Hello everybody,
I joined a week ago in an effort to learn all I could about a using
a mazda 13b on my Osprey 2 project...I feel that I definitely came to
the right place! I have a new 89 13b turbo II engine bought
a few years back for another project that I never got around to
finishing. I have spoken to Tracy Crook a few times about his PSRU and
ECM and believe that is the route I'm going to take. I have a
few questions, I was hoping I might get input on, however. I was
not planning on using the turbo (even thought it is new), but I'm
concerned about trying to deal with keeping a muffler on the
engine with the extreme exhaust heat. Since the engine is new, I
really do not want to tear it apart to replace the low compression
rotors, but I need all the power I can get (to get off the
water).
I have heard a turbo acts as a pretty good muffler, but the stock
turbo will not work for an aircraft. My question is... will the stock
turbo not work at all, or is it just not ideal. I
do not want anything complicated like altitude power compensation.
In my application, boost on take off is more important anyway. I'm
wondering if the stock turbo would provide reliable exhaust
sound reduction with enough power gain to offset the extra weight,
especially since I do not want to switch rotors if I don't use the
turbo. Speaking of weight, the turbo, manifold, and intercooler
weigh 33 pounds. What kind of weight would I be looking at for a
manifold and muffler?
In short:
Will I a stock turbo work at all? If so what kind of HP could I
expect? How much more complicated to tune?
Will I still need a muffler?
How much more weight will the turbo be than a muffler?
Anyway ... sorry this was so long. Any advice would be greatly
appreciated.
Thanks
Gregg Miley
The stock turbo works but you have to limit the boost to about 30" Hg
particularly at altitude or it will over speed and destroy itself. You
won't see
much more than about 200 HP. A Borg Warner TO4 at about $450 is
probably
is a lot more durable but much heavier. You would also need a heavier
exhaust manifold for a TO4.
On the other hand an Osprey is a small airplane designed for a 200
pound, 100 HP
O-200 as I recall so a turbo 13B would be extra heavy. I would go with
a
normally aspirated 13B even with low compression rotors. Save weight
wherever
possible. Perhaps an inconel muffler.
You could also sell the engine you have and pick up a normally
aspirated engine
to get the high compression rotors. Even an RX8 engine is a
possibility.
An RX8 engine would not require such a heavy duty muffler due to the
side exhaust.
You will still be looking at around 300 pounds for the engine and
cooling
system. With peripheral intake ports from Jerry Hey perhaps 220 HP at
7000 RPM.
For some big bucks you can get aluminum end housings from racing beat
to
further cut the weight of the engine.
Paul Lamar
Thanks for the info. The Osprey is actually designed for a Lycoming
0320. My understanding was the weight of the 13b and 0320 were close.
I want a simple and reliable installation, so it sounds
like I should drop the turbo idea and find a muffler that will
work....It is just hard to toss out a brand new turbo!!!!
Would the turbo quiet the exhaust enough to eliminate a muffler
anyway? As far as limiting the boost would the stock waste gate and a
pop off valve do the trick or is something more complicated in
order?
PS Thanks for reposting this - AOL is sometimes a pain!
Gregg
I stand corrected. I am impressed. It is a small amphibian say...
compared to a Coot.
The weight of the installed 13B is indeed close to a O-320. Bare engine
weight 190 pounds.
by the time you add everything need like PSRU/starter/alt/cooling system
you are up
to around 300 pounds. My guess is you will add about 45 pounds for a
TO4, intercooler
and exhaust manifold over a normally aspirated model. Somewhat less for
a stock turbo.
You can hear the sound of a turbo rotary by logging on to
http://www.bob-white.com/ACRE
and download a movie of Dave Leonard's turbo flying at low altitude.
I would say it is a bit noisier than some rotary mufflers and about the
same as others.
Paul Lamar