't buy an RX-8. They should have lobbed a nice gutsy V6 in it.
Edited by DP on 02/11/2009 at 08:44
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A friend had an RX7 turbo (the 944 lookalike model) in the mid-90s.
It was a Mazda approved used model, with warranty. And boy, did he need it -- it lunched 3 engines in 18 months. After the third warranted engine failure, he left the car at the dealer and got most of his money back.
The theory at the time was the motor didn't like the composition of UK fuel ... but it also seems that the rotor seals don't like short runs in cold temps, as the rich mixture washes the injector oil off the chamber walls, leading to rapid wear and scoring.
I would really, really like to have a ride on a Norton rotary bike, they are supposed to be special.
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People complain about oil usage . As far as I know all VW/Audi cars are supplied with oil from new and they certainly seem to burn it. Before I had the Audi I had never had to top up the oil between services, Now I do it 3 times a year and the neighbour across the road with a MK5 Golf is doing it more often than that.
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The VW oil usage problem always used to be associated with "new" engines and used to settle down as the engine got towards 50,000 miles.
Our PD TDI Golf (130 bhp) doesn't seem to use a drop of the stuff at 93,000 miles, but I can't comment on what it was like earlier in its life. I had a 1998 Polo 1.9D with 30,000 miles on it which, apart from being indisputably the most nigglingly unreliable, badly made and joyless car I have ever owned (including Ford, Vauxhall, Peugeot, Renault), used to need a litre of oil every 1500 miles or so. I had no inclination to hang on to the hateful thing to find out if it got better with miles.
Edited by DP on 02/11/2009 at 10:53
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My 170PD A4 B7 used about 1ltr of incredibly expensive VW 507 oil every 7K miles and other forums implied that this was actually good for this engine. My current BMW 330D has used less than 0.5ltr in 12K miles by comparison.
Like you I never needed to top up previous cars before the Audi although I guess with worryingly long (imho) service intervals of 18K for the Audi and with my BMW currently showing 23K for its first service then I guess the need to top-up is inevitable.
Back on subject, the rotary engine is a great theory and interesting technical diversion imho but the fuel consumption / emissions seem to kill it these days. I think it gets a lot of power from a small displaced volume but I assume that (for instance) aspects such as poorer thermal efficiency outweigh the benefits (e.g. friction) from less moving parts ?
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