United States

Environmental Protection

Agency

Air and Radiation EPA420-R-99-004

April 1999

EPA Laboratory

Evaluation of the

Aftermarket Retrofit

Device Tail Pipe Cat

 Printed on Recycled Paper
EPA420-R-99-004

March 1999

EPA Laboratory Evaluation of the

Aftermarket Retrofit Device Tail Pipe Cat

Vehicle Programs and Compliance Division

Office of Mobile Sources

U.S. Environmental Protection Agency

NOTICE

This technical report does not necessarily represent final EPA decisions or positions.

It is intended to present technical analysis of issues using data that are currently available.

The purpose in the release of such reports is to facilitate the exchange of

technical information and to inform the public of technical developments which

may form the basis for a final EPA decision, position, or regulatory action.

Data, commentary and conclusions contained in this report 

should not be taken out of context or restated to give alternate conclusions.
1

EPA Laboratory Evaluation of Tail Pipe Cat

Introduction

This report describes the U.S. Environmental Protection Agency (EPA) laboratory exhaust

emission and fuel economy testing of a product named Tail Pipe Cat (TPC) by the Vehicle

Programs and Compliance Division (VPCD) at EPA’s National Vehicle and Fuel Emissions

Laboratory (NVFEL) in Ann Arbor, Michigan. TPC is a product developed by Compliance and

Research Services, Inc. which identifies itself as CARS. The testing reported here was

volunteered for and paid by CARS as found in the following regulations: 42 USC 7525;49 USC

32918; and 40 CFR 610

EPA’s analysis of the independent test laboratory data furnished with the CARS application for

evaluation demonstrated a statistically significant reduction in exhaust missions when TPC was

installed on the vehicles tested. CARS is also an independent test laboratory qualified to conduct

EPA test protocols. They furnished test data acquired in their laboratory from testing a large

volume of vehicles during the development of the TPC. However, EPA could not consider that

data because CARS has a special interest in its own product and their data would not have been

considered to be independently derived.

TPC is a supplemental catalytic converter intended to operate in conjunction with the existing

original equipment manufacturer (OEM) converter. The purpose of this product is to further

reduce the exhaust emissions of vehicles which are reaching the end of their intermediate useful

life ( 50,000 miles as identified in their application). The initial targeted market identified by

CARS in its application is for operators of large vehicle fleets such as major corporations and

government organizations. CARS makes no fuel economy claims for TPC.

Although CARS has not disclosed the specific catalytic materials nor the amount of catalyst

employed (catalyst loading) in their product, it should be presumed that it will be at least the

same, or better, than that used in the test sample when offered to the marketplace. The 

TPC may also be marketed by two other names as indicated in the CARS application; these

names are Aux Cat and Cat-A-Pass. 

The conclusions drawn from EPA evaluation tests are necessarily of limited applicability. An all

encompassing evaluation of the effectiveness of a product in achieving performance

improvements on the many types of vehicles that are in actual use would require a large sample

of test vehicles. This is not economically feasible in the evaluation projects conducted by EPA. 

Therefore, the conclusions from such tests can be considered to be quantitatively valid only for

the specific test vehicles used; however, it is reasonable to extrapolate the results from EPA tests

to other types of vehicles in a directional manner; i.e., to suggest that similar results are likely to

be achieved on other similar types of vehicles.
2

Test Program

The purpose of the EPA test program was to conduct a controlled technical evaluation of TPC in

a manner that would address the manufacturer’s specific claims for additional reduction in

exhaust emissions with the product installed in conjunction with the vehicle’s existing emission

control components. An invitation was extended to CARS to have a representative present for

all phases of maintenance and testing at the EPA test laboratory.

