Initial
Testing
with
108
Red
Armstrong
Chip
1. Injection of approximately .75 ounces fluid
per
second (20.5 GPH @ boost over 12 lbs).
2. Injection of approximately .25 ounces per
second
(7.5 GPH @ 5-12 lbs boost).
3. Average of 3-6 knock counts during a typical
run
using 108 race chips and 25 lbs. boost pressure. All testing has been
done
with fuel pressure set to 43-46 psi with vac off.
4. Maximum retard recorded is less than 3.5
degrees.
5. Typical maximum retard is 0 -1.5 degrees.
6. Knock counts and retard are likely to be
higher
at COLDER temperatures (probably due to slightly higher boost pressures
and somewhat leaner mixture).Also the spoolup is likely to be quicker
at
lower temperatures.
7 One knock count usually occurs immediately
after
backing off the throttle hard. (Probably due to the throttle plate
restricting
the alcohol flow a bit more than the air flow).
8. Almost all of the knock counts and retard
occur
as the boost is climbing quickly and no knock (sometimes 1-2
counts
max) occur at a steady 23 - 25 lbs boost. (Best guess here is that the
fuel curve is slightly lean during the rapid rise in boost. Also, this
could be due to a lag in the time it takes for the pump to pressurize
the
nozzles and/or the time it takes for the injected fluid to begin its
cooling
effect. The atomized liquid may not travel through the intake at the
same
speed as the air velocity.)
9. Using a Red Armstrong chip, mix of
108,
116, and 93 octane,
NO ALCOHOL, 23 lbs boost this car knocked more
at full boost than it does now with the alcohol. The basic set up is
described
below.
10. This car tends to register some knock on a
Thrasher
93 chip in the upper gears using 93 octane (regardless of fuel pressure
setting) at boost pressures near 16-17 lbs. WITHOUT ALCOHOL.
Stepping
up to 94 octane eliminated all knock with that chip through
approximately
18 lbs.
11. If the water/ alcohol is injected in
concentrations
that are too high for the boost being used the engine will tend to
"flutter"
as if the mixture is not igniting but it is not violent by nature- no
knock
occurs and it is not like the surging that can happen when large
amounts
of timing are being pulled out.
12. If "fluttering" occurred it seemed to be most
likely
to happen at colder air temperatures.
13. Indications so far point to easier tun ability
of
the system at warmer temperatures than at extreme cold temperatures.
Basic
Setup
The turn on points (6 and 12 lbs)
have
worked well considering that I have used a Red Armstrong race
chip
while running on pure 93 octane gas. This car has 150,000 miles on a
rebuilt
stock block, heads, and valve springs. The car has a stock down pipe,
3"
exhaust, 9" cone filter, TE-44, stock inter cooler, and bluetop
injectors.
Best MPH was 105 while using 116 race gas with some 93 and 23 lbs boost
and not locking the stock convertor. Car ran on 235-60 worn regular
street
radials with 60 ft. times averaging 2.35 -2.6 seconds. Other turbo cars
that same day ran in the 12.6-12.8 range at speeds from 102 -103 MPH.
So
I guess that the car should be at least a mid 12 sec. car with some
traction,
good driving, and locking the convertor. I mention this only so that we
understand what kind of car this alcohol system is installed on !
Summary
.
-
Cost is reasonable for the performance
improvement
along with the advantage of lower cylinder temps and pressures at any
point
of injection.
-
It may be possible to use lower octane, a
street chip,
and still run boost over 15 lbs.
-
System allowed 20 lbs in upper gears on a 93
Thrasher
chip and 93 octane with NO KNOCK at all.
-
Other than keeping the tank full and arming it the
system
operates transparently. Lights provide monitoring of system armed, pump
and stage 1 turn on as well as pump cycling between pressure limits. A
third light glows during stage 2 on condition.
-
With a 80-100 psi pressure switch mounted on the
pump and
an adjustable bypass line routing excess flow back to the tank the
valve
has the ability to vary the pressure by nearly 20 psi. This can
effectively
help with fine tuning the application without having to actually change
the size of the nozzles.
-
An alcohol pressure gauge would be a nice addition
to the
system.
-
Injection cannot occur unless the fuel pump is
running to
prevent injection when engine is off.
-
Alcohol tank is not pressurized which reduces
hazard in the
engine compartment as well as eliminating additional plumbing and
simplifying
the system.
-
Intake, valves, cylinder heads, and spark plugs are
kept
clean.
-
Peak cylinder pressures and temperatures are
reduced
while horsepower and torque can be raised to higher levels. An engine
can
produce a horsepower level similar to a non alcohol injected engine but
with lower peak cylinder pressures due to the stabilizing of the
combustion
process.
-
According to tests done from the 1930's to the
present a
mixture of 50 % alcohol to H2O provide for maximum horsepower gains.
Mixtures
containing greater than 50% alcohol showed no additional horsepower
gains
and in some tests it methanol itself might br prone to pre ignition. A
good book with information on water/alcohol injection is
"Turbochargers"
by Hugh Macinnes. Anther books on the subject is entitled "The Higher
Speed
Internal Combustion Engine" by Harry Ricardo.
Next Page
Back to index and my other alcohol
injection pages
