Water Injection Thread

Tue Dec 29 15:14:31 GMT 1998

Greetings,

I haven't been keeping up, however having approximately 90 "water
injection" list messages prompted me to become more involved, at least
temporarily <grin>.

First of all, someone stated "Water/Alky injection is unnecessary with a
properly designed intercooling system".  While obviously stated by a Corky
Bell fan, the individual who stated this is entirely correct.  A properly
designed intercooling system will in fact lower your air charge
temperature, which reduces the possibility of detonation.  In fact, if you
could devise a system that ensures 40 F degree air going in, and
appropriate compensate this air with the proper amount of fuel, you will
have tremendous power.

If fact, I've done some tests on a non-turbo'd engine using a water-based
intercooler system, whereas the intake charge temperature was a constant 60
degrees, irregardless of the ambient air.  And yes, I made more power.  How
much power?  30 HP?  Is that worth a complex water intercooled system,
custom plumbed with all sorts of bizarre fabrication on an engine running a
9:1 c/r?

The reality of engines is they are not perpetual motion machines, whereas
all the energy pushed in results in power.  Engines run at such an
ineffecient level (something like 15-20% of their potential) that so much
energy is wasted, there are many, many ways of increasing the efficiency,
and in return, you get more performance.

You can port, polish, and dimple your intake, which everyone knows
increases airflow, especially with more cam.  You can increase the c/r
within the limitations of standard MTBE infested pump gasoline.  Yes, you
get more power, but at what cost?  You can add superchargers, wipple
blowers, turbo chargers, bigger injectors, etc, but as go increase your
power potential, you increase your risk of detonation, which we all know
destroys your engine real fast.

What I'm trying to say here, is water/alcohol injection is a crutch, but
its less expensive that building a radical engine.  It enables you to run a
slightly higher compression ratio than you normally would.  Alcohol
injection (with a little water spit into the mix) actually burns in the
cylinder, therefore its not entirely "taking up space gasoline would", and
since the alky/water mix actually cools the metal in the chamber before it
burns, you can effectively increase your c/r, inject alky/water, and not
detonate.

I achieved 849 HP and 900 ft/lbs of torque out of a junkard 4.1L Buick
engine, which ran for 22 minutes before the crank couldn't take it anymore.
 Or the block.  Not sure which gave first.

What we did was combine systems, and experimented trying to squeeze every
imaginable HP out of the engine, using support systems of many flavours.

First, the engine was overbored .030 to remove the scoring from the stock
pistons which slapped around.  Then, the entire block was polished top to
bottom, with any and all jagged edges in the lifter valley ground off to
remove the opportunity for stress cracks.  The rotating assembly was
balanced, polished, blueprinted after several attempts at magnifluxing to
ensure a reliable, solid bottom end.  A 1" thick 4046 aluminum block girdle
was made, drilled out for the main caps which were decked flat matching the
oil pan mounting surface, thus passing torque stress on the bottom of the
block webbing to each other as well as to the outside of the block.

The heads were off a front-wheel-drive Lesabre.  These heads out of the
junkyard flow slightly better than the RWD heads that came with the engine,
and have more material (read - thicker decks) to grind appropriate for more
airflow, with larger valves installed on the intake side.  Normally, the
ratio of intake diameter to exhaust diameter is 60/40, and we violated that
rule entirely going to a 70/30 ratio.  After much experimenting under
turbocharged conditions, we found this to be nearly ideal, except the
exhaust valves became extremely hot, opening up the potential for
detonation.  Anyway, the engine was assembled without head gaskets (I know,
that's nuts), but the resulting compression was 9.8:1 naturally aspirated
using custom made pistons from Wiseco, with a Wolverine cam ordered from JC
Whitney of all places with the following specs:

Wolverine Blue Racer (110 lobes)
Int:	advertised: 270 deg / .050: 204 deg / .448 lift
Exh:	advertised: 280 deg / .050: 214 deg / .472 lift

