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Date: Wed, 08 Feb 2006 00:10:25 -0700
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
From: "BillDube@killacycle.com" <billdube@killacycle.com>
Subject: Re: [FlyRotary] 6 port?
In-Reply-To: <list-974406@logan.com>
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If the six ports didn't make more HP, then Mazda wouldn't have gone through 
the trouble and expense to make them.

In an airplane, as long as it can idle, you don't care about low-end torque.

The prop absorbs HP proportional to the cube of the RPM. Thus, you are 
spinning mighty fast before any torque to speak of is required. At that 
point, you are on the curve for the manifold with all the valves open.

Indeed, the six port needs a properly tuned manifold to make the extra HP. 
If you are going to put a simple log on the end of some short runners, then 
there is no point of using a six port because the four port will make the 
same HP.

It will be a few months, but we shall see what HP I get when the dust 
settles. :^)

Bill Dube'

At 11:50 PM 2/7/2006, you wrote:
>I have never seen a race car (where the owner had a choice), run with a 6 
>port engine.
>
>The 6 port works with high revs and a very complex tuned manifold. Without 
>the valving to transition between the RPM ranges, it will be a dog at 
>lower revs. Poor runner velocity and the like.
>
>Save yourself a lot of pain and buy the 4 port. Simple manifolding, even 
>if you build it yourself.
>All of the racing stuff works fine, if you want porting.
>
>Look for 180-190 HP from the base engine with a big TB. If you really need 
>well over 200 at below 7,000 RPM buy the turbo now. Or learn to street 
>port. You will be surprised to find out that real airplane engines have 
>nothing close to their advertised HP. That 180 real dynoed HP of a rotary 
>will have you outrunning the real airplane engine powered stuff with the 
>advertised 200 HP.
>
>
>Lynn E. Hanover