[Aragorn]

Since I don’t have 93 in my area, I figured I would mix 95 and 91. Is 5.50 a fair price for 95?

[oldman]

How much ethanol in it?

[Aragorn]

Originally Posted by oldman

How much ethanol in it?

“ up to 10% “

[95 imp]

I'd use straight 95. Or, you can put 1 gal of xylene for every 5 of 91 and hit 95 octane.

Or, if you want 93, go 12 gal of 91 and 1 gal of xylene. It would probably be cheaper than 1:1 91/95.

[oldman]

I feel for you, about $1.60 for E85. I don't think it is worth it. Unless you are running boost boost?

[BDPhoto519]

We get 94 octane(10.6% E) at the pump here as our max, and no E85 sadly. I have to make a 10 minute drive over to Detroit to buy some of that glorious & cheap E85 at the pump even with the terrible US exchange rate right now.

But back on topic... The 94 is about $4.20/gal typically here which is about $0.80 more per gallon than the 93 but can run around 24-25 degrees timing daily with no issues. So I find it worth it especially over the 91 options.

[Aragorn]

Yes it’s expensive. Will look into xylene. Found another place with 100o for $10 g.

[TJay74]

Actually mixing in some E85 works just fine for 93/94/95. You can add up to 10% of E85 and it will help with detonation and spark knock.

The tank is 19.8g on the Camaro SS. That means you can add up to 2 gallons of E85 with no issues.

[KingLT1]

Originally Posted by TJay74

Actually mixing in some E85 works just fine for 93/94/95. You can add up to 10% of E85 and it will help with detonation and spark knock.

The tank is 19.8g on the Camaro SS. That means you can add up to 2 gallons of E85 with no issues.

I believe most Pump 93 already has 10% in it...so if you add 10% E85 you will be outside of the ECU's programmed stoich value of 14.07. Ideally you should install a flex sensor for this even though you can run up to E15 and the ECU can correct the fueling.

[Aragorn]

Argh. Still under warranty. Don’t want to void that.

[TJay74]

Originally Posted by KingLT1

I believe most Pump 93 already has 10% in it...so if you add 10% E85 you will be outside of the ECU's programmed stoich value of 14.07. Ideally you should install a flex sensor for this even though you can run up to E15 and the ECU can correct the fueling.

None of our 91 has E10 here in Oklahoma, for the limited 93 we have it doesnt have Ethanol in it either. Texas offers 93 and 93 E10 depending on the area and pumps/station.

I should have said as long as you are running pure gas, but as you said the stock programming can handle E15 just fine which is 3 gallons of E85 on the initial fill.

[TJay74]

Originally Posted by Heater

91 works fine, if you dont have any mods then i would use 91 and dont worry about it.

obviously if you live in a state with 93 you should use 93.

Actually based on data logs, this isnt fully accurate. 91 doesnt work just fine and even 93 doesnt stop knock fully. The LT1 and L86 (truck version) both knock on 91, more so when it is warm outside. 93 does help, but once it gets warm they will knock some on 93 as well.

Adding in some E85 does help, especially when it is warm outside. The cooler the outside weather and air is the better the 91/93 does under normal circumstances.

[KingLT1]

Opposite over here around the great lakes. Anything without Ethanol in it is considered Boat/small engine gasoline and it's normally a single pump that they charge a premium for.

Either way I think that all these newer vehicles should come with a Flex fuel sensor standard because of what you mentioned. A engine will always run the most optimal with fuel that targets it's programmed stoich ratio. If the fuel is outside of that window then your fuel trims start compensating by either going positive or negative. GM should allow it to be added on because you don't have to drastically change the tune to run it. It's like 3 settings in the ECU to activate it. Enable sensor, populate the stoich table accordingly, and populate the flex fuel spark table. You can use the data that GM has for flex fuel equipped vehicles from the factory

[Aragorn]

So nice that these engines were designed to run optimally at 93 yet it’s pretty hard to find. Awesome. ��*♂️