What octane level to use?

[REDLiNE]

What octane level should I be using in my car now? I'm runnung 89 octane in the car right now. It's slightly modded with an SLP CAI, NGK iridium plugs, carsound highflow cat, and a flow master american thunder cat back system.

[tWiStEdBird]

89 will do.. My car does on 89 if I'm under 90mph, seems to run better on 93 (No misses @90mph+.

[GPFish]

89-91 should be good. If you ever have a reprogrammed PCM, Id always run premium.

[oil pan 4]

If you live in a place that has crapy gas like I did just use premo, 91.
In Maine, 87 octain is just plain crap it is yellow like P and has a musky smell. Not like fresh gas should smell.
Older fords all seem to run like @ss on it.
For interstate crusing me and my friend form Va figured that even with 91 costing 20cent more a gallon it cost him about 1.1 cent less per mile to run his car off 91 then 87. His 1987 2.4L dodge daytona.
My Z28 got about the same results, I didn't calculate it as precisely as him and came out with about 1.3cent less per mile to run it off 91 then 87.
It won't hapen with every car you have to test it to know for sure.
100 octaine japinese gas that they sell here off base smells like gas mixed with break cleaner.

[V8 Killer]

87 is what GM recommends.

89 and up is simply a waste of money...

[Little G]

Originally posted by V8 Killer:
87 is what GM recommends.

89 and up is simply a waste of money...

Not true: The PCM has a high and low octane table. The high octane table will yield more performance and better gas milage. A friend of mine has a new four-cylinder alero and it gets 50 more miles out of a tank of 93 versus 87.

[00firebird]

here it says its designed for 87 ... http://engine.firebirdv6.com/

[V8 Killer]

Originally posted by Little G:
</font><blockquote>quote:</font><hr />Originally posted by V8 Killer:
87 is what GM recommends.

89 and up is simply a waste of money...

Not true: The PCM has a high and low octane table. The high octane table will yield more performance and better gas milage. A friend of mine has a new four-cylinder alero and it gets 50 more miles out of a tank of 93 versus 87. </font>[/QUOTE]So then whats the highest octane limitation?

If I dump in 120 Octane in my tank will I lift off? and get 4000 MPG?

[LwnGy83]

Do what I did... Try each octane level and see which runs the best, then use that. some will say that using the higher level is a waste of money, but I notice a big difference when I use different octanes. so, try em out and see.

[brink]

i have a jet pcm chip.. and w/o 93 octane my car is **** with the chip in.

but 93 octane, i can feel the performance

[BLLDOGG]

:rolleyes:

just use 87. do you guys sit around and come up with this stupid stuff or are you repeating what you see someone else says?

[38fury]

with 9.4:1 compression you don't need anything beter than 87. It's just wasting money.

[98Camaro3.8]

Lightly modded, untuned car: 87. Period.

[02PewterBird]

Originally posted by BLLDOGG:
:rolleyes:

just use 87. do you guys sit around and come up with this stupid stuff or are you repeating what you see someone else says?

[img]graemlins/rofl.gif[/img]

[camaroincal]

Um..My Chilton's manual says if a car..any car..has a compression ratio of 9.0:1 or higher, you should use a premium fuel. And, our cars do adjust to using a higher octane such as 91.