Yelwoc Motorsport

Since 1986

Introduction

I have always had a strong interest in cars and in motorsport and while at The University of Birmingham I started actively following Rallying, especially the RAC Rally as it passed through nearby Wales.

I also started a motorsport engineering brokerage; Advanced Racecar Engineering to bring F1 engineering resources to the clubman.

I have motor raced around the circuits of UK, at Spa Francochamps and Nurburgring in Europe in the pre-1983 Group 1 Touring Car Championship run by the Classic Saloon Car Club (GB) CSCC (under The British Automobile Racing Club (BARC), with Britcar and with VLN Langstreken Meisterschaft Nurburgring.

It all started properly when I met Jon Owen in Birmingham. Jon and his friends were heavily into Rallying and we'd go chasing cars through Yorkshire and Wales. Over a pint or two we decided that we'd do this ourselves and Jon's racing started. Eventually, I borrowed his Talbot (Chrysler) Sunbeam 1600cc Ti, a rear wheel drive, 860kg (1900lb), 4-speed 1978 hatchback with about 130bhp at the wheels. Finally I decided that I wanted my own car (encouraged by Jon!) and having looked at the success in the BTCC Championship in 1978-82, I decided to modify a road going Mazda RX7 with a 12A Wankel rotary engine. After several seasons of mixed results I eventually broke it at Spa in 2000. It had sat in the workshop since then going through a painfully slow re-egineering process, before coming out again for the Goodwood 72 Member Meeting in March 2014.

Video: ICMR - Win Percy who won the 1980 BSCC Brands Hatch in an RX-7.

In the meantime I have been out several times in Jon's Nurburgring 24-hr Grp N5 BMW E36 in the Britcar series in UK and with the German VLN Langstrecken Meisterschaft series in Nürburgring. Compared to the RX-7 its like racing in an armchair!

I have also supported teams at Nürburgring; Bravo European Endurance Racing (BMW M3 E36 - 5/2001 24hrs) and Saxon Motorsport's Honda Civic Type R in 10/2009 VLN 4hr) and 09/2012 Barcelona 24hrs.

The Technical Regulations

FIA
FIA Homologation Papers for the RX-7
FIA Homologation Papers for RX-7
CSCC/CTCRC Grp-1 Techical Regulations
CSCC/CTCRC Grp-1 Techical Regulations
Mazda Britisj Touring car Champion
Mazda British Touring Car Champion brochure

The Philosophy

As the Mazda RX-7 was a relatively rare race vehicle in UK at the time, every attempt was made to re-engineer it to use Ford Escort MK II components as far as was practicable and legal. Building it.

The chassis was originally prepared by TorqueSpeed in Worcester, UK and then by Ken Clarke Motorsport, who continued to prepare and maintain the car from the beginning of the 1998 season.
Largely due to work commitments the car was not run after destroying on engine on Eau Rouge in Spa in 2000, until March 2014.

The car was moved in 2009 to Saxon Motorsport in Kent, to be closer to me.

The orginal 12A race engines were built and serviced by Pip Gardner of WGT Auto Developments in Northwich, Cheshire, UK.
In 2008 an engine was prepared to allegedly very high standards from overseas. This engine was installed and was run up on a rolling road for an initial check; just 2 quick runs, with no adjustments to prove everything is OK. It produced a disappointing 185bhp @wheels, but we didn't do any fettling.
The car was taken for a shake down at Brands Hatch in Jan 2012. Unfortunately the engine blew on the trailer. Tim @RXMotors identified that the rotor housing had become porous around the sparkplug threads. It turned out to be probably over zealous cooling fins being cut into back of housings around lead plugs! Tim White rebuilt it for me.

It was also found that a not inexpensive custom oil cooler had been built using standard water coolant cores and despite us asking for it to be pressure tested to 150psi - great! Had it rebuilt by professionas at Serck.

Gareth Lloyd of West Wales Rally Spares provided many of the Mk II Escort parts such as the the front AP Forest brakes and the Quaife Type 9 transmission .
We received lots of good advice from SCCA RX7 racers on the now defunct CompuServe 'Motor Sports B' Forum and then the RX7 Club.

Tim White of RX Motors has been a great source of spare parts, engine repairs panels and advice, even though he prefers straightline racing!

