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Fuel

Do I REALLY need to use Unleaded Premium in my 2004 Subaru Forester (turbo)

Yep. Turbo = high output = premium.

Yes. Well, no you don’t HAVE to, but the car won’t run as well. The engine computer should note any potentially harfmful consequences of the lower octane fuel and retard ignition timing and turbo boost to compensate. But then you’ll lose power, fun, and possibly fuel mileage. In that case, what’s the point? Turbos are made to be fun to drive, not economical.

If you sit down and do the math to figure out any potential cost savings from premium to regular you’ll see it amounts to pocket change.

Use the fuel specified by the manufacturer (ie check the owners manual). If premium is required then use premium. Some turbos don’t require premium. My 2013 Ford Escape 2.0L ecoboost (turbo) runs fine on regular (regular is specified in the owners manual). Supposedly there’s a minor loss of hp using regular but not near enough for me to notice.

Read your owner’s manual carefully. The key words to look for are “recommended” or “required”.

Premium recommended means to get the most power you use premium, but you can use regular without damage to the motor. Depending how you drive the car you might notice a difference in performance and you might not.

Premium required means the motor needs premium period. Use of regular can damage the pistons and means an expensive repair. It will say that a premium required motor can use regular if for some reason no premium is available, but that is on an “emergency” basis only.

The answer for your specific car and motor is your owner’s manual.

UncleTurbo’s answer is correct, although it should be added that in the “recommended” case your fuel economy is reduced, wiping out some or all of your savings (or worse).

+1 to Uncle T’s answer.

Why buy the car if you want to save money on gas ? If it says required, you have a money guzzler.

Well, in fairness, people who buy Subie Foresters buy them to get to the ski slopes or the fishin’ holes. They don’t think of them as performance car. Many get surprised by a premium fuel requirement.

For the ones who post asking this question with M5’s, 370Zs, 'Vettes, and Caddilac CTS’s, I wholeheartedly agree.

“Well, in fairness, people who buy Subie Foresters buy them to get to the ski slopes or the fishin’ holes. They don’t think of them as performance car. Many get surprised by a premium fuel requirement.”

But…the only Foresters that require premium fuel are the turbo-charged ones, like the one that the OP owns.

I realize that the OP already owns this vehicle, but…simply looking at the Owner’s Manual or even looking at the wording on the gas cap prior to purchase can avoid being in a position of having to buy more expensive fuel. Just like with most other things in life, failing to research something adequately prior to making a decision can lead to unexpected consequences.

“…simply looking at the Owner’s Manual or even looking at the wording on the gas cap prior to purchase can avoid being in a position of having to buy more expensive fuel.”

Zackly.

Premium costs around $3.90 and regular about $3.45 in my neighborhood. If you buy regular, you save $237 every 10,000 miles - less than $5 per week. I don’t think that is too much to spend each year to use the car the way it was intended to be used.

It’s expensive to get a little extra surge in the seat of your pants.

“It’s expensive to get a little extra surge in the seat of your pants.”

So sayeth Gen Petraeus, Schwartzenegger, Bill Clinton, etc. etc.

I always wondered why people bought the supercharged nissan frontier or suv if they insisted on running regular gas in them-Kevin