EPA-AA-TEB-81-7
EMISSIONS AND FUEL ECONOMY OF THE
AUTOMOTIVE CYLINDER DEACTIVATOR SYSTEM (ACDS)
BY
EDWARD ANTHONY EARTH
October 1980
Test and Evaluation Branch
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Environmental Protection Agercy
-------
Background
The Environmental Protection Agency receives information about many
systems which appear to offer potential for emission reduction or fuel
economy improvement compared to conventional engines and vehicles. EPA's
Emission Control Technology Division is interested in evaluating all such
systems, because of the obvious benefits to the Nation from the identifi-
cation of systems that can reduce emissions, improve fuel economy, or
both. EPA invites developers of such systems to provide complete tech-
nical data on the system's principle of operation, together with avail-
able test data on the system. In those cases for which review by EPA
technical staff suggests that the data available shows promise, confir-
matory tests are run at the EPA Motor Vehicle Emission Laboratory at Ann
Arbor, Michigan. The results of all such test projects are set forth in
a series of Technology Assessment and Evaluation Reports, of which this
report is one.
The deactivation of one or more engine cylinders is a method that has
been proposed as offering potential for vehicle fuel economy improve-
ments. At low power output the throttle is nearly closed. This intro-
duces a "throttling loss", which is the energy the engine must expend to
draw the fuel-air mixture through the carburetor throttle opening. By
operating an engine on a reduced number of cylinders and operating these
at high power levels, the throttling losses are appreciably reduced. The
operating cylinders are therefore run at a high brake-mean-effective
pressure (BMEP) and therefore potentially more efficiently.
EPA received a request from Automotive Cylinder Deactivator System (ACDS)
to perform a 511 evaluation of their cylinder deactivator. Section 511
of the Motor Vehicle Information and Cost Savings Act (15 USC 2011)
requires EPA to evaluate fuel economy retrofit devices with regard to
both emissions and fuel economy, and to publish the results in the
Federal Register. Such an evaluation is based upon valid test data
submitted by the manufacturer and, if required, EPA testing.
Data submitted by ACDS showed appreciable fuel economy benefits for some
vehicles. Therefore EPA conducted a confirmatory test program on three
different test vehicles as part of the evaluation. This report details
the results of the confirmatory test program. However, this report is
not the full detailed evaluation of the device. That evaluation is
contained in the "Announcement of Fuel Economy Retrofit Device Evaluation
for the Automotive Cylinder Deactivator System (ACDS)".
ACDS is developing both manual and semi-automatic means of cylinder
deactivation. EPA agreed to test the vehicles only with one-half the
cylinders deactivated throughout the total, device installed, test
sequence. This would provide "worst case" emissions data, i.e. if emis-
sions were negatively impacted by the concept, this should be the worst
case. Utilization of the worst case would better permit an understanding
of the relationship between benefits and penalties attributable to the
concept.
EPA has also tested other cylinder deactivation systems. The Eaton
system was tested in a demonstration Cadillac provided by Eaton. The
-------
results of these tests are reported in TEB report 80-16 "Emissions and
Fuel Economy Tests of a vehicle equipped with the Eaton Valve Selector".
A prototype Cadillac was tested in a vehicle provided by the Cadillac
Motor Division of General Motors. The results of these tests are
reported in TEB report 80-14, "Emissions and Fuel Economy of a Cadillac
Prototype with Modulated Displacement Engine". Six years ago EPA also
tested a vehicle with 4 cylinders deactivated. The results of that test
are given in TAEB report 75-11, "Evaluation of the MSU 4 Cylinder Conver-
sion Technique for V-8 Engines."
The conclusions drawn from the EPA evaluation tests are necessarily of
limited applicability. A complete evaluation of the effectiveness of an
emission control system in achieving performance improvements on the many
different types of vehicles that are in actual use requires a much larger
sample of test vehicles than is economically feasible in the evaluation
test projects conducted by EPA, For promising systems it is necessary
that more extensive test programs be carried out.
The conclusions from the EPA evaluation test can be considered to be
quantitatively valid only for the specific test cars used; however, it is
reasonable to extrapolate the results from the EPA test to other types of
vehicles in a directional manner, i.e. to suggest that similar results
are likely to be achieved on other types of vehicles.
Summary of Findings
Overall the use of the ACDS to operate an 8 cylinder engine on 4
cylinders caused CO and NOx emissions to increase substantially, moderate
fuel economy increases, braking problems, and poor clriveability.
HC emissions were relatively unaffected by ACDS 4 cylinder operation for
both the FTP and HFET.
Use of ACDS to operate the engines on 4 cylinders caused 100% to 200%
increases in FTP CO emissions to levels near or above the 1979 CO
emission standard of 15.0 gm/mi. HFET CO emissions were increased to
levels 20 to 100 times higher than baseline.
Use of ACDS to operate the engines on 4 cylinders caused FTP NOx
emissions to rise to levels twice the 1979 NOx standard of 2.0 gm/mi.
HFET NOx emissions were increased 9% to 55% by operation on less
cylinders.
The operation of an 8 cylinder vehicle on 4 cylinders through the use of
the ACDS hardware did improve vehicle fuel economy 5 to 16% for th'i FTP
and 3 to 20% for the HFET.
The vehicles had poor driveablity when using the ACDS to operate on 4
cylinders.
The use of a higher octane fuel, indolene, had only a minor effect on
vehicle emissions or fuel economy in the 4 cylinder mode. Driveability
with 4 cylinders, was slightly worse with commercial unleaded.
Vehicle acceleration times were substantially increased when the 8
-------
cylinder vehicles were operated with 4 cylinders using ACDS. Accelera-
tion times were typically double the comparable times for 8 cylinder
operation.
The operation of an 8 cylinder vehicle on 4 cylinders caused a serious
loss of braking power assist under some driving conditions.
Operation of an 8 cylinder vehicle on 4 cylinders caused a reduction in
the air conditioner airflow when accelerating.
No mechanical problems were encountered that were due to the ACDS hard-
ware. However, no assessment of the durability of the ACDS system was
made.
ACDS Description
The purpose of the ACDS is to deactivate one half of the engine
cylinders. "This is accomplished by releasing the fulcrum point of the
rocker arm, thereby allowing the intake and exhaust valves to stay closed
on the deactivated cylinders. The kit also provides means for attaching
the pushrod to the hydraulic lifter and furnishes a spring which holds
the pushrod and lifter assembly up and away from the camshaft while
deactivated".*
The cylinders to be deactivated are selected so that every other cylinder
in the firing order is deactivated. This leads to the front and rear
cylinders in one bank and the two center cylinders on the other bank
being selected for desctivation.
This selection of active and deactivated cylinders means that, on typical
carburetor induction systems, the 4 active cylinders are fed the fuel-air
mixture by one side of the carburetor and the 4 adjustable, cylinders by
the other side. Therefore when cylinders are deactivated, there is no
air flow thru one side of the carburetor. Also, because the exhaust
valves are closed on deactivated cylinders, there is no exhaust flow from
deactivated cylinders.
The ACDS kit consists of two star clips, a washer, a. spring, a pushrod, a
wire clip and a rubber cup plug for each of the eight valves (4 intake
and 4 exhaust) deactivated.. The pushrod is usually identical to the
stock pushrod. The wire clip is a slightly thicker and reshaped replace-
ment for the valve lifter wire clip.
Installation of the ACDS requires removal of the intake manifold and
valve covers. Ignition wires, hoses, fuel lines, and other engine hard-
ware, as appropriate, must be removed to allow access to the valve
lifters and rocker arm assemblies. The lifters are removed and the wire
clip is removed. The lifters are re-installed and connected to the ACDS
provided pushrod and sprins? assembly with the ACDS star clip and wire
clip.
*ACDS product: literature "Instruction Manual for Installation of Mechan-
ical ACD System on small and big block Chevrolets", a copy of these
instructions is given in the Appendix.
-------
The hardware and its typical installation are shown in figures 1 and 2
below.
REPLACEMENT
~CUP
ACD CLIP
e.
