Should I put premium gas in my Subaru Ascent?

Premium gasoline is recommended for the Subaru Ascent's turbocharged 2.4-liter engine to maximize performance and efficiency. If premium isn’t available, you can use regular 87-octane gasoline, but you may see reduced power and throttle response.

What fuel does the Ascent require?

The Ascent uses a turbocharged 2.4-liter FA24 engine. Subaru’s guidance for this engine is to use premium unleaded gasoline (typically around 93 octane) for best performance and efficiency. If premium isn’t available, regular unleaded (87 octane) can be used, but timing may be adjusted to prevent knocking, which can reduce power and acceleration. Always refer to your model-year owner’s manual for the exact recommendation, since formulations and regional standards can vary.

Practical octane guidance:

• Premium gasoline (about 93 octane) is ideal for maximum performance, throttle response, and towing capability under load.


• Regular gasoline (87 octane) can be used if premium is unavailable, but you may notice slower acceleration and reduced peak power when the engine is under load.


• Midgrade options (when available in your market) can offer a middle ground, though benefits over regular and premium depend on driving conditions.

In practice, premium is the recommended choice for everyday driving and when you need maximum performance; regular is a temporary substitute when premium cannot be found.

Performance and efficiency implications

Higher-octane fuel helps the engine avoid knock and allows the turbo to operate with its designed timing and boost. This translates to stronger acceleration and more consistent performance, especially under load or during highway climbs. Regular octane can trigger knock or timing retard under heavy demand, which can reduce horsepower and potentially impact fuel economy over time.

• With premium, you typically get better throttle response and stronger, more consistent power, particularly when climbing hills or towing.


• Under hot days or sustained high-load driving, premium can maintain performance more reliably than regular.


• Using regular may result in noticeable power loss or reduced efficiency when the engine operates under load.

For drivers who regularly tow, haul heavy payloads, or frequently drive in demanding conditions, premium offers tangible benefits. For casual daily driving with light loads, regular will operate, but you won’t be optimizing the engine’s feel or efficiency.

When premium matters most

Consider premium most when you drive under the following conditions:

• Towing or carrying a heavy load


• Driving in hot climates or on long, steep climbs


• Aggressive driving or sustained highway speeds


• Frequent mountain driving at higher altitude

In these scenarios, premium yields noticeable benefits in power, responsiveness, and endurance during demanding stretches.

Fuel options and practicality

Understanding octane options can help you plan fuel purchases and costs more effectively. Here's how to approach it in typical markets:

• 87 octane (regular): Widely available; acceptable in a pinch but not ideal for daily driving or heavy loads.


• 89–91 octane (midgrade): Available in some regions; may offer a balance between price and performance where available.


• 93 octane (premium): Recommended for best performance and efficiency in the Ascent’s turbo engine; use when possible.

Bottom line: Premium is the recommended default for the Ascent. Regular can be used temporarily if premium isn’t accessible, but expect reduced performance under load and potentially lower efficiency. Midgrade can be a compromise where available, but always refer to the owner’s manual for your specific model year and market.

Bottom line and practical tips

For everyday driving, premium gasoline offers the best balance of performance and efficiency for the Subaru Ascent’s turbocharged engine. Use regular only when premium isn’t available, and plan to refuel with premium as soon as possible if you notice reduced performance. If you frequently tow, drive in hot climates, or navigate steep terrain, prioritize premium to maintain optimal power and driveability.

Summary

The Subaru Ascent’s turbocharged 2.4-liter engine is designed to perform best on premium gasoline (around 93 octane). Regular 87 octane can be used in a pinch, but you’ll likely experience reduced power and responsiveness, especially under load. For towing, hot weather, or demanding terrain, premium delivers the most noticeable advantage. Always consult your specific model year’s owner’s manual for exact octane recommendations and regional variations.

What are the weaknesses of the Subaru Ascent?

Common Subaru Ascent cons include poor fuel economy, a CVT (continuously variable transmission) that can feel disconnected and noisy, and brake issues like premature wear and juddering. Other drawbacks cited by owners are limited interior cabin width, inconsistent technology and infotainment, and engine noise, particularly under acceleration. Some owners also report issues with electrical systems, and despite a decent engine, some feel it is underpowered for the vehicle's size, particularly with its CVT. 
You can watch this video to learn about the common problems and weaknesses of the Subaru Ascent: 52sNexologyYouTube · Sep 11, 2025
Performance and powertrain

• Poor fuel economy: Some owners report fuel economy that is worse than advertised. 
• Underpowered engine: The turbocharged 2.4-liter engine is often considered underpowered for the Ascent's heavy weight. 
• Noisy CVT: The CVT can cause a "droning" noise and a disconnected feeling, while competitors use more traditional automatic transmissions. 
• Inconsistent throttle: Some drivers find the throttle too touchy at low speeds or sluggish at higher speeds. 

Brakes

• Premature wear: Owners report premature wearing of brake pads and rotors.
• Vibration and noise: Complaints include pulsating or vibrating brakes and squeaking noises. 

Interior and technology

• Limited interior width: Despite being a large SUV, the cabin is narrower than many competitors, reducing usable space for passengers. 
• Frustrating technology: Some owners find the technology and infotainment systems frustrating to use. 
• Driver assist system issues: In some conditions, such as heavy rain, the EyeSight driver assist system can shut down. 

Other issues

• Engine and transmission problems: In addition to the CVT, other engine and transmission-related issues have been reported by owners. 
• Electrical system issues: Reports include problems with interior lights and other electrical components. 
• Repairs: Some owners report that repairs for certain issues, like replacing a windshield, can be expensive and trigger other cascading problems. 

This video discusses several issues with the Subaru Ascent, including the CVT, brake problems, and electrical system: 1mFuel ForceYouTube · Aug 4, 2025

Does putting premium gas in your car really make a difference?

What happens if you use premium gas instead of regular? It's unlikely that your car will be harmed if you use premium gas in a car that requires regular gas. But it's a near-certainty that you won't see an increase in performance and a fact that you'll pay more for premium.

Does the Subaru Ascent need premium gas?

From the Crosstrek to the Ascent, Subaru designed its 2024 lineup for reliability and efficiency. Most models run on 87-octane regular unleaded gasoline, making them cost-effective for everyday use.

Do subarus run better on premium gas?

Regular gasoline has an octane level of 87 or so, while premium gasoline has an octane level of 90 or above. This can be a huge advantage for luxury and performance cars specifically, like the Subaru WRX and BRZ.