Approval Details

Valid E.O.

Validity

This Executive Order approved the specified parts on on October 24, 1991.
As of Tuesday, February 4th, 2025 this Executive Order has not been overturned or superceeded.

Approved Parts

Part NumberModels
303Y-S0, 303Y-DAO 388Y-S0, 354Y-1987-1992 GM vehicles powered by a closed-loop 400-454 CID engine

This Executive Order may be listed as:
  • C.A.R.B.E.O. D-200-5
  • Executive Order 200-5 / D200-5
  • ARB # D-200-5
  • Executive Order No: D-200-5
  • C.A.R.B. No. D-200-5
  • Resolution D-200-5
For Free CARB Executive Order Status verification, email an image of the device Executive Order label as well as the Year/Make/Model and Test Group # of the vehicle to [email protected]

Download: Executive Order D-200-5 PDF

D-200-5 Document:

CARB_D-200-5

(Page 1 of ?) State of Californta AlR RESOURCES BOARB EXECUTIVE ORDER D—20G0—5 Relating to Exemptions Under Section 27156 of the Yehicle Code DOuUG THORLEY HEADERS, INC. HEADER SYSTEM {P/N‘s 303Y—50. 303Y—DAO, 388Y—50, 354¢—50, 354Y—0A0, 392Y—50 AND 399Y—50) Pursuant to the authority vested in the Air Resources Board by Section 27156 of the Vehicle Code; and — Pursuant to the authority vested in the undersigned by Sections 39515 and 39516 of the Health and Safety Code and Executive Order G—45—5; I1T IS ORDERED AND RESOLYVED: That the installatiton of the Doug Thorley Headers, P/N‘s 303Y—S0, 303Y—DAND, 388¥—50, 3544—S50, 354Y—DAO, 392Y—S0 and 399Y—50, manufactured by Doug Thorley Headers, Inc. of 1561 Commerce Street, Corona, CA 91720 has been found not to reduce the effectiveness of the applicable vehicle pollution control system and, therefore, is exempt from the prohibitions of Section 27156 of the Vehicle Code for 1987—1992 model— . year General Motors vehicles powered by a closed—loop 6.6—7.4 liter {366§ ¥22°"°~ Y C€10—454 CID) engine. This Executive Order is valid provided that installation instructions for this header system will not recommend tuning the vehicle to specifications different from those submitted by Doug Thorley Headers, Inc. Changes made to the design or operating conditions of the header system, as exempt by the Air Resources Board, which adversely affect the performance of a vehicle‘s pollution control system shall invalidate this Executive Order. Marketing of this header system using any identification other than that shown in this Executive Order or marketing of this header system for an application other than those listed in this Executive Order shall be prohibited unless prior approval is obtained from the Air Resources Board. Exemption of the header system shall not be construed as exemption to sell, offer for sale, or advertise any component of the kit as an individual device. This Executive Order does not constitute any opinion as to the effect the use of this header system may have on any warranty sither expressed or implied by the vehicle manufacturer. THIS EXECUTIVE ORDER DOES NOT CONSTITUTE A CERTIFICATION, ACCREDITATION, APPROVAL, OR ANY QOTHER TYPE OF ENDORSEMENT BY THE AIR RESOURCES BOARD OF CLAIMS OF THE APPLICANT CONCERNING ANTI—POLLUTION BENEFITS OR ANY ALLEGED BENEFITS OF DCUG THORLEY HEADERS, INC.*‘S HEADERS, P/N‘S 303Y—SG, 303Y—DAO, 388Y¥—50, 354Y—S50, 354Y—DA0, 392Y—SO AND 399Y—S0.