TYPICAL
BIO BLOCK
CHEVROLET
SHORT ROD
AND SPRING
LOCATION
5
3
1 I
TYPICAL
BtO BLOCK
CHEVROLET
LONO ROD
BPRINQ AND
LOCATION
TYPICAL
BMAU
BLOCK
'CHEVROLET
PUSH ROD
ANDBPRINQ
LOCATION
Figure 1
ACDS Hardware
ROCKER ARM
ACO PUSHROD
RE-INSTALLED
ROCKER ARM
NEW WIRE CUP
ACD CLIP
IN&TAILED PUSHROO
WfTH ACO CUP
AND WIRE CUP
Figure 2
Typical Installation
-------
During installation, 1-1/8 inch holes are drilled in the valve covers.
These holes allow a socket wrench access to the rocker arm adjustment
nut. This readily permits manual conversion of the engine back and forth
between 4 cylinder and 8 cylinder modes. Rubber cup plugs are provided
to cap these holes.
No vehicle engine adjustments are required unless specific problems are
encountered.
Test Vehicle Description
Two of the test vehicles used in this study were selected on the basis of
their being typical full sized, late moael vehicles with large displace-
ment V-8 engines. A third vehicle, a Capri, was selected to represent a
current vehicle with a relatively larger power to weight ratio. These
vehicles were obtained from automobile rental firms.
The three test vehicles used in this study were:
A 1979 Chevrolet Impala equipped with a 5.7 liter V-8 engine,
automatic transmission and air conditioning. This vehicle used EGR and
an oxidation catalyst for emission control.
A 1979 Mercury Capri equipped with a 5.0 liter V-8 engine, auto-
matic transmission, and air conditioning. This vehicle used an air pump,
EGR, and an oxidation catalyst for emission control.
A 1979 Mercury Cougar equipped with a 5.0 liter V-8 engine, auto-
matic transmission and air conditioning. This vehicle used an air pump,
EGR, and an oxidation catalyst for emission control.
A complete description of these vehicles is given in the test vehicle
description in the Appendix.
Test Vehicle Inspection, Servicing, and Repair
Prior to baseline testing, each vehicle was given a specification check
and inspection. The ignition timing, idle speed, and fast idle speed
were checked for agreement with the manufacturer's specifications given
on the Vehicle Emission Control Information label affixed to the engine
compartment and adjusted it required. The vehicles were inspected for
engine vacuum leaks, proper connection of vacuum hoses, functioning PCV
valve, oil and water levels, and general condition of engine compartment.
The vehicles were also checked with an automotive diagnostic computer.
The tests performed were:
(1) Cranking - checks battery, starter draw, cranking speed,
dynamic distributor resistance, dwell, and relative cylinder
compression.
(2) Alternator - cnecks alternator power output at 2500 rpm.
-------
(3) Idle - checks rpm, dwell, HC and CO emissions, initial
timing, PCV, and manifold vacuum.
(4) Low cruise - checks ignition coil output.
(5) Power balance - checks power output of individual cylinders.
(6) Snap acceleration - checks spark plugs under load.
(7) High cruise - checks ignition dwell, dwell variation, total
timing advance.
The Impala and Capri passed the preceding tests. However, the Cougar had
insufficient distributor vacuum and mechanical advance. The lack of
vacuum advance was corrected by readjusting the vacuum advance control
set screw. The lack of sufficient mechanical advance was corrected by
grinding off part of the distributor plate to permit additional• mechan-
ical advance (it was later determined a part of the distributor plate was
installed backwards). After these distributor changes, the Cougar passed
the checkout tests.
The above mentioned Ford/Mercury distributor problem has been noted in
other Ford vehicles being tested. Apparently the cause of the problem is
that part of the distributor plate mechanism can be installed backwards.
The unit then functions normally except that it cannot achieve the last
few degrees of distributor mechanical advance.
The Impala and Cougar were serviced prior to testing. The air and oil
filters were replaced and the engine oil was changed. The Capri had been
serviced just prior to delivery and therefore required no servicing.
Test Procedures
Exhaust emission tests were conducted according to the 1977 Federal Test
Procedure (FTP) described in the Federal Register of June 28, 1977 and
the EPA Highway Fuel Economy Test (HFET) described in the Federal
Register of September 10, 1976. The vehicles were not tested for evapo-
rative emissions.
The vehicles were initially tested in the baseline (stock) configuration
to determine their emissions and fuel economy performance. The vehicles
were then modified by the installation of the ACDS hardware on 4 intake
and 4 exhaust valves (ACDS hardware installed on 4 cylinders, no
cylinders deactivated). They were then retested in 8 cylinder configura-
tion to insure that emissions and fuel- economy had not been changed by
the installation process.
The vehicles were then place:! in 4 cylinder operation. This was done by
backing off the rocker arm fulcrum nut and allowing the ACDS hardware to
pull the hydraulic lifter off the cam. The vehicles were tested for
emissions and fuel economy with 4 cylinders.
In the 4 cylinder mode, each of the 4 active cylinders would have to work
harder than in the 8 cylinder mode. These higher loads would tend to
-------
8
increase the engine's octane requirement. Because the EPA test fuel
(indolene) typically has a higher octane rating than commercial fuel, in
the 4 cylinder mode the vehicles were tested with both indolene and
commercial unleaded.
Additional tests were conducted as an evaluation tool. These consisted
of steady state emission tests, acceleration tests, ana road evaluations.
EPA supplied all three test vehicles. The Irapala and Cougar were
modified by ACDS personnel. The Capri was modified by EPA. Each initial
conversion took several hours. Most of the installation time was
required for removing and replacing engine components and gaskets. EPA
did not modify the valve covers but removed them each time a change in
the number of active cylinders was required.
Test Results
The objective of this test program was to evaluate the potential fuel
economy benefits of an aftermarket cylinder deactivation system and to
determine its effects on vehicle emissions. The test results are
summarized in the tables and figures in the following paragraphs. More
detailed tabulations of the data are given in the Appendix.
1. Federal Test Procedure (FTP) Results
Overall the operation of the vehicles on 4 cylinders caused CO and NOx
emissions to increase dramatically. HC emissions were not changed
substantially. In 4 cylinder mode, the vehicles failed to meet the 1979
emission standards of 1.5 gm/mi HC, 15 gm/mi CO, and 2.0 gm/mi NOx. Fuel
economy increased 5 to 16%. Vehicle driveability was poor in some
cases. The results are tabulated in Table I below. All results are the
average of two tests unless noted otherwise.
TABLE I
AUTOMOTIVE CYLINDER DEACTIVATION SYSTEM - ACDS
AVERAGE FTP MASS EMISSIONS
grams per mile
TEST CONDITION HC_ CO C02 NOx MPG
CHEVROLET IMPALA
8 cylinder baseline .52 4.03 548 1.50 15.9
8 cylinder w/ACDS(3 tests) .90 1C.13 529 1.54 16.2
4 cylinder w/ACDS .71 18.77 440 4.06 18.8
4 cylinder w/ACDS .79 22.36 440 4.04 18.5
commercial unleaded
-------
MERCURY CAPRI
8 cylinder baseline (3 tests) .78 3.11 507 1.31 17.2
8 cylinder w/ACDS (3 tests) .84 4.01 503 1.42 17.3
4 cylinder w/ACDS .68 7.75 459 4.38 18.8
4 cylinder w/ACDS .89 16.41 460 4.13 18.1
commercial unleaded
MERCURY COUGAR
8 cylinder baseline .62 3.42 561 2.41 15.6
8 cylinder w/ACDS .69 4.47 551 2.33 15.8
4 cylinder w/ACDS .72 11.27 500 4.57 17.0
4 cylinder w/ACDS .69 12.44 504 4.86 16.9
commercial unleaded
FTP BASELINE (Stock) Tests
The purpose of the baseline tests was to insure before testing began, that
all of these 1979 vehicles were representative and all of these 1979 vehicles
met the 1979 emission standard. The Impala's and Capri's emission levels met
the standard and were comparable to the certification tests. (See comparison
to the certification vehicles and Table III).
The Cougar's NOx emissions were appreciably above the standard. This infor-
mation was not available until after the vehicle had been modified. The
Cougar's emission control system was functionally checked. A new EGR valve
was installed, however the vehicle's emissions remained unchanged. Since
several replacement vehicles were unacceptable, and this Cougar was modified,
it was tested even though the baseline FTP NOx emissions were above the NOx
standard.
In stock configuration, all vehicles had acceptable driveability.
