Yes, it absolutely matters what gas you put in your car. Using the wrong octane fuel can lead to poor performance, reduced fuel economy, and potentially serious engine damage over time. The most critical factor is matching the fuel's octane rating—a measure of its resistance to premature combustion, or "knocking"—to your engine's requirements. This information is always found in your owner's manual and often on a sticker inside the fuel door. Most cars are designed for regular unleaded (87 octane), while high-performance or turbocharged engines often require premium (91-93 octane) to operate correctly.
Using a lower octane fuel than recommended can cause engine knock. This unsettling pinging or rattling sound occurs when fuel ignites too early in the cylinder, creating damaging pressure waves. Modern engines have knock sensors that can retard ignition timing to prevent damage, but this results in reduced power and lower gas mileage. Conversely, using premium fuel in a car built for regular is generally a waste of money. You won't gain any performance or efficiency benefits because the engine isn't designed to take advantage of the higher octane.
The only exception is for vehicles with specific "premium recommended" designations. These engines will adapt to run on regular without knocking but will deliver their advertised horsepower and torque figures only when premium fuel is used. Beyond octane, always ensure the fuel meets Top Tier™ standards. These fuels have a higher concentration of detergent additives that help keep fuel injectors and intake valves clean, which is crucial for maintaining long-term engine health and efficiency.
| Fuel Consideration | Key Data & Impact |
|---|
| Octane Rating | Regular (87), Mid-Grade (89), Premium (91-93). Using the correct rating prevents engine knock. |
| Engine Knock Risk | Using fuel with an octane rating 5 points lower than required can increase knock probability by over 70%. |
| Fuel Economy Loss | Using lower-than-required octane can reduce mileage by 2-4% due to retarded ignition timing. |
| Top Tier™ Detergents | Contains 3-5 times the EPA-required detergent levels, preventing 95% of intake valve deposit issues. |
| "Premium Recommended" | In these engines, switching to regular can result in a 3-7% drop in horsepower output. |
