Just a note about peripheral exhaust ports and apex seals.  Note that

Mazda has

only built exhaust ports up to a certain width - no wider.  There is a

reason for this -

if the port was wider there would not be enough support for the HOT

apex seal.  The

seal would become concave and actually extend into the exhaust port and

break

when the upper lip of the port was crossed.  This probably happens a

little right now

but not enough to be harmful.  Two stroke motorcyles use a 'verticle

bridge' in the

center of the port to give the piston rings support.  Unfortunately,

this can not be

done on a wankel due to the hot exhaust gases would warp or destroy the

bidge.

Ken Powell

Can Ken or someone help me understand this?  I thought the rotary had
higher exhaust temps due to not having exhaust valves to absorb some of the
heat from the hot exhaust gasses.  Like the rotary, two-strokes don't have
any exhaust valves either, and both burn pre-mix gasoline, so why would the
rotary have higher exhaust temps than a 2-stroke?

That could be partly the reason. I don't think anybody has precise data
on what parts of the increased heat are the result of any one particular
factor. We do know the exhaust is hotter. We do know there is excess unburned
fuel in the PP exhaust. We also know the peripheral exhaust port opens
sooner than it could. When we get data on the RX8 engine we will know more.

In other words I don't think we know.
 
Paul Lamar
 
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