#News

We have hardly talked about BMW 2 Series, but it is worth talking about this 220i. It is not one of BMW's usual (excellent) diesels but instead mounts a 2-liter turbo petrol with Valvetronic, Vanos, and Twin Scroll turbo (like Audi and Mercedes). BMW has opted for this downsizing route to limit displacement and fuel consumption.

The engine seems to have "emptied out" at the bottom end (loss of torque at lower rpm) while gaining in high-rpm stretch (more maximum power or at least more speed in revving up). In practice, there is often a gain at the top of the rev counter but at the expense of the engine's elasticity and thrust at lower revs.

First, let's see how the Stelvio 2.0 turbo 200hp runs in stock conditions. The engine is an Alfa Romeo 2-liter with a 16-valve cylinder head, turbocharger, and intercooler. The power is not very high for such an engine and is expressed at about 4500 rpm, while the maximum torque is not bad and is expressed at 1750 rpm with a force of 330Nm.

Electric turbochargers (in this case, we are talking about a Garrett model produced for Mercedes) are devices that incorporate an exhaust-gas turbine (with associated electronically-controlled waste-gate management), a central core (with associated lubrication and cooling system), a centrifugal compressor (with respective electronically controlled by-pass system), and a novel and unknown component on normal turbochargers: an electric motor powere

In vehicles that use the turbocompound system, before the exhaust gases reach the first part of the exhaust system, they are routed to a second turbine. This turbine is mechanically connected to a set of gears whose purpose is to demultiply the turbine's rotational speed and multiply its torque.