* It's a colloquialism or slang: Someone might use "studded engine" to describe an engine heavily modified or enhanced with numerous performance upgrades, almost as if it's been "studded" with improvements. This is purely speculative based on the word's imagery.
* It's a mishearing or misspelling: The term might be a misremembered or incorrectly spelled description of a different engine modification or characteristic.
* It's specific to a niche context: It might be used within a very specific community or group with a unique jargon.
Without more context about where you encountered this term, it's impossible to give a definitive answer. If you can provide more information (e.g., the source where you saw it, the surrounding conversation), a more accurate interpretation might be possible.