FTP - 8 CYLINDER WITH ACDS MODIFICATION (NONFUNCTIONAL)
The purpose of this series of tests was to establish a reference and to
insure that vehicle emissions and fuel' economy had not been inadvertently
changed because of the disassembly and reassembly operations required for
installation of the ACDS hardware. Except for the Impala's CO emissions
being doubled, none of the vehicles' emissions or fuel economy had shifted
appreciably.
The Impala's CO emissions changed from 4.03 gm/mi to 10.13 gm/mi. The
Cougar's CO emissions tended to increase slightly. The exact cause for these
changes was not determined. Since the vehicle's emissions were still
acceptable (met the standard and similar to the certification levels),
-------
10
testing was continued without additional adjustment of these vehicles.
The Capri's and Cougar's emissions and fuel economy were essentially
unchanged.
With 8 cylinders operating and ACDS installed, but nonfunctional, drive-
ability remained acceptable.
FTP - 4 CYLINDER WITH ACDS MODIFICATION - INDOLENE FUEL
The vehicles were converted to 4 cylinder operation by deactivating 4
cylinders. This was done by releasing the rocker arm fulcrum nut thus
permitting the ACDS hardware to pull the intake and exhaust lifters off
the camshaft. As noted before, this caused CO and NOx emission
penalties, fuel economy benefits, and driveability problems.
The Impala's HC emissions were decreased 21%. CO emissions doubled to
18.77 gm/mi, a level 25% above the CO emission standard. NOx emissions
increased by 160% to 4.06 gm/mi, double the allowable standard. Fuel
economy increased 16%. Driveability was acceptable.
The Capri's HC emissions were decreased 19%. CO emissions doubled to
7.75 gm/mi. NOx emissions tripled to 4.38 gm/mi, over double the allow-
able standard. Fuel economy increased 9%. Driveability was fair. There
were numerous transmission shifts. The vehicle had insufficient power to
follow the driving schedule during hard acceleration.
The Cougar's HC emissions were not significantly affected. CO emission
tripled to 11.27 gm/mi. NOx doubled to 4.57 gm/mi, over double the
allowable standard. Fuel economy increased 8%. Driveability was
marginal. There were numerous transmission downshifts and upshifts. The
vehicle had insufficient power to follow the driving schedule during hard
accelerations.
FTP - 4 CYLINDER WITH ACDS MODIFICATION - COMMERCIAL UNLEADED
As previously noted, EPA's indolene unleaded test fuel typically has a
higher octane rating than commercial unleaded gasoline. Since the test
vehicles would probably be more octane sensitive in 4 cylinder mode than
8 cylinder mode, the 4 cylinder tests were repeated using a commercial
unleaded gasoline. The octane ratings of these fuels were:
Indolene unleaded Commercial unleaded
Motor Octane Number 88.65 82.57
Research Octane Number 97.45 91.55
M+R (combined) 93.05 87.06
The combined number is the value typically posted on the service station
pumps.
-------
11
When tested with commercial unleaded gasoline, all three vehicle's emissions
and fuel economy followed trends noted previously for indolene. However,
there was additional driveability deterioration, especially detonation.
Compared to the 8 cylinder configuration, in 4 cylinder operation, the
Impala's HC emissions decreased 13%, but CO emissions further increased to
22.36 gm/mi. NOx emissions were again increased 160% to 4.04 gm/mi. Fuel
economy again increased 14%. Driveability was poor. There was considerable
hesitation and detonation on accelerations.
Compared to the 8 cylinder configuration, in 4 cylinder operation the Capri's
CO emissions, NOx emissions, and fuel economy followed the same trend noted
previously for indolene. HC emissions increased 6%, CO emissions increased
by a factor of 5 to 16.41 gm/mi, a level that exceeds the CO emission
standard. NOx emissions tripled to 4.13 gm/mi, over double the allowable
standard. Fuel economy increased 5%. Driveability was fair. There were
numerous transmission shifts. The vehicle lacked power for hard accelera-
tions. There was minor detonation on most accelerations.
Compared to the 8 cylinder configuration, in 4 cylinder operations, the
Cougar's emissions and fuel economy followed the same trends noted previously
for indolene. HC emissions were unchanged. CO emissions tripled to 12.44
gm/mi. NOx doubled to 4.86 gm/mi. Fuel economy increased 7%. Driveability
was again marginal. There were numerous transmission downshifts and up-
shifts. The vehicle had insufficient power to follow the driving schedule
during most accelerations. The engine had a tendency to "diesel" when shut-
off.
2. Highway Fuel Economy Test (HFET) Results
Overall the operation of the vehicles on 4 cylinders caused CO and NOx
emissions to increase substantially. HC emissions were relatively
unchanged. Fuel economy increased 3 to 20%. Vehicle driveability was
adversely affected in some cases. These results are Tabulated in Table
II below. All results are for two tests unless otherwise noted.
TABLE II
Automotive Cylinder Deactivation System - ACDS
Average HFET Mass Emission
grams per mile
TEST CONDITION
CHEVROLET IMPALA
8 cylinder baseline
8 cylinder w/ACDS (3 tests)
4 cylinder w/ACDS
4 cylinder w/ACDS
commercial unleaded
HC CO
CO 2
.12 .14 383
.10 .16 375
.20 5.48 303
.40 16.12 289
NOx
1.46
1.37
1.78
1.92
MPG
23.1
23.7
28.4
28.1
-------
12
MERCURY CAPRI
8 cylinder baseline (3 tests) .24 .07 374 1.31 23.7
8 cylinder w/ACDS (3 tests) .22 .11 373 1.37 23.8
4 cylinder w/ACDS .13 1.47 351 2.12 25.1
4 cylinder w/ACDS .13 4.41 353 2.08 24.6
commercial unleaded
MERCURY COUGAR
8 cylinder baseline .17 .31 403 2.54 22.9
8 cylinder w/ACDS .18 .56 400 2.42 22.1
4 cylinder w/ACDS .16 4.30 363 2.64 24.0
4 cylinder w/ACDS .12 3.33 363 2.67 24.1
commercial unleaded
HFET BASELINE (STOCK) TESTS .
The purpose of these tests was to insure the vehicles' HFET fuel economy
were representative. The three vehicles' HFET fuel economy were reason-
ably comparable to the certification tests. (See comparison to the
certification fuel economy vehicles and Table III). The vehicles' emis-
sions and fuel economy were acceptable. Driveability was acceptable.
HFET - 8 CYLINDER WITH ACDS MODIFICATION
The purpose of this group of tests was to establish a reference and to
insure the vehicles' emissions and fuel economy had not inadvertently
changed during the inital ACDS installation. The emissions and fuel
economy of all three vehicles had not significantly changed during
modification. Driveability remained acceptable.
HFET - 4 CYLINDER WITH ACDS MODIFICATION - INDOLENE FUEL
The Impala's emissions and fuel economy increased. HC emission doubled
to .20 gm/mi. CO increased substantially to 5.48 gm/mi. NOx increased
by 30% to 1.78 gm/mi. Fuel economy increased 20% to 28.4 mpg. Drive-
ability was acceptable.
The Capri showed similar emissions and fuel economy trends, HC decreased
by one third. CO increased substantially to 1.47 gm/mi. NOx increased
by 50% to 2.12 gm/mi. Fuel economy increased 5% to 25.1 mpg. However,
the Capri's driveability was fair. There were numerous tranmission
shifts and insufficient power to accelerate.
The Cougar also followed these emissions and fuel economy trends. HC
remained unchanged. CO increased substantially to 4.30 gm/mi. NOx
tended to increase slightly. Fuel economy showed a 9% increase. Drive-
-------
13
ability was marginal. There was insufficient power for acceleration and
the transmission shifted more frequently than normal.
HFET - 4 CYLINDER WITH ACDS MODIFICATION - COMMERCIAL UNLEADED GASOLINE
All three vehicles followed the trends previously noted in 4 cylinder
operation. However, as with the FTP, there was again an additional loss
in driveability when a commercially available fuel was used.
Compared to the 8 cylinder configuration, the Impala's HC emissions
quadrupled. CO emissions rose to 16.12 gm/rai, three times greater than
the tests using indolene and 100 times greater than the baseline. NOx
emissions increased 40% to 1.92 gm/mi. Fuel economy again increased
19%. Driveability was very marginal. There was hesitation and consider-
able detonation on acceleration.
