I absolutely love M10 Nissan Prairies. There, I’ve said it and I’m not ashamed. Why? Because not only are they super practical it was a humble Prairie which became one of the most fun cars I have ever owned. But it was not just any ordinary Prairie.
The purchase of my old M10 Prairie back in 2002 was the result of me trying to be a little sensible. Practical even. It seemed to be the ideal daily transport as it would provide me with a great measure of utility with its capacious load carrying ability, yet be as comfortable and economical as a car. Makes sense when you think about it, and it proved to be just as practical and economical as I had expected. That was until I started to meddle with it. Its downward spiral into a mix of stupid, with a dash of awesome, began when I had to replace the gearbox, after the original one began to emit unpleasant noises. So there I was in the workshop, with the engine and box out on the floor, and I began to think “Hey, why not replace the engine too now it’s out? I wonder if that Nissan Silvia engine I’ve got over there will fit?”…
I can indeed confirm that the 1809cc SOHC turbo CA18ET from an S12 Silvia will go in an M10 Prairie with minimal hassle. Driving via the relatively tall ratios of the original Prairie gearbox, the CA18ET not only afforded the Prairie with a hair raising top end speed, but also pretty alarming torque steer too. I elected to install the CA18ET more or less stock, to keep things simple, so no intercooler, just a better air filter, bigger throttle body and a fat exhaust system. The stock T2 turbo got wound up to nearly a BAR of boost which I’d guess would have given maybe 160-165hp , maybe more (stock CA18ET is 135hp). Either way it was a big jump from the stock 85hp! Thankfully the original, normally aspirated, carburettored CA18S in a Prairie runs a distributor which mounts off of the side of the cylinder head, rather than off the rear like most front wheel drive CA’s, so there’s plenty of room for the rear wheel drive S12 unit. The mounts were all pretty straight forward apart from the front stabilizer link which wouldn’t fit because of the turbo. To counter this I made a beefier rear stabilizer to keep the engine steady, but I still installed a flexy joint in the exhaust to allow for some engine movement.
Whilst cramming the turbo engine under the bonnet was plain sailing, converting the Prairie to fuel injection required a little more thought. The flat underfloor fuel tank pretty much precludes fitment of any kind of in-tank high pressure EFI pump, so an external pump had to be used. The flat, wide fuel tank also means there’s plenty of fuel surge in corners, so to prevent possible fuel starvation, I built a small surge tank out of an old disposable gas bottle. This was fed with a low pressure pump from the tank and fed into a high pressure EFI pump, which came from an imported S110 Silvia I’d previously stripped of its engine (an L18E).
Outwardly, the old Prairie looked nothing special, apart from some different wheels. I started with 15 inch Saab rims but dropped down to little 13″ ones in an attempt to drop the gearing a little, as the clutch had a bit of a hard time with hard launches due to the tall ratios. Prairie brakes are excellent, so no upgrade was required there and the suspension remained stock, as the odd rear torsion bar set-up proved to be all but impossible to lower without surgery with a welder. Turning one spline of the bars produced a massive drop, rendering the suspension useless so that was a no go. Despite this the Prairie had quite amazing road holding if you were brave enough to push its limits. Roll is actually quite well controlled, although it feels much, much worse due to the high seating position. I did install power steering from an Anniversary II model to help control the torque steer, but what it really needed was an equal length drive shaft arrangement from a Bluebird.
As mentioned earlier, performance was startling considering the limited budget, minimal mods, and… well just because it was a Prairie! From a standstill, 60mph would come up in under seven seconds, which is pretty awesome for any old front wheel drive. I think the secret weapon for the Prairie in this respect is its low overall kerb weight (only 1050kg before you start stripping it out) and most of the weight being up front over the driving wheels, meaning pretty good traction. The top speed was equally impressive with over 130mph being within reach, thanks in part to the tall gearing but also to the Prairie’s surprisingly decent aerodynamics. It may be a big square box, but it’s a very smooth big square box, with no sticky out bits like gutters or handles to impede air flow.
Above all the Prairie was massive fun to pilot, if a little frightening in the twisties. It could happily blow away hot hatch wielding boy racers from the lights, all the while looking completely innocent. I guess it did did retain a large part of its practical aspects too, although fuel economy was no longer one of them. Load carrying space was plentiful and with the extra grunt of the turbo motor, it could happily tow another car on a trailer behind, although its low kerb weight meant it couldn’t really do so legally.
The fun was not to last though. As is so often the case with the CA18ET, the bottom end decided it had had enough of the abuse one day and after developing severe bottom end knock, number three rod made a bid for freedom via the front front of the block. Remarkably the old CA was still coaxed into life with only three pistons and rods in situ, although not for long admittedly. At this point I figured I should take it to the next level and go for installing a CA18DET, along with a front mounted inter cooler and maybe a viscous LSD from a Sunny ZX. I got started on it but after a long period of abandonment due to other projects, I finally admitted defeat on the project in May 2005. By then the Prairie was beginning to look a little rough round the edges so it got stripped of its good bits and dragged off down to the scrapyard. A sad end.
Today I really regret not completing this build. A really wild turbo twin cam Prairie would have had a massive grin factor, especially if it remained stock looking. I always though the Prairie would have been reasonably well suited for a spot FWD drag racing, given its great traction from a standstill. I guess I’ll never know. These days M10 Prairies are very rare so the chances of building another gets less every year but who knows… maybe one day another M10 will cross my path…. and I still have all the conversion bits ready and waiting!