BOUG THORLEY HEADERS, INC. EXECUTIVE ORDER D—200—6 HEADER SYSTEM (Page 2 of 2) No claim of any kind, such as "Approved by the Air Resourcas Bsard" may be made with respect to the action taken herein in any advertising or other oral or written communicatiton. Violation of any of the above conditions shall be grounds for revocation of this order. The order may be revoked only after ten day written notics of ifntention to revoke the order, in which period the holder of the order may request in writing a hearing to contest the proposed revocation. If a hearing is requested, it shall be held within ten days of receipt of the request and the order may not be revoked until a determination after hearing that grounds for revocatfon exist. Executed at El Monte, California, this AA October, 1991. R&. &. Summerfiel Asststant Division Chief Mobile Source Division

State of California AIR RESOURCES BOARD EVALUATION OF—BOUG THORLEY HEADERS, INC.‘S HEADER SYSTEM FOR EXEMPTION FROM THE PROHIBITIONS OF VEHICLE CODE SECTION 27156 IN ACCORDANCE WITH SECTION 2222, TITLE 13, OF THE CALIFORNIA CODE OF REGULATIONS October 1981

State of California AIR RESOURCES BOARD EVALUATION OF DOUG THORLEY HEADERS, INC.‘S HEADER SYSTEM FOR EXEMPTION FROM THE PROHIBITIONS OF VEKICLE cODE SECTION 27156 IN ACCORDANCE WITH SECTION 2222, TITLE 13, OF THE CALIFORNIA CODE OF REGULATIONS by Mobile Source Division Statse of California Air Resources Board $528 Telstar Avenue E1 Monte, CA 91731—2990 {This report has been reviewed by the staff of the California Air Resources Board and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Air Resources Board, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.)

SUMMARY Doug Thorley Headers, Inc., of 1561 Commerce Street, Corona, California 81720 has applised for an exemption from the prohibitions in Section 27156 of the California Vehicle Code {YVC) for the Doug Thorley headers, P/N‘s 303Y—S0, 303Y—DA0, 388Y¥—50, 354Y—S0, 354Y—DA0, 392Y—S0 and 389Y¥—SQ. These headers are designed for installation on 1987—92 General Motors vehicles equipped with a closed—loop 6.0—7.4 liter (366 CID—454 CID) engine. Based on the results from comparative exhaust emission tests performed at an independent laboratory on a 1991 Chevrolet C2500 pick—up truck., the staff concludes that Doug Thorley Headers, Inc.‘s headers, P/N‘s 303Y—SO0, 303Y—DA0, 388Y—S0, 354Y—50, 354Y—DA0, 392Y—S50 and 399Y¥Y—S50 will not adversely affect exhaust emission from vehicles for which an exemption is requested. The staff recommends that Doug Thorley Headers, Inc. be granted an exemption as requested and that Executive Order D—200—5 be issued.

Page Number SUMMAR Y CcONTENTS 11 1. INTRODUCTION 11. CONCLUSION II1I. RECOMMENDATION IV. DEVICE DESCRIPTION V. HEADER SYSTEM EVALUATION AND OISCUSSION APPENDIX APPENDIX A: INSTALLATION INSTRUCTIONS 11

EVALUATION OF DOUG THORLEY HEADERS, INC.‘S HEADER SYSTEM FOR EXEMPTIOGN FROM THE PROKHIBITIONS OF VEHICLE CcODE SECTION 27156 IN ACCORDANCE WITH SECTION 2222, TITLE 13, OF THE CALIFORNIA CODE OF REGULATIONS I. INTROOUCTION Boug Thorley Headers, Inc. of 1561 Commerce Street, Corona, California 91720 has applied for an exemption from the prohibitions in Section 27156 of the California Vehicle Code for the headers, P/N‘s 303Y—S50, 303Y—DAO, 388Y—S50, 354Y—SO, 354Y—DA0O, 392Y—SO and 399Y¢—S50. These headers are designed for installation on 1987—92 General Motors vehicles powered by a closed—loop 6.6— 7.4 liter {366 CID—454 CID) engine. Doug Thorley Headers, Inc. has submitted data from comparative emission tests conducted on a 1991 Chevroltet €2500 pick—up truck at Milton Roy Laboratory, Orange, California. II. ONCLUS S Based on the results from comparative exhaust emission tests performed at Militon Roy Laboratory on a 1991 Chevrolet €2500 pick—up truck, the staff concludes that Doug Thorley Headers, Ihc.'s headers, P/N‘s 303Y—S0, 303Y¥—D0A0, 388Y—S50, 354Y¥—S0, 354Y—DAO, 392Y—S0 and 399Y—50, will not adversely affect exhaust emissions from vehicles for which an exemption is requested. II1. RECOMMENDATION The staff recommends that Doug Thorley Headers, Inc. be granted an exemption for their headers, P/N‘s 303Y—S0, 303Y—DA0, 388Y—SO, 354Y—SC, —1—