Compared to the 8 cylinder configuration the Capri's emissions followed
the same trends noted previously for Indolene. HC was decreased one
third. CO increased substantially to 4.41 gm/mi. Fuel economy again
increased 3% to 24.6 mpg. Driveability was fair. There were numerous
transmission shifts and insufficient power to accelerate.
Compared to the 8 cylinder configuration, the Cougar's emissions and fuel
economy followed the trends noted for indolene. Namely HC was decreased
by one third and there was a substantial increase in CO emissions to'3.33
gm/mi. NOx tended to increase slightly and fuel economy increased 9%.
Driveability was again conditionally acceptable.
3. COMPARISON OF TEST VEHICLES TO CERTIFICATION VEHICLES
For comparison, the emission and fuel economy results for comparable 1979
vehicles are given in the tables below. These vehicles had the same
displacement engine, same engine emission family, and same inertia test
weight as the comparable test vehicle.
TABLE III
1979 CERTIFICATION VEHICLES
Typical FTP Mass Emissions
grams per mile
Fuel Economy
FTP HFET
Vehicle HC CO NOx MPG MPG
1979 Chevrolet Impala .57 8.1 1.6 15.0 19.0
1979 Mercury Capri .63 6.9 1.3 16.7 23.0
1979 Mercury Cougar .49 6.9 1.7 14.7 20.2
These emission values include the appropriate deterioration factor for each
emission family. The most notable deviations of the three test vehicles
from the above certification results were:
1) The Capri's and Cougar's FTP CO emissions (stock) were about
• half the comparable certification value.
-------
14
2) The Mercury Cougar's FTP NOx emissions (stock) were above the
standard and approximately 1.0 gm/mile above its certification
levels.
3) All three test vehicles FTP fuel economy (stock) were approxi-
mately one mpg higher than the comparable certification vehicle.
4) All three test vehicles HFET fuel economy (stock) were one to
two mpg higher than the comparable certification vehicle.
Therefore, except for the Cougar's previously noted high NOx levels, the
vehicles were accepted as being representative of their make and model year.
4. COMBINED FUEL ECONOMY
A vehicles' combined Fuel Economy is calculated by using its weighted FTP
and HFET fuel economy. The weighting is 55% FTP and 45% HFET. These values
are harmonically averaged using the formula:
combined fuel economy = l/(.j^5_ + .45) mpg
FTP HFET
The results for these test vehicles are:
Combined Fuel Economy
(indolene test fuel)
8 cylinder 4 cylinder w/ACDS percent change
Chevrolet Impala 18.9 22.2 17.4%
Mercury Capri 19.7 21.2 7.8%
Mercury Cougar 18.1 19.6 7.9%
5. STEADY STATE TESTS
The largest net increases and largest percentage increases in fuel economy
occurred in the steady state test on all vehicles. HC and CO emissions were
relatively unaffected by operation of the vehicles with only 4 active
cylinders. The Impala's NOx emissions were also unaffected. However both the
Capri and Cougar had large increases in NOx emissions. Best fuel economy for
all vehicles was achieved at speeds between 25 and 35 mph. The steady state
test results are tabulated in Tables XII, thru XIV in the Appendix. The fuel
economy results are also plotted in Figure 3.
The vehicles were also tested for steady state fuel economy on the road
tests. The results of these tests are given in Tables XI, XII, and XIII in
the Appendix. In general, there was good agreement between the steady state
road test and chassis dynamometer test fuel economies. The most noticeable
difference was for the Impala at 25 mph. Apparently the vehicle's
transmission had not shifted into high gear when tested on the dynamometer.
-------
STE:HL>Y EJTHTE: FLJEIL. EKZDNQMY
S CYL. I NDEIR RNL> W I TH H 5
CDUSRR
OJUEHR U fKD5
Figure 3 8 cylinder and 4 cylinder (ACDS) fuel economy - dynamometer
VE:H i CLE: SPE:E:L> < MPH >
-------
16
6.
ACCELERATION TESTS
At the conclusion of the emission tests, acceleration tests were performed on
the vehicles using a chassis dynamometer. To minimize tire slippage, the
chassis dynamometer's front and rear rolls were coupled together for these
tests. The vehicles' speed versus time acceleration characteristics were
recorded on a calibrated strip chart recorder. The results are summarized
below in Table IVa. Complete results are given in the Appendix.
Table IVa
Average Acceleration Times on the Dynamometer
seconds
1979 Chevrolet Irapala
Speed
0-20
0-30
0-40
0-50
0-60
8 cylinder
commercial unleaded
3.1
4.5
6.1
8.3
11.2
ACDS (4 cylinder)
indolene unleaded
5.5
8.8
12.3
17.1
23.7
1979 Mercury Capri
Speed
0-20
0-30
0-40
0-50
0-60
8 cylinder
commercial unleaded
3.8
5.6
7.8
10.3
14.1
ACDS (4 cylinder)
indolene unleaded
6.3
9.8
14.4
21.5
29.4
1979 Mercury Cougar
Speed
0-20
0-30
0-40
0-50
0-60
8 cylinder
indolene unleaded
3.0
5.0
7.3
10.0
13.9
ACDS (4 cylinder)
indolene unleaded commercial unleaded
7.0
11.1
16.1
23.0
6.6
10.8
15.6
22.6
33.4
-------
17
During the steady state fuel economy road testing, the vehicles' acceleration
capability was also tested. The vehicles' speed versus time characteristics
were taken by the use of a stopwatch and the vehicles' speedometer. This was
considerably less precise than the preceding dynamometer tests. The test
results are summarized in Table IVb on the following page. Complete results
are given in the Appendix.
Table IVb
AVERAGE ACCELERATION TIMES ON THE ROAD
seconds
1979 Chevrolet Impala Not Tested
1979 Mercury Capri
8 cylinder ACDS (4 cylinder)
Speed indolene unleaded
0-20 Not 6.2
0-30 Tested 9.9
0-40 13.8
0-50 20.7
1979 Mercury Cougar
8 cylinder ACDS (4 cylinder)
Speed
0-20 ~ 7.2
0-30 4.8 11.4
0-40 7.2 16.5
0-50 9.5 23.7
Acceleration times were substantially increased by operation of the engine on
only 4 cylinders. Acceleration times were only slightly affected by the type
of fuel used. Acceleration times for the dynamometer and road tests were
similar.
7. SAFETY .
During the roa1 tests, braking problems were encountered with the Impala. At
times there was no braking power assist when the vehicle was operated with 4
cylinders deactivated. The source of this problem was 'the low manifold
vacuum available during most of the operation on 4 cylinders. Therefore a
repeated series of accelerations and braking could reduce the power brake's
vacuum reservoir vacuum to levels that are unable to provide power brake
assist. This could readily occur in heavy slow speed traffic or when highway
cruising is followed immediately by a series of brake applications. This
problem was further aggravated when the air conditioning was on, since the
air conditioner caused the loss of an additional 2-4 inches of vacuum..
-------
18
A braking problem was not encountered with the other two vehicles. However,
they were not driven in similar heavy traffic conditions and it is, there-
fore, not known if they too are susceptible to this braking problem.
8. OTHER
When accelerating with only 4 cylinders operating, the Impala's engine vacuum
provided insufficient vacuum to the air conditioner control system. This
lack of vacuum caused the air conditioner air valves to partially shut and
thus greatly reduced the cool air flow when accelerating. The two Mercury's
were not checked to see if a similar problem occurred.
When converted to 4 cylinders, the vehicle's idle speed (neutral) typically
increased several hundred rpm. However, as soon as the vehicle was placed in
gear, idle speed dropped below normal idle (drive) speed and the vehicles had
a tendency to stall, especially if the air conditioner was on. (The idle
speed was not adjusted since readjustment of idle speed was not given in the
ACDS instructions).
When cranking the vehicles (4 cylinder operation) the starter would
momentarily stop due to the loads imposed by the 4 deactivated cylinders.
This problem was more prevalent for warm engines. A limited check indicated
peak starting currents were twice as high as normal. This indicates that
there may be starting problems for vehicles with weak batteries or starting
systems.
Although the vehicles accelerated much slower on 4 cylinders, once a cruise
speed was achieved, the vehicles decelerated slowly when the driver's foot
was removed from the accelerator. Therefore, there was negligible engine
braking.
