
Finding a car that requires or recommends 89 octane gasoline, often labeled as "mid-grade," is quite common. This fuel is typically specified for engines that need a bit more knock resistance than regular 87-octane fuel provides, but don't require the high-octane premium (91-93) often found in high-performance models. Many modern turbocharged engines and some V6 or V8 engines from manufacturers like Ford, General Motors, and Stellantis (Jeep, Ram) are designed to run optimally on 89 octane. Using the recommended fuel is crucial for maintaining advertised performance and fuel economy while protecting your engine from knock or pre-ignition.
The key is to check your owner's manual or the label inside the fuel filler door. This is your definitive source. Do not assume that using a higher octane than recommended will provide benefits; it's an unnecessary expense. Conversely, using a lower octane than required can cause engine knocking and potentially lead to long-term damage.
Vehicles that often specify 89-octane fuel include numerous models with turbocharged four-cylinder or six-cylinder engines. For instance, many Ford EcoBoost engines (like the 2.3L in the Ford Mustang EcoBoost or Explorer) explicitly recommend 89 octane for peak power and efficiency. Similarly, several General Motors vehicles with turbocharged engines, such as the Chevrolet Silverado 2.7L Turbo or the GMC Acadia, call for mid-grade fuel. Some naturally aspirated V6 engines, particularly in larger SUVs and trucks from Jeep (Grand Cherokee) and Ram (1500), also recommend 89 octane.
Here is a table with examples of models that often require or recommend 89-octane gasoline:
| Manufacturer | Model | Engine Example | Fuel Recommendation |
|---|---|---|---|
| Ford | Mustang EcoBoost | 2.3L EcoBoost I4 | Recommended: 89 Octane |
| Ford | Explorer | 2.3L EcoBoost I4 | Recommended: 89 Octane |
| Ford | F-150 | 2.7L EcoBoost V6 | Recommended: 89 Octane |
| Chevrolet | Silverado 1500 | 2.7L Turbo I4 | Recommended: 89 Octane |
| GMC | Acadia | 2.0L Turbo I4 | Recommended: 89 Octane |
| Jeep | Grand Cherokee | 3.6L Pentastar V6 | Recommended: 89 Octane |
| Ram | 1500 | 3.6L Pentastar V6 | Recommended: 89 Octane |
| Acura | RDX | 2.0L Turbo I4 | Required: 91 Octane (Premium) but often runs on 89* |
| Hyundai | Sonata | 1.6L Turbo GDI | Recommended: 87 Octane, 89 for towing |
| Kia | Sorento | 2.5L Turbo GDI | Recommended: 87 Octane, 89 for max performance |
*Note: Some cars that "require" premium can often safely run on 89 octane with a slight reduction in performance, but always check your manual first.

Honestly, you’ll mostly find this in trucks and bigger SUVs. My Ram 1500 with the V6 specifically says 89 right on the fuel cap. It’s that sweet spot for engines that work a bit harder but aren’t full-on sports cars. Just pop open your fuel door—the answer is right there. Don't waste money on premium if it says 89; you won't feel a difference. But don't cheap out with regular either, the engine might start pinging, especially when you're hauling something heavy.

Think of octane as a fuel's resistance to uncontrolled ignition, or "knock." Engines with higher compression ratios or forced induction (like turbochargers) generate more heat and pressure, making them prone to knock. Using 89 octane in these engines provides a necessary buffer against this, ensuring smooth operation and protecting components. It's an engineering specification, not a marketing ploy. Forced induction is a key reason many modern, smaller-displacement engines are tuned for mid-grade fuel to achieve both power and efficiency goals.

From a cost perspective, 89 is the tricky middle child. I always tell people to check their manual. If it says "recommended," you might get away with 87 most of the time, but you could lose a mile or two per gallon, negating the savings. If it says "required," you really should use it. The potential cost of engine damage from long-term knocking far outweighs the extra 20-40 cents per gallon. It’s an insurance policy for your engine's health. Budget for it as part of your ownership costs.


