OCTANE: 89, 91, 93 or 94
TheDeal526
08-24-2005, 03:08 PM
Greetings all:
I have a 1989 thunderbird with a standard 3.8 v6 EFI. It has just over 154,000 miles. Does anybody know is a 93 or 94 octane rating better for me than an 89 octane rating. The reason I ask is, I use to have a 1985 Firebird (v8, 305 cubic inches, 4 barrel carberator). On the firebird i noticed an increase in performance with a higher octane rating, so I assumed a higher octane rating would increase performance in any car. back to my thunderbird, i try to buy gas from 1 or 2 companies (Exxon 85%, BP 15%). I use to only use 93 octane. But with rising gas prices, I decided to try 89 octane, and it almost seems like my car runs better with the lower octane gas. Is it all in my mind, or should i continue to use the lower octane? I just assumed that with older cars, it would be better for performance and fuel mileage to use the higher octane (it cost more, so it must be better right). I have to admit also, i do pour a bottle of Lucas (Tune up in a bottel) every month just to keep my fuel system clean and lubricated.
I guess my questions are, what is the difference between octane ratings and how do they relate to a cars performance? And what octane rating should i put in my thunderbird???
I have a 1989 thunderbird with a standard 3.8 v6 EFI. It has just over 154,000 miles. Does anybody know is a 93 or 94 octane rating better for me than an 89 octane rating. The reason I ask is, I use to have a 1985 Firebird (v8, 305 cubic inches, 4 barrel carberator). On the firebird i noticed an increase in performance with a higher octane rating, so I assumed a higher octane rating would increase performance in any car. back to my thunderbird, i try to buy gas from 1 or 2 companies (Exxon 85%, BP 15%). I use to only use 93 octane. But with rising gas prices, I decided to try 89 octane, and it almost seems like my car runs better with the lower octane gas. Is it all in my mind, or should i continue to use the lower octane? I just assumed that with older cars, it would be better for performance and fuel mileage to use the higher octane (it cost more, so it must be better right). I have to admit also, i do pour a bottle of Lucas (Tune up in a bottel) every month just to keep my fuel system clean and lubricated.
I guess my questions are, what is the difference between octane ratings and how do they relate to a cars performance? And what octane rating should i put in my thunderbird???
flewthecoupe
08-24-2005, 07:29 PM
You don't have a high compression, high performance motor. Stick with the cheap stuff.
TheDeal526
08-25-2005, 02:26 PM
how would a high performance motor benifit from higher octane fuel??? wouldnt the lower octane gas dirty a cars fuel system more so than higher octane???
flewthecoupe
08-25-2005, 05:52 PM
the higher the octane the less prone the fuel is to predetonation. Lower compression motors don't require as much octane unless you start advancing your timing. My '67 Firebird requires premium. It's is around 10:1 compression ratio and initial timing is at 14*. If my compression ratio was higher or I advanced my timing more I would need higher octane fuel than what I can get at the pump to prevent pinging. If your ignition system and your emissions components are in good condition you should have no problem running the cheap stuff.
coondawg6
08-29-2005, 01:30 AM
just an extra thought is that MOST, not all, but MOST cars get better fuel mileage running the higher octane fuels and tend to get less carbon buildup
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