----- Original Message -----
Sent: Thursday, July 27, 2006 10:02
PM
Subject: [FlyRotary] Re: Intake design
101
Hi Joe,
Each chamber has a secondary and a primary port (six
ports have an auxiliary port which is like an additional secondary
port). Even thought a chamber has a primary and secondary, the primary
and secondary for a port normally have different intake timing.
Additionally, the opening of the intake port generally generates a very
strong pulse (residue exhaust gas bursting out of the intake when it
opens). Since the intake and secondary port of each rotor are 60
deg out of phase timing wise with the other rotor, the pulse generated by
each port can interfere or assist with intake airflow (depending on rpm,
manifold air temp, density, etc).
I personally prefer to keep the intake ports separate
to preclude interference. Having said that - I have successfully
flow with a system that combined the secondary intakes and primary intakes,
so what you propose can be done. However, after trying six different
intake configurations, I have found though that I get the best
performance (for our rpm) with 4 separate tubes feeding the throttle
body. Keeping in mind I have a "Plugs Up" installation which generally
gives me a bit more room in running intake tubes. Other
arrangements have been tired and certainly work, so this is no magic formula
- just based on my personal experience.
Yes, the tuning (length) of the tubes should be
determined by the rpm band that you want the most airflow enhancement.
It appears that a tube length from block to Throttle body between 17 and 21"
generally gives good results. Also, avoid excessive large
tubes diameters as intake air velocity is important in
stuffing the chambers and larger tubes results in less
velocity. I found that 1.25" dia tubes for the primary and 1.5" dia
tubes for the secondary works well.
I originally had my intakes merged into a two runner
Weber style manifold. A two port Weber style throttle body with two 2"
dia intakes. While this was the cats' meow for a racer turning 9000+
rpm, it turned out to be disappointing in aircraft use with lower
5000-6000 rpm. When I replace this "racers'" set up with 4
smaller dia tubes my ROC increased by 300 fpm immediately.
Unfortunately my original fuel injection system died and I did
not get to collect further data on my old six port 1986 engine before
deciding to switch to a 91 turbo block.
Hope this helps.
Ed
1----- Original Message -----
Sent: Thursday, July 27, 2006 9:24
PM
Subject: [FlyRotary] Intake design
101
I am using a 89 block for mock up and maybe
rebuild. Looking at the intake ports, there are two ports at the
front and rear of the block then there are two rectangular ports in the
center housing close to each other. Others have fabricated intakes
using 4 tubes. I assume it is OK for the two outboard front and rear of
block to be fed by one tube while the center two ports need to be fed
individually. Is this correct? The length of the tubes is determined
by where on the rpm vs Hp band you want to operate at? Thanks
Joe Berki
Limo EZ
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