Jerry Hey wrote:
 > >>
 > >> Predictable performance is a critical part of making up a firewall
 > >> forward package for any design.    For the Tailwind,  I originally  

set

 > >> the goal of 180 hp/6000 rpm with a NA 13-B.  I was told that should be
 > >> no problem.   But exactly how does one achieve that performance?
 > >> Assuming Tracy's ignition and fuel injection,  we still have the
 > >> exhaust
 > >> system  and intake manifold design.   Also, there is the issue of
 > >> Street  Porting or even a mild PP if there is such a thing.  Can 

anyone

 > >> say that if I do the following, the HP will be............?   If the 

NA

 > >> rotary can deliver180 hp, then it may very well become the engine of
 > >> choice for the Tailwind.
 > >>
 > >> Of course,   the recommendations have implementable.  No point in
 > >> talking about a tuned exhaust, if there is no place to put it.
 > >>
 > >>   I want to go on record to the Tailwind community saying what is
 > >> possible.  I would like to provide a list of SPECIFIC  RECOMMENDATIONS
 > >> on  how to set up the engine to achieve the performance.
 > >>
 > >>     Although, I have followed the debate about spinning engine faster
 > >> (and faster) to gain more hp that is not what I am talking about.
 > >> What
 > >> HP can be made at 6000 rpm?    I like this engine speed for the TW
 > >> because of the reduction ratios of Tracy's drive and  because bearing
 > >> loads are lightest at this rpm.  The Tailwind does not need more than
 > >> 180hp under any circumstances.   It is a very  hot performer with an
 > >> 0-320.
 > >>
 > >> Jerry

  
The current output for 13B with two 38MM chokes is 225 HP at 9,300 RPM. That 
is with as big a street port as you can grind. It wouldn't last long at that 
speed. At 6000 RPM I don't know. The racers need power from 7,000 on up. 180 
HP at 6000 sounds about right. I would leave the inserts in the exhaust 
ports. Run 1 7/8" ID headers as long as possible before collecting. The exact 
same length of both pipes is the most important feature. In GT-2 you can run 
a bridge port and two 44MM chokes. Best power at 9,300 is just over 300HP. I 
would build it with a mild street port, and if you don't like it you can add 
the bridge port later on. If you are still unhappy you can go to the 
periphery port later and just epoxy the side ports shut. You can assemble 
part of the engine and copy the side port timing onto the rotor housing with 
a marking pen and a small square. I used a piece of exhaust pipe formed into 
a square on one end, and epoxied into place. I think this will be "air show" 
power on a Tailwind. 

Lynn E. Hanover