The confirmatory test plan developed and conducted by EPA (see Appendix: Test Plan

Agreement) and agreed to by CARS used the following two vehicles: A 1996 Dodge Caravan,

Vehicle Identification Number (VIN) 1B4G44R8TB142323, Engine Family Code

TCR3.328GKEK, 3.3 liter, with automatic transmission and 80,724 miles on the odometer at the

start of testing. This vehicle was furnished by CARS. The second was a 1996 Ford F-150,

Vehicle Identification Number (VIN) 1FTEF15N3TLA62042, Engine Family Code

TFM5.088GBJK, 5.0 liter, with automatic transmission, and 17,123 miles on the odometer at the

start of testing. The F-150 was furnished by EPA and came from its test vehicle lease program.

The federal certification standards, in grams per mile for each pollutant, for these model year

(MY) 1996 vehicles are:

Pollutant 5 years/50 K miles 11 years/120 K miles

Carbon Monoxide 4.4 5.5

Oxides of Nitrogen 0.7 0.97

Non-methane Hydrocarbons 0.32 0.40

Although the two test vehicles were light duty trucks chosen for the ease of installing the TPC,

this does not imply that the product may be difficult to install on other vehicle types nor that its

use should be limited to light duty trucks. It was merely expedient and resource effective to use

these vehicles.

Prior to testing, the test vehicles were inspected and maintenance performed identical to that

employed on consumer owned vehicles in the VPCD in-use emissions program. The vehicles

were tuned to manufacturer’s specifications, and any malfunctioning part was replaced as

necessary. Engine oil and filter change is included in the maintenance procedure. Once the

testing program was started, no adjustments were made to either vehicle.

The test phases were:

1. Three Federal Test Procedure tests (FTP, the simulated city drive test) and three Highway Fuel

Economy Tests (HFET) with the vehicle in stock configuration were performed to establish the

emissions and fuel economy characteristics prior to the installation of TPC. No adjustments were

made to any engine components between tests.
3

Note: Although CARS makes no fuel economy claims with use of the TPC , it is EPA policy to

conduct the fuel economy tests to determine whether there are negative effects when using any

device or fuel additive in the evaluation program. 

2. After stock configuration testing, the TPC was installed in the exhaust downstream of the

stock catalytic converter per CARS’ instruction and five FTP and HFET tests were conducted to

measure emissions and fuel economy. No adjustments were made to any engine components

between tests.

3. After conducting the test series with the TPC installed, each vehicle was driven 1000 miles

over the standard EPA driving course in the Ann Arbor, Michigan area to provide some degeree

of aging of the TPC.

4. An additional five FTP and HFET tests were conducted to measure emissions and fuel

economy after 1000 miles were accumulated on each vehicle. No adjustments were made to any

engine components between tests.

5. The TPC was removed after testing the product and another triplicate set of stock

configuration tests was conducted on each vehicle. Again, no adjustments were made to any

engine components between tests.

Results

All test data generated in the EPA laboratory test program are presented in Tables 1-8.

 The results of the testing are shown in the three following comparisons: the results of testing

after initially installing the TPC against the stock configuration, the results of testing after 1000

miles accumulation with the TPC against the stock configuration, and the results of testing after

removal of the TPC and restoration to stock configuration against the stock configuration before

installation of the TPC.

The emissions for both vehicles in stock configuration were below the MY 1996 federal emission

standards. Although there is no federal standard for total hydrocarbons for these MY 1996

vehicles, we have provided the test results in conjunction with non-methane hydrocarbon data

since CARS had furnished this data with their application.

First Installation of the TPC

The Dodge Caravan had a 17% reduction in both non-methane hydrocarbons (NMHC) and

hydrocarbons (HC), a 30% reduction in carbon monoxide (CO), and a 38% reduction in oxides

of nitrogen (NOx). These reductions were all statistically significant improvements. There was

no significant difference in either city or highway fuel economy.

The Ford F-150 had a 4% reduction in both non-methane hydrocarbons (NMHC) and carbon

monoxide (CO), a 6% reduction in hydrocarbons (HC) and an 18% reduction oxides of nitrogen
4

(NOx). The reductions in HC and NOx were statistically significant improvements; the

reductions in NMHC and CO were not statistically significant. There was no change in the city

fuel economy, but there was a two percent reduction in highway fuel economy. This change in

highway fuel economy was statistically significant.

The results of these test series are found in Tables 1 and 4.

