Octane Boost
Seasoned HDF Member
Joined: May 2012
Posts: 32,934
Likes: 36,027
From: Carlsbad, CA
Think what you want. But, when Im on a trip, occasionally I've only been able to get 87 octane. Yes, that happens if you ever ride out of a metropolitan area. Sequoia national park, Death Valley, were recent experiences. Then if I add 1oz of Lucas octane boost per gallon of gas...the bike runs better. This was very noticeable on my TrGlide that had SE255 cams, and a performance tune. Thats my experience. If its snake oil fine...this snake oil does what I need.
oh yeah, Ive never said octane or octane boost gives you more power.
edit: Id love to see us put this to bed, on a dyno as follows:
Running a fully stock Harley M8, in identical (blind) test conditions on each test as follows:
- top tier 93 octane
- top tier 91 octane
- top tier 87 octane
- same gas as the 87 octane, and add 6 oz of Lucas Octane boost.
My hypothesis: The 93 octane run will produce the most power, with a reduction running 91, then a further reduction running 87. Then the 87 with octane boost will produce more power than the plain 87 octane.
Why; The higher octane allows the ECU to advance the spark more before backing it off to reduce pre-detonation.
Who wants to bet the cost of the dyno runs on this experiment. Looser(s) pay the cost of the dyno, and beers & grub for all in attendance.
oh yeah, Ive never said octane or octane boost gives you more power.
edit: Id love to see us put this to bed, on a dyno as follows:
Running a fully stock Harley M8, in identical (blind) test conditions on each test as follows:
- top tier 93 octane
- top tier 91 octane
- top tier 87 octane
- same gas as the 87 octane, and add 6 oz of Lucas Octane boost.
My hypothesis: The 93 octane run will produce the most power, with a reduction running 91, then a further reduction running 87. Then the 87 with octane boost will produce more power than the plain 87 octane.
Why; The higher octane allows the ECU to advance the spark more before backing it off to reduce pre-detonation.
Who wants to bet the cost of the dyno runs on this experiment. Looser(s) pay the cost of the dyno, and beers & grub for all in attendance.
Last edited by TriGeezer; Jun 6, 2019 at 05:22 PM.
Club Member
Joined: Mar 2016
Posts: 11,678
Likes: 22,162
From: Clearwater, Idaho
Think what you want. But, when Im on a trip, occasionally I've only been able to get 87 octane. Yes, that happens if you ever ride out of a metropolitan area. Sequoia national park, Death Valley, were recent experiences. Then if I add 1oz of Lucas octane boost per gallon of gas...the bike runs better. This was very noticeable on my TrGlide that had SE255 cams, and a performance tune. Thats my experience. If its snake oil fine...this snake oil does what I need.
oh yeah, Ive never said octane or octane boost gives you more power.
edit: Id love to see us put this to bed, on a dyno as follows:
Running a fully stock Harley M8, in identical (blind) test conditions on each test as follows:
- top tier 93 octane
- top tier 91 octane
- top tier 87 octane
- same gas as the 87 octane, and add 6 oz of Lucas Octane boost.
My hypothesis: The 93 octane run will produce the most power, with a reduction running 91, then a further reduction running 87. Then the 87 with octane boost will produce more power than the plain 87 octane.
Why; The higher octane allows the ECU to advance the spark more before backing it off to reduce pre-detonation.
Who wants to bet the cost of the dyno runs on this experiment. Looser(s) pay the cost of the dyno, and beers & grub for all in attendance.
oh yeah, Ive never said octane or octane boost gives you more power.
edit: Id love to see us put this to bed, on a dyno as follows:
Running a fully stock Harley M8, in identical (blind) test conditions on each test as follows:
- top tier 93 octane
- top tier 91 octane
- top tier 87 octane
- same gas as the 87 octane, and add 6 oz of Lucas Octane boost.
My hypothesis: The 93 octane run will produce the most power, with a reduction running 91, then a further reduction running 87. Then the 87 with octane boost will produce more power than the plain 87 octane.
Why; The higher octane allows the ECU to advance the spark more before backing it off to reduce pre-detonation.
Who wants to bet the cost of the dyno runs on this experiment. Looser(s) pay the cost of the dyno, and beers & grub for all in attendance.
I want to be clear. Yours isn't the type of situation I was addressing in my post above. I was talking about the guys who are running stock bikes on 93 octane gas who get a magical 15 extra "sotp" horsepower with a little added octane booster.
Seasoned HDF Member
Joined: May 2012
Posts: 32,934
Likes: 36,027
From: Carlsbad, CA
Right...that aint gonna happen.
Club Member
Joined: Mar 2016
Posts: 11,678
Likes: 22,162
From: Clearwater, Idaho
I'm guessing you missed the sarcasm....
Without changing ignition timing you actually make more power with lower octane fuel. (assuming you're not getting spark knock). If you bike runs good on 93 octane and you are not getting spark not you will NOT benefit from running octane boost.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider
Verdad Gallardo
Road Master
Joined: May 2012
Posts: 865
Likes: 159
From: Vermont
The ECU will only PULL timing when it detects knock. It will not increase timing beyond what is written into the spark tables because it senses fuel with higher octane. You could put race gas in the bike and NOT see an increase in performance unless you were to flash some advance into the spark table to take advantage of the higher octane fuel.. Notice that i said higher octane fuel and not better fuel. Higher octane does not always mean "better"
Road Warrior
Joined: May 2025
Posts: 1,281
Likes: 657
From: Eastpointe, MI
Add me to the it's snake oil consensus of octane boosters
Same with premium gas.
Some premium gas is even octane boosted with ethanol.
The same ethanol we all tried to avoid because of the way it hardens plastic and rubber hoses.
I use ethanol neutralizers like Startron Starbrite or Seafoam or even blue Stabil - some might consider those snake oil.
Regular gas and an ethanol neutralizer.
Red stable in the winter.
But I don't swear by any one brand. Many do. They love Starbrite and think Seafoam's garbage or vice versa. I don't think the brand matters that much.
My chainsaws have warning stickers on them. "Do not use premium gas" and "Premium gas may cause overheating".
I don't think it's necessary or desirable.
My 2 cents.
Same with premium gas.
Some premium gas is even octane boosted with ethanol.
The same ethanol we all tried to avoid because of the way it hardens plastic and rubber hoses.
I use ethanol neutralizers like Startron Starbrite or Seafoam or even blue Stabil - some might consider those snake oil.
Regular gas and an ethanol neutralizer.
Red stable in the winter.
But I don't swear by any one brand. Many do. They love Starbrite and think Seafoam's garbage or vice versa. I don't think the brand matters that much.
My chainsaws have warning stickers on them. "Do not use premium gas" and "Premium gas may cause overheating".
I don't think it's necessary or desirable.
My 2 cents.
Last edited by Robertbc3141; Jun 1, 2025 at 07:28 AM.