‘FX – Function over style’

Once the package arrived at our testing HQ, expectations of the FX Engine were high as a result of the brilliant brand launch from the Hudy family. Most of you will remember the incredibly detailed images and introduction to the brand to an eager audience worldwide, the brand ethos continues with the packaging the FX team used to box their products. Everything based on a very strong red&black contrast, the engine and muffler boxes are small pieces of art themselves. A printed cardboard sleeve decorated richly with FX logos, pictures and infos slips onto the actual dark grey box that contains the engine.

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“Much closer to the experience of unboxing a luxury watch purchase than an RC engine”

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Inside the box, the unit lays on a black silk-effect cloth for a typical “Eastern-European luxury look”.before getting to the actual gem, though, you stumble upon a conspicuous amount of cool stuff, such as: a certificate of authenticity reporting the serial number for your engine and a verification key, in addition to the signatures of the people involved in the production/assembling process; a decal sheet; a very detailed outstanding instruction manual; an exploded view of the engine and a small book called “how it’s made”. Much closer to the experience of unboxing a luxury watch purchase than an RC engine of the past.



“The aesthetics of the engine itself aren’t in line with the hype and as as ‘luxurious’ as one would expect”

The moment you lift the envelope containing all of that paper, you’re struck by a bittersweet sensation: despite the magnificent presentation and build up, the aesthetics of the engine itself aren’t in line with the hype and as as ‘luxurious’ as one would expect. With no logos on the sides of the crankcase – which is left in its original grey color – and a very very discrete laser engraving on the head, at first sight you might wonder if you got the right engine in the box or if it’s just an RTR unit.



“Its clear the attention to detail has been applied to the mechanics rather than the aesthetics.”

The feeling improves when removing the engine from its silky boudoir, holding it in your hands allows you to understand the real quality of both the materials and the manufacturing. Included are dust caps for all exposed parts (something all engines should have), and a sweet diamond-coated crankshaft which sports a very aggressive black color, its clear the attention to detail has been applied to the mechanics rather than the aesthetics.


When disassembling the FX we pleasantly noted large amounts of oil deposits, not quite enough to warrant aggressive interest from N.American-led crude drilling, but clearly significant amounts were used during the production process.

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Nothing to worry though, as the oil ensures a very good protection for the parts. The head is beautifully machined and well designed, even if we personally would have loved a bit more wow factor to make it stand out a bit. The piston/sleeve is tight, but with the sleeve we were very impressed; a piece of fine craftsmanship.


The materials involved in the process are of the highest quality, even the sensation of touching the parts confirms this. A 5 port sleeve, with a very linear layout rather than attempting to innovate to differentiate FX on the contrary aims to perfect existing theories. We can say the same about the piston, that sports a flat head and 2 grooves to retain the oil and guarantee the correct lubrication during running. The conrod reports, as every other part of the engine, its serial/batch number and looks very light though solidly reliable.


The crankshaft is simple but vivid: black coated, it sports a red silicone insert and no balancing dots. It fits flawlessly and effortlessly into the crankcase, this meaning everything is machined with the exacting tolerances.


The crankcase itself is simple, with three channels to combustion chamber, all with precise and refined details. It houses two bearings that differ not only in make up but also geography: the front one from Japan, whilst the rear one German-made, and features ceramic balls.

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Everything looks well thought out and  beautifully finished, a result of the long process of development of such a delicate product. Even the carburettor looks to be very simple and well-made. It features three adjusting screws, this being something different from many other competitors. The quality is outstanding, the movement of the throttle cylinder is silky smooth and the venturi, molded in plastic, sports wo little grooves to help extracting it using your finger and nail tips.

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To assure a correct thermic isolation from the crankcase, a nylon collar is pressed onto the venturi tube that will bring the mixture into the crankshaft. Please note that we cleaned away the oil before shooting the pictures, and reassembled the engine using engine oil (Runner Time).