After 1000 Miles with TPC Installed

The Dodge Caravan had an 11% reduction in both hydrocarbons (HC) and non-methane

hydrocarbons (NMHC), a 17% reduction in carbon monoxide (CO), and a 37% reduction in

oxides of nitrogen (NOx). These were all statistically significant improvements. There was no

significant difference in either city or highway fuel economy.

The Ford F-150 had a 10% reduction in both hydrocarbons (HC) and carbon monoxide (CO), an 

8% in non-methane hydrocarbons (NMHC), and a 20% reduction in oxides of nitrogen (NOx).

These were all statistically significant improvements. There was no significant difference in

either city or highway fuel economy.

The results of these test series are found in Tables 2 and 5.

After Removal of the TPC - Vehicles Returned to Stock Configuration

The Dodge Caravan had a 1% increase in hydrocarbons (HC),an 11% increase in carbon

monoxide (CO), a 2% increase in non-methane hydrocarbons (NMHC),and a 4% reduction in

oxides of nitrogen (NOx). These results were not, however, statistically significant differences.

Although there was no significant difference in city fuel economy there was a 2% improvement

in highway fuel economy which was significant.

The Ford F-150 had a 2% reduction in hydrocarbons (HC), an 8% reduction in carbon monoxide

(CO), and a 19% reduction in oxides of nitrogen (NOx). There was no change in the nonmethane hydrocarbons (NMHC) emissions. These were statistically significant improvements for

NOx and CO but not for HC. There was no significant difference in either city or highway fuel

economy.

The results of these test series are found in Tables 3 and 6.

The individual exhaust gas bag data generated for all of the test series for both test vehicles can

be found in Tables 7 and 8.

Conclusions

The exhaust emissions reductions were statistically significant using the Tail Pipe Cat on both

test vehicles in the initially installed configuration as well as after one thousand miles of driving

with the device installed with two exceptions. The carbon monoxide and non-methane
5

hydrocarbon reductions of four percent on the Ford after initial installation of the Tail Pipe Cat

were not statistically significant.

The impact of using the Tail Pipe Cat on the Dodge vehicle (with 80,724 miles at test start)

generated greater relative reductions in emissions than those for the Ford (with 17,123 miles at

test start). It is suspected that these differences are due to the mileage differences between the

two vehicles. 

The Ford also maintained a statistically significant reduction in CO and NOx when returned to

stock configuration after removal of the Tail Pipe Cat. It is suspected that the Ford may have

“drifted” from the original stock configuration test series since removal of the device should not

have had an effect on emissions. This phenomenon did not occur with the Dodge.

Use of the Tail pipe Cat did have a beneficial effect of reducing exhaust emissions. The product

was not designed to have an effect on fuel economy, and this was confirmed in this evaluation.

Although this evaluation was confined to light duty trucks to ease installation of the device, it

would be reasonable to assume that similar results might be realized with the device installed on

light duty vehicles (i.e., passenger cars) provided that the catalyst loading is not reduced for

commercially available units. 

This evaluation did not include any testing for long term durability of the device itself or the long

term durability of the vehicle with the device installed. This would have required extended

mileage accumulation which was beyond the scope of this evaluation. Therefore, no conclusions

about long term durability can be drawn from this report.

Conclusions and results of this evaluation may not be taken out of context for promotional

purposes.
6

1996 DODGE CARAVAN (with 80,724 miles at test start)

TABLE 1

Initial Installation of Tail Pipe Cat Versus Stock Configuration

Pollutant/Fuel

Economy

Stock Configuration Tail Pipe Cat Installed (No mileage accumulation)

Test 1 Test 2 Test 3 Average Test 1 Test 2 Test 3 Test 4 Test 5 Average 

HC

(grams/mile)

0.215 0.195 0.206 0.205 0.181 0.174 0.169 0.161 0.170 0.171 

CO

(grams/mile)

1.593 1.499 1.909 1.667 1.255 1.166 1.210 0.980 1.251 1.172 

NOx

(grams/mile)

