2003: A rear diffuser to cure those suspect aerodynamics

We were busy insulating the garage over the winter, so the Rochdale hasn't seen much progress.

A snowboarding holiday has reduced the number of weekends available for working on the Rochdale Olympic.

Only at the end of March is there movement.

23rd March 2003. In one weekend the sills were repaired and filled with structural foam. It's taken a further two weekends to strip the paint from the salvageable panels. Luckily there weren't too many of these.

30th March 2003. The repair in the photograph is part of a much bigger scheme. The decision has been made to incorporate a rear diffuser. There will be a sharp change in angle of the floor as it passes the rear axle where the boot floor will ramp upwards.

The diffuser is intended to create a low pressure area under the rear of the car to reduce rear end lift.

19th April 2003. In order for a rear diffuser to be effective the floor ahead of the diffuser must be flat and smooth. The original Rochdale Olympic floor wasn't suitable as it curved downwards towards the center and was traversed by the exhaust system.

The whole floor has been removed and will be replaced by a flat panel. The exhaust will run straight, and will be recessed further into the floor pan, although it won't be fully enclosed as the car is made of plastic and might melt.

10th May 2003. The mould for the new floor has been completed. The diffuser is clearly visible to the rear of the mould. The part that looks rather like a drain pipe will form the channel where the exhaust pipe will run.

The exhaust will run into an enclosure above the diffuser where the silencer will be placed. Two cooking rings and a small grill will be molded into the boot floor above the silencer.

11th May 2003. After a morning of laying up glass fibre the new floor with the mould still attached was mounted under the car. The edges of the existing floor had already been chamfered ready to join to the new floor.

21st June 2003. Nothing much seemed to happen for a couple of months, but suddenly the new floor has been bonded in place and the bulkheads are mostly there. The bulkheads Robert is working on are the ones where the front suspension torsion bars bolt on.

Tolerances for the torsion bar mountings are very tight. If these new bulkheads aren't in exactly the right place then the torsion bars will pop out, flail around and most likely spear the unlucky passenger. We'll keep you posted.

The diffuser and subtle fins are visible in the photograph. The large oval hole above the diffuser is where the silencer will exit the car.

2nd July 2003. Here's a spanner in the works. Robert couldn't resist buying this Davrian. It's like a half scale model of a real car. The Davrian is a mark 1, chassis number 5. It has an MOT and works, although it has those niggling problems you would expect from an old kit car. The Rochdale Olympic will probably not get a lot of attention over the next couple of weeks.

The steering system and throttle pedal needed to be unseized on the Davrian, and Robert cut the bottom out of the seats so he could fit inside. The suspension will need a lot of sorting out, and there is a wobble in the rear.

14th September 2003. What's this? It certainly isn't the up to the high standards of repair we have come to expect from Robert. This is a sneak photograph of the inside of the rear wing which appears to be held together with bits of aluminium and pop rivets....

...The guy who looks after the original Rochdale Olympic moulds has been unable to make new panels over the last year so the rear wing is being reshaped to be used as a mould for a completely new rear wing.

It will be interesting to see how Robert applies that technique to the front of the car which is largely missing. Perhaps he will accept my offer of taking a mound off the front of my Renault 4.