>>
>> Thanks for the update, Rino.  You are definitely doing ground-breaking
>> work in our arena.
>>
> snips....
>
>>
>> BTW, did you fabricate your own intake manifold or sub it out?  I'll
>> be
>> building one for my Renesis -- haven't decided on using aluminum vs.
>> molded CF for the upper manifold yet.  My engine is still at Bruce's
>> getting the final touches.
>>
>> Scott Gettings
>>
>> Scott what all are you doing to your Renesis? What are your manifold
>> plans?
>>
>> Ken
>>
>
> Ken,
>
> I bought a Renesis with 2K miles on it from a Rx-8 getting a 3-rotor
> conversion.  It is currently in Bruce Turrentine's shop.  He is doing
> all the standard internal modifications, such as replacing the side
> seals, doing some porting, adding silicone to dampen the tension bolts,
> as well as lightening, etc.  The internal variable intake tubes will be
> ported, then set-screwed in place to optimize about 7K rpm.  They can
> be adjusted if needed.  Redrive and ECU will be Tracy's.
>
> I plan on cutting off the  lower intake manifold (exact position not
> yet determined), and weld on 4 elbows to keep the profile much closer
> to the engine than stock.  From the elbows, I'll have 4 runners flow
> across the block, with injector, a plenum and throttle body on the cool
> side (similar to many existing installations).  This upper manifold
> will most likely all be carbon fiber and high-temp epoxy, but I haven't
> completely ruled out welded aluminum yet.
>
> Having had considerable composite experience, I'm pretty confident I
> can build plugs, molds and produce a manifold with smooth internal and
> external surfaces from carbon fiber.  The plugs will be built from foam
> or paraffin wax, 1/2 at a time (upper and lower surfaces.  The bonding
> between the upper and lower runner products will be a flat flange that
> runs between the tubes.  So the upper side looks (roughly) like:
> _/\_/\_/\_/\_     The flanges also allow mounting surfaces.
>
> Blending in bell-mouths and the plenum chamber will be a little tricky,
> but is not beyond reason.  I might build the plenum chamber so that one
> could attach a throttle body on either end, making it useful for
> pushers or tractors.  Positioning the injectors on the side  of the
> plenum chamber (pointing at the bellmouths) would allow a much easier
> installation than fitting them against the curved edges of the runners.
>   The latter case is easier in aluminum, but can be done with a
> composite version.
>
> The downsides of epoxy/CF are that it needs to be strong enough to
> withstand a backfire (anyone want to estimate a psi from a backfire?),
> it is a little difficult to integrate metal components, and it is
> eventually capable of burning (but so is the cowling).  I'll have
> multiple temperature sensors and a fire-suppression system to mitigate
> the latter.  Regarding a backfire, the weakest area of the manifold
> would be the bonding flanges, which could 'peel' apart long before the
> tension of the carbon fiber was exceeded.  If I have a optional
> position for the throttle body, this (unused) end of the plenum could
> be capped with blow-off capability at a certain pressure.  Some
> secondary CF tapes placed at the bond line inside the runners might
> also be possible (at least in some areas), or a secondary internal
> flange that spans the bond line also seems possible.
>
> Pending issues:
> 1. Exhaust:  probably three, 321 pipes to a tangential muffler,
> exhausting at the prop hub area.
>
> 2. Thermostat:  Bruce wasn't certain if I should use a restrictor
> plate, keep the thermostat, or modify it to accept no restrictions at
> all.  I haven't seen the internals on the RX-8 pump yet
>
> 3. Cooling: using Paul's concepts, with internal ducting.  Large, thin
> main radiator up front and the oil cooler below the engine.  There
> should be more than enough frontal intake area to handle the main
> radiator, oil cooler, intake, and exhaust tube.  This will have to
> follow the engine installation.  I'll probably be able to shrink the
> original cowling once everything is optimized.
>
> This will keep me busy for a long time!
>
> Scott Gettings
>
> If you are exhausting to the rear (flywheel) of the engine, why don't
> you
> just use the stock exhaust manifold?  It only weighs 15 lbs and will
> need
> about a foot of pipe on the end to reach out of the cowl.  How much
> weight
> can you save by building your own and how much will that wt savings
> cost?
>
> Bill Bradburry


Bill,

That is definitely an option.  I (will) have a stock exhaust  manifold
with my Renesis, I just don't have it yet.

Scott

Hi Scott,   I have the stock exhaust manifold for the Renesis, I am not
going to use it.  If and when you decide to use one, tell me.

Rino Lacombe