0.549 0.461 0.485 0.498 0.291 0.293 0.295 0.305 0.351 0.307 

NMHC

(grams/mile)

0.189 0.171 0.181 0.180 0.159 0.153 0.148 0.140 0.150 0.150 

“City” Fuel

Economy (mpg)

18.8 19.3 19.4 19.2 19.2 19.5 19.5 19.1 19.2 19.3 

“Highway” Fuel

Economy (mpg)

29.6 29.3 29.2 29.4 29.3 29.2 30.3 29.2 28.6 29.3 
7

1996 DODGE CARAVAN (with 80,724 miles at test start)

TABLE 2

After 1000 miles with Tail Pipe Cat Installed Versus Stock Configuration

Pollutant/Fuel

Economy

Stock Configuration Tail Pipe Cat Installed (After 1000 miles)

Test 1 Test 2 Test 3 Average Test 1 Test 2 Test 3 Test 4 Test 5 Average 

HC

(grams/mile)

0.215 0.195 0.206 0.205 0.187 0.173 0.183 0.177 0.189 0.182 

CO

(grams/mile)

1.593 1.499 1.909 1.667 1.307 1.325 1.484 1.284 1.490 1.378 

NOx

(grams/mile)

0.549 0.461 0.485 0.498 0.279 0.331 0.320 0.301 0.327 0.312 

NMHC

(grams/mile)

0.189 0.171 0.181 0.180 0.168 0.151 0.161 0.157 0.167 0.161 

“City” Fuel

Economy (mpg)

18.8 19.3 19.4 19.2 18.8 18.9 19.5 18.9 19.1 19.0 

“Highway” Fuel

Economy (mpg)

29.6 29.3 29.2 29.4 29.3 28.9 29.4 28.9 29.7 29.2 
8

1996 DODGE CARAVAN (with 80,724 miles at test start)

TABLE 3

Stock Configuration After Removal of Tail Pipe Cat Versus Stock Configuration

Pollutant/Fuel

Economy

Stock Configuration Returned to Stock Configuration

Perce

Differe

Test 1 Test 2 Test 3 Average Test 1 Test 2 Test 3 Average 

HC

(grams/mile)

0.215 0.195 0.206 0.205 0.211 0.206 0.208 0.208 1 

CO

(grams/mile)

1.593 1.499 1.909 1.667 1.926 1.728 1.885 1.846 11 

NOx

(grams/mile)

0.549 0.461 0.485 0.498 0.474 0.487 0.469 0.477 - 4 

NMHC

(grams/mile)

0.189 0.171 0.181 0.180 0.185 0.182 0.183 0.183 2 

“City” Fuel

Economy (mpg)

18.8 19.3 19.4 19.2 19.3 19.4 19.4 19.4 1 

“Highway” Fuel

Economy (mpg)

29.6 29.3 29.2 29.4 30.0 29.9 29.6 29.8 2 
9

1996 FORD F-150 (with 17,123 miles at test start)

TABLE 4

Initial Installation of Tail Pipe Cat Versus Stock Configuration

Pollutant/Fuel

Economy

Stock Configuration Tail Pipe Cat Installed (No mileage accumulation)

Test 1 Test 2 Test 3 Average Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Average 

HC

(grams/mile)

0.162 0.151 0.154 0.156 0.141 0.155 0.137 0.148 0.141 0.152 0.146 

CO

 (grams/mile)

1.051 0.941 1.042 1.011 0.916 1.050 0.841 0.983 1.001 1.012 0.967 

NOx

(grams/mile)

0.415 0.421 0.407 0.414 0.359 0.346 0.323 0.324 0.349 0.344 0.341 

NMHC

(grams/mile)

0.119 0.108 0.114 0.114 0.101 0.115 0.104 0.114 0.107 0.115 0.109 

“City” Fuel

Economy (mpg)

16.2 16.0 16.1 16.1 16.0 16.1 16.0 16.1 16.2 16.2 16.1 

“Highway” Fuel

Economy (mpg)

