72-22
   EVALUATION OF THE LANDRUM
        RETROFIT SYSTEM
          April 1972
        Henry L. Gompf
  Test and Evaluation Branch
Environmental Protection Agency

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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 with  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 screivs 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
101 and carbon monoxide by 15%.  A 71 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
.251 CO.  This was roughly the same idle CO level as obtained
with the Landrum device installed.

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                           -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 been
appreciably higher if the test vehicle had been adjusted to
normal maintenance levels of carbon monoxide.

     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.

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                             -3-

                         APPENDIX

               •  1975 Federal Emission Test
           All Emission Results in Grams Per Mile
Date
HC
CO

Baseline
4
4

-17-72
-18-72
Average
Landrum Sys
4
4
4
4

-4-72
-5-72
-6-72
-7-72
Average
2.
2.
2.
tern
2.
2.
2.
2.
2.
81
44
63

46
28
42
29
36
13.
11.
12.

12.
11.
10.
9.
10.
9
0
5

0
0
2
3
6
co2

644.
651.
647.

690.
732.
724.
690.
709.
NOx

1
4
8

4
3
9
7
6

5.
5.
5.

6".
5.
5.
5.
5.

35
42
39

10
05
23
27
41
Fuel
MPG

12.
12.
12.

12.
11.
11.
12.
11.


9
9
9

0
5
6
4
9
°o Reduction
from Baseline  iu%
increase  in
7% penalty

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                             -4-
                 1972 Federal Emission Test
                All Results in Grams Per Mile
Date
Baseline
4-17-72
4
-18-72
Average
HC
3.25
2
2
.68
.97
CO
24
19
21
.4
.2
.8
co2
677
678
678
NOx
.9
.7
.3
5
5
5
.37
.27
.32
Landrum System
4
4
4
4
-4-72
-5-72
-6-72
-7-72
Average
2
2
2
2
2
.96
.61
.61
.51
.67
21
19
16
15
18
.0
.8
.6
.9
.3
720
760
776
710
741
.0
.0
.9
.1
.8
6
4
5
5
5
.13
.97
.10
.12
.33
% Reduction
from Baseline  10%       161       9% increase  0%

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