Yelwoc Motorsport

2014 Season

2014 Season - The Phoenix Rises

Goodwood 72MM - 720MC Birkett

After 14 years off the track and 5 years in storage the RX-7 is revived.

At the end of September 2013 I get a call from Ken Clarke; who used to look after and prepare the car for me when I was running it in the CTCRC Pre-83 Group-1 Championship. Ken asked if I was interested in resurrecting the RX-7 to run in a Group-1 race at Goodwood in March 2014. The car was last raced (and blown up) in Sept 2000 at Spa and had spent the intervening years in Ken’s workshop or in a container at Saxon Motorsport.

As a result I started speaking to Jack Tetley of Goodwood. He was looking for an RX-7 to partner the Motul liveried ‘Spa 24hr’ car that he’d already secured. He wanted it to have the alternate livery of the ‘Pentax’ cars.

The RX-7 had been built; as has been described here, as what might be referred to as Group-1+ for was the CSCC Pre-83 championship and had a few enhancements above the original Group-1 Technical Regulations. The main sticking point was brakes. The massive disc brakes that Ken had engineered under the 13” wheels would have to come off and the rear brakes would need to be drum brakes. Even though the production cars had discs all round from 1981, the Group-1 Homologation papers were never updated. We investigated options to re engineer Ford Escort Mk2 drums onto the axle but it wasn't going to be easy.

Throughout the remainder of 2013 I searched all the usual places for a series 1 road car. Ken Clarke found one in that was less than 20 miles from the racecar and only 300m from where my sister works, but it had gone by the time we got to it!

By the end of January it became apparent that the Motul car had been built to European Group 1B regs and had rear discs, so that we could also run discs but they had to be period items. So we had the ‘Go’.

We started by deciding which livery to run as there were 2 choices of 'Pentax' schemes from 1979 and 1980

1979 TWR Tom Walkinshaw

We decided to go with the earlier 1979 scheme and the car came back from the paint shop:

Pentax Schema Front  Wing Pentax scheme front Pentax scheme rear quarter Pentax Schema rear quarter Pentax scheme rear Pentax scheme rear quarter

The next major issue was re-engineering the brakes especially the rears. It had already been decided that the big front APs would be replaced with calipers from a BMW 3 series; just as TWR had. They are only sliding yoke devices and would be the worst calipers to go on the car since we built it in 1995. The rear calipers came of the back of an early VW Golf Mk II that have the same sliding yoke design and single 50mm piston as the Mazda originals. The mechanical handbrake mechanism was not reconnected.

There was no time to re-engineer the master cylinders that remained .70 and .75 front and rear, respectively.

The 1981 bumpers were removed and 1979 steel components fitted. There were some body panels missing under the 1979 bumper that would contribute to the over cooling later, but we were unable to source them in time.

We ran the engine up on the Sunday before Goodwood and the day before its scheduled visit to the rolling road. We forgot the importance of letting the car completely warm up before revving the engine and promptly blew the rear oil seal. The oil pressure runs at 130 psi and so the oil must be warm. Its over 110 psi at idle when cold. A panic call to Tim @RXMotors got a new seal delivered which was fitted on Wednesday. So no rolling road, let alone testing at Brands Hatch.

The engine had been fitted with a Weber ‘51’ (a highly modified 48) which was believed to be too big for this engine, but no time to find out before Goodwood.

The car had run with Gold Minilte wheels, which worked well with a red car, but looked out of place with the new scheme. So a quick fix was decided on. The wheels were rubbed down and spray painted black with silver rims.

The team finished at 0200 Friday morning.

Goodwood 72nd Members Meeting 2014

72MM Race Report

We had an absolute ball of a time and despite the lack of preparation we got away with it. The whole team with the exception of Patrick Watts were very much 'freshers' and hope to be seasoned house members for next year.

The Goodwood events team put on an absolutely brilliant show. This has been the best motorsport event we've been to.

Post Race

Lots to do to the car to make it properly fit for racing and for Goodwood Group-1 should they run it again next year.

The car has been fettelled and the oversized carburetor has been replaced with the original Weber IDA 48. The car was taken to the rollers and the engine was properly tuned. A significant amount of power has been recovered though the engine is still down on one of Pip Gardners; of WGT, best.

Early in 2015; while in preparation for the 73MM I was advised by Goodwood that the RX-7 had been recorded at over 122dbA by the track side meters and this was considered to be too loud even for an unsilenced event! It will run with some silencing in the future!

750MC 2014 Birkett 6-hr Relay

The 750 Motor Club run the The Birkett 6 Hour Relay Race every year at Silverstone on the full GP circuit. Its open to a wide variety of race vehicles from Radicals to Austin A30s.

Saxon Motorsport had a client withdraw from the event and so at the last minute the RX-7 was roped in to join the team.

  • Mark Lloyd-Jones running his Corrado VR6
  • James Broad and his father Alan sharing their BMW E36 M3
  • Gary Watkins running his Production GTI VW Golf GTI Mk2
  • Simon Arthrell also running a Production GTI spec VW Golf GTI Mk2

This would also be an opportunity to use it as an extensive test session. The car would run the same as at Goodwood and on the same Post Historic tyres. Since we’d last run the car the suspension had been all bolt-checked and aligned and the engine had been setup on the rollers to produce over 20bhp more at the wheels. I’d never raced on anything but the Silverstone Club circuit and that was in March 2000. I did a few practice runs on PS3 F1 2013!

Birkett Relay Race Race Report

The weekend was quite an event and after forgetting my license and getting a thorough soaking on Friday the car went really well and was remarkably easy to drive. For probably the 1st time ever I was happy to slide the tail around. I managed to flood the engine for its last run which was a pain but otherwise it ran well.

It was also a real pleasure to meet the 1st Mrs Tom Walkinshaw.