I’ve been building and racing my own sedans and buggies for basic level motorsport here in Australia for thirty years, winning a few club championships and state titles along the way. A number of things have motivated me to do this new project.
I’ve just about finished building my V6 EG Civic and have decided to keep it just as a tar car. Dirt events take a fairly high and constant toll on bodywork, but as rallysprints are my favourite events and I wanted to return to them, I decided to build something specifically for them. Wanting no bodywork meant it’d have to be a buggy, and the four previous ones I’d made have given me good experience in how to do it. Looking around at the current buggies I couldn’t get away from how ancient most of the winners technology was, with most of them using VW suspension designed before World War II, floor pans over forty years old, and engines from the 1980’s at best.
If I was going to invest the time, money and effort this’d take I was confident I could construct a new bench mark, and race for outright victories. A front wheel drive buggy would be way too light in the rear to handle and drift well on the dirt. Although I’ve successfully raced rear engined / rear wheel drive buggies, I felt there had to be something better than the VW type rear end with an engine swap that’s been so done to death. That only left a mid-engined racer. I’d seen a few of these made by moving a complete front wheel drive front end to the rear, and the design and race performances I’d seen had always impressed me.I'd mapped out a basic chassis design incorporating what I thought was the best features from a number of buggies and build sites I'd cruised.
Then by chance a few weeks ago a good mate of mine told me he had a buggy chassis for sale - an old "Bushmaster"off roader. It had held a VW front and rear and didn't meet the new Confederation of Australian Motor Sport (CAMS) requirements for buggies because: 1) The diagonals are not within the main hoop 2) The rear braces have a curve in them 3) The roof is not covered nor braced to the floor and main hoop 4) The bar which holds the steering column isn't the same size as the roll bars. 5) There are no braces across the floor between the base of the front pillars nor half way between them and the main hoop. 6) The bar running up the middle of the chassis is too small. 7) It has no rear wheel protector side bars.
but it'd provide me with a lot of the right steel already bent to shapes I was sure I could adapt into my build. I love the sound of an angle grinder in the morning!
I built a levelled, raised false floor in my garage and have marked a 100cm grid onto it. This gives me quick measurements and ensures everything will be square. A perfectly flat floor equals a perfectly flat chassis floor. I've begun with the new centre rail and the cross member on which the main hoop will stand. The cross member is the width of the outside rear tyre track.
Next I've added the side floor rails and the cross members as CAMS requires - all made from 40mm square tubing.
The main hoop is then shown without a cross member and after I re-cut the old one into it. This design is one CAMS approves.
These fifteen 3mm gusset plates will strengthen the chassis and also serve as mounting points for the floor.
They avoid weakening the frame with bolt holes, and will allow me to drop the floor out when it gets full of muddy slop like I got buried in at Ansell Park late last year. I will employ them as needed throughout the chassis to eliminate any cracking at high stress points.
I searched the net without any preconceptions to find the most powerful, readily available, and most affordable car fwd car from which to derive a powertrain and suspension to move to the rear of my buggy. I’m notorious in my home town of Newcastle as a Honda nut, but to everyone’s surprise – I settled on a 3.5 V6 Magna with a manual gearbox as the ideal donor car.
I watch the car salvage auction listings up here almost every day, and within 5 weeks what I wanted came up, and I got it with a mere $350 bid.
It had rolled into an empty storm water drain, damaging no mechanicals but just about every panel on the car… perfect for my needs and virtually no-one elses.
With an electric winch mounted overhead, I was easily able to lift the body up and remove the entire front end.
The aluminium subframe locates most of the suspension geometry and would save me weeks of work.
I filled the shell with spare motors and car scrap and took it off to the metal munchers where I got $167 for it. This is a scary industrial site where cars go to die… and be re-born as god knows what or where.
I carefully positioned the powerplant and subframe squarely and level on my table lined up with marks for my 2 metre wheelbase.
Screwing the drivers compartment frame and cage in place on the table enabled me to design and fabricate a rear subframe before my welding mate came over for what’ll be a mammoth session. I picked up the six lower subframe mounting points.
After the lower frame I bent up the main rear chassis rail.
Then cut it’s supporting diagonals.
She’s starting to get a look about her that suits the name she’ll carry “Raptor”!