When i first bought my cruiser i was using 93. Then i switched to Regular 87. I noticed a slight knock during start up now but it goes away after a while.
87 for the most part. But, as said above, the cheapest I can find. I have never had any knocks. These beasts need quantity, and I haven't noticed any difference when using higher quality/octane gas.
Elsie is normally aspirated hence she gets either regular 87 Shell or Chevron and a shot of Lucas fuel additive every other $80 tankful. If I'm pulling a trailer I'll sometimes drop in the 89/91 grade stuff but it kinda depends on your engine (knocking). As a rule I go with the owners manual (87) and run the 89/91 stuff if really needed (knocking).
I use 100% gas, 91 octane, after 10 years of extensive testing. I get better gas milage, however slight, and its cheaper to drive in the long run. Usually, the premium gas is 20 cents per gallon more expensive, which equals $4.20 for 21 gallons. I tend to get about 20 to 30 more miles out of a tank using the premium grade, which is about 2 gallons of gas worth, and at $3.80 a gallon that equals $7.60. So, by using the 91 octane, I save $3.40 per fill up, and I look like I have money at the pump. Still hasn't worked with the ladies yet but I'm hoping
