| Description | Date | Identifier | |
| Request to instruct a new exhaust manifold for Japan engines on the lines of the Phantom II. | 21th Apr 1931 | Box 6 \ 7 07-page112 | |
| Delay in designing improved exhaust manifolds for P. 1. & G. 1. models due to illness. | 23th Apr 1931 | Box 6 \ 7 07-page113 | |
| Power loss in the 25 HP exhaust system and proposing modifications to improve performance. | 6th May 1931 | Box 6 \ 7 07-page114 | |
| Comparison of specifications for the 40/50 and 20/25 models, including capacity, downtake, and swanneck dimensions, along with their ratios. | 6th May 1931 | Box 6 \ 7 07-page115 | |
| The development and testing of an exhaust system for the 'Japan' engine to reduce power loss. | 9th May 1931 | Box 6 \ 7 07-page116 | |
| Comparison table of pipe and fish tail area inside diameters for 40/50 HP and 20 HP models. | 9th Mar 1931 | Box 6 \ 7 07-page117 | |
| Graph of power curves for a 25 HP Japan Unit with a standard carburetter and 112° camshaft. | 9th Mar 1931 | Box 6 \ 7 07-page118 | |
| Blueprint graph of power curves for a 25 HP Japan Unit, testing various silencing system configurations. | 9th Mar 1931 | Box 6 \ 7 07-page119 | |
| Graph plotting Brake Horsepower (BHP) and Brake Mean Effective Pressure (BMEP) against RPM for Engine No IV G.8 with various exhaust system configurations. | 11th May 1931 | Box 6 \ 7 07-page120 | |
| Modifications for an exhaust system for a 25 HP model, utilizing a 40/50 HP type silencer. | 11th May 1931 | Box 6 \ 7 07-page121 | |
| 'Japan 1' exhaust system and carburettor requirements, comparing it to the Silver Ghost. | 10th Mar 1931 | Box 6 \ 7 07-page122 | |
| Performance of the Phantom II exhaust system and comparing it to a new manifold design for the Japan 1 model. | 19th May 1931 | Box 6 \ 7 07-page123 | |
| Performance graph and diagrams comparing two different exhaust manifold designs. | 12th Mar 1931 | Box 6 \ 7 07-page124 | |
| Customer demand for extended exhaust tail pipes and considering two schemes for standardization on the F.2 & 25 HP models. | 2nd Jun 1931 | Box 6 \ 7 07-page125 | |
| The increased cost of a hinged support for Phantom II and 25 HP exhaust tail pipes. | 1st Jun 1931 | Box 6 \ 7 07-page126 | |
| The design and proposed testing for the J.1 exhaust silencing system. | 1st Jun 1931 | Box 6 \ 7 07-page127 | |
| Back pressure tests on the existing 25 HP J.I. exhaust system. | 9th Jun 1931 | Box 6 \ 7 07-page128 | |
| Graph of exhaust back pressure curves versus RPM for Engine Unit N.R.G8 with various silencer configurations, noted for 'Japan'. | 30th Jun 1931 | Box 6 \ 7 07-page129 | |
| Improved silencer for car model 19-G4. | 30th Jun 1931 | Box 6 \ 7 07-page130 | |
| Fitting and testing of two exhaust system options on car 19-G4, which is delayed due to radiator alterations. | 22th Jul 1931 | Box 6 \ 7 07-page131 | |
| Request to supply and test modified exhaust manifolds for 20 HP and Phantom I cars. | 22th Jul 1931 | Box 6 \ 7 07-page132 | |
| Testing modified exhaust manifolds to resolve cracking issues on 20 HP and Phantom I cars. | 22th Jul 1931 | Box 6 \ 7 07-page133 | |
| Quarterly complaints of cracked exhaust manifolds on Phantom 1 & Phantom 11 models. | 28th Jul 1931 | Box 6 \ 7 07-page134 | |
| Large number of ongoing complaints about the short life of exhaust system silencers. | 6th Aug 1931 | Box 6 \ 7 07-page135 | |
| Instruction to create a new manifold for a W.W. exhaust system on car 19-GIV for an imminent 10,000-mile test. | 7th Aug 1931 | Box 6 \ 7 07-page136 | |
