COMPETITION BUILD MANUAL NOVA/CORSA
COMPETITION BUILD MANUAL NOVA/CORSA COMPILED AND DEVISED BY Andrew Duerden WITH Gordon Birtwistle
ISBN 0 9516102 0 1 © GM EURO SPORT 1991 2nd Edition All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage or retrieval system, without permission in writing from the copyright holder. Front cover: Graham Turner Produced by: Martin Meadows Marketing. Printed by: J.T. McLaughlin Ltd., Euxton, Chorley.
FOREWORD Ever since the basic Nova appeared on the competition scene back in 1985, clubmen have been recording success after success. In its first year of rallying, the potent GM Dealer Sport Nova GTE in the hands of Dave Metcalfe, showed a fantastic turn of speed, emphasising its competitiveness and serving notice of its potential for honours. That initial Nova GTE was put together by Engineer Brian Ashwood and his team.
DISCLAIMER Every effort has been made to ensure that the contents of this publication were accurate and up-to-date at the time of going to press. No liability can be accepted by the authors or publishers for loss, damage or injury caused by errors in, or omission from, the information given. Motor sport can be hazardous and the inclusion of any information does not necessarily make it safe to use in any form of competition or testing.
CONTENTS I ntroduction Model Availability Homologation Preparation - Bodyshell - Front suspension - Power Steering - Rear suspension - The Braking system - Engine - Transmission - Electrical Group N guidelines Appendix - Clubmans Kit contents - Homologation papers
INTRODUCTION This manual has been specifically produced in conjunction with the GM Euro Sport package of parts assemblies and components produced by Motor Sport Developments and known as the "Clubmans Kits". Consequently, the text refers exclusively to the preparation of a Nova/Corsa model to FIA International Group A level to the specification within the Clubmans Kit.
MODEL AVAILABILITY When preparing a vehicle to the clubmans specification contained in this manual, it is i ntended that the base vehicle used will be an existing Nova GTE or Corsa GSi. These models are identical save for badging and very small differences in trim. Additionally, some slight variations on standard specification occurs, territory to territory. For instance, most Nova GTE models sold in the U.K. come equipped with central locking and sunroofs.
The Vauxhall Dealer Sport Nova in Scrutineering HOMOLOGATION The use of production series cars in international motorsport is governed by a set of rules and regulations laid down in the annual `Year Book of Automobile Sport' issued by the FIA (the governing body) and specific vehicles require documents to verify their approval for use, and these are issued by the International Motor Sport Federation (FISA) as the Sporting Ministry of the FIA, and are contained in Homologation Papers. The 1.
BODYSHELL The Bodyshell preparation and strengthening procedures outlined in this manual are fundamental to the success of the finished project. They will both extend the competition life of the shell and by increasing its torsional stiffness contribute favourably towards the handling characteristics of the finished vehicle.
BODYSHELL Access for this operation is from the underbonnet and underside of the bodyshell. However, before welding this bracket into place, the bearing housing itself should be modified to fit the bracket correctly. This will entail cutting away a portion of the bearing housing flange just below two of the attachment holes. Three holes should then be drilled through the housing and bracket, using the housing as a template. Three nuts should then be tack welded to the rear face of the bracket.
Please note that both front wings MUST be removed for this operation. Thoroughly check items supplied against the component parts list to make sure that there are no shortages. It is advisable with a complex, multi-point cage such as this to loosely assemble the cage prior to making any attempts to actually fit the structure to the car. Reference to the roll cage assembly drawing will give a clear indication of the intended final construction.
BODYSHELL PROTECTION the two holes alongside the suspension turret and drill out to 10mm. A third 10mm. hole has to be drilled at the point where the diagonal support meets the front tower arm, but opened out to 25mm on the outer skin of the chassis member, to enable the fixing bolt to be inserted and tightened. Bodyshell and rollcage tolerances again may require spacing washers to be fitted to ` bridge the gap' between the tower arm and the body panel prior to tightening the attachment bolt.
