Originally Posted by BillBoost37
Originally Posted by vital49
Nope. You will gain nothing from it other than a lighter wallet which may make you go a tiny bit faster.
IIRC other members with L27 and L36'* have mentioned seeing slight mileage gains from higher octane fuel.
SingsCountry1967 comes to mind, totally stock
Yes I did state that. Unfortunately, I'll need to retract that statement about the N/A at this point in time and I apologize for that. The car I found that out on was not the Bonnie. I made the error of assuming it was the same with all cars. It was with my 92 Cadillac, which likely required the higher octane.
I'm conducting experiments right now... it will take me at least a month or so (one tank per week) before I can make conclusions. I'm trying to keep the variables the same which may be difficult if the weather turns nasty (i.e. longer idleing time) and if the gas mixture changes (I usually see a drop in mpg around October. I have NOT seen it yet this year).
89 (midgrade) DIC MPG: 25.5 Calculated MPG: 24.5
1st tank: 87 (low grade) DIC MPG: 25.5 Calculated MPF: 23.0 (???)
2nd tank: 87 - tbd