Cross-plane engines use substantial counterweights to counteract the rocking moment created by their 90° pin layout. That improves smoothness and low-speed torque, but adds rotational mass and limits free revving.
Flat-plane cranks are lighter and promote better exhaust scavenging because pulses alternate between banks. This helps high-rpm power, but the design behaves like two inline-fours and therefore produces more secondary vibration.
Think of a cross-plane V8 as a comfortable V8: smooth, torquey and characterised by a lumpy burble. A flat-plane V8 is a sports/racing V8: lighter, more responsive, more willing to rev, but rougher and usually louder in a sharper, more mechanical way.
In Europe, flat-plane V8s are mostly Ferrari, McLaren, Lotus and some Porsche engines; cross-plane V8s are the usual choice for Mercedes-AMG, BMW, Audi, Jaguar, Bentley and Rover/Land Rover.
| Engine | Maker / cars | Character |
|---|---|---|
| Mercedes-Benz M100 | Mercedes 300 SEL 6.3, 600 | Large, smooth, torquey classic German V8; helped establish Mercedes’ V8 reputation. |
| Mercedes-AMG M156 / M159 | C63 AMG, E63 AMG, SLS AMG | Naturally aspirated 6.2-litre cross-plane V8 with the classic AMG growl. |
| Mercedes-AMG M177/M178 | AMG GT, C63, E63, S63 | Modern 4.0-litre twin-turbo cross-plane V8; the Black Series M178 LS2 is the notable flat-plane exception. |
| BMW S65 | BMW E90/E92 M3 | High-revving 4.0/4.4-litre naturally aspirated cross-plane V8, derived conceptually from BMW’s S85 V10. |
| BMW M60/M62/N62 | BMW 5 Series, 7 Series, X5 | Smooth luxury and sporting cross-plane V8s. |
| Audi 4.2 V8 / RS4 B7 engine | Audi A8, S4, RS4, R8 | Audi’s 4.2-litre V8s are cross-plane; the RS4’s 420 bhp version is particularly well regarded. |
| Audi BCY 5.2 V10-derived V8 | Audi RS6, S6, S8 | Cross-plane V8s used in Audi’s performance and luxury models. |
| Jaguar AJ-V8 | Jaguar XK, XJ, XF, F-Type; Land Rover models | Jaguar’s long-running V8 family, in naturally aspirated and supercharged forms. |
| Rover V8 | Range Rover, TVR, Morgan, various British specialist cars | A lightweight British cross-plane V8 used from 3.5 to 5.0 litres. |
| Rolls-Royce/Bentley L-series | Bentley Mulsanne, Rolls-Royce Silver Cloud II, Bentley Arnage | A 6.75-litre cross-plane V8 produced from 1959 to 2000 in road-car use, renowned for effortless torque. |
| Porsche M28 | Porsche 928 | Porsche’s early 4.5-litre V8 was cross-plane, unlike the later 918 Spyder engine. |
