74-21 DWP A Study of Fuel Economy Changes Resulting from Tampering with Emission Controls January 1974 Test and Evaluation Branch Emission Control Technology Division Office of Mobile Source Air Pollution Control Environmental Protection Agency ------- Fuel Economy Chcn^es.Resulting from Tampering with Emission Controls INTRODUCTION As a result of recent concern over vehicle fuel economy, EPA has received numerous inquiries relating to the influence of emission controls on vehicle fuel consumption. Statements have appeared in the press and elsewhere indicating that motorists r.ight ir.prove their fuel economy as much as 25% by merely having a service station adjust the emission control systems. Because to EPA technical staff such claims appeared to be exaggerations, a test program was undertaken to quantify the fuel economy and emission change which would result from disconnecting emission controls and to determine whether private service garages could effectively improve fuel economy. A group of ten late model (1973 and 1974) cars were obtained representing the full range of typical vehicle weights encountered in the existing vehicle population. The 1973 and 1974 automobiles selected for this program incorporate more alterations for low emissions than earlier models. (See Appendix A for a technical discussion of such alterations.) These vehicles have shown the greatest change in fuel economy from uncontrolled cars. On a sales weighted average 1973/74 cars are 10 to 11% lower in economy than the uncontrolled cars of equivalent weight. Successful re-optimization of these vehicles for best fuel economy would result in greater improvements than should be possible for 1972 and earlier models. A number of garages were contacted with the request that "they do whatever they could" to improve gasoline mileage. In most of the cases the garages were not informed that the work was part of a test program for EPA so that results of any work done would be comparable to that performed for any private individual. The majority of garages contacted declined to do the work either for the reason that they thought, such work was illegal or because they did not want to contribute to deterioration of air quality, but 25% of the garages agreed to do the work. Some of these garages claimed that they could improve both performance and fuel economy with little impact on emissions; others were uncertain and asked for customer assessment of the results. ------- The basic test approach utilized in the program consisted of the following sequence of events: (1) EPA inspection of vehicle and engine tune-up to manufacturers' specifications. (2) Recording of carburetor and distributor specifications. (3) Replicate EPA dynamometer test of vehicle to measure emissions and fuel economy utilizing the Federal Test Procedure. (4) Tampering of the emission control system by either EPA mechanics or private garages. (5) EPA dynamometer test of vehicle to measure emissions and fuel economy as in (3) above. (6) EPA mechanics restore vehicle to manufacturers' specifications. (7) EPA dynamometer test for emissions and fuel economy as in steps (3) and (5). (8) Repeat test sequence above to Insure that each vehicle was tested at least once to EPA and garage tamper. Seven out of the ten vehicles were subjected to this basic approach. (Some vehicles were used more than once, for a total of 13 garage tampering episodes.) The dynamometer tests [steps (3), (5), and (7)] provided the comparative basis for determining the changes in fuel economy and exhaust emissions resulting from the tampering effort. This permitted conclusions to be drawn as to what