23.5 23.3 23.5 23.4 23.1 22.7 23.0 23.2 22.8 23.2 23.0 
10

1996 FORD F-150 (with 17,123 miles at test start)

TABLE 5

After 1000 miles with Tail Pipe Cat Installed Versus Stock Configuration

Pollutant/Fuel

Economy

Stock Configuration Tail Pipe Cat Installed (After 1000 miles)

Test 1 Test 2 Test 3 Average Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Average 

HC

(grams/mile)

0.162 0.151 0.154 0.156 0.131 0.130 0.141 0.149 0.141 0.150 0.140 

CO

 (grams/mile)

1.051 0.949 1.042 1.011 0.873 0.865 0.899 0.965 0.933 0.929 0.911 

NOx

(grams/mile)

0.415 0.421 0.407 0.414 0.333 0.298 0.346 0.363 0.301 0.348 0.332 

NMHC

(grams/mile)

0.119 0.108 0.114 0.114 0.098 1.050 0.841 0.983 1.001 1.012 0.105 

“City” Fuel

Economy (mpg)

162 16.0 16.1 16.1 16.1 16.1 16.1 16.2 16.2 16.1 16.1 

“Highway” Fuel

Economy (mpg)

23.5 23.3 23.5 23.4 23.1 23.3 23.4 23.3 23.4 23.7 23.4 
11

1996 FORD F-150 (with 17,123 miles at test start)

TABLE 6

Stock Configuration After Removal of Tail Pipe Cat Versus Stock Configuration

Pollutant/Fuel

Economy

Stock Configuration Returned to Stock Configuration

Perce

Differe

Test 1 Test 2 Test 3 Average Test 1 Test 2 Test 3 Average 

HC

(grams/mile)

0.162 0.151 0.154 0.156 0.155 0.143 0.158 0.152 - 2 

CO (grams/mile) 1.051 0.949 1.042 1.011 0.925 0.947 0.911 0.928 - 8 

NOx

(grams/mile)

0.415 0.421 0.407 0.414 0.339 0.330 0.344 0.338 - 19 

NMHC

(grams/mile)

0.119 0.108 0.114 0.114 0.114 0.107 0.119 .0.113 0 

“City” Fuel

Economy (mpg)

162 16.0 16.1 16.1 16.2 16.2 16.2 16.2 1 

“Highway” Fuel

Economy (mpg)

23.5 23.3 23.5 23.4 23.5 23.7 23.7 23.6 1 
12

Individual Gas Bag Data for the 1996 Dodge Caravan (with 80,724 miles at test start)

TABLE 7

Test Test Bag 1 Bag 1 Bag 1 Bag 1 Bag 1 Bag 2 Bag 2 Bag 2 Bag 2 Bag 2 Bag 3 Bag 3 Bag 3 Bag 3 Bag 3 FTP FTP FTP 