BODYSHELL PARTS LIST
BODYSHELL PARTS LIST
FRONT SUSPENSION The basic concept of the standard road car's suspension layout has been retained but extensive modifications have been made to the way that the components have been constructed. A revised front suspension assembly has been designed, fabricated and homologated specifically for use in Group A motorsport, and MUST be used as a complete package. There is no compatibility between individual components and those found on the standard car.
hardened washer supplied should be fitted to the plain side. These bolts must be tightened by a torque wrench immediately after the geometry has been set to the required figures. This is a very critical area on the suspension, and as a precaution the torque figure should be checked as a service operation during vehicle use. TIGHTENING TORQUES Top Bolt, Bottom Bolt, 14mm to 18kg/m. (130 Ib/ft.) 12mm to 12kg/m. ( 90lb/ft.
FRONT SUSPENSION PARTS LIST
A power assisted, high ratio, steering rack system has been designed and developed as a complete package for the Group A car. This includes the steering rack, steering pump, external power ram, oil reservoir, mounting brackets, all oil pipes and fittings. The power assistance characteristics closely match those developed for the Group A Kadett GSi and Astra GTE models. This minimises the torque steer effects usually associated with high powered front wheel drive cars and considerably reduces driver fatigue.
REAR SUSPENSION The standard rear axle beam is retained for the Group A specification, and does not require additional strengthening. Special competition bushes are supplied in the kit, and should be fitted to the body mounting pivot point of the rear axle. De-carbon gas filled shockabsorbers have been developed in conjunction with superprogressive `minibloc' rear springs for gravel and tarmac events.
THE BRAKING SYSTEM A dual circuit hydraulic system, with in-car brake balance control, actuates Automotive Products four-pot calipers at the front, fitted to 267mm diameter by 25.4mm thick ventilated discs. Solid rear discs, 251mm diameter by 9.6mm thick are supplied complete with appropriate caliper mounting brackets and alloy hubs. An hydraulic handbrake conversion kit is supplied, and includes the modified bracket, spacer and hydraulic cylinder.
THE BRAKING SYSTEM NOTE: The brake master cylinder combination supplied will give adequate brake balance compensation for almost every surface condition. However, should the balance become a problem on events that include a large percentage of extremely tortuous downhill sections on dry tarmac, the rear braking can be reduced even further by fitting a 7/8" master cylinder to the REAR brake system.
BRAKES PARTS LIST
ENGINE AND MANAGEMENT SYSTEM The Group A engine specification has been fully developed in the International rallying arena during 1989 and has shown to be powerful and very reliable. The special components required to build a replica power unit form the basis of the Group A engine parts kit. Heavy duty engine mounting rubbers are included and fit as a direct replacement for the standard components.
ENGINE already very good and no further balancing is required. If the crankshaft is not as new, lightly polish the journals with a suitable grade of crankshaft finishing tape. Thoroughly clean the component with petrol or other suitable solvent. Blow out the oil passages with compressed air prior to reassemble. The main bearing shells and bolts are as production.
ENGINE opening conditions. The take-off position for this system can be found on the inlet face of the cylinder head below the inlet ports for cylinders No.2 and 3. This hole must be blanked off, using the alloy blanking plug provided. The hole in the angled abutment on the camshaft housing (camshaft case), for the standard breather system should also be blanked off. Apply `studlock' or si milar product to give additional retention. The photographs show the two finished conditions.
ENGINE made from a non-translucent material must i nclude a transparent window for compliance with Appendix `J' Group A. See photograph showing additional elbow in place. LUBRICATION SYSTEM The standard oil pump is retained and is capable of giving adequate flow and pressure for this engine specification. However, in view of the modifications to the oil feed in the cylinder head casting, the oil pressure relief valve must be adjusted to compensate. This entails the fitting of a 3mm.
ENGINE There is an alternative solution for donor vehicles that do not comply and for those requiring a better management system than the Bosch L3.1 Jetronic anyway. Since the introduction of the Group A engine parts kit, several engine preparation specialists associated with Nova/Corsa engine building have been developing their own alternative engine management systems.