fuel economy gains are achievable and what gains typical mechanics would make. Data on the emission and economy changes are shown in the attached tables and discussed in the Test Results section. Three of the ten vehicles also followed the basic test approach above except the vehicles were not tuned by EPA prior to EPA dynamometer test and delivery to garages for tampering. The purpose of this deviation from the basic test approach was twofold: to ascertain whether the EPA tune-up was inadvertently assisting or biasing the garage tampering attempts and to obtain data on a real-world basis, i.e., tampering with an "as-received" vehicle would represent the normal challenge to the garage. ------- The attached Table 1 lists the ten test vehicles. Also shown is whether EPA tampered with the vehicle, and the garages that did tamper with the vehicle. All vehicles were rented from rental agencies or new car dealers. During the test program the 1972 Federal Test Procedure (FTP), as described in the November 15, 1972, Federal Register was used to determine emissions. Fuel economy for the '72 FTP driving cycle, which represents the typical urban commuter trip, was determined using the carbon mass balance technique. For a detailed discussion of this fuel economy test, see A Report or. Automobile Fuel Econory, October 1973, by the United States Environmental Protection Agency, Office of Air and Water Programs, Office of Mobile Source Air Pollution Control. The first seven vehicles listed in Table I were tuned to manufacturers' specifications by EPA before initial baseline testing. Except in the case of the '74 Pinto, for which replacement parts could not be obtained in time, the tune-up included installation of new plugs, points, condenser, rotor, and air cleaner. These vehicles were then modified by EPA and by at least one of eight garages in the Detroit metropolitan area. Except for garages B & D, there was no knowledge by the garages that their work was part of an EPA tampering test program. Emission and fuel economy testing was conducted by EPA after each modification. The last three vehicles listed in Table I were tested by EPA as received and then taken to garages for modifications without initial tune-ups in order to see what gross effect could b°e associated with a vehicle in a "typical" state of tune. In all cases the EPA modification consisted of adjustment of ignition and fuel system parameters without modification or replacement of parts, and the disconnection of specific emission control devices that are external to the basic engine system. The EPA modifications were made by engineers and technicians who have detailed knowledge of automotive emission control systems, as well as access to sophisticated test equipment. This level of skill and facilities is not ordinarily found in the average repair garage, as the test results will indicate. ------- TEST RESULTS Table II summarizes the results of this test program. It can be seen from the EPA codification results that an average improvement of fuel economy of 7.0% was achieved. On the other hand, modifications by eight different garages in 13 different cases showed an average decrease in economy of 3.5%. The increases in emissions associated with the tampering are included in the tables, and must be compared to applicable standards of HC = 3.4 grams per nile (gpm), CO = 39 gpm, NOX = 3.1 gpm, and to average emissions from pre-controlled cars of HC = 9.6 gpm, CO * 95 gpm, and NOX = 3.5 gpm. Tables III and TV give a breakdown by vehicle of the percentage change from the baseline tuned-up condition results. Table V Illustrates what can be achieved by tuning