"Weinstock, Rob" wrote:

One of the things I'd like to understand better is how/why the 13B
is
superior to the Renesis, breathes better, but makes ~66% of the peak
power.

Otherwise, very informative!

Regards,

Rob

They raised the RPM where peak power is generated by adding 30% to
the intake
and 17% to the exhaust port areas.

HP = (Torque x RPM) /5252

Assume for the moment torque is constant.

So 8500/6500 x 185 HP is 240 HP.

I also think they made some sort of improvements in the oil pressure
system.
I am pretty sure the rotors are not significantly lighter in weight.

A peripheral port version of the RX8 motor should generate well over
325 HP with a Lemans type fixed intake system at 8500 RPM. Even with
side exhaust ports.

I don't agree the RX8 engine is a step backwards. Perhaps a little
more
heat is rejected to the cooling system but the later timing of the
side
exhausts ports does indeed result in more energy being extracted
from the
fuel.

Until we have an RX8 engine on a dyno I don't think we will find out
what
the best BSFC is. I am sure the BSFC at low RPM/power levels is far
better than the older engines. That was Mazda's main focus on
developing
the side exhaust ports.

When the electric assisted turbo charged version of the RX8 engine
appears
you will see much better acceleration performance out of the RX8.
Probably exceeding the acceleration performance of the stock 1995
third
gen 260 HP sequential turbo charged RX7 despite the extra weight of
the RX8.

Paul Lamar

Rob, and Paul

 All engineers are a wee bit biased towards what they know works:)
Mazda
people are no exception. Remember one of guys, Mr. Kagawa, designed
the
LeMans 4 rotor intake system. The context in which they were speaking
was
that the  P port exhaust engines breath easier and....

Mr. Nakane said for turbo applications the exhaust P-port is
superior to

the the high drag and heat absorbing side port RENESIS.

 I sure if I asked them what is good about the RENESIS they would
could have
mentioned a lot of things, such as a bigger water pump, and, and?

No seriously if the engine has enough ummph to power a turbo-charger
the
configuration should get better BSFC. and I'll still want to use it.
If not
then I'll be more than happy to make up a 20B from parts. For
potential
power and all around use in majority of aircraft I think the 13B has a
fantastic cost/performance ratio and this dog still has a few tricks
to show
us.

Speaking of P ports.  Jerry do you need to know the exact ID
dimension of
the P-port used in the LeMans?  A little late perhaps since I see you
already have it bonded in.

Doug in Japan

Sure,  the Leman Port was my starting point.  Here is a jpeg comparing
the Leman port with my p port. The Leman port is the black dashed line
and the blue inner circle is my port.  The red line shows a possible
modification to my port to be made with the die grinder.  This is an
early drawing.  My final port opens and closes a bit later.   Note the
opening time of the Leman port is much earlier.  Big time overlap.  The
numbers are hard to read but I have the original drawing from which I
could make a new and better jpeg from if  you need it.  The Leman Port
numbers were derived from a drawing published by Mazda which did not
have measurements.  The numbers are close but by no means exact.
Jerry

 
The Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2004 All world wide rights reserved.