THE EXHAUST SYSTEM CLUTCH A revised front downpipe, centre pipe and tail silencer have been developed in conjunction with the engine development programme. The dimensions selected for the front downpipe and centre pipe enhance the torque characteristics of the Group A engine, and the engine management system has been optimised for this system. Whilst the total system is considered effective as a silencing device and meets current U.K.
ENGINE PARTS LIST
GEARBOX AND DIFFERENTIAL ASSEMBLY A close ratio 'dog type' gearbox kit has been specially developed for this model. This gearbox utilises the casing and intermediate housing or ' sandwich plate' from the standard car's F13 speed gearbox but the component parts of the close ratio kit must be assembled along with a revised end cover and gearshift cover assembly. As this is a heavy-duty gearbox unit, many of the component parts are larger that the corresponding standard item.
GEARBOX AND DIFFERENTIAL ASSEMBLY and 1st motion shaft bearings as a precaution. Now at this stage the mainshaft bearing can be fitted into its housing in the sandwich plate and secured with the correct circlip. For ease of assembly, press the other bearing on to the 1st motion shaft and loosely position its large retaining circlip behind the bearing in readiness for final assembly. This circlip CANNOT be fitted AFTER this shaft and bearing have been pressed into the sandwich plate.
GEARSHIFT COVER AND DIFFERENTIAL ASSEMBLY In conjunction with this gearbox a revised gearshift mechanism has been developed ensuring precision gearchange characteristics and better durability. The standard gearshift cover assembly is replaced by a modified assembly supplied as a complete unit. This is a heavy duty construction, and is compatible with the redesigned gearchange linkage.
TRANSMISSION PARTS LIST
GEARBOX & FINAL DRIVE DATA The Homologated ratios for the heavy duty gearbox are as follows. It is important to remember that these are internal and not the overall ratios. RATIO 1st . . . . 2.54:1 2nd .... 1.76:1 3rd .... 1.42:1 4th .... 1.19:1 5th .... 1.04:1 Rev .... 3.31:1 NUMBER OF TEETH 33:13 30:17 27:19 25:21 24:23 29:13 x 43:29 Several optional final drive ratios have been homologated but the crown-wheel and pinion sets that equate to the ratios are not necessarily readily available.
ELECTRICAL SYSTEM The standard wiring loom and 55 ampere alternator are completely satisfactory and need only be modified when several extra electrical components are to be fitted. Under certain event conditions, four additional driving lamps, a short wave radio and additional navigational i nstruments may be required. Under these circumstances we would advocate the fitment of a 90 ampere alternator and additional individual wiring harnesses appropriately relayed and fused.
ELECTRICAL SYSTEM NAVIGATIONAL EQUIPMENT AND RADIO Take two feeds, one from each main terminal on the master switch and connect into a fuse box. This then gives the option of a permanent live feed (for radio) or switched feed (for instruments). AUXILIARY LIGHTING The main supply should be taken directly from the master switch and connected to the power i nput supply of the relay/s.
ELECTRICAL PARTS LIST
ELECTRICAL WIRING DIAGRAM
ELECTRICAL WIRING DIAGRAM
ELECTRICAL WIRING DIAGRAM
ELECTRICAL WIRING DIAGRAM
ELECTRICAL WIRING DIAGRAM
ELECTRICAL WIRING DIAGRAM
ELECTRICAL WIRING DIAGRAM
GROUP N GUIDELINES A Group N car is fundamentally a standard production car fitted with obligatory additional safety items such as a roll cage, safety harnesses and plumbed-in fire extinguishers, to comply with specific FIA Regulations for Touring Cars Group N. In addition you will have to carry out some further permitted modifications to make the car more competitive.
CLUBMANS KIT BUILD LIST
CLUBMANS KIT BUILD LIST
CLUBMANS KIT BUILD LIST