a vehicle to manufacturers' specifications. That is, an average of 9.0% improvement was achieved by tuning up the "as received" rental vehicles to manufacturers' specifications. Of these vehicles two cases out of three showed improvement in fuel economy. Table V also shows the change in fuel economy resulting from independent garage tampering on as-received vehicles. The data illustrate that the improver.er.t vas greatest by tuning the vehicle to manufacturers' specification. It should be noted that in the case of the Fury II station wagon one plug was fouled as received and was replaced by the garage. In the-case of the '73 Vega a new air cleaner and spark plugs were installed as part of the garage modification. Costs of the garage tampering averaged $22.86 with a range of $12.50 to $37.50. The tampering modifications made by private garages and their associated costs are listed in Appendix B. ------- In no case were franchisee! new car dealers requested to perform the tampering. The Clean Air Act forbids dealers from tampering. The purpose of this program was to acquire technical information; the program was not oriented toward determining the compliance of dealers with Federal law. Therefore the garages that did tamper with the vehicles were all independent organizations. They represent a cross-section of the automobile service industry, and include corner gas stations, commercial tune-up centers, as well as a garage that is widely advertised in the Detroit metropolitan area as a specialist in the removal of emission control devices. Of significant note, the garage that advertised its expertise in emission control removal modified two cars for EPA and in both cases was unsuccessful in improving fuel econbmy. Of even greater interest may be the fact that this organization knew that it was participating in the EPA program. It was necessary to inform them of the EPA program because their workload schedule was such that to get an anonymous test would have required a .45-day delay. The failure of this organization to achieve improved fuel economy may be attributable to the fact that it is oriented toward improved performance (for example, acceleration and top speed). This would indicate that application of a hot rodder's knowledge does not insure achievement of improved fuel economy. This study indicates that at the hands of highly skilled emission control experts who have access to first-class tools and equiprr.ont, average passenger vehicle fuel economy improvements of approximately 7.0% can be obtained by tampering on '73-'74 cars equipped with the most stringent emission controls. However, emissions of air pollutants (HC, CO, and NOX) increased an average of approximately 65.9%, 20.9%, and 125.7% resspectively, through such readjustment. Lesser gains in fuel economy would be expected from tampering with earlier model year controlled vehicles (i.e., 1972 or earlier) which have less stringent emission controls. This study also suggests that independent garages in most cases (70%) perform modifications in which fuel economy losses result. The average change in fuel economy for thirteen cases of garage tampering was a reduction of (-)3.5%. Only four cases out of thirteen achieved even minor improved fuel economy. Thus, at present it appears that the result of widespread independent garage emission control system tampering would be expected to increase fuel consumption, at significant cost in terms of increased air pollution. ------- A further caution should be. made. These studies did not address the potential damaging effects that tampering may have over long-term mileage accumulation. It is known