Al Gietzen wrote:

Jeff Spitzer wrote:

In a normally aspirated engine the tuned intake yeilds more power.

The question is: "how much more".  Dave Atkins had indicated to me some time
ago the he thought is was only about 2%.  Paul Yaw's comment I think was
"not much.  I realize that it; compared to what?  Do we have some measure of
the effect of tuned intake vs easy breathing intake on output at around 6000
RPM on a stock ported engine?

Al Gietzen

I would say more like ten or twenty percent. Especially if you have done
something to hurt it like make them too short.

This too has been extensively discussed on the ACRE news letter 
in the past with many such charts. As I recall this one is for the
four rotor Lemans winning engine with peripheral ports.

Divide the torque by two.

It was the variable length intake system and it was referrenced
to the shortest pipe given in the chart at 0.

Note increasing the length by only 75 mm moved
the torque peak down from 7500 to 6000 RPM.

The total overall length of this pipe was around 18-20 inches
at 6000 RPM and with a diameter around two inches.

With a long pipe like this and peripheral ports a two rotor
would generate about 240 HP at 6000 RPM.

What are we getting now-a-days 180 HP? 

Heck Power sport is getting 210 HP at 5850 RPM  with long tuned
smaller diameter pipes and smaller peripheral ports.

Paul Lamar
 
The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org