Do you have to use premium gas in a Cadillac with a North-star engine?

You have to use premium gas in the Northstar engine because lower octane fuel WILL damage it. No tricks. No gyps. High compression engines require premium gas because there's no other way to prevent detonation, preignition and mechanical failure without water injection and other very sophisticated and expensive systems. You might be looking at two more dimes and thinging it's silly, but that extra 20 cents means you won't need the engine replaced for playing cheap with an expensive machine.

The 1963 Jetfire Olds 3.5 liter turbo (215 HP- 215 cu.in) with 10.5:1 compression required premium, which was 100+ octane in those days, plus a mixture of water and alcohol for induction to the engine. People didn't always take it seriously and a lot of those engines blew up, huffing the turbo through the hood of the car. GM only admitted to "engine fires" in reference to their defect. With the Northstar, Cadillac knows better than to even ask you to *think* about maintaining a supply of extra additive to preserve the engine.

Well some facts are that Cadillac is american made car, they want you to use expensive fuel and parts, its common sense. I own a cadillac and when the fuel is expensive i always use regular but from good gas stations not old ones, and when the gas is low then i pump premium for a while, but either way regular or premium the cadillac still hovers down the road great!

It says its required for a reason. High compression engines require a high octane fuel to avoid knocking and damaging the engine. Eventually its going to wreck your engine and its going to cost a lot more than you could dream of saving by being cheap and not using the correct gas. If you cant afford $0.20/gal which amounts to less than $3/tank of gas then you cant afford the car.

Car companies don't get anything out of telling you to use a higher grade of gas. The gas companies do.