| Request to test a front expansion box for the 20/25 HP exhaust system using a different gauge material to overcome a 'tinny' effect. | 19th Aug 1931 | Box 6 \ 7 07-page137 | |
| Communication regarding a design issue where the exhaust silencer mounting interferes with gearbox removal. | 26th Aug 1931 | Box 6 \ 7 07-page138 | |
| Dispatch of experimental Phantom I and 20 HP exhaust manifolds for testing and feedback. | 4th Sep 1931 | Box 6 \ 7 07-page139 | |
| Standardisation document for a lengthened rear exhaust pipe. | 27th Jun 1931 | Box 6 \ 7 07-page140 | |
| Standardisation form for a new chassis part, detailing costs and application. | 2nd Oct 1931 | Box 6 \ 7 07-page141 | |
| Request for information on the progress of tests for experimental modified exhaust manifolds on Phantom I and 20 HP cars. | 2nd Oct 1931 | Box 6 \ 7 07-page142 | |
| 10,000-mile test on a 25 HP engine to resolve exhaust valve trouble by comparing different materials. | 6th Oct 1931 | Box 6 \ 7 07-page143 | |
| Status of fitting experimental modified exhaust manifolds to customer vehicles. | 6th Oct 1931 | Box 6 \ 7 07-page144 | |
| Requesting urgent experimental instructions for a 10,000-mile trial on a new exhaust valve design for a 20/25 HP chassis. | 8th Oct 1931 | Box 6 \ 7 07-page145 | |
| Testing of exhaust manifold modifications on customer vehicles. | 9th Oct 1931 | Box 6 \ 7 07-page146 | |
| Request to test modified exhaust manifolds on customer cars to address a cracking issue on 20 HP and Phantom I models. | 22th Jul 1931 | Box 6 \ 7 07-page147 | |
| Arrangement to fit modified Phantom I & P.2 exhaust manifolds to customer cars to address cracking issues. | 28th Jul 1931 | Box 6 \ 7 07-page148 | |
| Modification to the support design for an exhaust silencer. | 11th Sep 1931 | Box 6 \ 7 07-page149 | |
| Letter regarding the dispatch and testing of experimental Phantom I and 20 HP exhaust manifolds. | 4th Sep 1931 | Box 6 \ 7 07-page150 | |
| Request for information and monthly progress reports on experimental modified exhaust manifolds for P.1. and 20 HP cars. | 2nd Oct 1931 | Box 6 \ 7 07-page151 | |
| Design, criticism, and testing of improved exhaust manifolds for various chassis models. | 16th Oct 1931 | Box 6 \ 7 07-page152 | |
| The progress of fitting experimental modified exhaust manifolds to cars. | 6th Oct 1931 | Box 6 \ 7 07-page153 | |
| Use of fescolised steel versus Staybrite for exhaust downtake pipes on Phantom II and 20/25 HP chassis. | 8th Oct 1931 | Box 6 \ 7 07-page154 | |
| The failure of experimental mild steel and 'fescolised' exhaust pipes. | 2nd Oct 1931 | Box 6 \ 7 07-page155 | |
| Request to modify a silencer by substituting a 1.5 inch diameter swan neck flange for the present 2 inch flange for test bed use. | 2nd Oct 1931 | Box 6 \ 7 07-page156 | |
| The requirement for bigger silencers on P.2 and 25HP exhaust systems. | 20th Oct 1931 | Box 6 \ 7 07-page157 | |
| The design and materials for the silencer on the 'U' series 25HP chassis. | 10th Oct 1931 | Box 6 \ 7 07-page158 | |
| Modifications to the 20/25 HP exhaust fittings for improved silencing tests. | 20th Oct 1931 | Box 6 \ 7 07-page159 | |
| Investigation and proposed solution for a broken exhaust manifold. | 24th Oct 1931 | Box 6 \ 7 07-page160 | |
| Record of a telephone conversation regarding issues with the Phantom II and 20/25 HP models. | 22th Oct 1931 | Box 6 \ 7 07-page161 | |
| Trial of an improved 20/25 exhaust manifold on the 'China' chassis for a 10,000 miles test. | 23th Oct 1931 | Box 6 \ 7 07-page162 | |
