23/05/2026
• 🔧 Padova. A mechanic. An S4. He’ll take it from here.
There’s a kind of knowledge you don’t learn from books. You get it with your hands inside an engine, year after year, until you can feel certain things before you even see them. What he’s explaining is the most insane powerplant rally racing ever put on four wheels.
The Lancia Delta S4 ran a 1,759 cc four-cylinder with a magnesium alloy block, Cermetal-coated cylinder liners and four valves per cylinder. Serious stuff already. But then comes the twin forced-induction system that rewrote the rulebook: below 3,500 rpm the Roots-type Volumex supercharger built boost from as low as 1,500 rpm, eliminating turbo lag entirely. Above 4,000 rpm the K*K K27 turbocharger took over, cutting out the Volumex electronically. Two air-to-air intercoolers chilled the charge before the cylinders. Peak boost: 2.2 bar.
The exhaust runners share the same diameter and length, tuned to the engine’s operating range and merged into the turbine in a 4-2-1 configuration. In competition spec the manifold went carbon fibre with a rotary barrel throttle valve. One lesser known detail: the oil feed line ran clamped against the hot exhaust manifold and would slowly coke internally until, in the worst cases, the turbo seized. The one flaw of an almost perfect machine.
From 480 hp at its 1985 debut to 650 hp in the final evolution. On 600 kg of car.
Explained in Venetian dialect. No subtitles needed.
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