Vance W Jaqua wrote:

----- Original Message -----
From: "ACRE NL" <rotaryeng@earthlink.net>
Sent: Monday, September 09, 2002 11:58 PM
Subject: 20B turbo...calcs

Now you are getting into a real can of worms :-)
Considered as a two cycle it is 1.3 liter but it is not a two cycle.
It is equivalent, as far as the volume of air it pumps, to a 2.6

liter

4 cycle 4 cylinder engine. However the volumetric efficiency is at
least 20% higher than any piston engine. No poppet valves to get in

the

way of the intake ports. Therefore in terms of turbo charger
selection I would use about a 3 liter equivalency.


Paul Lamar

Royce, its 40 cu per rotor face. Each face as it makes its pass by the
intake "scoops" up approx 40 CID of air/fuel mixture..   A two rotor

has 6

rotor faces (3 per rotor) x 40 CID= 240CID.  For a 3 rotor that would

be 9 x

40 = 360CID equivalent. But, as Paul points out - with considerably

better

flow due to the lack of a poppet valve so the 240 CID for the two

rotor is

more equvilant to 240 x 1.20 = 288 CID in a reciprocating engine.

Ed Anderson

I did not really want to get into this as we will hear from Vance :-)
Engines are rated on displacement related to output shaft revolutions.
Forget rotor faces. The rotor rotates at one third output shaft
RPM. The 13B engine displaces 1.3 liters or about 80 cubic inches
per output shaft revolution and it fires twice

It fires twice per revolution????

Yes.

just like a two
cylinder two cycle engine would do. It pumps the same amount of air
per rev as a two cycle 1.3 liter engine but with higher vol eff.
A three rotor is therefore about 2 liters or about 119 cubic
inches. This is important as it explains the small physical size
and weight of the rotary related to its large amount of HP generated.

Paul Lamar

No more questions for now, still digesting the rest for now.
Royce

Yes! you guys have rassled with this so long that I have to chime in.
The turbocharger does not give a damn what rpm your engine is running
it only sees the exhaust and air flowrate, and that is directly related to
horsepower. If you pick a turbo that has a design point around 300hp
it does not matter if that is a 550 cubic inch Continental at 2700
or a 55 inch engine at 27000. if the boost pressure is in the useful
compressor map it does not care  - Vance

 
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