Chris Maries gave some excellent instruction and proved the car was quick at Silverstone giving Brian Stevens in hos Jaguar XJS a scare through Woodcote. Chris also gave some excellent coaching notes.

Specifications

The car is geared @9,000rpm for 185kph (115mph) in 4th, 212kph (132mph) in 5th. Hear something like it!
A major benefit to testing, practicing and racing was the installation of an in-car Rollcentre T100 Lap Timer. Though its very simple by today's standards and at some stage a GPS data logger will be installed.
The suspension is set-up for 100mm ride height, 6deg castor, -2.75 deg camber and weighs about 920kg wet

Pre-2002 Running Racecar Post-2002 Pre-Goodwood 72MM
Semi Works Bridge ported 12A circa 220bhp @wheels for 2000 Monster Bridge ported 12A anticipated 230bhp @wheels.
Ford Sierra Type 9 5-speed all steel Quaife Professional Box
(Similar spec/ratios to Mazda Comp.)
- unchanged -
AP Twin Plate 7¼" Sintered Paddle Clutch Tilton Twin Plate 7¼" Sintered Paddle Clutch
Modified Saab Co-axial Clutch Release Mechanism - unchanged -
Twinned Standard Oil Coolers Bespoke High Flow Oil Cooler (Re-built by Serck)
Modified standard radiator - 3-core and 100mm deeper 4-Core Alloy Radiator original height/width
Custom 2 piece prop/drive shaft - unchanged -
Custom Multipoint Safety cage with cross door bars by TorqueSpeed - unchanged -
Leda Front Struts 20 point adjustable dampers & platform springs - unchanged -
Leda Rear 20 point adjustable dampers Spax Trax dampers with coilover springs on adjustable platforms
RacingBeat 1 1/8" stabiliser/rollbar on front, none on rear Custom hollow tube and adjustable pickup arms
250mm x 26mm (10.252 x 1") front disks with Escort AP Forest CP2271 calipers - AP disks 285mm x 30mm (11.25" x 1.25") front disks with AP "Palmersport" CP4567 calipers - Peugot 406 M16 disk
Series II Standard rear disks and callipers 260mm x20mm Ford Granada MkIII disk, Hispec Dynalite calipers
4.89:1 cwp with Mazdasport diff - unchanged -
Custom 70L Fuel tank [in car] Custom 80L Fuel Tank [under]
Standard ignition MSD Ignition Packs
Dunlop 185x60x13 D83 tyres, on 6Jx13 Minilites - unchanged - also likely Toyo R888 on 15x7 Dynamags
Instruments: 2x Greddy EGT, Racetech Oil Temp, Oil Pressure, Water Temp, 10500RPM Armtech Tacho + Fuel Pressure, Fuel Flow Meter, Gearbox Temp
Mild Steel 2" id exhaust with two 'bomb' pre-silencers and single back box with ceramic packing Mild Steel 2" id exhaust with two RB pre-silencers and single back box with ceramic packing

2014 Goodwood 72MM

As can be read in the 2014 Phoenix Rises we had a last minute call to rebuild the car to Goodwood's group-1 spec. Not only was this a challenge given the car hadn't run since 2000 but we also had to remove many of the 'good' bits to make it eligable.

Goodwood 72MM
Monster Bridge ported 12A open rear exit exhaust anticipated 210bhp @wheels.
1980 Pentax Livery Paint job
Weber 51A - over carbed
Bespoke High Flow Oil Cooler - over cooled
4-Core Alloy Radiator - over cooled
20 year old Leda Front Struts 20 point adjustable dampers & platform springs
Spax Trax dampers with coilover springs on adjustable platforms
RX-7 MkI bumpers - missing front valence trim - over cooled
230mm x 25mm (9" x 1") Ford Capri front disks with BMW 320 sliding yoke single piston calipers
18mm x 15mm Golf MkII disk and single piston sliding yoke rear calipers
Custom 80L Fuel Tank [in and under boot]
MSD Ignition Packs firing standard coils and triggered by standard dizzie
Dunlop Post Historic 175x550x13 Crossply tyres, on 6Jx13 Minilites
Mild Steel 2" id exhaust with two RB resonators and Megaphone extractor anticipated 140dBA