| Change from a WW silencer to a short type Phantom II silencer, with instructions for creating and testing alternative pipe arrangements. | 23th Oct 1931 | Box 6 \ 7 07-page163 | |
| Test report detailing vehicle performance issues, adjustments, and exhaust system trials. | 26th Oct 1931 | Box 6 \ 7 07-page164 | |
| Test report on various exhaust system configurations, clutch slip, and engine rattles. | 4th Nov 1931 | Box 6 \ 7 07-page165 | |
| Best dimensions for a 40/50 model, downtake, intermediate, and an anti-ticking pipe issue. | 27th Oct 1931 | Box 6 \ 7 07-page166 | |
| Engine power output tests for the 10,000-mile car, comparing different camshafts and exhaust configurations. | 27th Oct 1931 | Box 6 \ 7 07-page167 | |
| Performance graph comparing a C.I. unit with a C/R & C.XI unit over 10,000 miles. | 25th Oct 1931 | Box 6 \ 7 07-page168 | |
| Blueprint graph of engine power curves from a 10,000-mile unit test, comparing various exhaust system configurations. | 25th Oct 1931 | Box 6 \ 7 07-page169 | |
| The findings from tests on the Phantom II exhaust system and plans for future improvements. | 2nd Nov 1931 | Box 6 \ 7 07-page170 | |
| Performance graph detailing power losses for the Phantom II Short Type exhaust system, comparing Brake Horsepower and Brake Mean Effective Pressure against engine RPM. | 2nd Nov 1931 | Box 6 \ 7 07-page171 | |
| Graph analyzing power losses in a Phantom II short type silencer exhaust system under various configurations. | 2nd Nov 1931 | Box 6 \ 7 07-page172 | |
| Graph analysing power losses in a Phantom II short type silencer exhaust system at different RPMs. | 2nd Nov 1931 | Box 6 \ 7 07-page173 | |
| Requesting an update on the progress of tests for modified P.I. and 20 HP exhaust manifolds. | 2nd Nov 1931 | Box 6 \ 7 07-page174 | |
| Modernization of an engine unit and work on exhaust systems for car 19.G.IV. | 4th Nov 1931 | Box 6 \ 7 07-page175 | |
| Status report on the testing of experimental modified exhaust manifolds on various chassis. | 6th Nov 1931 | Box 6 \ 7 07-page176 | |
| Record of a telephone conversation with West Wittering regarding progress on exhaust manifold and carburetter designs. | 6th Nov 1931 | Box 6 \ 7 07-page177 | |
| Design of a J.S. Exhaust Manifold, referencing blueprint LeC. 2970. | 7th Nov 1931 | Box 6 \ 7 07-page178 | |
| Design of exhaust pipes for an engine model codenamed 'China'. | 10th Nov 1931 | Box 6 \ 7 07-page179 | |
| Notification regarding a modification to the J.S. Exhaust Manifold & Pipe. | 21th Nov 1931 | Box 6 \ 7 07-page180 | |
| Letter discussing car performance issues and potential modifications for models 19-GIV and 18-GIV. | 6th Nov 1931 | Box 6 \ 7 07-page181 | |
| Vehicle road testing, issues with a slipper wheel, and improvements to the gearbox. | 6th Nov 1931 | Box 6 \ 7 07-page182 | |
| Various exhaust system tests conducted on a 25 HP engine. | 6th Nov 1931 | Box 6 \ 7 07-page183 | |
| Exhaust system tests focusing on various configurations to reduce noise and improve performance. | 8th Nov 1931 | Box 6 \ 7 07-page184 | |
| Quarterly report from September 1931 analyzing customer complaints about exhaust systems. | 8th Nov 1931 | Box 6 \ 7 07-page185 | |
| Summary of necessary modifications and complaints regarding manifolds, washers, and silencers for various car models. | 8th Nov 1931 | Box 6 \ 7 07-page186 | |
| Quarterly report detailing customer complaints about noisy exhausts and their remedies. | 11th Nov 1931 | Box 6 \ 7 07-page187 | |
| Summary of customer complaints and remedies for 20 HP, 20/25 HP, Phantom I, and Phantom II car models. | 1st Nov 1933 | Box 6 \ 7 07-page188 | |
