Engine & Mechanical

Carburettors: Single Normale vs Twin-Weber Veloce

IntermediateThe induction that defines the two Giulia Spiders — the Normale's single carburettor and the Veloce's twin Webers — why balance matters, and reading a lumpy idle.

Induction is the defining mechanical difference between the two Giulia Spiders. Knowing which you have — and how it should behave — saves you from mistaking normal fettling for a fault.

Normale: a single carburettor

The Normale breathes through a single carburettor for around 92 bhp. It is the simpler, more docile set-up, and the easier of the two to keep in tune.

Veloce: twin Webers

The Veloce runs twin Weber carburettors and hotter camshafts for roughly 112 bhp — and needs the raised bonnet scoop to clear the taller engine. Twin Webers reward correct set-up with a wonderful response, but they want balancing and fettling to stay sweet.

Balance and tuning

On either car, expect to fettle and balance the carburettion as part of ownership. A lumpy or uneven idle is very often just tuning — synchronisation, mixture, worn spindles — rather than anything expensive. Don't condemn a car on a rough idle alone; a proper set-up transforms it. Equally, a Veloce that has never been balanced will feel flat and fluffy, so budget for a good carburettor specialist if you are not set up to do it yourself.

What to check

Confirm the induction matches the car's claimed identity: a "Veloce" should have twin Webers and the scoop; a single-carb car under a scooped bonnet raises questions. Drive it warm — it should pull cleanly and evenly.