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Re: [turbobike] Water injection

Patrick Inniss (inniss@sprynet.com)
Fri, 1 Oct 1999 23:59:40 -0700

I think that water injection was used in the old turbocharged Corvair
Spyder. Water injection was also available on turbocharged fighter
planes like the Corsair and kicked in when emergency power was needed at
low altitudes. Some engines actually injected a water/methanol mix. I
also seem to remember seeing some crude bike installations maybe using
windshield washer pumps. It does seem like a good idea. Here's some
stuff I found on the web -

Here's a company that sells components for water injection systems:
http://www.aquamist.co.uk/cp/cp.html

Also http://bert.netcolony.com/members/csdaytona/water.html


Water injection systems are only needed in turbo charged engines. The
system has been around for a long time since it was already used in some
World War II aircraft engines. A water injection system works similarly
to a fuel injection system only  it injects water instead of fuel. In
high pressure turbocharged engines the air/fuel mixture that enters the
cylinders can explode prematurely (before the spark plug ignites,
effect also known as engine knock) due to the extreme engine environment
conditions. This situation results in severe engine damage in the long
run (piston piercing). To avoid damaging the engine, water is injected
in the combustion chambers in order to provide a  water/air/fuel mixture
which not only burns more efficiently and avoids spontaneous detonation
but also provides additional cylinder and piston cooling. There are
mainly three variations of water injection devices. They are dependent
on the location of the water injector(s). The first technique consists
of injecting water at the entrance of the
intake manifold. The second injects water at the exit pipe of the
intercooler. The third technique injects water at the entry of the
intercooler and is only used in competition vehicles. In this latter
variation most of the in-cylinder detonation prevention is done by
injecting additional fuel which is used as coolant (i.e. not burned).
  How water injection works
The system, usually, is made up of 3 elements. A water injector (similar
to a fuel injector) a high pressure pump (capable of 3 to 4 bar pressure
and sometimes even more) and a pressure sensor connected to the inlet
manifold. The most advanced systems add 3D cartography similar to what
is used in fuel injection systems.

When the pressure in the inlet manifold exceeds a certain, predefined,
value the system starts injecting water. The cartographic based devices
take into account many more parameters such as inlet air temperature,
air/fuel ratio, ...

Copyright 1997-1999 by Tryphon Georgallides, all rights reserved.

from
http://www.fortunecity.com/silverstone/morgan/161/how/waterinj.htm:

Water injection systems are mainly used on turbo-charged engines. It
works similarly to a fuel  injection system only it injects water
instead of fuel. In high pressure turbo-charged  engines the air/fuel
mixture that enters the cylinders can explode prematurely  due to the
extreme conditions. This situation results in severe engine damage in
the long run (piston piercing). To avoid this, water is injected in the
combustion chambers, usually through the intercooler, in order to
provide a water/air/fuel mixture which not only burns more efficiently
but also provides additional cylinder and piston cooling. The use of
water injection seems to have re-emerged in recent times. APS (sellers
of a performance kit for Subaru WRX's) have included it as part of their
package and others such as aquamist sell independent kits.

  There is a great deal of skepticism amongst tuners about the benefits
and the effectiveness of water injection. However, some of the
manufacturers, such as aquamist, do have some very comprehensive kits
that incorporate features such as 3d mapping.

Good luck,

Pat Inniss
inniss@sprynet.com
http://home.sprynet.com/~inniss/
----- Original Message -----
From: Bob Buehler <ribicf@hotbot.com>
To: Turbo Bike Mailing List <turbobike@natvideo.com>
Sent: Thursday, September 30, 1999 9:04 PM
Subject: [turbobike] Water injection


> Hi Gang:
>
> I need some advice on water injection. I was told or read somewhere
that water injection was relitively simple and inexpensive and would
alow for the use compression ratios of 9 or 10 to 1 as is found with
stock pistons.  I believe it also was supposed to inhibit detonation
using stock compression ratios even at boost pressures as high as 12 or
14 psi.
><snip>