shepuz2

iTrader: (2)

I have a BP close by that sells 93 octane but is always about 5 cents per gallon higher than Shell and Conoco who sell a max of 91.

Is it worth the extra $.70 every time I fill up to get the 93?

What will I notice (performance-wise) with 93 vs. 91?

Thanks.

FL01SS

I can't answer this for you, but it might help others answer it more accurately if you list some of you mods.

shepuz2

iTrader: (2)

no mods yet except the flowmaster and 3.5 " tips that came on it.

02 Formula with 5.7

jmm98LS1

iTrader: (28)

There's a common misconception that higher octane gas = more power. Not true. Higher octane simply means it take's more spark to light it off. The only reason anyone would need high octane gas is to fight off detonation. Unless you are running higher than stock compression, 91 octane is fine. Filling with 93 octane will give you no performance gain.

NoSlowSS posted this in the "what octane" thread, it explains this pretty well:

ls1charged

iTrader: (8)

if u look in this forum you will find a thread about what octane is the best for u, its been going on for a while now its like 5 pages long, im sure if u check in that thread you will find that your question has prolli already been answered there.

GXPPOWER

you will see harldy no difference....... uless your pushing large amount of HP. stock ls1 can run 87 octane under normal conditions and you will SEE NO difference only in wide open throttle does octane really matter.

ChocoTaco369

there is absolutely NO difference mpg-wise or performance-wise unless your compression is insane.

run 91 octane all the time. that way, if you ever hear pinging in the engine's older life, you can up it to 93 to fight it off. if you get your motor broken in and used to running 93, that's all it'll know so when it starts to eventually ping late in life, you'll have nowhere to go. it's always best to stick to the recommended minimum. i use 91 octane, sunoco always, and consistantly get 21-22mpg in my stop-and-go hour long drive to work (only the last 7 miles are stop and go, the other 22 are cruising).

blkZ28spt

I would never run 87 in an LS1. Some seem to run okay on it, some don't. Even if it runs alright on it you never know if it's pulling timing without a good scan tool.

At your point 91 is plenty.

PS: Ditch the flowcrapper.

GoldenBird

I had this same thought but unfortunately in Mass 99% of stations offer 87-89-93....ones with a 91 or 92 are few and far between so I'm forced to jump to 93.

'Trust'

iTrader: (24)

Its totally the opposite here, there is maybe one station with 93 for every hundred or so with 91.

N4cer

iTrader: (11)

Well, if you get any problems from the lower octane, your car is gonna switch to the low octane program, so you're gonna get some worse performance and mileage. So spend the $.70, ya tightwad!

ChocoTaco369

no...no it won't. there's no difference. it's a myth. all it does is get your engine used to more octane than it needs. that'll really screw you when it eventually develops pinging later in life. if you start 91 now and get it used to running 91, when it does ping, you always have 93 to fall back on.

you're not supposed to run higher octane than necessary. follow what the manual says. if it performed better on 93 octane, they would have advertised 93 octane since it would have given them a higher hp and mpg rating. there's a reason why they don't advertise to use 93 octane. it's useless. waste of money and bad for the engine in the long run.

N4cer

iTrader: (11)

So you don't actually have a low octane fuel map in our LS1's?
HPtuners is wrong?

'Trust'

iTrader: (24)

There is definately low octane tables, I messed with em' trying to figure if I had false knock, which I did. I changed em' all to match the high octane table and the knock was gone. I dont advise it though, they are back to stock now, because if I ever got bad gas, detonation would be alot more probable and no timing would have been pulled = bad.

ChocoTaco369

i said 91 octane minimum. if you use 87 it will probably hamper performance/mileage as it is not a recommended fuel. i'm saying if you go with 91, which is recommended, you'll see no difference if you up it to 93. all you're doing is getting your engine accustomed to using more octane than it needs which is harmful down the line. it needs 91. it should get 91. no more, no less. don't raise a rich kid of a car.

Michael55123

iTrader: (3)

[QUOTE=ChocoTaco369]no...no it won't. there's no difference. it's a myth. all it does is get your engine used to more octane than it needs. that'll really screw you when it eventually develops pinging later in life. if you start 91 now and get it used to running 91, when it does ping, you always have 93 to fall back on.
QUOTE]

What??? "Used to more octane" ? Why did the engine deleop pinging later on in life? all things equal? Moving to 93 isn't a fix. Not even sure this makes logical sense. How does a motor get used to an octane rating?

Mr Incredible

I've used some BP 92 octane. Usually I use 91. Occasionally, I've used the 10% ethanol (89) and even regular (87).

SOTP tells me the BP 92 made my ride more confident and it felt better to drive. I can't quantify that opinion, but it seemed to make a difference in the way it ran...for the better. I swear it even gave me better mileage to a small degree. That's difficult to prove over time since I don't buy it very often.

In the past I've stated it was perfectly OK to run 87 and ethanol. It is. It even says so in the owner's manual. Looking back, my car seemed to sound harsher and not as strong while slumming at the gas pumps. The mileage wasn't the greatest I've gotten, either. However, I've never experienced pinging at all with any gas choice.

I haven't done a cost benefit survey between the octanes, but if somebody asked I'd say I prefer the higher octane. If I had to choose between milk for the kiddies and buying gas, I'd have to choose cheap gas and simply live with it.

$.02

knowitman

How does a car get used to a certain octane?

4sconcepts

Agreed the higher octane you put in her will just improve your gas mileage bc the higher octane the slower it will burn but as said might not be the best thing in the long run might not improve proformance as stated. I live in charlotte where the gas is one of the most high priced on the east coast but I run nothing but 93 if I got to the strip 100 octane $5.99 a gal there is my 2 cents

jmm98LS1

iTrader: (28)

You're kidding right?
In no way does your car "become accustomed" to 93 octane fuel and start bitching when you dump 91 in (assuming an unmodified stock motor)....it's an engine, not a spoiled 16 yr old girl.

The only difference between 87 and 93 is that 93 takes more energy to light off than 87 does.....that's it. Your car has two timing tables, a low octane and high octane. If you fill up w/87 octane for some reason, it will probably induce some spark knock and switch to the low octane table with less timing to compensate for the "easier to light" 87 octane gas. You could use 93 octane for years and then switch back to 91 with absolutely no adverse effect. These cars come from the factory with a compression ratio that will run just fine on 91 octane. Using 93 will not harm anything, but isn't necessary with a stock motor unless you are experiencing spark knock with 91, which could (although unlikely) happen under lower elevations/high heat & humidity. Now using say 100 octane in a stock motor would probably hinder performance a bit, without adding the necessary timing to light off that fuel.