74-3
RBM
An Evaluation of Aquablast's
Wyman Valves
July 1973
Emission Control Technology Division
Office of Air and Water Programs
Environmental Protection Agency
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Background
Representatives from Aquablast Inc. of Scarborough, Ontario
Canada, contacted the Emission Control Technology Division
inquiring about the possible testing by EPA of vehicles with
their Wyman valves installed. Data was supplied showing
significant reductions of carbon monoxide on vehicles with
the valves installed. ECTD agreed to test their product on
two vehicles.
Device Tested
The Wyman needles, developed by Mr. Curt R. Wyman of Germany,
replace the standard idle mixture adjusting screws of a car-
buretor in a 4-cycle internal combustion engine. Each needle
has a hole drilled through the middle so that air flows through
at conditions of idling and coasting when the vacuum is high
but when the vacuum drops below 15" Hg, as in the case of
acceleration and high speed, a coil spring inside the needle
pushes a ball against a seat closing off the air stream so
that a richer mixture is provided. A diagram of one of the
needles is shown below:
Tig. 1
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-2-
Test Program
Two vehicles were used in the test program; a 1963 Ford
Galaxie 289 CID, V-8 engine, 2-V carburetor with automatic
transmission tested at 4000# inertia weight, and a 1970
Chevrolet Impala 350 CID V-8, 2-V carburetor engine with
automatic transmission tested at 4500# inertia weight.
Before any testing was started both vehicle engines were set
to the recommended idle rpm and timing; idle CO for the
Chevrolet was set at .5% and for the Ford 2%. Two emissions
tests* were then performed on each vehicle in this stock
configuration to be used as the baseline results.
The stock idle needles (two in each vehicles carburetor) were
then replaced by Wyman needles. These needles were screwed
in far enough so that idle CO was identical to the stock
configuration. Idle rpm and timing were checked, but no
admustments were necessary to stock specifications. The
vehicles were then each tested twice with the Wyman needles
installed.
Test Results
The test results are presented in the Appendix of this report
These results are summarized below. In addition to emission
results, fuel economy was calculated for each test using a
carbon balance technique.
Summary of Test Results
% Decrease from Baseline
1970 Chevrolet HC 13%
CO 191
NOx 4%
MPG 01
1963 Ford HC 61
CO 291
NOx -17% (increase)
MPG -3% (increase)
Conclusions
On the two EPA test vehicles HC and CO emissions were reduced
with the Wyman valves installed while NOx emissions decreased
slightly in one vehicle and increased in the other. Fuel
economy was not significantly affected.
* All testing was performed according to the 1975 Federal Test
Procedure (FTP) as outlined in the November 15, 1972, Federal
Register for light duty vehicles.
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APPENDIX
Aquablast Test Program - 1975 Federal Test Procedure
Fuel
Test HC CO CO2 NOx Economy
No. gpm gpm gpm . gpm mpg
Chevrolet 16-386 2.20 26.85 641.8 4.76 12.93
Baseline 16-391 1.95 24.88 678.0 4.68 12.44
Average 2.08 25.86 659.9 4.72 12.68
Chevrolet 16-397 1.79 21.10 666.0 4.87 12.71
Wyman 16-400 1.81 20.96 662.7 4.20 12.77
Needles Average 1.80 21.03 664.4 4.54 12.74
Ford 16-493 6.11 85.85 437.85 2.63 14.82
Baseline 16-495 6.23 84.31 447.35 2.95 14.74
Average 6.17 85.08 442.60 2.79 14.78
Ford 16-507 5.67 61.34 452.7 3.12 15.53
Wyman 16-515 5.96 60.27 466.8 3.41 15.04
Needles Average 5.82 60.80 459.8 3.26 15.28
* U.S. GOVERNMENT PRINTING OFFICE: 1979- 651-112/0109
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