What's in your tank?
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
- it's definitely one of the best docs ever on the topic, especially for those completely unfamiliar with EFI and HD Delphi. It's not pages of droning text, just the high points and some good diagrams / pics, and broken out into nice sections.
Stellar HDF Member
Joined: Jan 2013
Posts: 2,721
Likes: 103
From: St. Louis, MO
Sure glad to share the wealth - it's definitely one of the best docs ever on the topic, especially for those completely unfamiliar with EFI and HD Delphi. It's not pages of droning text, just the high points and some good diagrams / pics, and broken out into nice sections.
- it's definitely one of the best docs ever on the topic, especially for those completely unfamiliar with EFI and HD Delphi. It's not pages of droning text, just the high points and some good diagrams / pics, and broken out into nice sections.This is perhaps the next step along on the understanding, I find the articles by Dr. Dyno interesting as well.
http://www.drdyno.com/AIM_2010-07.html
Seasoned HDF Member
Joined: May 2012
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From: Carlsbad, CA
I run E10 87 octane for the last 3 hundred thousand miles + in all of my bikes which have all versions of H-D offerings from an 883R to a 120R.
They have been through most of the mountain ranges in the US and Canada,through deserts and Death Valley, caught in accident tie ups on the Interstates and never an issue at all.
They get great mpg. But I help them along with oil coolers if not standard equipped, SE wires and iridium plugs, periodic carbon removal, stock exhaust but high flow intakes and a proper AFR. All that makes for a cooler running engine and an uptick in power.
I am not caught up in the nonsense of what type pump or hose there is. I just fill that sucker up and ride baby ride. I did 42,380 in 2015 and saved around $600 over the 93 octane cost in this area.
I have run too many engines for too many miles to even listen to the high octane total BS. EPA/DOT mandates that any vehicle sold to operate on US roads MUST be able to run on 87 octane.
They have been through most of the mountain ranges in the US and Canada,through deserts and Death Valley, caught in accident tie ups on the Interstates and never an issue at all.
They get great mpg. But I help them along with oil coolers if not standard equipped, SE wires and iridium plugs, periodic carbon removal, stock exhaust but high flow intakes and a proper AFR. All that makes for a cooler running engine and an uptick in power.
I am not caught up in the nonsense of what type pump or hose there is. I just fill that sucker up and ride baby ride. I did 42,380 in 2015 and saved around $600 over the 93 octane cost in this area.
I have run too many engines for too many miles to even listen to the high octane total BS. EPA/DOT mandates that any vehicle sold to operate on US roads MUST be able to run on 87 octane.
Stellar HDF Member
Joined: Jan 2013
Posts: 2,721
Likes: 103
From: St. Louis, MO
I run E10 87 octane for the last 3 hundred thousand miles + in all of my bikes which have all versions of H-D offerings from an 883R to a 120R.
They have been through most of the mountain ranges in the US and Canada,through deserts and Death Valley, caught in accident tie ups on the Interstates and never an issue at all.
They get great mpg. But I help them along with oil coolers if not standard equipped, SE wires and iridium plugs, periodic carbon removal, stock exhaust but high flow intakes and a proper AFR. All that makes for a cooler running engine and an uptick in power.
I am not caught up in the nonsense of what type pump or hose there is. I just fill that sucker up and ride baby ride. I did 42,380 in 2015 and saved around $600 over the 93 octane cost in this area.
I have run too many engines for too many miles to even listen to the high octane total BS. EPA/DOT mandates that any vehicle sold to operate on US roads MUST be able to run on 87 octane.
They have been through most of the mountain ranges in the US and Canada,through deserts and Death Valley, caught in accident tie ups on the Interstates and never an issue at all.
They get great mpg. But I help them along with oil coolers if not standard equipped, SE wires and iridium plugs, periodic carbon removal, stock exhaust but high flow intakes and a proper AFR. All that makes for a cooler running engine and an uptick in power.
I am not caught up in the nonsense of what type pump or hose there is. I just fill that sucker up and ride baby ride. I did 42,380 in 2015 and saved around $600 over the 93 octane cost in this area.
I have run too many engines for too many miles to even listen to the high octane total BS. EPA/DOT mandates that any vehicle sold to operate on US roads MUST be able to run on 87 octane.
Twin cam Harleys have a pretty ingenious Ion knock detection which uses no extra sensors - see more details here. Because the way this system works, I only use HD wires and plugs, as I don't want to vary resistance from what the ION system is designed to use.
https://www.hdforums.com/forum/engin...explained.html
However, same as the Vette, if timing is being pulled, performance will suffer.
My manual specifies 91 octane in my 2003 but I just didn't notice any difference with regular in either performance or mileage so I run 87. With 9.0 compression I can't see how it could ever need premium, that's pretty low compression in today's world.
