• Bet You Never Thought You’d See a Porsche 911 GT3 That’s Powered By a Motorcycle Engine

And yet, here it is

The Porsche 911 has been the subject of many engine swaps over the years. In fact, the Neunelfer has seen its fair share of LS engines being dropped under its tail, but nobody ever thought of fitting a motorcycle engine inside the 911. Or, if they thought about it, they didn’t get to do it. Mind you, the 911 you’re about to see is not a real 911. We mean, it’s real, but it started out life as a toy. Yet somehow, someone crammed a KTM dirt bike motor under its hood and we can’t stop drooling.

First Things First: Who Did This?

The brilliant mind behind this is Steve Hessick, who envisioned this nasty little piece of machinery on “custom chassis built for shenanigans.” From the off, it’s pretty clear that this thing doesn’t look like a toy anymore and can be easily be labeled as a full-blown go-kart. Starting it is no piece of cake either: you’ll have to make sure that the run switch is on, then turn on the fuel pump, put the gearbox in neutral, and then push the e-start button.

As we mentioned earlier, the thingamajig - we still haven’t figured out what to call it - is powered by a 450-cc KTM dirt bike engine twinned to a six-speed transmission and, as Steve Hessick himself puts it, “it’s a bad, bad machine.”

No counterarguments here, Steve, not after we’ve seen you lift the front wheels off the ground upon acceleration from a standstill. And aside from being freakishly loud, the build also features a dragster-grade rear wing of sorts - which we guess also has some sort of balancing purpose during those wheelie moments - and chunky extra-wide low-profile tires that simply ooze from under the wheel arches.

Bet You Never Thought You'd See a Porsche 911 GT3 That's Powered By a Motorcycle Engine
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Of course, the build itself is not without flaws. And by that, we mean design flaws: just have a look at that transmission chain and how closely it is positioned to a man’s precious organs and left foot. Now, we’re not saying that it will snap, but the thought alone will raise the hair on the back for most of us. So, yeah, that chain needed a guard of some sort, unless you want the driver to actually wear some sort of medieval armor. And a guard it got, albeit a pretty basic one but hey, better than nothing.

Sure, naysayers will no doubt point out that unlike a real Porsche 911, this thing carries its engine in the front, but that won’t do anything to dent the awesomeness on the build. Which, by the way, was fitted with a custom made 1.7-gallon fuel cell and an exhaust setup that sees two pipes coming out centrally from the kart’s rear end, just like in a real Porsche 911 GT3.

Oh, and the steering wheel was taken from a Honda Odyssey buggy while the wheels are 10-inch ATV rollers - but we must admit, they fit the build’s overall vibe like a charm.
Bet You Never Thought You'd See a Porsche 911 GT3 That's Powered By a Motorcycle Engine
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That’s not all, though. The front and rear brakes were given separate controls and according to Motor1, the whole project is still a work in progress, as Steve plans to add a hood to cover the engine, a suspension setup, and even headlights. We’d say he should start with the suspension, as two or three rides look like enough to grant a visit to your chiropractor.

Now, about the engine. If it’s the one found inside the KTM 450 XC or KTM 450 XC-W, then you’re looking at a power output of 51 horsepower coming from a single-cylinder, fuel-injected, four-valve mill that runs a compression ratio of 11.9:1. When fitted on the motorcycle, the engine pairs to a six-speed chain-driven gearbox, so we’re guessing Steve kept that setup for his mad 911 GT3 go-kart.

Either way, 50-something horsepower is A LOT for such a small and, subsequently, lightweight rig, but judging from the videos, controlling it doesn’t look like a problem despite the short wheelbase and generous power-to-weight ratio.

Bet You Never Thought You'd See a Porsche 911 GT3 That's Powered By a Motorcycle Engine
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We’ll keep an eye on this one and get back to you with more info on the build. In the meantime, we hope Steve makes the necessary safety and comfort adjustments because, at the end of the day, nobody wants to risk an injury regardless of how much fun they’ve had before.

Further reading

2018 Porsche 911 GT3 High Resolution Exterior
- image 710284

Read our full review on the 2018 Porsche 911 GT3.

2014 Porsche 911 GT3 High Resolution Exterior
- image 495274

Read our full review on the 2014 Porsche 911 GT3.

2010 Porsche 911 GT3 High Resolution Exterior
- image 343552

Read our full review on the 2010 Porsche 911 GT3.

Tudor Rus
Tudor Rus
Assistant Content Manager - Automotive Expert - tudor@topspeed.com
Tudor’s first encounter with cars took place when he was only a child. Back then, his father brought home a Trabant 601 Kombi and a few years later, a Wartburg 353. At that time, he was too young to know how they worked and way too young to drive them, but he could see one thing – each of them had a different ethos and their own unique personality. As time went on, he started seeing that in other cars as well, and his love for the automobile was born.  Read full bio
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