Author Topic: Octane... does it make a difference in power?  (Read 1539 times)

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Offline connie_rider

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Re: Octane... does it make a difference in power?
« Reply #25 on: June 07, 2018, 10:26:12 pm »
I called it premium instead of saying 91+ as I consider them the same.
The sticker on my gas actually sez to use 90+..

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Offline Egodriver71

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Re: Octane... does it make a difference in power?
« Reply #26 on: June 08, 2018, 10:15:19 am »
I use 91+, but would use 89 if it is safe for the motor.   I'm surprised it requires 91+.    Have any of you used anything other than 91+ for years / miles ?

I ran 87 here in FL until I installed the ZX-14 exhaust, then I got a noticeable ping with throttle roll on in the lower rpm range.

Switched to 93 never looked back.  Difference here is about $1.00 per tank in the C14
Thomas Mann
Jacksonville, FL

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Offline Daytona_Mike

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Re: Octane... does it make a difference in power?
« Reply #27 on: June 08, 2018, 02:18:11 pm »
I use 91+, but would use 89 if it is safe for the motor.   I'm surprised it requires 91+.    Have any of you used anything other than 91+ for years / miles ?

I ran 87 here in FL until I installed the ZX-14 exhaust, then I got a noticeable ping with throttle roll on in the lower rpm range.

Switched to 93 never looked back.  Difference here is about $1.00 per tank in the C14
Interesting. I wonder if your engine went lean with the ZX14 pipe?  Is your bike reflashed?
Normally aspirated engines have perpetual turbo lag
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2011  KLR650   688 piston ported and polished
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Offline Roger B

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Re: Octane... does it make a difference in power?
« Reply #28 on: June 08, 2018, 02:21:10 pm »
If Cliff could of ran 89 instead of "Premium" could of paid for 3 sets of tires.   40mpg, 20 cents / gallon, equals $1,000.

Offline smokin

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Re: Octane... does it make a difference in power?
« Reply #29 on: June 09, 2018, 01:57:13 am »


Steve didn't you see something similar regarding Australian fuel versus USA fuel in a previous situation?


  I couldn't pin anything down. I looked at the stoic values of pure gas and 10% ethanol fuel. there's a .5 difference, about 3-4% . A little more research indicated that the specipic gravity is about 4% heavier with pure gas. I adjusted my fuel maps to reflect that. Feedback has been positive.







What ever magic you performed Steve it certainly made a difference to our Aussie GTR 1400's.Outstanding results.


Offline Egodriver71

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Re: Octane... does it make a difference in power?
« Reply #30 on: June 11, 2018, 10:34:55 am »
I use 91+, but would use 89 if it is safe for the motor.   I'm surprised it requires 91+.    Have any of you used anything other than 91+ for years / miles ?

I ran 87 here in FL until I installed the ZX-14 exhaust, then I got a noticeable ping with throttle roll on in the lower rpm range.

Switched to 93 never looked back.  Difference here is about $1.00 per tank in the C14
Interesting. I wonder if your engine went lean with the ZX14 pipe?  Is your bike reflashed?

It is now, but I haven't ridden it since the installation of the new flash.

Also, I went with the early ZX header without the built in cat.

I don't doubt the mixture leaned out a bit, but it otherwise runs great.
Thomas Mann
Jacksonville, FL

COG #8321

1930 Indian 101 Scout (the first bike)(still in the garage)
1986 Yamaha Radian (the first modern bike)(Sold)
1996 Kawasaki Vulcan 500LTD (the wife's first bike)
1996 Kawasaki Eliminator (Wife's)
1999 Kawasaki Concours (The Warbird)
2006 Kawasaki Vuclan 900 (Wife's)
2009 Kawasaki Concours 14 (Totaled)
2009 Kawasaki Concours 14 (Second Chance)

Offline Daytona_Mike

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Re: Octane... does it make a difference in power?
« Reply #31 on: June 11, 2018, 12:42:44 pm »
So based on that dyno  I wil be running 89 instead of 91.
Question:  I thought normally torque and HP always cross at about 5200RPM. Whats different here or did I miss something?
Normally aspirated engines have perpetual turbo lag
2000 Red C10 1052 kit
2008  C14 Silver Dammit Full AreaP- Flies are put back in SISF_Flash
2011  KLR650   688 piston ported and polished
2011  KTM 530    This thing is FUN!!

Offline Colt45

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Re: Octane... does it make a difference in power?
« Reply #32 on: June 11, 2018, 12:47:03 pm »

I've been riding a C14 for four years, have yet to see a reasonable explanation for why I need to use premium fuel other than "the manual says so." (although Steve's response above that it's smoother is a darn good reason for me to continue to use 92+). 

Most likely it is because there is some combination of heat, load and RPM that will cause spark knock on some versions of 89 pump octane and 91+ is just the next available increment. 

In the US, pump octane is the average of Motor Octane and Research Octane.  It is possible, mathematically, to have a fuel with a pretty good Research Octane of 95 and a pretty abysmal Motor Octane of 83 and still get to call it 89.  I think it was my '87 Mustang that would ping on BP 89, but not on Conoco 89 octane. 

Octane rating is the equivalent resistance to spark knock of that percentage of octane in an octane/heptane mix. 
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Offline Steve in Sunny Fla

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Re: Octane... does it make a difference in power?
« Reply #33 on: June 11, 2018, 10:26:12 pm »
So based on that dyno  I wil be running 89 instead of 91.
Question:  I thought normally torque and HP always cross at about 5200RPM. Whats different here or did I miss something?

  They do cross an 5252,  I have the torque rendered on a different scale on the right side of the graph. I should have re- rendered before I posted, but I use the graphs this way so I can make of more of the torque changes because it's a larger graph.  Steve
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Offline TinDog

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Re: Octane... does it make a difference in power?
« Reply #34 on: June 13, 2018, 04:28:26 pm »
I just noticed your test dates and that they were 5 weeks apart from each other.  I believe that most - if not all - of the country uses seasonally adjusted fuel blends to help address pollution from evaporating gas.   Could your 89 octane test have been run using end-of-season winter blend, and could THAT be what the graph is showing rather than [just] octane differences?


https://www.eia.gov/todayinenergy/detail.php?id=11031

Offline Steve in Sunny Fla

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Re: Octane... does it make a difference in power?
« Reply #35 on: June 13, 2018, 04:30:23 pm »
I just noticed your test dates and that they were 5 weeks apart from each other.  I believe that most - if not all - of the country uses seasonally adjusted fuel blends to help address pollution from evaporating gas.   Could your 89 octane test have been run using end-of-season winter blend, and could THAT be what the graph is showing rather than [just] octane differences?


https://www.eia.gov/todayinenergy/detail.php?id=11031

  I'm in Florida, and I think the dates were more like 2-3 weeks apart. If one of them says "2008" it's because my laptop went wonky... I've since fixed it.  Steve
C-14 ECU flashing for performance and rideability enhancement
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