Chuck,
Everything I hear about Japan indicates an obsession with clean engines to
the point that they replace engines rather than rebuild them. Where does
the rotary fit in that scheme? I would assume the variety of domestic
rotary engined models offered there would have to be quite good on
emissions. What does Mazda do to make them comply? Have they changed the
seals? The triple rotor motor has to wear on the walls of the block at a
rate three times that of a four cycle engine If what I understand of the
engines is right.
Wes in SLC
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> From: Chuck Rothfuss <crothfuss@coastalnet.com>
> To: land-speed@autox.team.net
> Subject: Rotary engines
> Date: Fri, 03 Dec 1999 19:34:50 -0500
>
>ArdunBill, John, List,
>
> The rotary fell out of favor more in the US because of Mazda's
>unwillingness to release the engine in anything but an RX7, and it's
>extensive list of patents, which made the engine uneconomical for anyone
>else to produce. Then they priced the RX7 out of most mortals reach, and
>had gotten a little over their heads with the sequential turbos. (Not
>something you sell the "put gas in it and drive" public.) Last time I was
>in Japan ('91-'92) there were rotaries in slick two door sedans, large
>(Lincoln Sized) 4 door sedans and the RX7. The three rotor hadn't reached
>the tiny island of Okinawa yet, but at 450 HP in stock trim I was hoping to
>make another trip after some hit the junk yards. My priority aboard
>military aircraft has been degraded somewhat since I retired, but I'm
>getting ideas! ;)
>
> Mazda's latest redesign of the Wankel will radically change the exhaust
>port configuration, from a peripherial design to a side port, like the
>conventional intake. Basically the exhaust will have to go around a corner
>instead of blasting straight out into the header. This will also allow the
>exhaust to exit from two sides of the rotor, so a much more gradual exit
can
>be achieved. This will allow fuller combustion and soften the exhaust note
>considerably. The possibilities for rotary tuners to alter this new design
>are equally exciting, since it will allow greater flexability in where the
>power band begins, and where peak HP will be acheived. By altering the
>intake and exhaust ports we can change the lift and duration and timing,
>just like your conventional camshaft. That's the largest thing rotary
>tuners have to play, since we can't easily change the engines displacement
>or compression ratio. (Although there are several compression ratios
>available for turbo and non turbo applications.) There is little to limit
>the port size or configuration as long as you keep all the internal engine
>parts from falling out through the holes. Naturally, some ports work
better
>than others, but the engine can be tailored to the task.
>
> Yep, an altered rotary without all it's factory emission gear is a bit
>dirty, but even in the 240 HP range my street driven 13B will get 21 MPG on
>the highway. I get something like 4 MPG at Maxton. The latest RX7's and
>the earlier (second generation) RX7's were fuel injected and were pretty
>clean burning. Mazda had reduced the oil, which is injected into the rotor
>housings to lubricate the seals, to almost nothing. Older engines have
this
>oil injected into their carburetors at a rate of about a cc per minute.
New
>seal materials being tested by Mazda may eliminate the need for any oil
>injection, further reducing emissions. The rotary is also the engine with
>the greatest potential for running on alternative fuels, since there are
far
>fewer parts to corrode or which must be sealed. Don't write the little
>round engine off just yet. Remember, this is an engine whose design was
>created, and certainly perfected during only the past 40 or so years.
Gotta
>love that rotary sound!
>
>Chuck "deaf as a post" Rothfuss
>ECTA
>Pole Cat Hollow, NC
>
>
>
>
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