354Y—DA0O, 392Y—S0 and 399Y—SQ, for installation on 1987—1992 model—year General Motors vehicles powered by a closed—loop 6.6—7.4 liter {(366 CID—454 CIN0) engine. The staff also recommends that Executive Order D—200—5 be issued. IV. EVICE DESCRIPTIO The Doug Thorley headers, P/N‘s 303Y—S0, 303Y—DA0, 388Y—S0, 354Y—50, 354Y—DAO, 392Y—S50 and 399Y—$0, are designed for installation on 1987—92 General Motors vehtcles powered by a closed—loop 6.6—7.4 liter (366 CID—454 CIB) fuel injected engine. As with the original equipment manufacturer‘s {OEM) exhaust system, the function of Doug Thorlsey‘s header system is to route exhaust gases through the header pipes from the two exhaust manifolds of the engine into a common pipe which then feeds to the catalytic converter. Each cylinder has a 1.75" diameter pipe that combines with the adjacent pipe into a 2" diameter pipe. On each side of the engine, tfiese two 2" pipes combine into a 2.5" diameter pipe. Finally, all the exhafist gases are then routed into a pipe which feeds into the pre—catalyst piping. The system operates in conjunction with the OEM computer controlied electronic port fuel injection and emission control systems already certified with the stock engine. Installation of Doug Thorley exhaust system does not alter the OEM location of the oxygen sensor and the catalyst. The tune—up specifications also remain the same. Appendix A contains a sample of the installation instructions.

V¥. HEADER SYSTEM EVALUATION AND DTSCUSSTON A 1991 fGeneral Motors C2500 pick—up truck with a 7.4 liter (454 CID) fuel injectsed gasoline engins was used for the evaluation of the header P/N‘s 303Y—$0, 303Y¥—DA0, 388Y¥—50, 354¥—50, 354Y—DA0, 392Y—50 and 399Y—S0. The dynamometer inertia weight and loading used were 7000—lbs and 15.4—hp respectivaly. Comparative emissions tests conducted by Milton Roy Laboratory for Doug Thorley Headers, Inc. consisted of one Cold—Start CVS—75 emission test in the unmodified {baseline)} configuration, followed by one Cold—Start CVS—75 emission test in the modified (header system installed) configuration. The ARB did not perform tests to confirm the test results submitted by the applicant. A summary of the test results is shown below: Exhaust Emissions Test Results On A 1991 Chevrolet C2500 pick—up truck _ Test Exhaust Emissions {gm/mi) . Mode NMHC CO NQx. Baseline 4178 6.619 2.552 Device .552 7.2176 2 .779 Difference +.074 +.657 +.22] % Difference +15.5% +9.9% +8.9%

The differences between the device emission test results and baseline emission test results submitted by the applicant were within the allowed lHimits of .1 gm/mile or 10 percent of baseline HC, 1.0 gm/mile or 15 percent of baseline CO and .1 gm/mile or 10 percent of baseline NOx as specified in the "Procedures for Exemption of Add—On and Modified Parts." Based on the test results, the staff concludes that the installation of the Doug Thorley headers, P/NX‘s 303Y—SQ, 303Y¥—DA0, 388Y¥—50, 354Y—50, 354Y¥—DA0O, 392Y—S50 and 399Y¥—50 did not have an adverse effect on exhaust éfiissions of the affected vehicles. Doug Thorley Headers, Inc. submitted all the required information and fulfilled the requirements for exemption.