-------
19
Appendix
TEST VEHICLE DESCRIPTION
Chassis model year/make-1979 Chevrolet Impala
Vehicle I.D. 1L47L9S115799
Engine
type Otto Spark, V-8, OHV
bore x stroke 4.00 x 3.48 in/101.6 x 88.4 mm
displacement 350 CID/5.7 liter
compression ratio 8.3:1
maximum power @ rpm 170 hp/ 126 kW
fuel metering 4 venturi carburetor
fuel requirement unleaded, tested with indolene
HO unleaded, and a commercial unleaded
Drive Train
transmission type 3 speed automatic
final drive ratio 2.41
Chassis
type 2 door sedan
tire weight FR 78 x 15
curb weight 3840 lb/1742 kg
inertia weight 4000 Ib.
passenger capacity 6
Emission Control System
basic type EGR
. Oxidation Catalyst
Vehicle odometer mileage 17050 miles at start of
test program. . •
-------
20
TEST VEHICLE DESCRIPTION
Chassis model year/make-1979 Mercury Capri
Vehicle I.D. 9F16F638851
Engine
type Otto spark, V-8, OHV
bore x stroke 4.00 x 3.00 in./101.6 x 76.2 mm
displacement . 302 CID/5.0 liter
compression ratio 8.4:1
maximum power @ rpm 135/101 kW.
fuel metering 2 venturi carburetor
fuel requirement unleaded, tested with
indolene HO unleaded
and a commercial unleaded
Drive Train
transmission type 3 speed'automatic
final drive ratio 2.47
Chassis
type 2 door sedan
tire size CR 78 x 14
inertia weight 3500 Ibs.
passenger capacity 4
Emission Control System
basic type Air Pump
EGR
Oxidation catalyst
Vehicle odometer mileage 13,800 miles at start of
program.
-------
21
TEST VEHICLE DESCRIPTION
Chassis model year/make - 1979 Mercury Cougar
Vehicle I.D. 9H93F692442
Engine
type Otto spark, V-8 OHV
bore x stroke 4.00 x 3.00 in/101.6 x 76.2 mm
displacement 302 CID/5.0 liter
compression ratio 8.4:1
maximum power @ rpm 135 hp/101 kW
fuel metering 2 venturi carburetor
fuel requirement unleaded, tested with indolene
HO unleaded and a commercial
unleaded
Drive Train
tranmission type 3 speed automatic
final drive ratio 2.75
Chassis
type 2 door sedan
tire size GR 78x 15
inertia weight 4500 Ib
passenger capacity 6
Emission Control System
basic type Air Pump
EGR
Oxidation catalyst
Vehicle odometer mileage 16,850 miles at start of test
program
-------
22
TABLE V
AUTOMOTIVE DEACTIVATOR SYSTEM (ACDS) TEST
ON 1979 CHEVROLET IMPALA
FTP Mass Emissions
grams per mile
Test No. HC CO C02 NOX MPG
8 Cylinder stock
80-1805 .52 3.88 555 1.47 15.8
80-1807 .52 4.18 541 1.53 16.1
8 cylinder w/ACDS
80-1938 .84 9.08 530 1.46 16.2
80-1975 .83 9.54 529 1.49 16.2
80-2455 1.03 11.77 527 1.67 16.2
4 Cylinder w/ACDS
80-1829 .66 15.91 436 4.20 19.2
80-1833 .76 21.63 443 3.91 18.5
4 Cylinder w/ACDS Commercial unleaded
80-1835 .85 23.88 439 4.08 18.5
80-1912 .73 20.84 441 3.99 18.6
-------
23
TABLE VI
AUTOMOTIVE DEACTIVATOR SYSTEM (ACDS )TEST
on MERCURY CAPRI
FTP Mass Emissions
grams per mile
Test No.
80-2016
80-2020
80-2151
80-2133
80-2135
80-3089
80-2421
80-2423
80-2417
80-2419
HC
CO
C02
8 cylinder stock
8 cylinder w/ACDS
4 cylinder w/ACDS
4 cylinder w/ACDS
.77
.78
.78
.79
.80
.92
.67
.69
3.33
2.67
3.34
3.45
3.62
4.97
7.45
8.04
508
505
509
501
502
507
459
458
Commercial unleaded
1.00
.77
20.79
12.02
467
453
NO.,
1.27
1.31
1.34
1.44
1.51
1.32
4.38
4.39
4.16
4.10
MPG
17.2
17.3
17.2
17.4
17.4
17.1
18.8
18.8
17.6
18.7
-------
24
TABLE VII
AUTOMOTIVE DEACT1VATOR SYSTEM (ACDS) TEST
on MERCURY COUGAR
FTP Mass Emissions
grams per mile
Test No. HC CO C02 NOx MPG
80-1724
80-1726
80-1743
80-2457
80-1744
80-1748
8 Cylinder stock
.61
.62
8 Cylinder w/ACDS
.62
.75
4 Cylinder w/ACDS
.73
.71
2.95
3.88
3.60
5.33
12.33
10.20
562
560
548
554
499
501
2.51
2.31
2.47
2.18
4.73
4.41
15.6
15.6
16.0
15.7
17.0
17.1
4 Cylinder w/ACDS Commercial unleaded
80-2219
80-2221
.73
.64
12.88
12.00
500
507
4.89
4.82
17.0
16.8
-------
25
TABLE VIII
AUTOMOTIVE DEACTIVATOR SYSTEM (ACDS) TEST
on 1979 CHEVROLET IMPALA
HFET Emissions
grams per mile
Test No. HC CO C02 NOX MPG
80-1806
80-1808
80-1937
80-1976
80-2456
80-1830
80-1834
80-1836
80-1913
8 Cylinder stock
.11 .18 387
.12 .10 379
8 Cylinder after ACDS modification
.10 .01 360
.10 .02 371
.11 .44 394
4 Cylinder w/ACDS
.19 4.88 302
.21 6.08 304
4 Cylinder w/ACDS Commercial unleaded
.47 19.32 283
.33 12.92 294
1.48
1.43
1.23
1.42
1.46
1.84
1.72
1.86
1.98
22.9
23.4
24.6
23.9
22.5
28.6
28.2
28.2
28.1
-------
26
TABLE IX
AUTOMOTIVE DEACTIVATOR SYSTEM (ACDS) TEST
on 1979 MERCURY CAPRI
HFET Mass Emissions
grams per mile
Test No., HC CO C02 NOX MPG
80-2017 .24 .06 376 1.27 23.5
80-2104 .25 .05 375 1.32 23.6
80-2152 .24 .09 370 1.34 23.9
80-2134 .25 .03 371 1.35 23.9
80-2136 .15 .00 366 1.42 24.2
80-3090 .27 .29 381 1.34 23.3
80-2422 .13 1.55 355 2.17 24.8
80-2424 .12 1.38 346 2.07 25.4
80-2418 .13 5.96 355 2.06 24.3
80-2420 .13 2.86 350 2.09 25.0
8 Cylinder stock
8 Cylinder w/ACDS
4 Cylinder w/ACDS
4 Cylinder w/ACDS
.24
.25
.24
.25
.15
.27
.13 1.
.12 1.
Commercial
.13 5.
.13 2.
06
05
09
03
00
29
55
38
376
375
370
371
366
381
355
346
unleaded
96
86
355
350
-------
27
TABLE X
AUTOMOTIVE DEACTIVATOR SYSTEM (ACDS) TEST
on 1979 MERCURY COUGAR
HFET Mass Emissions
grams per mile
Test No. HC CO C02 NOX MPG
80-1725
80-1727
80-1918
80-2458
80-1745
80-1749
80-2220
80-2222
8 Cylinder Stock
.17
.16
8 Cylinder w/ACDS
.17
.18
4 Cylinder w/ACDS
.16 3.
.15 4.
4 Cylinder w/ACDS Commercial
.12 2.
.12 4.
24
37
17
95
65
94
406
400
396
403
358
367
2.57
2.51
2.47
2.37
2.63
2.64
21.8
22.1
22.3
21.9
24.4
23.6
unleaded
52
13
361
364
2.81
2.52
24.3
23.9
-------
28
TABLE XI
AUTOMOTIVE DEACTIVATOR SYSTEM (ACDS) TEST
on 1979 CHEVROLET IMPALA
Steady State Emissions
grams per mile *
Test No.
