Types of Engine Kits Explained: V8, V12, W16 and More

Picking an engine kit is a different decision from picking a car. The same layout shows up under wildly different badges — a V8 sounds nothing like another V8 depending on one component buried in the crankshaft — and some layouts exist for reasons that have nothing to do with power at all. This is a guide to the layouts themselves: what actually separates them, and which one you’re really choosing when you pick a kit.

V8: the same eight cylinders, two completely different characters

Every V8 has eight cylinders in a V, but the crankshaft inside decides everything about how it feels. A cross-plane crankshaft — the layout under almost every American muscle car — fires the cylinders in an uneven rhythm, which is exactly why muscle V8s have that lopey, uneven idle. A flat-plane crankshaft fires evenly instead, trading that low-end character for an engine that revs harder and sounds sharper — which is why most exotic supercar V8s sound nothing like a muscle car despite sharing the same cylinder count.

The V8 world also splits by history as much as by crank layout. Ferrari’s turbocharged V8 line only exists because the F40 briefly broke a 27-year naturally-aspirated streak, then the F154 (in the 488) brought turbos back for good in 2013. McLaren’s modern V8 has a stranger past: its lineage traces to a 1987 Nissan-designed twin-turbo V8 built purely for Group C Le Mans racing — a car that never actually raced — later developed into the M840T that powers nearly every modern McLaren. If you want a specific V8 story, our V8 range covers both the muscle and supercar sides properly.

V12: naturally aspirated, until it mostly wasn’t

The naturally aspirated V12 had one of the longest unbroken runs of any layout in the supercar world. Lamborghini alone ran one continuously from 1963 to 2022, closing it out with the Aventador Ultimae — which the company itself called “the grand finale of the traditional V12.” Ferrari’s version of the same story is still closing: the Daytona SP3’s F140 V12 revs to 9,500rpm without a turbo in sight, and it’s widely expected to be Ferrari’s last non-hybrid V12.

Aston Martin’s Valkyrie went further than anyone — a Cosworth-built 6.5-litre V12 revving to 11,100rpm, the most powerful naturally aspirated production engine ever built. And Pagani’s story shows the transition happening in real time: every Zonda and Huayra has run a Mercedes-AMG V12, naturally aspirated for the earlier cars, switched to twin-turbo once the old NA unit could no longer meet emissions rules. Same manufacturer, same basic engine family, two very different chapters.

W16 and W12: solving a packaging problem, at two very different scales

A “W” engine is really two narrower-angle blocks sharing one crankshaft. W16 takes two V8s and joins them at 90 degrees — and exactly one manufacturer has ever put it into production. Bugatti built it exclusively, from the 2005 Veyron through the Chiron, and stopped for good in 2024. Nobody else ever went near it; sixteen cylinders arranged this way is a genuinely strange, expensive way to build an engine, but it’s also how Bugatti packed roughly 1,500 horsepower into something that fits a road car at all.

W12 is the more practical relative — two narrow-angle V6 blocks joined at 72 degrees, first appearing in the 2001 Audi A8 and still used in some Bentleys today. It’s not chasing hypercar extremity; it’s chasing twelve-cylinder smoothness in a block barely bigger than a V8.

Flat-six (boxer) and straight-six: two different routes to the same smoothness

Both layouts exist to solve the same problem — vibration — but they get there differently. A flat-six (boxer) lays six cylinders horizontally in two opposing banks; the pistons move like boxers trading punches, and the layout is naturally balanced with no extra counterweighting needed. Its shorter crankshaft (versus an inline-six of the same size) can handle higher rpm, and its low, flat shape is exactly why Porsche has built the 911 around this layout for generations — it fits behind a rear axle in a way a straight-six never could.

A straight-six gets balance a different way: opposite pairs of pistons moving in sync cancel each other’s vibration out, with a firing order spaced so no two adjacent cylinders ever fire back to back. BMW has built its reputation on this exact layout since the 1930s. It’s a longer engine than a flat-six, which is why you’ll find it in the front of a saloon rather than behind a rear axle — including in one of the most famous inline-sixes ever built, Toyota’s 2JZ-GTE, the engine most associated with the Mk4 Supra and JDM tuning culture generally.

V10: rare for a reason

V10s barely exist in road cars, and the ones that do tend to be memorable specifically because the layout is unusual. The Lexus LFA’s Yamaha-co-developed V10 is the standout case: it revs from idle to 9,000rpm in six-tenths of a second — fast enough that Lexus fitted a digital tachometer, because a conventional analogue needle couldn’t physically sweep the dial that quickly. If you want an engine that’s rare mostly because almost nobody else attempted it, this is the layout.

Rotary: not really an “engine” in the usual sense

Everything above is a variation on pistons moving in cylinders. A rotary throws that out entirely — a triangular rotor spins inside a housing, with only three moving parts in total. Mazda is the only manufacturer to have taken the Wankel rotary to sustained production success, and the engine’s small size is exactly why the RX-7 achieved its famous near-perfect 50:50 weight balance. If you want to build something that looks almost nothing like a conventional engine once you open it up, this is the one layout on this list that genuinely isn’t a piston engine at all.

Aviation and specialist layouts: a different category entirely

A handful of kits in the range aren’t car engines at all — radial aircraft engines (cylinders arranged in a circle, the standard for WWII-era piston aircraft), turbojets and high-bypass turbofans (the difference being how much intake air bypasses the core — bypass air is why modern airliners are dramatically more fuel-efficient than early jets), and gas turbines (the same continuous-combustion principle behind jet engines and power stations, which Chrysler famously and unsuccessfully tried putting in road cars in the 1960s). These exist for builders who want the mechanical variety of the collection to extend past cars entirely.

So which layout should you actually build?

• Want the sound and history of American performance? Cross-plane V8.
• Want the highest-revving, sharpest-sounding character? Flat-plane V8 or a V10.
• Want naturally aspirated purity at its most extreme? The Valkyrie-style V12.
• Want something almost nobody else has ever built? W16.
• Want smoothness as the entire point? Flat-six or straight-six — pick flat-six if you want the compact, rear-engine-friendly version, straight-six if you want the classic front-engine layout.
• Want a genuinely different mechanism, not just a different engine? Rotary.

Whatever you land on, our Engines & Gearboxes collection covers every layout above, and larger, more mechanically complete builds cluster in our 1:8 scale range — the bigger the scale, the more physical room there is for a working crankshaft, a real gearbox, and a differential that actually divides power through a corner.