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Caging The Beast: Nissan S15 Ep2 -
6 min read Tuesday 08 March 2022

Caging The Beast: Nissan S15 Ep2

We've got the car, we've all but killed the massive Hoosier rubber with more than a few burnouts, so what's next for our big 2022 project? Well, if somehow you haven't seen our Silvia dragster already, you can check it out here in our article - Life's A Drag. But, for everyone else, as the AF S15 build kicks into overdrive, what's the very first step? The clue's in the title here - we'll be caging the beast.

But hang on, you might be thinking, the S15 already has a pretty substantial cage, right? Yes, it does - even the most hardcore tuners in Japan aren't crazy enough to build a monster like this and go drag racing without adding a little protection along the way. So, when this rather bonkers S-Body Nissan made the journey across the pacific, it already had a bolt-in, dash dodger fitted. But, although there's no doubt that the street-cage that was installed in Japan is a great quality item, it's hardly one that inspires confidence to push the limit in the corners, especially in a car with an almost silly amount of power.

You see, this kind of cage may be fine (just about) for a weekend straight-liner, but we've got something much more focused on the twisty stuff in mind for this season - including sending it up the hill at Goodwood. The truth is that you just can't put a price on the handling benefits of a proper weld-in cage, especially when you're dead set on using all of those 900 raging horses under the bonnet… not to mention 200 more when you turn on the laughing gas. Besides, there's no denying that a full set of gusseted, touring-car-spec monkey bars, look the business, too. And they're pretty damn good for keeping the occupants in one piece if it all goes wrong. No, a special build like this requires an extra special blend of one-off, metalwork, so we quickly decided to take our Endless S15 Racer 250-miles up north to meet up with the guys at SW Motorsports

Now, it has to be said that SW Motorsports have been our engineering partners for some time when it comes to our track day cages. In fact, our M2 Competition, 20V Mk2 Golf, Yaris GR, R32 GT-R and our heroic little Twingo RS Cup have all received the SW treatment in the past couple of years - that's a serious amount of custom-made rear cages thorough the doors at The Detailing Academy! But, there's no denying that there's a huge difference between custom built, bolt-in cages expertly crafted on a jig, and a totally bespoke CAD designed work of art engineered especially for this car. So, as it turns out, the S15 would present quite the challenge. Luckily, they're more than acquainted with some of Europe's maddest race builds, so our little coupe would be in good hands.

First thing's first though, the old cage, centre-mounted battery, nitrous system and dashboard had to be removed, before we could get it loaded up on a trailer an on the long road to Lancashire…

The first part of the process, aside from removing all the windows, is creating the cage design. There have been S15 motorsport cages constructed before of course, but not the same as this one. The idea is to 3D scan the whole interior to create a model, before building the cage in a CAD programme, this ensures that everything fits around the obstacles, and it all works together to triangulate the chassis and eliminate as much cornering flex as possible. Of course, there's the added bonus that, should the worst happen, you're significantly more likely to walk away from a shunt, too.

This cyber cage must be designed to tie together and brace reinforced chassis points and suspension turrets, to create a full-on interior spaceframe. The goal is that, once finished, you could literally take away the rest of the car panels and still have a perfectly ridged structure. Once this master design is built and tested on the computer, and the engineers are happy that it will all be up to the job, it's time to take it out of the metaverse, and make the cage a reality.

There's no denying that all the new-fangled computer-controlled laser cutters, milling machines and pipe benders are extremely clever. These make sure that all the angles and cut-outs are precise to the millimetre, there's no material wastage, and all the parts can be installed with a minimum of fuss. It's a far cry from using a power saw and an angle grinder, nothing is done purely by eye here… and trust us when we say that there's a plenty of parts to get through when you're building a cage to this motorsport-approved standard.

That said, after all the precision cutting, the actual construction still comes down to the skill of the craftsman and his welding kit. The guys here have to make sure every single weld is spot-on, getting full penetration and tying everything together to give the final structure its strength.

This being Auto Finesse too, we also threw in a small curve ball along the way. What, we thought, could be better than installing a full set of Le Mans-style air jacks for lightning quick wheel changes in the pits? The fact that these look amazing, and there can't be many S15s with this sort of setup, doesn't even come into it… well, maybe a little! Still, there's nothing like going full racecar, is there?

These pneumatic rams require holes in the floor and reinforced boxes built into the chassis to locate each jack and to be able to hold the car up in the air for extended periods without twisting the chassis. All these extra parts were CAD designed by SW Motorsports and constructed to be integral at strategic chassis points. All that's left for us to do is fully install, and plumb in the system.

As you can see the guys at SW Motorsports do sterling work, but what you may not realise is this all this was turned around in record time. They even went far beyond the call of duty by creating custom AF floor plates, and a few other amazing one-off parts that will be powdercoated in-house and revealed in good time.

But, much more importantly, what's next for the AF S15 build? Well, stay tuned for Episode 3 where we'll be revealing our plans for the exterior, don't worry, that one will be along shortly…


SW Motorsports -


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