89 octane on a 87 rated car?

(2010-12-10 03:10:17)

1. Ricky Says: I have a 93 Jeep Grand Cherokee with the 5.2 motor and it is rated for 87 octane fuel.a friend of mine told me that the bigger the motor the higher the rating and fuel it is supposed to use and recommended using 89.I know its true for sports cars and such they would have to use 89/91 or higher but would using 89 on a regular car like mine while its rated at 87 damage the engine at all?

2. mailbox1024 Says: This question has been asked more than 100 times in the past few weeks alone. Search it on the forum and read all the responses. This seems to be a personal preference . I use 89 for the added benefits of the detergents to help reduce carbon build up in the engine and injection system. I get pros and cons about this all the time, but i have yet to have any of my engines fail due to gummed up injectors or carbon build up in the intake system and cause pinging or hesitation.
If you drive a lot of highway, then yes stick with the 87, but if you do a lot of city driving, then i go with the 89. And your friend is wrong about the bigger engine using higher octane fuel. As far as lightening your wallet, if 89 is say 10 cents per gallon more than the 87, and your tank uses 10 gallons of fuel, it takes only a buck to help keep the internal aspects of your engine clean. To me this is a buck well spent.
Again this is a personal preference and i am not trying to sway anyone from changing their fueling habits for their own car. I have been doing this for 50 years with no problems, so my proof is in my experience of saving money on long term maintenance.
good luck..........

3. Michael Says: It won't damage the car and will make it slightly faster because you won't have to haul all that heavy money around. There is no advantage to using higher octane than recommended by the owner's manual. Until about a decade ago upper grades were typically more detergent also, but then the EPA reduced detergency requirements for gasoline and everybody went to the new minimum in all grades. That was so lousy that a consortium of Honda, Toyota, GM, and BMW created a new standard for detergency, called Top Tier. All grades of top tier gasolines meet the standard. BP supposedly is marching to their own drum.

4. mdk68gto, ase certified m tech Says: the larger engine does not require the higher octane unless it is a higher compression engine. the 89 octane will not do you any good really aside from making your wallet lighter.

5. Darrell Says: In my car that is rated for 87 I use 89 only because Shell brand gas shows on the tank that middle grade and premium have no ethenol.