Chuck;
2 (dumb?) questions:
If you add a muffler, does this create power-robbing back pressure?
How the heck do you verify displacement at teardown after a record run?
Ed
Chuck Rothfuss wrote:
>
> 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
>
>
|