Series Date HC NOx CO NMHC FE HC NOx CO NMHC FE HC NOx CO NMHC FE HC NOx CO N

SC 1-1 8/07/98 0.812 1.210 4.869 0.766 18.9 0.041 0.275 0.493 0.024 17.7 0.091 0.566 1.192 0.065 21.1 0.215 0.549 1.593 SC 1-2 8/11/98 0.733 1.145 4.680 0.689 19.0 0.037 0.168 0.417 0.021 18.6 0.087 0.497 1.139 0.062 21.3 0.195 0.461 1.499 SC 1-3 8/12/98 0.791 1.087 6.541 0.744 19.2 0.040 0.245 0.585 0.022 18.6 0.078 0.484 0.907 0.054 21.4 0.206 0.485 1.909 TPC-1 8/14/98 0.746 0.918 5.046 0.703 18.9 0.023 0.064 0.082 0.009 18.5 0.053 0.245 0.597 0.031 21.1 0.181 0.291 1.255 TPC-2 8/18/98 0.716 0.888 4.444 0.676 19.1 0.017 0.058 0.055 0.005 18.8 0.061 0.287 0.784 0.037 21.3 0.174 0.293 1.166 TPC-3 8/19/98 0.701 0.881 4.833 0.659 19.0 0.018 0.075 0.064 0.006 18.8 0.052 0.268 0.638 0.030 21.4 0.169 0.295 1.210 TPC-4 8/25/98 0.654 0.927 3.566 0.615 19.0 0.020 0.064 0.085 0.006 18.3 0.056 0.291 0.716 0.033 20.9 0.161 0.305 0.980 TPC-5 8/27/98 0.695 0.948 4.364 0.658 19.0 0.018 0.079 0.103 0.006 18.4 0.062 0.413 1.067 0.038 21.1 0.170 0.351 1.251 TPCM-1 9/22/98 0.783 0.906 5.094 0.744 18.7 0.014 0.054 0.078 0.004 17.9 0.064 0.229 0.756 0.042 21.0 0.187 0.279 1.307 TPCM-2 9/25/98 0.693 0.961 4.897 0.652 18.7 0.022 0.089 0.152 0.008 18.0 0.063 0.310 0.839 0.040 21.0 0.173 0.331 1.325 TPCM-3 9/29/98 0.729 0.887 5.521 0.687 19.0 0.027 0.098 0.213 0.014 18.7 0.065 0.310 0.839 0.042 21.5 0.183 0.320 1.484 TPCM-4 10/02/98 0.722 0.918 4.862 0.682 18.7 0.020 0.071 0.131 0.008 17.9 0.062 0.270 0.753 0.039 21.3 0.177 0.301 1.284 TPCM-5 10/06/98 0.789 0.909 5.701 0.746 18.9 0.018 0.096 0.196 0.005 18.1 0.058 0.323 0.747 0.036 21.5 0.189 0.327 1.490 SC 2-1 10/14/98 0.803 1.103 5.666 0.759 18.8 0.034 0.193 0.751 0.015 18.5 0.097 0.528 1.312 0.073 21.6 0.211 0.474 1.926 SC 2-2 10/15/98 0.770 1.173 5.304 0.725 19.2 0.043 0.203 0.530 0.027 18.5 0.088 0.503 1.279 0.064 21.6 0.206 0.487 1.728 SC 2-3 10/16/98 0.794 1.079 6.118 0.746 19.2 0.037 0.214 0.546 0.020 18.5 0.089 0.487 1.215 0.065 21.6 0.208 0.469 1.885 HC = Hydrocarbons, grams per mile Test Series:NOx = Oxides of nitrogen, grams per mile SC-1 = Stock configuration before Tail Pipe CatCO = Carbon monoxide, grams per mile TPC = Tail Pipe Cat installedFE = Fuel economy, miles per gallon TPCM = Tail Pipe Cat installed;1000 accumulated milesFTP= City Drive Test SC 2 = Stock configuration after removing TPCHWY = HFET, Highway Test
13

Individual Gas Bag Data for the 1996 Ford F-150 (with 17,123 miles at test start)

TABLE 8

Test Test Bag 1 Bag 1 Bag 1 Bag 1 Bag 1 Bag 2 Bag 2 Bag 2 Bag 2 Bag 2 Bag 3 Bag 3 Bag 3 Bag 3 Bag 3 FTP FTP FTP F