that engine maladjustments and certain engine modifications can increase engine deterioration rates. Thus fuel economy losses should become even greater with mileage accumulation because of deleterious engine effects such as increased spark plug fouling from enrichment, and from detonation or preignition damage to valves, spark plugs, piston tops, and rings due to improper ignition timing. ------- TABLE I Vehicle Selection and Modification Schedule Vehicle VW Type I Chevy Impala Vega Ford SW Ford Torino Pinto Duster Nova Vega Fury II, SW Year '73. '73 '74 '73 '73 '74 '73 '74 '73 '73 Engine Disp. 96 CID 350 " 140 " 400 " 351 " 140 " 225 " 350 " 140 " 400 " Carb. IV 2V IV 2V 2V 2V IV 2V IV 2V Trans . Std 4 At 3 At 3 At 3 At 3 At 3 At 3 At 3 At 3 At 3 Test Inertia 2250 Ibs 4500 " 2750 " 5500 " 4500 " 2750 " 3500 " 4000 " 2750 5500 Access . No A/C P/S P/B No A/C P/S P/B A/C P/S P/B No P/S P/B P/S P/B No A/C P/S P/B Approx. Mileage 14,800 4,600 4,000 12,200 9,500 3,700 4,200 2,000 9,100 6,700 EPA Mod Yes Yes Yes Yes Yes Yes Yes No No Yes Number Garage Mods 1 2 2 , 1 2 1 1 1 1 1 Garage F A,D . A,E G B,E G B C D M ------- TABLE II Summary of Tampering Results on Fuel Economy/Emissions Expressed as % Change from Baseline Tune-Up (Mfg's Spec) Number of Number of Fuel HC CO NOy Econ. Mods Tested Econ. Increases Garage Mod '72 FTP 39.3 89.5 63.0 -3.5 13 4 EPA Mod '72 FTP 64.7 21.0 116.0 7.0 8 7 ------- TABLE III Fuel Economy/Emissions Effects of Garage Tampering Expressed as % Change from Basline Tune-up (Mfg's Spec) Vehicle '73 VW '73 Impala '73 Impala '74 Vega '74 Vega '73 Ford SW '73 Torino '73 Torino '74 Pinto '73 Duster '74 Nova '73 Vega '73 Fury SW Garage F A D A E 6 B E G B C D H HC 35.5 92.0 91.0 -12.9 14.5 33.4 28.9 - 3.3 106.3 0.7 -17.7 10.0 90.4 CO -11.7 116.9 317.0 - 7.3 29.9 191.5 69.8 4.3 66.9 38.8 -10.3 11.2 208.8 NOx 104.9 33.9 10.9 -21.3 0.4 603.4 50.6 5.7 61.7 3.2 1.6 72.4 49.0 Economy 2.1 - 9.1 -15.5 9.9 - 5.2 - 9.3 - 0.9 - 7.2 0.6 0.0 - 1.0 - 4.6 - 3.2 ------- TABLE IV Fuel Economy/Emissions Effects of EPA Tampering Expressed as Vehicle '73 VW '73 Impala '74 Vega '73 Ford SW '73 Torino '74 Pinto '73 Duster '73 Fury SW % Change HC 41.5 39.6 61.6 169.3 63.6 146.9 -15.3 31.8 from Baseline Tune-up CO -15.8 59.9 -17.5 -37.2 83.7 48.7 -30.4 - 4.9 (Mfg's Spec) NOX 2.1 107.5 151'. 3 442.1 38.7 87.9 26.2 58.0 Fuel Economy 10.8 13.6 17.8 -5.7 6.3 2.2 9.0 6.5 ------- TABLE V Summary of Effects of Tampering on Three "As Received" Vehicles Garage Mod & Change from "As Received • * 73 Fury SW ** 73 Vega 74 Nova EPA Tune-up to Mfg's spec Z Change from "As Received" * 73 Fury SW ** 73 Vega 74 Nova HC CO NOx -85.6 29.6 0 -92.5 17.6 21.5 0.7 25.2 25.2 -67.4 12.6 39.6 71.4 11.2 -62.6 14.8 -35.5 -63.2 Economy 9.3 6.4 -2.9 18.2 11.5 -1.9 I/ Only one emission test on each car, as compared to replicate tests for the other cars in test program. * Plug fouled in #4 cylinder ** Air cleaner and plugs ------- Appendix A Discussion of Emission Control Systems A very large number of factors influence the fuel economy of passenger cars. These factors fall into the general areas of vehicle operation (e.g., driver habits), ambient and road factors (e.g,, temperature0 wind, quality of road surface)D and vehicle design factors. To determine the difference in the fuel economy of two automobiles, or two configurations of one automobile, it is necessary to hold the vehicle operation, ambient, and road factors constant. This is done during the Federal Emissions Test Procedure, as the test is run using the same conditions in the closely controlled environment of a chassis dynamometer test cell. There are two key vehicle design