Can regular gas be used in vehicles where premium gas is recommended or the manual says you have to use premium.
Yes.
If the manual says “premium recommended” the motor has a knock sensor and adjusts the timing to minimize damage from pre-ignition. The motor may have a bit less power and will get a bit less mpg, but will run and not be damaged.
If the manual reads “premium required” this gets a different answer. Yes, the motor will run on regular, but damage could result. Regular gas should only be used if premium gas isn’t available and only on a temporary basis. Once you can put premium in the tank again, that’s what you should do. In this case a driver who uses regular all the time could cause damage to the motor which would be very expensive to repair, like several thousand dollars.
Recommended means recommended. If you don’t use premium you’ll lose some power and probably some mileage, but the engine will adjust to regular.
Required means required. You should not anything except premium if the owner’s manual says “premium required.”
it’s only a couple bucks more per fill up, when you do the math, why bother?
I agree with bscar. Regular gas is $4.05 and premium is $4.35 at a station near me. If you fill a near-empty intermediate car like an Accord, you will put 13 gallons in it. The cost to fill up is $55.25 for regular and $56.55 for premium. The difference is $1.30 - less than 2.4%. You are not saving much money, and may be losing it if you decrease your mileage enough when the timing adjusts for lower octane fuel. If you have a turbocharger, you really must use premium.
While you will not suffer damage due to using regular, you will loose some power and mileage will be reduced. It varies depending on the car and conditions, but you might end up paying more to use regular, so why not use the recommended fuel. You might even save money.
@jtsanders-- your math is way off.
You quoted a $.30/gal difference. With 13 gallons that woudl be $3.90, not $1.30.
yeah, the math is off a bit, I put in just over 13 gallons at $4.39 and figured about $2.60 I would have saved by buying 87 @ $4.19
Checked the date I uploaded this and it was the 29th of April, and I haven’t filled up since, but will need it this weekend. Looked friday and our gas had gone down to $3.99 for 87