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Len,
I bow to your superior knowledge & experience.
But when the Renesis first came on the market, one of the big
rotary speed shops did everything they could with custom exhaust
systems (headers) and IIRC, the most HP gain they got over the
stock Renesis exhaust manifold was 7 HP. (The only custom exhaust
header I see for the Renesis has a claimed increase of 4 HP.
http://www.racingbeat.com/RX8/Exhaust-Headers/16133.html )
Their conclusion was that with the Renesis' zero intake/exhaust
overlap, all that mattered on the exhaust side was keeping back
pressure to a minimum. They concluded that the only 'tuning'
available on the Renesis was on the intake side, since the exhaust
couldn't contribute to increasing intake flow like it does on
'normal' engines with overlap. Do you disagree with this?
(Remember, I'm only talking about the Renesis, with zero overlap.)
Charlie
On 4/11/2016 2:38 PM, Lehanover wrote:
For intake lengths, the ideal is the enemy of the good.
There is only one perfect length and diameter for each full
throttle RPM. So a very large number of lengths and diameters
work very well for AC use. Tracy's Race winning engine had
rather short compact tube lengths and outran everybody. My
racer has 170 HP at 6,500 RPM and 250 HP at 9,600 RPM from a
12A engine with 2292 CCs. This with a very large bridge port.
The 13Bs you are building are bigger with 2,606CCs.
The engines tune like a 2 cycle dirt bike. The exhaust
system makes a far bigger difference than does the intake
design. My Drummond built race engines us a stock intake
manifold gasket. The intake runners are polished but NOT
enlarged. You want the highest possible intake flow velocity
at every RPM. The intake manifold to mount a Weber 48 IDF has
a plenum below each throat so the actual runner length is very
short. This in turn tunes a bit better at stupid high RPM but
works well enough to deliver good performance above 6,000
RPM. You would not have to add much length beyond the stock
lower manifold to be about perfect for aircraft use. The HP is
in the exhaust system. The side port engines have fewer
degrees of overlap than does a Pport (Massive overlap).
Renesis has no overlap at all. Smoother the idle for less the
overlap.
Lynn E. Hanover
Racing rotaries since 1980.
Actually on paper I’m still the CEO
of the company but all the day to day operations are
handled by Laura since my retirement. She has been a
great business partner.
Tracy
Sent from Mail for
Windows 10
Actually,
The company is owned by Laura, Tracy's EX.
(reminds me of the license plate of a Mercedes, in
my area," WAS HIS"
Although
they don't have aviation parts any more, they
still stock a complete line of Tracy's seals,
rebuild kits etc.
Sorry
for lack of detailed info; I was away from home
& pecking at my phone to reply.
Wayback machine:
https://archive.org/web/
Tracy's old website was:
http://www.rotaryaviation.com/
which no longer has aviation info on it (currently
only car performance parts under different
ownership).
=
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