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Joined: Jun 2014
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From: 90210
^^ also it will depend on the dynamic (operating) compression of the motor, as dictated by the cam intake close event. I believe the 120's intake cam is not overly aggressive on dynamic compression even with the 10.5:1 static ratio.
and yes the Delphi EFI does a lot better job of compensating for lower octane fuel, knock events, E10 vs straight gas, etc. - it won't be a problem (short term).
But personally I always run 91. If for no other reason it's just what I'm used to running in all of my bikes. But then again all the bikes I've had are designed for it.
and yes the Delphi EFI does a lot better job of compensating for lower octane fuel, knock events, E10 vs straight gas, etc. - it won't be a problem (short term).
But personally I always run 91. If for no other reason it's just what I'm used to running in all of my bikes. But then again all the bikes I've had are designed for it.
Last edited by LA_Dog; Feb 12, 2016 at 02:11 AM. Reason: clarification
Outstanding HDF Member
Joined: Jun 2014
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From: 90210
Higher octane fuel requires more heat / precision to burn correctly. If the car/bike is designed to burn 87, it will not burn 93 correctly. Gas mileage will suffer. The inability of the engine to burn higher octane gas correctly will cause the engine to produce less power and will require more fuel to perform at the same level.
It is ok to put 87 in an engine designed for high octane, or high octane in a low octane engine in a pinch / emergency. The car / bike will run and you'll get where you need to go. While the engine may seem like it is running ok, be assured it is not. Fortunately, it usually takes continued and sustained abuse of running an incorrect octane to cause issues.
All that said- some engines are much more forgiving than others / less prone to long term damage with running an incorrect octane by nature of their design.
Thread Starter
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Ultimate HDF Member
Joined: Jul 2014
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From: MASS_hole
this page was a fun read and very intuitive as well. Thanks for the links also guys. Been busy here and haven't had the time to ingest them accordingly. Saving them for later in the week.
Thanks again and glad you guys are here.
Thanks again and glad you guys are here.
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Outstanding HDF Member
Joined: Jun 2014
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From: 90210
Here's an interesting short read (pdf) on fuel types and testing results by Virginia Military Institute, using a dyno and powervision. American Motorcycle, American Fuel
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
some additional fun and entertaining info:
Air/Fuel (A/F) Ratios of Common Fuels
Fuel-------------------A/F---Lambda (λ)
Gas Stoichiometric-- 14.7 -- 1.000
Gas Max Power Rich-- 12.5 --0.8503
Gas Max Power Lean-- 13.23 --0.900
E10 Stoichiometric-- 14.08 --1.000
E10 Max Power Rich-- 12.0 -- 0.8523
E10 Max Power Lean-- 12.70 --0.9020
E15 Stoichiometric-- 13.79 --1.000
E15 Max Power Rich-- 11.75 --0.8521
E15 Max Power Lean-- 12.43 --0.9018
E85 Stoichiometric-- 9.765 --1.000
E85 Max Power Rich-- 6.975 --0.7143
E85 Max Power Lean-- 8.469 --0.8673
Ethanol Stoichiometric-- 9.00 -- 1.000
Ethanol Max Power Rich-- 6.43 -- 0.7137
Ethanol Max Power Lean-- 7.8 -- 0.8659
Methanol Stoichiometric-- 6.45 --1.000
Methanol Max Power Rich -- 4.0 -- 0.620
Propane Stoichiometric -- 15.7 --1.000
Propane Max Power Rich-- 13.18 --0.8395
Air/Fuel (A/F) Ratios of Common Fuels
Fuel-------------------A/F---Lambda (λ)
Gas Stoichiometric-- 14.7 -- 1.000
Gas Max Power Rich-- 12.5 --0.8503
Gas Max Power Lean-- 13.23 --0.900
E10 Stoichiometric-- 14.08 --1.000
E10 Max Power Rich-- 12.0 -- 0.8523
E10 Max Power Lean-- 12.70 --0.9020
E15 Stoichiometric-- 13.79 --1.000
E15 Max Power Rich-- 11.75 --0.8521
E15 Max Power Lean-- 12.43 --0.9018
E85 Stoichiometric-- 9.765 --1.000
E85 Max Power Rich-- 6.975 --0.7143
E85 Max Power Lean-- 8.469 --0.8673
Ethanol Stoichiometric-- 9.00 -- 1.000
Ethanol Max Power Rich-- 6.43 -- 0.7137
Ethanol Max Power Lean-- 7.8 -- 0.8659
Methanol Stoichiometric-- 6.45 --1.000
Methanol Max Power Rich -- 4.0 -- 0.620
Propane Stoichiometric -- 15.7 --1.000
Propane Max Power Rich-- 13.18 --0.8395