| Remedies for sliding joints and an analysis of cracked or broken exhaust manifold complaints across various car models. | 1st Nov 1931 | Box 6 \ 7 07-page189 | |
| Ongoing issues and proposed solutions for various car components. | 1st Nov 1931 | Box 6 \ 7 07-page190 | |
| Replacing cracked 20 HP exhaust manifolds due to persistent failures. | 8th Nov 1931 | Box 6 \ 7 07-page191 | |
| Exhaust silencers for P.2 & 'U' Series 25HP models, suggesting spot welding instead of riveting. | 20th Nov 1931 | Box 6 \ 7 07-page192 | |
| Dynamometer tests to determine the power lost in the carburetter air silencer. | 23th Nov 1931 | Box 6 \ 7 07-page193 | |
| Graph plotting power loss against engine RPM for a P.H. carburettor air silencer on a 20 EX standard car. | 29th Nov 1931 | Box 6 \ 7 07-page194 | |
| Extract detailing a modification to the exhaust swan neck and fishtail support. | 26th Nov 1931 | Box 6 \ 7 07-page195 | |
| Design change for an exhaust swan neck pipe to avoid fouling brake countershafts on the axle. | 19th Dec 1931 | Box 6 \ 7 07-page196 | |
| Unsatisfactory steering and a cracked exhaust manifold during a 15,000-mile car test in France. | 29th Dec 1931 | Box 6 \ 7 07-page197 | |
| Blueprints and a list of parts for the 'Japan III' project. | 11th Dec 1931 | Box 6 \ 7 07-page198 | |
| Parts list and instructions for an induction system with nonexpanding carburetters. | 16th Nov 1931 | Box 6 \ 7 07-page199 | |
| Requesting the fitting of a flywheel inertia ring and bolts to a Wraith 27-G-VI. | 7th Aug 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page01 | |
| Squeaking brakes on a Wraith, requesting a trial of Ferodo R.U. linings. | 19th Aug 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page02 | |
| Request to modify car 27-G-VI by fitting larger 2BA studs to the radiator steam escape pipe flange. | 20th Aug 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page03 | |
| Request to fit standard 25/30 HP front engine feet and a new pair of rear bumper brackets to a Wraith III car. | 23th Aug 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page04 | |
| The application of part N.Sch.5145 to the brakes of a Wraith car. | 25th Aug 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page05 | |
| The replacement of the Kansas Snubber bonnet rest strip with Ferodo lacing on car 270 VI due to wear. | 30th Aug 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page06 | |
| Requesting the urgent modification of a car's radiator to stop water loss by fitting a baffle scheme. | 16th Sep 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page07 | |
| Test to address idling overheating on a Wraith 27-G-VI by increasing water flow. | 30th Sep 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page08 | |
| Urgent memo requesting the replacement of an inaccurate steering cam for chassis 27.G.Vl. | 15th Oct 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page09 | |
| Fitting a standard Borg & Beck 11' driven plate with Thermoid facings and testing thrust springs. | 25th Oct 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page10 | |
| Request to reduce the thickness of a rear axle pinion bearing washer to investigate an over-run rattle on a Wraith 27.G.VI. | 4th Nov 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page11 | |
| Requesting the fitting of a combined inlet nozzle and filler cap to car 27.G.VI. | 2nd Dec 1937 | Box 7 \ 1 600b 27 G V1 Mx Car-page12 | |
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