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Hi Bill,
Ok, just thought since Ben mentioned water/methanol
injection he was also interested in cooling the intake charge. I don't
think I would want to inject sufficient water to bring the EGT down that
much. Changing the phase state of water undoubtedly absorbs heat from the
combustion process - if it is necessary to prevent detonation/preigntion then of
course its worth it - but its bound to reduce the power output.
From what I have read in the Turbo books, most experts now
adays appear to consider water injection a poorer approach than - say backing
off ignition time via knock sensors.
Yes, the turbo housings (without the exhaust splitter)
have tended to pound anything that is close to perpendicular to the front of the
shock wave into pieces - in short order. I've never had any trouble with
the heat as I use stainless steel pipe for my headers (which are 18" long) and
by the time it gets to the muffler, the temp has decreased - but apparently not
the shock wave.
Ed
----- Original Message -----
Sent: Wednesday, December 05, 2007 10:15
AM
Subject: [FlyRotary] Re: Methods of
charge cooling was Water/Meth injection
Ed, intake charge cooling is fairly easily understood, but I believe Ben
was talking about cooling the rotary EXHAUST. You have mentioned that the
exhaust tends to melt or batter everything in front of it.
Ben, here is a URL that gives a
number of different ways to cool the intake charge. You may find it
interesting
Ed
----- Original Message -----
Sent: Tuesday, December 04, 2007 3:00
PM
Subject: [FlyRotary] Water/Meth
injection
I have moved away from the Rotary (shame on me) and toward the Subaru.
I have been researching how to get more torque and found the only way is
with boost. The street Subaru guys are injecting water and methanol to avoid
detonation under high boost--getting 450 hp from 2.5 liters. The methanol
and water cool the charge while the methanol also increases the octane.
This allows them to run 89 or 91 octane fuel under low boost w/o injection
and have high octane-high boost with injection. The injection is set to
start at a certain boost pressure or rpm level.
I am going to go this route in my aerobatic biplane so I can run on
cheap fuel in econo cruise and still not detonate while doing full throttle
aerobatics.
One of the side benefits of this injection is lower EGTs--as much as
400 degrees. Has anyone done any testing with water injection to lower
EGTs?
Another benefit is much cleaner combustion chambers. That sounds
useful to me, too.
Ben
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