[1le Maro]

I understand 91 octane is the recommended octane for the car but I'm curious about running non ethanol fuel as that is an option at a couple of my local stations. Am i better off sticking with the non ethanol, or are there any downsides?

[pitrott1]

I use 93 O and Top tier gas only. Was using Sams 93 but got wise and shifted to top tier. Hope ur running a catch can. M2C's

[piening2150]

Costco 93 is always the cheapest around here, it's Top Tier, and I get enough cash back from Executive Membership to pay for itself. Win x3.

[IMCWORTH]

Originally Posted by piening2150

Costco 93 is always the cheapest around here, it's Top Tier, and I get enough cash back from Executive Membership to pay for itself. Win x3.

Here in California 91 is at almost all pumps. there is a Sunco fuel station near by that has 94, 96, 98, 101 right out of the pump

And the prices you see are not up to date. we pay almost $6 a gallon for regular 87 right now

[arpad_m]

You don't want your LT1 engine to see anything below 93 octane, otherwise your ECM tune will drop down to its low octane table, the engine will lose some power and be more prone to detonation. Don't do it. If you can only get 91, then sure, use that (and curse your state for not offering you at least 93), but 87 should be out of the question.

100% 93 octane is a unicorn, I've never seen it at any gas station, so I'd suggest that you stick with regular 93 that has 10% ethanol. The car is set up for this fuel. Running something with less ethanol will technically improve your fuel economy, but only a tiny bit, it's not worth the typical $0.90 to $1.10 surcharge.

High octane race fuels will not help your engine much either: as long as the high octane table is being used and there is no knock, the engine is operating under ideal conditions, adding more octane while still running the stock tune doesn't help (it can even be inferior as it can slow down combustion).

[bishopts]

Originally Posted by arpad_m

You don't want your LT1 engine to see anything below 93 octane, otherwise your ECM tune will drop down to its low octane table, the engine will lose some power and be more prone to detonation. Don't do it. If you can only get 91, then sure, use that (and curse your state for not offering you at least 93), but 87 should be out of the question.

100% 93 octane is a unicorn, I've never seen it at any gas station, so I'd suggest that you stick with regular 93 that has 10% ethanol. The car is set up for this fuel. Running something with less ethanol will technically improve your fuel economy, but only a tiny bit, it's not worth the typical $0.90 to $1.10 surcharge.

High octane race fuels will not help your engine much either: as long as the high octane table is being used and there is no knock, the engine is operating under ideal conditions, adding more octane while still running the stock tune doesn't help (it can even be inferior as it can slow down combustion).

This is the best answer

[KingLT1]

These engines will knock even on 93 octane with the stock timing maps. I usually end up around 23 degrees on cars with intake / headers and 93 octane... which is about 1 degree less timing than stock. This is why they pick up so much power on E85. The LT1 picks up about 25-30whp on E85. The older LS3 will only gain about 6-8whp. I know you didn't ask about E85 but I am trying to paint a clear picture why octane is important for this engine.

[JT6Speed]

Never seen non-ethanol gas here.

Part of the reason why I use stabilizer in the winter.

Luckily we do get 93 though. V-Power it is.

[FlukeSS]

Originally Posted by arpad_m

You don't want your LT1 engine to see anything below 93 octane, otherwise your ECM tune will drop down to its low octane table, the engine will lose some power and be more prone to detonation. Don't do it. If you can only get 91, then sure, use that (and curse your state for not offering you at least 93), but 87 should be out of the question.

100% 93 octane is a unicorn, I've never seen it at any gas station, so I'd suggest that you stick with regular 93 that has 10% ethanol. The car is set up for this fuel. Running something with less ethanol will technically improve your fuel economy, but only a tiny bit, it's not worth the typical $0.90 to $1.10 surcharge.

High octane race fuels will not help your engine much either: as long as the high octane table is being used and there is no knock, the engine is operating under ideal conditions, adding more octane while still running the stock tune doesn't help (it can even be inferior as it can slow down combustion).

Jeez is it that bad?

I mean 93 here is like toilet paper availability.

We also have a common selection of E85 as well.

[ember1205]

Originally Posted by piening2150

Costco 93 is always the cheapest around here, it's Top Tier, and I get enough cash back from Executive Membership to pay for itself. Win x3.

Executive cash back doesn't include gasoline purchases. :(

Costco VISA -does- and it's 5%.

[arpad_m]

Guys, I do understand that E is better (I run it, too), but OP asked the question with regard to his stock engine and even specifically mentioned ethanol free gas. Chances are he isn't running headers or intake, much less a flex fuel kit with a tune, so 93 is what he needs.

The alternative is him spending a lot of money, which he didn't ask us about.

[piening2150]

Originally Posted by ember1205

Executive cash back doesn't include gasoline purchases. :(

Costco VISA -does- and it's 5%.

Learn something new everyday. Oh well, we still apparently buy enough shit from them to make it worthwhile.

[djctoto]

Sunoco is now offering 94 Octane instead of 93 at most locations in New England. Not sure where else but easy to search here:
https://www.sunoco.com/find-a-station

[DamonZ28]

Wow, great info here. I thought that Premium 91 was good enough, and I've been running it for a couple of years. I will switch back to 93 Top Tier (Mobil/Exxon in my area) immediately!