Turbocharging was accomplished by two TA-49's, with a cross-over "H" pipe
post-turbo.  The exhaust system was a 180 degree design, custom fabricated
by my friend, which enabled every other exhaust pulse to enter alternating
turbos.  The custom aluminum intake I fabricated out of aluminum
rectangular tubing and aluminum plate also supported the "every other
cylinder" mentality - ending up with two intake logs, connecting three
chosen cylinders, connected to the OPPOSITE turbo.  These crossovers ensure
balance in performance as well as consistant airflow into the engine, out
of the engine, and into the turbos.  The intake log(s) origianlly were one
large rectangular log with an aluminum oil cooler brazed in for ice water
to be pumped though, thus cooling the intake charge.  The seperation of the
intake plenums created a complex issue, however the result was two much
smaller power steering line coolers brazed into each plenum, plumbed in
parallel rather than series, attached to an igloo cooler with a bilge pump,
ice water, and a water-tight lid/seal.  I had attempted to cool the water
using freezer coils from an old freezer, however this was not portable or a
serious enough fabrication for permanent installation (couldn't find a 2
mile extension cord <g>).

The intake had two injector per cylinder, controlled diligently by the
Haltech ECM we had, and worked very well.  First (main) injectors were
fired sequentially, and the second tier were fired in batch mode, with the
Haltech ECM driving several MOSFETS wired in parallel, which opened and
closed the "7th" injector (which was six injectors).

The system worked absolutely fine until 32lbs of boost was achieved, then
the engine started to develop hot spots, detonate, and cause trememdous
problems.  This is using racing fuel, not even cheap, crappy MTBE-laiden
pump gasoline.  There was NO way I could run this motor on street gas.

So, we turned to other alternatives, and tried tons of mixtures of toulene,
methanol, isopropol, distilled water, tap water, etc.  After vast
experimenting, a third injector per cylinder was drilled and mounted, with
a mixture of 20% distilled water and 80% commercial grade isopropol by
volume (not weight), injected in batch mode, driven by a simple op-amp
comparer setup as well as the Haltech ECM.  The results in injector
operation were this:

Injector 1 (main injector) injects pump gasoline, firing just before the
intake valve opens (or at, not sure which) as if the engine is turbocharged
in a small way.  Fuel rail increases pressure from 45 psi to 60 psi based
on boost discovered (mechanical)

Injector 2 (secondary injector) injects pump gasoline, firing in batch
triggered off the haltech 7th injector lead based on boost level and RPM
settings.  Fuel rail increases pressure from 40 psi to 55 psi based on
boost discovered (mechanical)

Injector 3 (tricondary injector) injects water/alky firing in batch in
sequence with above, enabled by the Haltech ECM as well as an OP-AMP that
monitors boost.  This way, at 15-40 lbs of boost, the secondary injectors
fire, and over 25-40 lbs of boost, the tricondary alky injectors fire as well.

A cheesy knock sensor schematic leached off the web fed a third input to
the op-amp circuit so if the engine knocked, it alky'd itself just to be
sure detonation was squashed, squashed, squashed.

Pack ice into the cooler, fire the engine, warm up appropriately, and run
at 2200 RPM for about 20 minutes straight, then vary the RPM around as to
break in the cam appropriately, per the directions on the box.  Once
everything was satisfactory, we dyno'd the engine until it broke to pieces,
achieving 39lbs of boost at 6200 RPM, 849 HP and 900 ftlbs of torque for
about 22 minutes until it went boom.

In summary, I agree that water/akly injection is NOT the ideal way to
design a proper intercooled turbo/supercharged system, however, it does add
a lot of value.  You can use it if controlled properly to enable your
engine to utilize more boost, generate more power, and prevent detonation.
It enables you to use all this other "crap" to drastically increase your
volumetric effiecency, which is the name of the game.

Anyone want a 3-piece crank?

Frederic Breitwieser
Fairfield County CT
http://www.xephic.dynip.com/
1989 500cid Twin-Turbo HMMV
1993 Supercharged Lincoln Continental
1973 460cid Lincoln Continental
1975 Dodge D200 3/4 Ton Club Cab
2000 Buick Twin-Turbo GTP (in progress)

"Forced Induction as a Way of Life!"