Once the engine was together, attention turned to the exhaust system. Made up of a 2108 muffler (reminiscent of an OS pipe in its shape) and, in our case, a medium length manifold that should ensure good power at any rpm range. However a bit of a let down when it comes to actually putting together the exhaust, seemingly springs and gaskets not included in the kit and need to be bought seperately. A bit of a mistake from FX in our book however tiny, the upside of buying seperately means you might end up with a few spares which is always useful.

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Time for the FX to show us some Special Effects, Neo-Stig bolted on a four shoe Serpent clutch  – 3 aluminium, 1 nylon and medium springs, then proceeded to fit the engine to our trusted Serpent Cobra 2.0 test rig.

Once at the track, we had a slight concern with the tightness of the engine causing problems for the starter box, at least for the first start. That proved unfounded, the first start was a bit of a struggle, yes, but the engine fired on the fourth attempt, not so bad! To help things along we suggest loosening the glow plug a fraction, and tighten it again immediately after the engine has started.


The break-in process took a bit longer than the usual 4 tanks on the box Japanese style (we remind you that this means full throttle and engine very rich, so that the wheels spin slowly and the temperatures stay quite low) we went for 6 tanks. We noted the engine seems to be pre-tuned for this kind of break-in. We stopped after the first and the second tank to let the engine cool off, but went on continuously for the remaining 4 tanks with the FX showing a remarkable stability and ability to burn the fuel even when tuned that rich.

After another cooling-off break, we started the engine again – effortless – and started tuning it. The tuning wasn’t the easiest thing to do, as with the third screw you always look for absolute perfection, but after a couple laps on the track still rich we were able to refine it and start running the engine properly. So we could say that the actual test starts here, in the best possible conditions: 22° celsius and a slightly cloudy day, with a dry but firm surface that provided a nice “natural” amount of traction, exactly what we need to prove the power and the usability of a powerplant.


The FX seemed to be immediately friendly and very predictable, despite the enormous (yeah, enormous) amount of power supplied. What is stunning about this engine is how much available power you have. It is completely up to your use of the trigger if the FX will be a wild stallion or rather a smooth purring cat ready to bite when required. This is the main difference we found between the FX and the many other engines Neo-Stig had tested or raced: with most of them you can have either brutal power OR a smooth band; with the FX you can have both and it all depends on how hard you pull on the throttle.


“Its reliability is impressive, never having to face the walk of shame to the middle of the track to collect a flamed-out car.”

Apart from this aspect, the unit we have been testing meets all the standards required for a top-end engine: the top speed is good and the bottom power is what you need to clear any kind of troubles. Under the trigger it resembles an OS, and the way it burns the fuel is again similar to the famous Japanese engine marque. It is remarkable that, apart from the third tank on the track when we had two engine cuts due to the low idle, its reliability is impressive, never having to face the walk of shame to the middle of the track to collect a flamed-out car.


The last step in our test looks at a crucial aspect in todays offroad racing: the fuel consumption. After almost 2 litres of  fuel we went testing the mileage after the ultimate fine tune, the stopwatch giving the result of 9 and a half minutes on the usual tank measuring 123cc, which would allow us to pit every 9 minutes in a 45 minutes final without taking too many risks. Note the7mm diameter insert was used, so we reckon that going for a 6.5 or 6mm restrictor with a 124.5cc tank could allow us to reach and go beyond 10 minutes. I’d personally think about losing some power to gain some mileage, as the engine perhaps even overperforming with the stock setup.

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“FX have achieved so much; balancing sheer brute force with drivability”

As a first engine from a brand new manufacturer FX have done a sterling job, the most important bit is the quality of the product, and this is second to none, the fit and finish of internals to a standard that other manufacturers will struggle to match consistently, but for a few small details on aesthetics which do let it down but ultimately have little bearing on performance you have a 5 port beast which is capable of jabbing but also boasts a knock-out upper cut of raw power. FX have achieved so much; balancing sheer brute force with drivability,  bottom line: very impressed by FX.

Links: FX Engines 5K Review gallery | FX-Engines.com

Buy FX 5K @ A Main Hobbies