Series Date HC NOx CO NMHC FE HC NOx CO NMHC FE HC NOx CO NMHC FE HC NOx CO NM

SC 1-1 8/26/98 0.480 0.706 4.631 0.421 16.0 0.054 0.249 0.021 0.016 15.4 0.126 0.509 0.286 0.083 17.8 0.162 0.415 1.051 SC 1-2 8/28/98 0.472 0.765 4.332 0.413 15.6 0.051 0.233 0.025 0.015 15.5 0.096 0.514 0.108 0.055 17.5 0.151 0.421 0.941 SC 1-3 9/02/98 0.497 0.782 4.594 0.438 15.9 0.046 0.205 0.025 0.015 15.5 0.098 0.505 0.275 0.057 17.7 0.154 0.407 1.042 TPC-1 9/10/98 0.441 0.708 4.131 0.386 15.6 0.043 0.151 0.025 0.011 15.4 0.100 0.488 0.168 0.057 17.3 0.141 0.359 0.916 TPC-2 9/11/98 0.495 0.641 4.735 0.435 15.7 0.036 0.150 0.034 0.006 15.4 0.124 0.492 0.184 0.079 17.8 0.155 0.346 1.050 TPC-3 9/15/98 0.420 0.658 3.724 0.374 15.6 0.037 0.130 0.021 0.013 15.5 0.111 0.434 0.213 0.072 17.5 0.137 0.323 0.841 TPC-4 9/16/98 0.452 0.648 4.416 0.401 15.6 0.036 0.144 0.026 0.011 15.5 0.132 0.417 0.195 0.091 17.6 0.148 0.324 0.983 TPC-5 9/17/98 0.453 0.643 4.533 0.401 15.7 0.034 0.158 0.021 0.011 15.7 0.107 0.485 0.187 0.068 17.6 0.141 0.349 1.001 TPC-6 9/18/98 0.470 0.668 4.447 0.412 15.7 0.037 0.151 0.022 0.011 15.6 0.128 0.463 0.280 0.087 17.7 0.152 0.344 1.012 TPCM-1 10/22/98 0.431 0.670 3.823 0.381 15.6 0.033 0.128 0.021 0.011 15.5 0.090 0.462 0.251 0.050 17.7 0.131 0.333 0.873 TPCM-2 10/23/98 0.431 0.583 3.747 0.383 15.6 0.031 0.140 0.026 0.008 15.6 0.088 0.382 0.275 0.047 17.8 0.130 0.298 0.865 TPCM-3 10/29/98 0.456 0.667 4.007 0.401 15.5 0.041 0.167 0.027 0.013 15.5 0.092 0.442 0.197 0.053 17.7 0.141 0.346 0.899 TPCM-4 10/30/98 0.460 0.623 4.356 0.407 15.6 0.042 0.195 0.027 0.015 15.7 0.117 0.487 0.192 0.076 17.7 0.149 0.363 0.965 TPCM-5 11/05/98 0.441 0.619 4.125 0.391 15.6 0.036 0.116 0.034 0.012 15.7 0.113 0.411 0.218 0.073 17.9 0.141 0.301 0.933 TPCM-6 11/20/98 0.447 0.669 4.171 0.391 15.7 0.050 0.163 0.009 0.014 15.5 0.116 0.453 0.218 0.073 17.9 0.150 0.348 0.929 SC 2-1 12/02/98 0.476 0.652 4.131 0.420 15.9 0.049 0.173 0.010 0.070 15.5 0.111 0.415 0.228 0.070 18.0 0.155 0.339 0.925 SC 2-2 12/03/98 0.451 0.667 4.183 0.399 15.8 0.043 0.132 0.006 0.059 15.5 0.098 0.446 0.276 0.059 18.0 0.143 0.330 0.947 SC 2-3 12/08/98 0.482 0.660 4.014 0.429 15.8 0.044 0.169 0.010 0.084 15.5 0.128 0.435 0.264 0.084 18.0 0.158 0.344 0.911 HC = Hydrocarbons, grams per mile Test Series:NOx = Oxides of nitrogen, grams per mile SC 1 = Stock configuration before installing TPCCO = Carbon monoxide, grams per mile TPC = Tail Pipe Cat installedFE = Fuel economy, miles per gallon TPCM = Tail Pipe Cat installed;1000 accumulated milesFTP= City Drive Test SC 2 = Stock configuration after removing TPCHWY= HFET, Highway Test 
14

APPENDIX

The following appendix documents are only available with the hard copy version of this report copies of

which may be purchased from National Technical Information Services (NTIS). Prices and order information

may be obtained by calling: 800-553-6847.

1. Tail Pipe Cat Application for Evaluation

2. Independent Test Lab Test Reports

 a. 1991 GMC Jimmy

 b. 1991 Jeep Cherokee

c. 1994 Jeep Wagoneer

d. 1995 Dodge Intrepid

3. Test Plan Agreement