SPEED
HC
CO
C02
NO,
MPG
Road Test Avg. MPG
8 Cylinder Stock
80-1827
80-1827
80-1828
80-1828
80-1828
80-1831
80-1831
80-1832
80-1832
80-1832
0 mph*
25 mph
35 mph
45 mph
55 mph
8 Cylinder
0 mph
25 mph
35 mph
45 mph
55 mph
4 Cylinder
0 mph
25 mph
35 mph
45 mph
55 mph
2.90
.22
.46
.23
.08
after ACDS
2.68
.23
.31
.16
.07
w/ACDS
.84
.09
.13
.07
.04
.00
.00
.00
.00
.00
4957
302
360
346
372
Modification
.00
.00
.00
.00
.00
.15
.01
.00
.00
.00
4506
304
335
338
362
4605
312
261
266
304
1.47
.17
.34
.54
1.30
1.71
.19
.34
.65
1.79
4.75
.17
.23
.57
1.21
.53
29.3
24.5
25.6
23.8
.50
29.1
26.4
26.2
24.5
.53
28.4
34.0
33.3
29.2
@79° F
39.9
36.4
34.6
29.2
*0 MPH (idle) speeds emission values are given in grams per hour and
gallons per hour.
-------
29
Test No.
80-2019
80-2019
80-2018
80-2018
80-2018
80-2138
80-2138
80-2137
80-2137
80-2137
80-2650
80-2426
80-2650
80-2426
80-2650
80-2425
80-2651
80-2425
80-2651
80-2425
TABLE XII
AUTOMOTIVE DEACTIVATOR SYSTEM (ACDS) TEST
on 1979 MERCURY CAPRI
Steady State Emissions
grams per mile *
SPEED
HC
CO
C02
NO,
MPG Road Test Avg. MPG
8 Cylinder
0 mph*
25 mph
35 mph
45 mph
55 mph
8 Cylinder
0 mph*
25 mph
35 mph
45 mph
55 mph
4 Cylinder
0 mph
0 mph
25 mph
25 mph
35 mph
35 mph
45 mph
45 mph
55 mph
55 mph
Stock
4.39
.29
.55
.38
.18
after ACDS
4.35
.16
.52
.39
.20
w/ACDS
3.85
5.49
.32
.40
.21
.21
.11
.10
.07
.07
.00
.00
.14
.00
01
4866
695
323
343
368
3.85
1.50
.90
.76
1.25
.56
12.7
27.3
25.8
24.1
Modification
.00
.09
.00
.01
.01
.46
.20
.07
.18
.00
.01
.01
.01
.01
.02
4779
289
314
336
360
4882
4086
204
210
230
234
316
312
339
346
4.80
.71
.93
.81
1.39
16.99
44.06
1.83
2.09
4.36
4.45
.62
.66
1.40
1.47
.53
30.7
28.1
26.3
24.6
.56
.45
43.2
42.0
38.4
37.8
28.0
28.4
26.2
25.6
@ 70° F
29.9
28.2
26.4
24.9
@ 83° F
40.1
38.2
32.1
26.5
* 0 mph (idle) speed emission values are given in grams per hour and
gallons per hour.
-------
30
Test No.
80-1838
80-1838
80-1837
80-1837
80-1837
80-1746
80-1746
80-1747
80-1747
80-1747
80-2269
80-2269
80-2273
80-2273
80-2273
TABLE XIII
AUTOMOTIVE DEACTIVATOR SYSTEM (ACDS) TEST
on 1979 MERCURY COUGAR
Steady State Emissions
grams per mile*
SPEED
HC
CO
C02 NO,
8 Cylinder
0*
25 mph
35 mph
45 mph
55 mph
4 Cylinder
0 mph*
25 mph
35 mph
45 mph
55 mph
4 Cylinder
0 mph*
25 mph
35 mph
45 mph
55 mph
stock
2.44
.12
.40
.18
.13
w/ACDS
2.36
.14
.19
.15
.11
w/ACDS
3.46
.12
.15
.12
.08
.00
.02
.00
.00
.01
1.08
.01
.00
.00
.02
Commercial
.31
.00
.00
.00
.04
4053
329
341
359
394
4596
237
262
296
351
1.83
1.16
1.46
1.58
2.51
14.45
3.20
4.98
2.41
2.07
unleaded
4131
237
264
297
359
7.98
2.94
4.12
2.15
1.85
MPG
.46
26.9
25.9
24.7
22.5
.53
37.4
33.7
29.9
25.2
.48
37.3
33.6
29.8
24.7
Road Test Avg. MPG
@ 70° F
27.7
26.2
25.5
22.5
@ 65° F
38.9
33.1
31.5
27.4
* 0 mph (idle) speed emission values are given in grams per hour and
gallons per hour.
-------
31
TABLE XIV
Dynamometer Acceleration Tests on 1979 Chevrolet Impala
seconds
SPEEDS
8 Cylinder
Indolene unleaded
Run 1 Run 2 Run 3
ACDS 4 Cylinder
Indolene unleaded gasoline
Run 1
Run 2
0
0
0
0
0
0
0
0
0
0
0
0
- 5
- 10
- 15
- 20
-25
- 30
- 35
- 40
- 45
- 50
- 55
- 60
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
1
1
2
2
3
4
5
5
6
8
9
11
.0
.6
.2
.8
.4
.2
.0
.8
.8
.0
.5
.0
1
2
2
3
4
4
5
6
7
8
10
11
.5
.2
.8
.3
.0
.8
.6
.3
.3
.6
.0
.6
1
1
2
3
3
4
5
6
7
8
9
11
.2
.8
.4
.1
.7
.5
.2
.1
.0
.2
.6
.0
1.2
2.6
4.0
5.7
7.4
9.0
10.8
12.5
14.4
17.2
20.3
1.0
2.1
3.5
5.2
6.9
8.5
10.3
12.0
13.9
16.9
19.9
24.0
23.3
TABLE XVa
Dynamometer Acceleration Tests on 1979 Mercury Capri
seconds
8 Cylinder
Indolene Unleaded Gasoline
SPEEDS
Run 1
Run 2
0
0
0
0
0
0
0
0
0
0
0
0
- 5
- 10
- 15
- 20
- 25
- 30
- 35
- 40
- 45
- 50
- 55
- 60
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
MPH
1
2
3
3
4
5
6
8
9
10
12
15
.3
.1
.0
.9
.7
.7
.8
.0
.3
.8
,9
.2
.1
2
2
3
4
•5
6
7
8
9
11
13
.4
.1
.8
.7
.6
.5
.4
.5
.5
.8
.4
.0
ACDS 4 Cylinder
Indolene Unleaded
Run 1 Run 2
Run 3 Run 4
2.0
3.2
4.6
6.4
8.1
9.8
11.9
14.3
17.5
21.7
25.4
-
- 1.9
3.2
5.1
6.8
8.4
10.2
12.3
14.8
18.0
22.6
26.0
1.5
2.8
4.4
6.2
8.0
9.8
11.9
14.3
17.5
21.0
24.9
29.8
1.3
2.6
4.1
5.9
7.6
9.4
11.5
14.0
17.2
20.7,
24.5
29.0
-------
32
TABLE XVb
Road Acceleration Tests on 1979 Mercury Capri
seconds
SPEEDS
0-20 MPH
0-30 MPH
0-40 MPH
0-50 MPH
8 Cylinder
Not
Tested
Run 1 Run 2
ACDS 4 Cylinder
Run 3 Run 4
Run 5
7.5
11.5
15.5
23.5
5.8
9.2
13.4
19.7
6.0
9.5
13.5
20.0
5.8
9.5
13.4
20.2
5.7
9.8
13.3
20.0
SPEEDS
TABLE XVIa
Dynamometer Acceleration Tests on 1979 Mercury Cougar
seconds
8 Cylinder
Indolene unleaded Gasoline
Run 1 Run 2
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
5 MPH
10 MPH
15 MPH
20 MPH
25 MPH
30 MPH
35 MPH
40 MPH
45 MPH
50 MPH
55 MPH
60 MPH
.8
1.5
2.2
3.0
4.0
5.0
6.1
7.4
8.6
10.0
11.9
13.9
.8
1.4
2.1
3.0
3.9
4.9
6.0
7.2
8.5
9.9
11.8
13.8
ACDS 4
Commercial
Run 1
1.8
3.3
5.0
7.0
8.9
11.0
13.3
16.0
19.5
22.9
28.0
-
Cylinder
Unleaded
Run 2
1.5
3.2
4.9
6.9
9.0
11.2
13.4
16.2
19.5
23.1
28.1
-
ACDS 4
Indoleni
Run 1
1.5
2.9
4.6
6.6
8.6
10.7
13.0
15.6
19.0
22.5
21 A
33.4
1.5
2.9
4.6
6.6
8.6
10.8
13.1
15.6
19.1
22.6
27.4
33.3
TABLE XVIb
Road Acceleration Tests on 1979 Mercury Cougar
seconds
8 Cylinder
Indolene unleaded Gasoline
ACDS 4 Cylinder
Indolene
Gasoline
0
0
0
0
SPEEDS
- 20 MPH
- 30 MPH
- 40 MPH
-50 MPH
Run 1
__ __
4.5
6.8
9.1
Run 2
_ _
5.5
8.2
10.0
Run 3
_
4.6
7.0
9.5
Run 4
_ _
4.5
6.7
9.2
Run 1
7.5
11.8
16.7
23.5
Run 2
7.2
11.2
16.2
24.5
Run 3
7.0
11.1
16.7
23.2
-------
33
1440 HILL STREET • EL CAJON, CA 92021 • (714) 440-7585
INSTALLATION INSTRUCTIONS
Typical Chevrolet V-8 •
PREPARATION:
[Mechanical Systems Only)
HOW IT WORKS
The purpose of this kit is to deactivate one-half
of the engine. This is accomplished by releasing
the fulcrum point of the rocker arm. thereby
allowing the valves to stay closed on the deacti-
vated cylinders.' .