Appendix

DOUL riiomiry HEHNDER ParRtif3IG3¥ & 303Y¥—S0 CHEVROLET/CMC Pick—ups, Suburbans, Blazers: 1973—1905 2464vD CLass "A" MOTORROMERS: 19785—1985S 396~—427—454 HEugine when the enclosed instructions are followed precisely you will £f ind the O‘,'l{.:r — instaliation of your headers to be relatively simple. We canmnot ecmphasize of adnering strictly to this proven approuch. NOTE: Installation of headers for vehicles equipped with emissi ons control devices and/or catalytic converters imust be inade in accord— ance with government rbgulatlonu pertaining to emissions standargd:an. Due to restricted room in the engine compartinent, your headers may Come closse to certain body and chassis components This is a normal contlition for an installation of this type. WARNING: MAKE sURE YOU MAVE ENOUGIH CLEARANCE AROUND BRAKE, FUEL & ELECTRICAL LINES, RTC. ln some c ascs it may be necessary to relocate those iteims which miqght be adver.ALJ.Y affectoed by exhaust heat. 1. Disconnect battery cable to avoid damage to vehilcle elcciric alo sys tom. 2. Raise front of vehicle approx. 24" and support with jack s ta nds . WARNING : DO NOF RELY ON BUMPER JACKS FOR SUPPOIWTII 3J.— Remove spark plugs, hecadpipes, and oil fllter. lt is not ne cessaury to remove clutch linkage or front drive shaft on vehicles so equipped . It may be necessary to lift the engine from its mounts to rsInOV O the stock manifolds ‘and to install the loeft side header. 4.. Loosen starter motor, but do not remove. Remove dipstick tu ba . , 5. Clean accumulation of carbon from exhaust port gasket surfacCuGd . 656. Place headers into position from the underside of the vehicl @, using the gaskets and hardware provided, We strongly recommend th e use of high—temp silicone gasket sealer between the header and t hbe gaskeL. Start all header bolts. Re—install dipstictck and oil filter, ctCe. 7.— Tighten all bolts securely. It is important that on the hea der flanigs you start with the center bolts and work your way outward. Re—tightoen bolts to starter, motor mounts, ctc. NOTE:— All engines are not mounted exactly the same at the f actory and is sometimes necessary to shift the moutor from si de £o side to obtain maximum clearanco. If motor mounts ure wOoLn or broken, they should be replaced at this time. 8. Attach reducer adapters to header collectors and attach to ©>yxhausdL systen by clamping or welding. 9. After completion of the oentire systom, start the engine and chook for leaks. After the engine has run for approx. 204 iminutes, i — tighten all header bolts ({approx. 35 ft/lbs}). Headar bolls shoul d be inspected periodically for tightness in order to prevent gqaslket damage and leakage. Due to varying conditions in different gceographieal arecas, we strongly recommend having your engine re—tuncdad after the installation of hcaders . This will assure that you reccoive the maxilmuin increase scavenging in performance and cconomy. It may be notcd that due to the incroused scavenging effcect: of FTri—Y headers, that your air—fucel mixture uaund/or timing may roequire modAification. PHK :/ ut LEGaLk FOR SALE Ol USEH LR CA ON POLLUTIGOGH CONTROLLEL )t{Si\JC * 1501 CnlflflNefi ..‘A DOUG T}{O} YY f‘“";‘\l C(.)H‘na.;, C‘f". v1720 \71” 7_,') Tmi‘r\fr' 5/ i) ?j: A—"


Document Created: 2005-09-01 12:45:01
Document Modified: 2005-09-01 12:45:01

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