----- 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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