72-22
EVALUATION OF THE LANDRUM
RETROFIT SYSTEM
April 1972
Henry L. Gompf
Test and Evaluation Branch
Environmental Protection Agency
-------
Background
Mr. Porter Landrum of Birmingham, Alabama, supplied
the Test and Evaluation Branch with test data indicating
significant reduction in hydrocarbon and carbon monoxide on
a vehicle equipped i^ith his retrofit system. Based on this
preliminary testing, a confirmatory evaluation was conducted
in the EPA laboratory at Ann Arbor.
Device Tested
The Landrum system employs the replacement of stock idle
mixture screws with hollow bleed-type screws. These screws
are tranversely drilled near the ends to allow gasoline to
enter mixing with air. The air supplied to the screws is
preheated by means of a vacuum actuated cylindrical resistance
heater. For this test the stock idle screws were removed from
a 1971 Ford, 351 CID engine with automatic transmission.
Mr. Landrum's screws were installed with the associated heating
element. No idle mixture adjustment was necessary as the
Landrum screws are seated solidly in the carburetor.
Test Program
Testing of the vehicle, both baseline and device equipped
was done in accordance with the November 10, 1970, and July 2, 1971,
Federal Register. These documents describe the 1972 and 1975
Federal Test Procedures, respectively. In addition, fuel
consumption has been calculated from the exhaust emissions for
each test.
Test Results
The test data is presented in the Appendix of this report.
As indicated the Landrum system appears to reduce hydrocarbon by
10% and carbon monoxide by 15%. A 7% fuel consumption penalty
is associated with the system. It should be noted that the
baseline vehicle, in this case, was set at a lean idle of
.25% CO. This was roughly the same idle CO level as obtained
with the Landrum device installed.
-------
-2-
Conclusions
While the reductions obtained appear small, this was
partially due to careful adjustment of the baseline vehicle
to a lean idle setting. The setting for the Landrum system
required merely the seating of the special idle screws. No
doubt the effective reduction of carbon monoxide would have
appreciably higher if the test vehicle had been adjusted to
normal maintenance levels of carbon monoxide.
been
Due to the use of small passages in the idle screw concern
is expressed over deposit plugging. This tendency could result
in rough idle, stalling, or misfire. Durability testing would be
required to quantitatively evaluate this condition.
-~""-w-_._-~....--........---,.-"--'- -_.._..._~...-~.....,... -- ~.........-~- .-.
~ '-' - -- ~ ~...~. --<-, '.'-
~----~.-.,.-~.~ ,...,-".- ,,_._~,-:- ~"'---I
-------
-3-
APPENDIX
1975 Federal Emission Test
All Emission Results in Grams Per Mile
Date HC
Baseline
4-17-72 2.81
4-18-72 2.44
Average 2.63
Fuel
CO C02 NOx MPG
13.9 644.1 5.35 12.9
11. 0 651.4 5.42 12.9
12.5 647.8 5.39 12.9
Landrum System
4-4-72 2.46
4-5-72 2.28
4-6-72 2.42
4-7-72 2.29
Average 2.36
12.0 690.4 6:10 12.0
11. 0 732.3 5.05 11. 5
10.2 724.9 5.23 11. 6
9.3 690.7 5.27 12.4
10.6 709.6 5.41 11.9
% Reduction
from Baseline
10%
15%
10% increase
0%
7% penalty
-------
' -
.4.
A
1972 Federal Emission Test
All Results in Grams Per Mile
Date
Baseline
4-17-72
4-18-72
Average
Landrum Sys
4-4-72
4-5-72
4-6-72
4-7-72 '
Average
H£
3.25
2.68
2.97
tern
2.96
2.61
2.61
2.51
2.67
CO
24.4
19.2
21.8
21.0
19.8
16.6
15.9
18.3
Cp_2
677.9
678.7
678.3
720.0
760.0
776.9
1
710J1
741.8
NOx
5.37
5.27
5.32
6.13
4.97
5.10
5.12
5.33
v Reduction
from Baseline 10% 16% 91 increase 0%
------- |