The VXR Clubman build picks up pace with work on the cooling system.
Thanks to the R53 eating into my bank account and a newfound obsession with go-karting, progress on the project Mini has ground to an unscheduled stop. The same cannot be said, however, of my dad’s VXR-engined Clubman. He’s recently retired, and has plans to get his mad creation finished in time for the IMM in Ireland later this year.
We left off with a mystery hole in the boot and a loose plan to re-locate the radiator to where the battery and shopping once lived. The previous XE engine gave just enough space to install a slim radiator behind the front grille (many use an MPi Mini or A-series Metro type) but with all the extra turbo gubbins, intercooler and larger gearbox, that would no longer work. So the unorthodox radiator-in-the-boot thing seems to be the only option. Another issue comes with the limited budget – it’s all being fabricated at home in the garage, and it’s just for fun, so a custommade aluminium rad was out of the question. Instead, the original Astra rad and fan will have to do for now, and even if it leaks, a new one’s only £55 online.
Custom mounts were fabricated to position the radiator in place, which only just squeezes in the boot area, and then it came to trial fitting the standard fuel tank back in place. Of course that no longer fitted, and a couple of evolutions of rad bracket were required, eventually with it mounted off centre to get everything in OK.
Stage one complete, there’s was a very obvious question of how to plumb it all in. It’s kind of the opposite to most Z-Car conversions, where the rad sits up front and the engine in the back, but the principle is the same. It needs two things – an electric coolant pump, and pipework from front to back, presumably fed under the exhaust tunnel. Unlike a rear-engined Mini
though, two large coolant pipes wouldn’t fit under the tunnel, as there’s also an exhaust pipe to deal with. In this case, the 300bhp Astra engine came with a 2.5-inch diameter exhaust system and catalyst, which could potentially be swapped for a smaller de-cat pipe later on. Either way, there’s not much wiggle room. I did suggest a short front-exit exhaust system as seen on many drag racing FWD turbo cars, but Dad was understandably concerned about clearance and noise.
First off he got to work fabricating some mounts for the exhaust system, to get a more accurate idea of how much space there would be under the car, then ordered up a coolant pump. Davies Craig (The Crowd Say Bo Selecta) seems to be the most common choice of electric pump, and as a result they’re quite affordable these days. A kit arrived complete with a temperature sender and speed controller, so the coolant flow will adjust depending on the temperature. An Astra header tank was then unearthed from a box of bits and installed high up on the bulkhead, just below the scuttle panel so the bonnet still closes. With those bits in place it was finally time to work out a plan and plumb it all together.
The Vauxhall radiator uses 35mm diameter outlets, which is also used in many commercial plumbing applications. I wasn’t so sure it would work, but the idea was to plumb it all in with soldered copper pipework and rubber/silicone hoses where movement is required. Keeping with a 35mm diameter meant that industrial hose brackets were easy to come by and cheap, and it was decided to run one pipe under the tunnel and one back through the cabin to the header tank. It’s going to need some serious heat insulation in there to stop things getting toasty, although Dad reasons that Z Cars Minis get away with having the entire engine behind your head, so it’ll probably be OK. The thing it will need for sure is some kind of ventilation from the bootlid. To get a fresh supply of cool air to the front of the rad there’s now neat aluminium ducting from under the boot floor. The fuel tank may need a barrier of heat protection too – there’s plenty of work yet to be done.
Now the cooling system is taking shape, the engine will come back out again to finish off the bulkhead and inner wing fabrication, to neaten everything up and apply a coat of paint. Once the battery is relocated and the fuel system planned out, the interior will probably get painted too before reassembly. Being fuel injected it’ll need a return line and swirl tank installed for good measure. In theory then it should all come together in time for the IMM, but that all hinges on getting the engine running again. It ran well in the donor car, but with the benefit of a factory-fitted CAN bus wiring system and all the complication that entails. He’ll probably work it out…
“In theory then it should all come together in time for the IMM...”
Who needs luggage space when there's a radiator to install? The Vauxhall rad is a tight fit. Piecing it together, bit by bit.
Mario's sure been busy.
Custom exhaust mounts to get the exhaust and cooling pipes under the tunnel.
Return pipe will run inside the cabin, hopefully with decent heat insulation. Fixed coolant pipes fed up and into the engine bay. There's always loads of space in theory...
Triple clock binnacle will be adapted to suit a digital speedo.
The header tank came straight from the Astra donor car too.