"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

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