I'm curious what the owner's manual (don't have one) for a '91 Camaro 3.1 MPFI recommend for gas octane?

What octane are you guys with a stock 3.1 using?

I searched this board and concluded that people with older 2.8s are recommending 87 octane, and people with performance chips are recommending a higher (92) octane, and that everyone (at least) occasionally "treats their ride to some good stuff", and that 87 probably yeilds the best milage per dollar, ...
but what should I (with a stock 3.1) be using on a regular basis?

Is there a real performance increase in 87 vs. 89 vs. 92 octane?

 

Stick w/ the 87 octane. We don't have high compression engines so 87 is just fine.

------------------
Red 1986 SC, 2.8L, rebuilt 700R4, 3.42 Posi, t-tops, 138K miles and counting, K&N air filters w/ removed air baffles, hopefully more to come!
RIP #3

 

Ok, here we go... hopefully this will shed a little light on what exactly octane is, for those of you who don't know (and don't even ask why I know so much about it... I was just bored one day I guess):

Octane is a measurement of how well a fuel RESISTS burning. (It's also a chemical, related to propane, but that's another story.) Now, this means running really really high octane, say 110, doesn't do you any good, other than allow you to run higher compression and advanced spark timing without preignition. It does NOT make more power in a motor that runs well. Therefore, if you have a car with a carb on it, that doesn't have computer controlled
ignition, and you get more power with better fuel, it means that you need a tuneup, becuase you're losing power to detonation when you run cheaper fuel. SOME (notice the emphasis there) cars with fuel injection and spark management systems will make more power on better fuel, becuase they're adjusting the spark timing and fuel to air ratios. I've not noticed this in many cars, but for example, the Ford Tarus FFV version, (a special model,
made to burn cleaner, and use as much as 70% alcohol) will make more power, noticably so, becuase it's computer allows a wide range of ignition settings, according to the fuel. Otherwise, becuase premium fuel resists ignition, you'll tend to LOSE power vs a lower octane fuel.
Basic summary? Pretend 89 octane burns when the piston is at TDC. Now, put in some 87 octane, and it's gonna actually start burning while it's still coming UP on the compression stroke. 92 octane, would probably resist burning until the piston was actually on started down on the power stroke (piston going down on power stroke, but fuel not ignited yet = bad thing...). Something to remember when you're sitting at the pump.

------------------
--'87 Camaro LT --
Currently undergoing a 2.8->3.4 swap.....

 

Ive noticed better milage with 92 when my car was boone stock my mom has a 3.1 olds cutless and she puts 92 in becasue she gets more miles per gallon and her car is bone stock only mods are well none. just my .02

 

So does the owner's manual recommend 87 (or 89)?

 

I had a quick question for anyone that could help me out. I have a jacobs electronics ignition system in my 92 3.1L V-6 Firebird and it burns 100% of the fuel so supposidly octane has no impact on preformance and mileage. I was thinking of getting a preformance chip but haveing a preformance chip requires higher octane gas. If I get a preformance chip should I put higher octane gas or just run it with 87???

 

The manual says you can use 87 and up on our cars