The starting point with any new car has to be the preparation of the bare bodyshell. The Vauxhall Corsa is known to be a weak standard shell compared to its predecessor the Nova and so careful attention has to be given to strengthening of critical areas to ensure a safe and strong finished car. But before any of that work can start I have to remove the engine, gearbox and suspension which came with the shell. The car is also fitted with a basic bolt in cage which has to be removed, unfortunately this is a tricky job as someone thought it would be a good idea to weld up all the bolt in joints. Time for the angle grinder!! Two days later and the cage is out, Sadly it didnt survive the operation and is now scrap.

There are several stages to preparing the bare shell. Firstly remove anything that isnt required in the interests of weight saving. I have cut off all the unused standard brackets and scraped off much of the heavy seam sealer that manufacturers love to spray everywhere. Its surprising how the weight of these small items add up.

Step two is to strengthen the shell with a combination of additional welding around the joints and seams and the addition of strengthening plates and gusset brackets in areas of high load or stress. Its also a good idea to plate over all the holes in the floor to keep out water and dirt. Deciding where to strengthen is a combination of common sense and good advice from other people. Its probably worth mentioning that I dont have a lot of experience with a welder as you can tell from the pictures, but practice makes perfect which is why Ive started on areas that wont be seen!.

The next stage (Possibly the most difficult of the entire build) is to fabricate new rear arches and suspension pick up points. This is for a number of reasons, firstly, because Im building a widetrack version and secondly because the rear dampers are being replaced with the more efficient coil over type damper.

picture one shows the removal of the fuel filler tunnel and original arch. Pictures two and three show the fabrication of completely new rear inner arches and suspension mounting tubes which will allow the rear ride height to be lowered but maintain wheel arch clearance and allow correct mounting of the Proflex damper. Picture four shows the extension of the arch beyond the bodywork to meet the new fibreglass wide arch.

I have raised the arch height by 30mm and for the top mount have used a Ford Fiesta rear damper bracket, which I machined round in a lathe and welded into a section of ordinary 4" exhaust tube. the top pickup point is raised by 55mm from standard. From the last picture you can see that there is lots of clearance around the 15" wheel, even though the car now sits lower. This will also allow a future switch to 16" wheels without any problem.

For me the most difficult part of the job is welding the relatively thin sheet together without blowing holes in it, sadly in a few small places this happened and needed repair. I must say thanks to Martin at MEF MOTORSPORT for the loan of the Plasma cutting machine which makes a huge difference when cutting and shaping sheet metal.

Possibly the most important step is the installation of the rollcage. As well as the obvious safety benefits, a good cage will also massively stiffen the bodyshell which helps maintain the correct geometry of the suspension and improve the overall handling of the car. I have chosen a comprehensive MSA approved weld in cage from Custom Cages.

I now have the lightweight T45 Cage, Its a bit of a jigsaw as you can see in the picture. After welding in the supplied floor plates for the main feet I test fitted the entire cage into the car with tape as I needed to modify the back stays to suit the new rear arches. Overall Im impressed with the profiled ends of the cage which saves endless hours of tricky messy grinding.

After many hours spent getting the rear of the cage to meet up with the new arches, Its finally time to start welding. After tacking together the rear diagonals, back stays and seatbelt rail, I moved to the front, making sure the forward triangulation bars are all in place. This involved cutting some fairly large holes in the wheel arch to help align things, but its pretty straight forward to plate up afterwards.

In order to fully weld the A post legs to the Main hoop (The join above and behind the drivers head) the main hoop has to be lowered as much as possible. I achieved this by pulling the legs in with a big ratchet strap so the hoop would drop just enough to get the welder in around the top. This joint is often only welded were it can be seen (even on some professionally built cars) but the car can fail scrutineering if its picked up on by the MSA scrutineer.

Once this was complete I persuaded the the main hoop back into place and welded the rear diagonals to It. With the main elements of the cage tied together, next comes the windscreen top bar (which is a little tricky as you have to trim one end to length), the roof diagonal, dash bar and the cross brace behind the seats. The door bars will be left untill just before painting to allow easy access to the car. A little touch I have added myself is a pair of thin steel seatbelt 'guides' on the seatbelt bar, this ensures that the belts are always correctly aligned behind the seat when you tighten them up! (this is another scrutineers pet pickup) Custom cages certainly make a nice fitting product, Its very tight to the inside shape of the car. Wherever possible I have tied the shell and the cage together with various plates and brackets.

After completing the cage installation I have fitted a pair of 25mm tubes to the sills to accept axle stands, The important thing with this mod is to take the tubes through the sill to the inside, then weld both inside and outside ends, Its also important to add a sturdy reinforcment plate on the outside as the sill metal is quite thin and can buckle under the weight of the car. I have blanked off the inside end with a washer to prevent water entering the car. The final major modification to the shell is the front strut top mounting points, they have to be moved outward as part of the widetracking of the suspension, After carefull marking and measurement, I cut away the standard top mount with the grinder, then made a new 'heavy duty' mount from 6mm flat steel plate, cutting an 80mm hole and three bolt holes to suit the Proflex top mount. This plate was then welded carefully into place giving an extra 30mm per side of track and maintaing the same castor angle (front rear tilt) as the standard mount. Its obviously impossible to form such thick steel to match the awkward shape of the turret top, so it was a case of welding the plates into place and tidying things up with the angle grinder afterwards.