Can you use regular unleaded gas in a car that requires premium unleaded?

Answer 1

Technically yes, but it's important to note that you could potentially use any flammable liquid that could actually get to your fuel cylinders and ignite to run your car on. That doesn't mean it's a good idea.

Without going into too much detail the octane rating is essentially a rating of how reliable, for lack of a better word, that particular gasoline is. By that I mean if it's not reliable, ie lower grade, there is a chance of an 'off' ignition in that it has a high or low pressure combustion or doesn't ignite instantly or an air pocket ignites off-timer, and this is bad because your engine is a highly tuned machine that relies on a steady sequence of even compression.

Most engines can account for this, but some cars are designed for peak performance and not for being able to accommodate cheap gas, and so they recommend using premium. I would say if you can afford it, an extra 10% on the price of gas is a decent price to pay for an average of 5% less uncontrolled explosions in your engine.

if your car requires premium gas, then that' what it needs. If you try to run it on regular it might start to knock, spike and run poorly. This may even damage the engine.

If you really feel the urge to experiment, you can put some regular gas in and see what happens.

Start with 1/4 of regular and 3/4 of premium.

If it runs OK on that, even on hard acceleration, try 1/2 premium, 1/2 regular.

If it runs OK on that, even on hard acceleration, try 1/4 of premium and 3/4 of regular.

If it runs OK on that, even on hard acceleration, try all regular.