The kit also provides means for attaching the
pushrod to the hydraulic lifter and furnishes a
spring which holds the pushrod and lifter as-
sembly up and away from the cam shaft while
deactivated. : '
NOTE: This installation requires removal of the
ignition distributor. If you don't know how to remove
and replace it. get help either by referring to a
service manual, or by talking with an experienced
mechanic.
The top side of the engine should be cleaned, either
with solvent or steam.
A' set of rocker cover and intake manifold gaskets
will be needed.
Special tool required. 1" HOLE SAW. with V pilot
drill and shank.
INSTALLATION: ' --
1. Disconnect ground cable clamp at battery terminal.
2. Drain coolant from radiator by opening drain cock
on bottom radiator tank, or by removing bottom
hose at radiator. • •
3. Before removing rocker arm covers, identify which
cyldiners will be deactivated: Choose those with no
access problems ON or OVER the rocker covers;
that is. clear of OIL FILTER CAPS. PCV VALVE.
MOUNT BRACKETS, or WIRING. ETC.
4. Remove rocker arm covers.••
5. Remove ignition distributor, intake manifold, and all
f related lines, hoses, or wires. Use masking tape
and felt pen to tag or mark any hoses, or wires.
which might become mixed. ......'
6. Remove rocker." • • :
arms and pushrods
for EVERY OTHER
cylinder in the firing
order: EITHER 1.4.
6. 7; OR 8. 5. 3. 2.
[See III. A.)
NOTE: Whichever cylin-
ders you choose to deac-
tivate, the combination
should be as follows: on
one bank, the FRONT and
REAR cylinders will be af-
fectecf; AND. on the other
bank, the TWO CENTER
cylinders. Pick a combina-
tion that will not interfere
with the items listed in
Step #3. above.
-------
34
7. Remove the Adjusting nut. PIVOT BALL, and
ROCKER ARM from the two STUDS of each of the
affected cylinders. You may choose not to mix
rocker assemblies, but if they are mixed by mistake.
it is NOT critical. On BIG BLOCK Chevrolets. (395.
402. 427. 454 C1D] intake and exhaust pushrods
are different lengths, but rocker assemblies are
the same.
B. Remove the INTAKE AND EXHAUST lifters for each
cylinder to be deactivated. Place on the bench. •
being as clean as possible. Remove the WIRE CLIP. .
PUSHROD CUP,and flat disc from top of lifter. It is
necessary to collapse the lifter for reassembly. You
can do this by removing the inner plunger assembly
and simply pouring out a portion of the oil under-.
neath, OR. by depressing the ball check while push-
ing down on the plunger. You may now replace flat
disc and pushrod cup. Do not install wire clip at this
time.
9. Using a flat or triangular shape file, place a small
groove 1/S" from top of pushrod. This is to help
hold the AGO clip on the pushrod so it will not move.
10. Install'Star!clip onto . •_ - .-.'••
a PUSHROD a dis-
tance of approx-
imately 1/2" from
the ball on the end..
Slide 5/16" I.D.
WASHER against
CLIP and install
SPRING onto PUSH-
ROD. [See III. B)
11. After completing all 8
PUSHROD/SPRING
assemblies, the KIT
is ready to install in
the engine. ...:
12. Install lifters into their respective holes in engine.
'without wire clips. Slide, pushrod into hole above
lifter. . •-"-• ' : ' .
13. Install ACD clip on ball of pushrod being.,sure not.
to distort AGO clip.. [See III. C)
14. Push pushrod into "
lifter cup. down far
enough to install
wire clip [supplied
with kit] into lifter
groove on top of ACD
clip. Repeat pro-
cedure on the other
7 lifter assemblies.
1ST. Re-install the intake
manifold, ignition dis-
tributor, and all lines, hoses, and wires. DOUBLE
CHECK all connections for proper routing.
REPLACEMENT
CUP
16. Install ROCKER ARMS. PIVOT BALLS AND NUTS.
For 4 cylinder operation, adjust valves with each
CAM LOBE UP at its HIGHEST point. (Crank engine.
watch pushrods—they should not move.) To operate
in FOUR-CYLINDER mode. ROCKER ARMS are
HELD UP so that the lifters do not contact_the cam .
on the high side.
17. CLEAN ROCKER
COVERS THOR-
OUGHLY. INSTALL
TRANSFER PUNCH
on each ROCKER .
STUD to be deacti- .:
vated. and mark-- •
ROCKER COVER
[Tap with hammer)
for 1" hole
cutout. [See III. 9)
1B. With the rocker
cover held securely
in a vise or bench
clamp, align the PI-
LOT DRILL of the . 1" HOLE SAW "with each
PUNCH MARK; drill and cut out FOUR access
holes. Remove all BURRS, inside and out, finishing
with smooth half-round file or emery cloth. BE
SURE NO METAL PARTICLES CAN FALL INTO EN-
GINE. Reinstall rocker covers.
19. To adjust ROCKERS for B-CYLINDER operation.
remove cup plugs in rocker covers, insert socket
wrench. MAKING SURE cam lobe is DOWN. (This is
; "most easily done by removing ignition distributor
. .cap. and turning engine over until rotor points at
., spark plug wire location for that cylinder.) Then
.". adjust as with a STOCK engine. Turn down adjust-
ment nut until there is zero clearance. (Make sure
, you are not depressing lifter.) Advance nut 1 /2 turn.
This is the running adjustment. .'•...:
20. For the BEST FOUR-CYLINDER economy and per-
... formance. tune to factory specification. If you have
•,. .any specific tune-up problems.or .questions, con-
tact ACDS inc. direct. ' ' .
FOR MORE INFORMATION OR
TO REORDER, WRITE TO: ACDS
1440 Hill St.
El Cajon, CA 92020
(714)440-7385
-------
HOW IT WORKS
The purpose of this kit is to deactivate
one-half of the engine. This is accom-
plished by releasing the fulcrum point of
the rocker arm, thereby allowing the
valves to stay closed on the deacti-
vated cylinders.
The kit also provides means for
attaching tfie pushrod to the hy-
draulic lifter and furnishes a
spring which holds the pushrod
and lifter assembly up and away
from the cam shaft while deacti-
vated.
INSTALLATION INSTRUCTIONS
Typical Chevrolet V-8
PREPARATION:
[Mechanical Systems Only)
NOTE: This installation requires removal of
the ignition distributor. If you don't know how
to remove and replace it. get help either by
referring to a service manual, or by talking
with an experienced mechanic.
2. The top side of the engine should be cleaned.
either with solvent or steam.
3. A set of rocker cover and intake manifold
gaskets will be needed.
4. Special tool required;' 1 1/8" HOLE SAW.
with y«." pilot drill andshank. /
-------
"AUTOMOTIVE CYLINDER DE-ACTIVATOR SYSTEM"
-------
INSTALLATION:
1. Disconnect ground cable clamp at battery
terminal.