factors that have been modified by the vehicle manufacturers to achieve lower exhaust emissions: spark timing, and carburetion (air/fuel ratio). Additionally, there have been compression ratio reductions made to allow for the use of low octane low lead fuel and to reduce NOx formation. These compression ratio reductions have reduced fuel economy by an average of 3.5%. Retarding of the spark advance from its optimum setting for best fuel economy can reduce exhaust emissions within the cylinder and outside of the cylinder. With retarded timing the combustion is initiated later and the piston is further down the cylinder during the main portion of the combustion event. This results in reduced exposure to the high temperatures which are conducive to high oxides of nitrogen (NOx) formation. Retarded timing also results in increased exhaust temperature because of the reduced expansion of the burned gases which result when the combustion is intiated later in the cycle, The high exhaust temperature promotes the further oxidation (combustion) of hydrocarbon (HC) and carbon monoxide (CO) in the exhsus£ system,, The carburetion required for minimum emissions depends .on the type of control technique being used on the engine. Th® high oxygen availability of lean mixtures results not only in low EC and CO ©missions, but also in optimum fuel economy., Most current vehicles use the lean carburetion approach to meet the ©mission standards. Alteration of carburetion on such vehicles can result in reduced economy and higher ©missions. i@ae systerns o however0 ueilia® control approaches in which rich carburetion is used £© provide high HC and CO emissions £o the exhaust manifold. These pollutants ©r© then burned in the sxhausfc with the help of additional air pumped into the exhaust ports. The high emissions ------- A-2 are required to provide sufficient "fuel" to the exhaust manifold so that the temperatures generated are high enough for near-complete combustion. This type of thermal after-treatment approach can.be more effective than the lean carburetion approach as far as emissions are concerned, but fuel economy suffers. An additional emissions benefit of the rich carburetion approach is that it results in lower NOX emissions due to the lower availability of oxygen during the combustion in the cylinder. Air pumps are sometimes employed to facilitate HC and GO reductions in the exhaust of lean and rich burning engines by increasing the oxygen availability. Air pumps have no significant effect on fuel consumption because the small amount of power required to drive the pump results in only a small (almost immeasurable) loss. Exhaust gas recirculation (EGR) reduces NOX emissions by reducing the oxygen concentration and flame temperature during the combustion event. EGR can affect economy in several ways. With well controlled EGR rates economy can be improved slightly because the recirculated exhaust gas reduces the amount of throttling required to run the engine and it also allows more spark advance to be used. Because EGR reduces the octane requirement of an engine, a well-controlled system can allow higher compression ratios. Most EGR systems on current cars, however, do not take advantage of the octane improving properties of recirculated exhaust gas nor are they well controlled. If EGR rates are not properly controlled, or if they are excessive, then fuel economy can suffer. High EGR rates slow down combustion and occasionally cause misfire. These phenomena in themselves reduce efficiency but even more loss can be incurred if richer carburetion is used to help clear up the poor combustion quality. Current (1973-74) automobiles incorporate the above mentioned emission control techniques in a variety of ways. Most models incorporate some spark retard, EGR, carburetion enleanment, and low compression ratio in order to meet the emission standards. ------- Appendix B Garage A Neighborhood garage " B Speed Shop (knew cars were from EPA) " C Neighborhood garage 11 D Service station (knew cars were from EPA) 11 E Service station " F Neighborhood garage - specializing in VW " 6 Neighborhood garage 11 H Franchised tune-up center ------- B-l Garage Modification Description and Cost I. 73 VW Type I a) Garage F - $26.00 1) Adjust valves 2) Advance timing 3) Adjust carburetor to lean Idle 4) Change oil II. 73 Chevrolet Impala a) Garage A - $24.00 1) Change centrifugal advance springs 2) Adjust carburetor to rich Idle 3) Advance timing 4) Readjusted carburetor floats b) Garage D - $16.00 1) Changed centrifugal advance springs 2) Advanced timing 3) Disconnect EGR 4) Disconnect air pump 5) Adjust carburetor to rich idle III. 74 Vega a) Garage A - $25.00 1) Installed lean main jet 2) Advance- timing 3) Set lean idle ------- B-2 b) Garage E - $37.00 1) Disconnect EGR 2). Adjust idle to rich idle IV. 73 Ford station wagon a) Garage B - $12.50 1) Disconnect EGR 2) Full vacuum advance 3) Adjust carburetor to rich idle 4) Advance timing V. 73 Torino a) Garage B - $20.00 1) Remove spark delay valve 2) Change centrifugal advance springs 3) Advance timing 4) Set carburetor to rich idle b) Garage E - $37.50 1) Disconnect EGR 2) Set carb to rich idle VI. 74 Pinto a) Garage G - $17.75 1) Disconnect air pump 2) Disconnect EGR 3) Advance timing 4) Full vacuum advance 5) Adjust carburetor to rich idle ------- B-3 VII. 73 Duster a) Garage B - $20.00 1) Advance timing 2) Went to full manifold vacuum advance 3) Adjust carburetor to rich idle VIII. 74 Nova a) Garage C - $15.00 1) Full vacuum advance 2) Advance timing 3) Adjust carburetor to lean idle IX. 73 Vega a) Garage D - $32.57 1) Replace spark plugs 2) Replace air cleaner 3) Retarded timing 4) Disconnect EGR 5) Adjust idle to lean idle X. 73 Fury Station Wagon a) Garage H - $13.90 1) Replace fouled plug 2) Tighten fuel line 3) Retune to specifications tuning (was performed in error) A) Disconnect EGR 5) Disconnect vacuum spark advance thermal override and connected directly to ported carburetor vacuum ------- B-4 6) Tune carburetor to richer idle and lower idle speed 7) Inverted air cleaner thereby disconnecting evaporative and carburetor preheat systems. Average Cost; $22.86 ------- C-l Appendix C Average Average Average 1972 FTP Results Fuel 1973 VW Type HC g/mi 2.35 2.84 2.60 4.91 2.44 3.68 aseline 41.5 3.47 3.56 3.52 aseline 35 . 5 Economy Tampering I (96 CID) CO C02 g/mi g/mi Baseline 22.99 421.5 21.81 401.8 22.40 411.7 EPA Mod 16.40 358.6 21.29 384.5 18.85 371.6 -15.8 -9.7 Garage F Mod 20.68 417.3 18.87 393.8 19.78 405.6 -11.7 -1.5 NOX g/mi 1.54 1.34 1.44 1.51 1.43 1.47 2.1 2.98 2.92 2.95 104.9 Eco MPG 19.1 19.9 19.5 22.2 20.9 21.6 10.8 19.3 20.4 19.9 2.1 ------- C-2 Appendix C Average Average Average Average 1972 FTP Results Fuel Economy Tampering 1973 Chevrolet HC g/mi 3.29 2.56 2.80 2.88 4.38 3.65 4.02 seline 39.6 6.96 4.10 5.53 seline 92.0 5.77 5.23 5.50 seline 9.10 Impala (350 CID) CO C02 g/mi g/nd. Baseline 45.64 723.2 24.22 702.2 47.9 783.3 39.25 736.2 EPA Mod 64.45 603.7 61.10 592.4 62.78 598.1 59.9 -19.0 Garage A Mod 81.33 743.9 88.98 731.9 85.16 739.9 116.9 0.5 Garage D Mod 177.41 683.3 149.9 693.3 163.66 688.3 317.0 -6.5 NOX B/mi 1.66 1.81 .92 1.46 3.16 2.90 3.03 107.5 2.09 1.81 1.95 33.6 1.41 1.83 1.62 10.9 Eco MPG 11.0 11.9 10.2 11.0 12.3 12.7 12.5 13.6 9.9 10.0 10.0 -9.1 9.1 9.4 9.3 -15.5 ------- C-3 Appendix C Average Average Average Average 1972 FTP Results Fuel Economy Tampering 1974 HC g/mi 1.65 1.53 1.81 1.91 1.72 2.44 3.11 2.78 iseline 61.6 1.45 1.63 1.41 1.50 iseline -12.9 1.99 1.95 1.97 iseline 14.5 Vega CO C02 g/mi g/mi Baseline 18.68 421.6 18.58 405.8 25.87 441.0 23.03 439.2 21.50 426.9 EPA Mod 18.89 349.73 16.59 365.45 17.74 357.6 -17.48 -16.2 Garage A Mod 19.50 385.9 22.05 403.5 18.28 371.1 19.94 386.8 -7.25 -9.4 Garage E Mod 30.23 431.6 25.60 447.9 27.92 439.7 29.86 2.9 NOX g/mi 2.71 2.45 2.67 1.40 2.30 5.80 5.76 5.78 151.3 1.50 2.13 1.80 1.81 -21.3 2.08 2.55 2.31 0.4 Eco MPG 19.6 20.2 18.2 18.4 19.1 22.9 22.1 22.5 17.8 21.1 20.0 21.9 21.0 9.9 18.3 17.9 18.1 -5.2 ------- C-4 Appendix C Average Average Average % Chg. from Baseline 1972 FTP Results 1973 Ford HC g/mi 3.01 2.85 2.93 8.18 7.6 7.89 eline 169.3 3.91 eline 33.4 Fuel Economy Tampering SW (400 CID) CO C02 g/mi g/mi Baseline 25.06 807.1 16.87 754.5 20.96 780.8 EPA Mod 14.8 823.1 11.7 828.0 13.2 825.6 -37.2 5.7 Garage G Mod 61.10 792.5 191.5 1.5 N°mi 1.83 1.07 1.45 6.95 8.76 7.86 442.1 10.2 603.4 Eco MPG 10.4 11.2 10.8 10.17 10.19 10.18 -5.74 9.8 -9.25 ------- C-5 Appendix C Average Average Average Average 1972 FTP Results Fuel 1973 Ford Torino HC g/mi 4.76 2.99 3.21 3.65 6.13 5.80 5.97 .seline 63.6 4.57 4.94 4.76 .seline 30.4 3.53 iseline -3.3 Economy Tampering (351 W CID) CO O>2 g/mi g/mi Baseline 63.0 665.01 40.9 717.60 39.95 767.3 47.95 716.64 EPA Mod 91.0 597.56 85.2 594.26 88.1 595.91 83.7 -16.8 Garage B Mod 75.0 672.81 78.5 671.52 76.8 672.17 60.2 -6.2 Garage E Mod 50.0 757.28 4.3 5.7 NOX g/mi 1.66 2.15 1.39 1.73 2.55 2.24 2.40 38.7 3.41 3.43 3.42 97.7 2.33 34.7 Eco MPG 11.4 11.2 10.6 11.1 11.7 11.9 11.8 6.3 11.0 10.9 11.0 -00.9 10.3 -7.2 ------- C-6 Appendix C 1972 FTP Results Fuel Economy Tampering 1974 Ford Pinto (2.3 1) CO C02 NOX Eco g/mi g/mi g/mi MPG Baseline 1.32 32.0 509.3 1.42 15.7 1.53 34.0 495.9 1.01 16.0 Average 1.43 33.0 502.6 1.22 15.9 EPA Mod 3.37 51.6 464.8 2.36 15.9 3.15 46.4 452.4 2.22 16.6 Average 3.26 49.1 458.6 2.29 16.3 % Chg. from Baseline 146.9 48.7 -8.8 87.9 2.2 Garage G Mod 2.97 55.3 454.2 2.17 16.1 2.92 54.8 464.0 1.77 15.9 Average 2.95 55.1 459.1 1.97 16.0 % Chg. from Baseline 106.3 66.9 -8.7% 61.7 0.6 ------- 07 Appendix C Stock Baseline Average Average 1972 FTP Results Fuel 1973 Duster HC g/mi 2.55 2.71 2.66 2.72 .seline 0.7 2.15 2.16 2.16 seline -15.3 Economy Tampering (225 CID) CO C02 g/mi g/mi 25.77 522.2 Garage B Mod 33.4 503.1 38.2 514.9 35.8 509.0 38.8 -2.5 EPA Mod 16.18 502.2 19.68 480.8 17.93 491.5 -30.4 -5.9 NOX g/mi 3.70 3.31 3.85 3.58 3.2 5.22 4.13 4.67 26.2 Eco MPG 15.5 15.7 15.2 15.5 0.0 16.6 17.1 16.9 9.0 ------- C-8* Appendix C 1972 FTP Results Fuel 1973 Fury HC g/mi 3.11 4.10 % Chg. from Baseline 31.8 5.92 % Chg. from Baseline 90.4 Economy Tampering II SW CO C02 NOX " E /mi £/ mi & /mi Baseline 30.8 920.4 4.41 EPA Mod 29.3 838.1 6.97 -4.9 -8.9 58.0 Garage H Mod 95.1 814.5 6.57 208.8 -11.5 49.0 Eco MPG 9.1 9.9 6.5 9.0 -3.2 ------- C-9 . Appendix C 1972 FTP Results—As Received Vehicles HC CO NOX Eco g/mi g/mi g/mi MPG 74 Nova As Received 1.77 18.5 1.71 10.5 Garage C Mod 1.77 23.1 0.64 10.2 EPA-Spec. Tune 2.15 25.8 0.63 10.3 73 Vega As Received 2.26 34.9 2.59 17.3 Garage D Mod 2.93 43.7 2.88 18.4 EPA-Spec. Tune 2.66 39.3 1.67 19.3 73 Fury III SW As Received 41.3 94.4 3.84 7.7 Garage H Mod 5.92 95.1 6.58 9.0 EPA-Spec. Tune ;___ 3.11 30.8 4.41 9.1 ------- C-10 Appendix C Overall Average 72 FTP Results HC CO NOX Eco 8/mi g/mi g/mi MPG Baseline (spec, tune) 2.57 30.7 2.00 14.2 EPA Mod 4.23 37.1 4.31 15.2 Garage Mod 3.58 58.2 3.25 13.7 ------- |