Octane required for big block 8V?

[Cool Runnings]

91?

Been running 93, am I wasting my money?

[rocker59]

Is there a difference in price, in your area, between 91 and 93 ??

In my area, stations randomly have either 91 or 93 as their premium, and prices are about the same.

[Two Checks]

Whatever octane is required to prevent spark knock.

[oldbike54]

 What does the owner's manual call for ???

 Dusty

[rocker59]

What does the owner's manual call for ???

 Dusty

90 (RON+MON)/2

my point was, rare is the occasion where you'll pull up at a station and have the choice of 91 or 93.  The station will have one, but not the other.  And few stations have 90.  At least here in flyover country.

[Lannis]

Whatever octane is required to prevent spark knock.

That's how they determine what octane rating a fuel mixture has, so it should be a good way of determining what to use in your bike.

My owner's manual says 90 octane (using the standard (R+M)/2 rating).    Since I can't buy exactly 90 octane gas typically, I use my judgment to fill with either 89 octane or 91 octane depending on how close to "knocking" my next 200 miles of use might take the motor ....

Seems to work.   Never had any knocking from the motor.

Lannis

[oldbike54]

90 (RON+MON)/2

 Well , there is your answer 

 Dusty

[fanattic]

A local Sunoco station here offers both 91 and 93. 91 is about 10 cents/gal cheaper than most other place's 93.

[rocker59]

Well , there is your answer 

 Dusty

Try finding some 90 here in The Four States.   

Price difference in the premiums is moot.  You pull up and premium will be 91 or 93, and that's it.

This is rare:


This is common:


I've only seen this in Colorado:

[oldbike54]

Try finding some 90 here in The Four States.   

Price difference in the premiums is moot.  You pull up and premium will be 91 or 93, and that's it.

This is rare:


This is common:


I've only seen this in Colorado:

 I agree , but that wasn't the question . Maybe in CR's locale there is a difference in price between 93 and 91 . Oddly enough , where I purchase most of my fuel because the have a separate hose for non ethanol , the only choices are 87 straight gas and 87 or 89  E10  . The owner told me the demand for 91 was so small it wasn't worth the effort .

 Dusty

[Cool Runnings]

Well , there is your answer 

 Dusty

lol 

[Cool Runnings]

I'm going to run 91 (can't drive 55) on my trip.