37
MOUTOa HOM
2. Drain coolant from radiator by opening drain
cock on bottom radiator tank, or by remov-
ing bottom hose at
radiator. (See III. A]
3. Before removing
rocker arm covers,
identify which
cylinders will be
deactivated: 1, 4,
6. 7 or 2, 3, 5, 8.
Choose those with
no access problems
ON or OVER the rocker covers; that is, clear
of OIL FILTER CAPS, PCV VALVE, MOUNT
BRACKETS, or WIRING, etc. [See III. B]
Afte
combination that will not interfere with the
items listed in Step *3, above.
[See III. C and D]
4. Remove rocker arm covers. CLEAN
ROCKER COVERS THOROUGHLY. INSTALL
TRANSFER PUNCH on each ROCKER STUD
to be deactivated, and mark ROCKER
COVER [Tap with hammer) for 1 1/8" hole
cutout. (See III. E] With the rocker cover held
securely in a vise or bench clamp, align the
PILOT DRILL of the 1 1/8" HOLE SAW with
each PUNCH MARK; drill and cut out FOUR
access holes. Re-
move all BURRS, in-
side and out, finish-
ing with smooth
halfround file or
emery cloth. BE
SURE NO METAL
PARTICLES CAN
INTO JENG-
TYPICAL CHEVROLET
nuiNOomn
TYPICAL PUNCH LOCATION
PVCOH
•RCATHEM
SMALL HOCK CMtVROUT
TYPICAL MOLI WHU. LOCATION
pvcon
BREATHCR
' BIO KOCK CHEVROLtT
TYPICAL HOU DRILL LOCATION
(VIQTE: Whichever cylinders you choose to
deactivate, the combination should be as
follows: on one bank, the FRONT and REAR
cylinders will be affected; AND, on the other
bank, the TWO CENTER cylinders. Pick a
5. Remove ignition distributor, intake manifold,
and all related lines, hoses, or wires. Use
masking tape and felt pen to tag or mark any
hoses, or wires, which might become mixed.
6. Remove Rocker Arms and Pushrods from
cylinders to be deactivated.
Remove the Adjusting nut. PIVOT BALL, and
ROCKER ARM from the two STUDS of each
of the affected cylinders. You may choose
not to mix rocker assemblies, but if they are
mixed by mistake, it is NOT critical. On BIG
BLOCK Chevrolets. (396. 402. 427, 454
C1D] intake and exhaust pushrods are dif-
ferent lengths, but rocker assemblies are
the same.
Remove the INTAKE AND EXHAUST lifters
for each cylinder to be deactivated. Place on
-------
PUSH BOO
CUP
the bench, being as clean as possible. Re-
move the WIRE CLIP, PUSHROD CUP and
flat disc from top of lifter. It is necessary to
collapse the lifter for reassembly. You can do
this by removing the
inner plunger as-
sembly and simply
pouring out a por-
tion of the oil under-
neath. OR. by de-
pressing the ball
check while pushing
down on the plung-
er. You may now re-
place flat disc and
pushrod cup. Do not
install wire clip at
this time. [See III. F) F
8. Install ACD clip onto a PUSHROD a distance
of approximately Vz" from the ball on the
end. Slide 5/16"
I.D. WASHER
against CLIP and in-
stall SPRING onto
PUSHROD. [See III.
G] [This is pre-
installed at ACDS
factory but must be
checked.)
NOTE: Big Block
Chevrolet clip to be
1 5/8" from top of
Long Rod. Short
Rod 1/a" from top.
9. After completing all 8 PUSHROD/SPRING
assemblies, the KIT is ready to install in the
engine.
1O. Install lifters into their respective holes in
engine, without wire clips. Slide ACD
pushrod, with springs installed, into hole
above lifter. [See III. H)
TYPICAL
MO BLOCK
CHEVROLET
&HOOT BOO
AMD SPRING
LOCATION
TYPICAL
BIO BLOCK
CHEVROLET
LONO ROD
SPRING AND
LOCATION
TYPICAL
BLOCK
CHEVROLET
PUftH ROD
AND ftPOlNO
LOCATION
11.
ftf-4N«TAUJKD
H y J _
Install ACD clip on ball of pushrod. being sure
not to distort ACD clip. [See III. J) CUp Up
Push pushrod into lifter cup, down far enough
to install wire clip
[supplied with kit] in-
to lifter groove on
top of ACD clip.
[See III. K) Should be
inserted after clip.
Repeat procedure
on the other 7 lifter
assemblies.
[See III. K]
NOTE: Big Block
WBTU1XD PtWHftOO
WTTXACOCU*
ANDWffi»CU»
K
Chevrolet Long Spring installed
under Pushrod Guide. Short Spring
installed on top of Pushrod Guide.
[See III. M and N. on back)
12. Re-install the intake manifold, ignition distrib-
utor, and all lines, hoses, and wires. DOUBLE
CHECK all connections for proper routing.
Install ROCKER ARMS. PIVOT BALLS AND
NUTS. For 4 cylinder operation, adjust
valves with each CAM LOBE UP at its
HIGHEST point. [Crank engine, watch
pushrods—they should not move.) To
operate in FOUR-CYLINDER mode. ROCKER
ARMS are HELD UP so that the lifters do
not contact the cam on the high side. [See III.
L on back) - . _
-------
39
14. To adjust ROCKERS for 8-CYLINDERopera-
•, / tion. remove cup plugs in rocker covers, in-
"~ sert socket wrench, MAKING SURE cam
lobe is DOWN. [This is most easily done by
removing ignition distributor cap, and turning
engine over until rotor points at spark plug
wire location for that cylinder.) Then adjust
as with a STOCK engine. Turn down adjust-
ment nut until there is zero clearance. [Make
sure you are not depressing lifter.] Advance
nut Vz turn. This is the running adjustment.
[See III. L, M and N)
15. For the BEST FOUR-CYLINDER economy
and performance, tune to factory specifica-
tion. If you have any specific tune-up prob-
lems or questions, contact ACDS Inc. direct.
BATCH rrWHIHCH
ANDMCKIT
ACDPUIHDOO
WITH BMINO
BIO BLOCK CHIVPOLIT
LONG ROD INSTAiiATION WITH tONO BPftfMO
TROUBLE-SHOOTING
N
BIO BLOCK CHIVAtHXT
•HORT ROD IMBTALLATtOM WITH SHOOT I
CONDITION
Noisy on 4-cylinders
Noisy on 8 -cylinders
Rough idle on 4-cylinders
Rough idle on 8 -cylinders
Stalls at stop light on 4-cylinders
Runs too rich on 4-cylinders
Hard start on 4 -cylinder (cold)
Hard start on 4-cylinder [hot]
CAUSE
1. Valves, deactivated, still con-
tacting cam shaft
2. Loose tinning chain
1. Improper valve adjustment
1. Idle speed too slow
2. Vacuum leaks
3. Improper idle adjustment •
4. Improper timing adjustment
1. All of above on 4-cylinder model
2. Tight valves
1 . Idle too slow in gear or operating
Air Conditioner while in gear
1. Dirty carburetor [choke sticking,
etc.
2. Jets in carb. too large
1 . Choke not functioning
2. Needs tune-up
1. Hooding
2. Needs tune-up
CORRECTION
1. Loosen adj. nuts until all deacti-
vated valve lifters do not con-
tact cam shaft
2. Replace chain and gears
1 . Recheck and correct adjustment
1. Raise speed until smooth
2. Check all hoses and connections;
replace as necessary
3. Adjust idle mixture screws
4. Adjust timing
1. Same
2. Recheck and correct
1. Raise idle
1 . Clean carburetor arid correct aH
adjustments
2. Replace with smaller jets
1. Repair choke
2. Tune engine
1. Do not pump accelerator
2. Check condition of carb. plugs,
etc.
-------
"."*
•" u
'.'-.I
Federal law requires that no changes be made to your pollu-
tion control equipment.
For "Flip of a Switch" convenience on your Chevrolet, your
Mechanical ACD System can be converted to a hydraulic
system at a later date.
FOR MORE INFORMATION OR
TO RE-OROER, WRITE TO:
s; oevei_op;vieMT
1440 HILL ST., EL CAJON, CA 92021 [714] 440-7585
------- |