Fuel octane question
 

Is there benefits for gas over 91 octane for a stock LT4?

Where I live I have access to Shell V-Power 91 and Petro-Canada Ultra 94 which I think is like Sunoco 94 in the USA. There is supposed be ethanol in the Ultra 94.

What should I do?

What gas do you feed your beasts?

Yes, per the owners manual, you will have less power and worse gas mileage using 91 vs 93. In your case, I’d happily use the 94.

I use a race fuel concentrate to bring my available 91 to 95.

I’d run the 94 for sure

91 is fine to use. For the track 93 is recommended for increased protection from detonation and the reduced performance due to the ECU pulling timing. You are good with 91.

Depends on your goal...
 

If you carefully read the owners manual it states that you get 650 horse power and 650 pound feet of torque only when using 93 octane . However if your car is stock and will stay stock your car will run just fine on 91 octane however you will have slightly reduced power output . If you plan to modify your car in any significant way you should absolutely use the higher octane fuel .

I get confused by this every fill up. I’m using Shell Vpower but the local pumps are not labeled what octane they are. So I really don’t know if they are 91 or 93. Every other gas stations pumps are clearly labeled. Not Shell...

91 is garbage. It is the bare minimum to be used if you want performance. I would say go with 93 or 94 if that is available. Anything over that is not worth the extra money. Out here in NJ we have some gas stations that have 92 octane and I avoid them like leprosy.

I guess 91 is garbage....because he said so! :noidea:

Related and slightly off topic:

Shell V Power is 99 RON (or so I’ve read). I see the OP mention 91 octane. I was always under the impression that 99 RON was the equivalent of 93 octane?

It was always my intent to use a top tier 93 or higher octane. Have I missed the mark using Shell V power?

91 is garbage because I've used it in the past and each time my car had issues that cleared after a tank and a half of 93. I learned my lesson using the cheaper stuff. And now I spend the money because it isn't worth the hassle. Now if I'm driving long distances, then I'll use the lower octane stuff for most of the trip and then switch to 93 towards the end of the trip. But other than that I won't use it.

Incidentally, my brother, who isn't much of a car guy BTW, tried using 91 octane and called me asking why his car was driving funny. I told him to ride it out and switch back. He did and his problems went away. Now perhaps it's just the stations in my area. But I learned enough to not test it. Especially on a car that I plan to keep past the warranty period.

T O R C O. Use it. Close thread.

HAHA!!
:sign0052:

Helpful

Octane is the fuels resistance to detonation. That’s it! Nothing more. The higher the number the more resistant to detonation. Did you get a knock amp and count the number of times the ecu pulled timing on you when using 91 octane? Your story is anecdotal and without any factual info. Not to mention that it sounds completely ridiculous.