Rocket Fuel
Road Master
Joined: Jun 2010
Posts: 913
Likes: 0
So why does my Miata recommend Premium fuel - It`s not exactly a hi-perf car and I`m sure it does`nt have hi compression pistons - but the manual says premium - I don`t get it but have I been wasting my money for nothing and not getting any chicks for free?
Road Master
Joined: Jul 2010
Posts: 798
Likes: 4
From: southern MO
you said and i quote "higher octane fuels burn slower and create no more hp" or something like that... thats totally bogus info you could have a 71 pinto running on 3 cylinders and higher octane fuel would make it create more power.. not saying that his bike is going to run a 9 second quarter but it will create more power with higher octane..put 87 octane in your bike then put 92...just regular pump gas from both spectrums and see if higher octane fuel doesnt make a diff...im just saying higher octane fuel DOES make a diff no matter what your driving
Elite HDF Member
Joined: Dec 2008
Posts: 3,947
Likes: 1
From: Little Apple, Iowa, U.S.S.A.
I got out of racing a few years ago. It's why I have a Harley today. Having built several race cars and engines over 30 years, I gotta say that this thread is pretty entertaining. The great octane debate even surpasses other controversial topics such as nitrous oxide ("noss" as the kiddies say) and stall converters.
There is a lot more to determining proper octane of fuel you need than just static compression. Today more than ever this is true with the ignition programs and what not. I knew the dealership was just trying to cover their asses when they told me; "You need to run 93 octane". I knew better. I didn't even bother to discuss it. Sorry, but at 9:1, nope. When I have had to run under 89 octane due to lack of choice, my bike feels a little better. It does however, run hotter. I can feel it.
Based on the information I have gotten over the years, not from the internet or magazines (yes, both are full of **** more often than not), but from people who know more than any of us on this thread, octane does NOT increase hp. It allows the engine to produce the power output that is already there. If you have a 13:1 engine and you finally took the plunge to go from say, 90 something to 103 octane, I would expect it would run better because relatively speaking, it ran like **** before that.
Professionals have a dyno for a reason and trust me, it's not to see the big numbers hacks like to plaster on the covers of their magazines. They are for baselines, making changes, and results. One more thing to remember too... 110 octane in brand X, may not be the same as 110 octane in brand Z. Chemical composition makes a difference from blender to blender. Oh, ya, and one last thing, not all race gas is leaded.
There is a lot more to determining proper octane of fuel you need than just static compression. Today more than ever this is true with the ignition programs and what not. I knew the dealership was just trying to cover their asses when they told me; "You need to run 93 octane". I knew better. I didn't even bother to discuss it. Sorry, but at 9:1, nope. When I have had to run under 89 octane due to lack of choice, my bike feels a little better. It does however, run hotter. I can feel it.
Based on the information I have gotten over the years, not from the internet or magazines (yes, both are full of **** more often than not), but from people who know more than any of us on this thread, octane does NOT increase hp. It allows the engine to produce the power output that is already there. If you have a 13:1 engine and you finally took the plunge to go from say, 90 something to 103 octane, I would expect it would run better because relatively speaking, it ran like **** before that.
Professionals have a dyno for a reason and trust me, it's not to see the big numbers hacks like to plaster on the covers of their magazines. They are for baselines, making changes, and results. One more thing to remember too... 110 octane in brand X, may not be the same as 110 octane in brand Z. Chemical composition makes a difference from blender to blender. Oh, ya, and one last thing, not all race gas is leaded.
Last edited by Ratster; Sep 6, 2010 at 07:55 AM.
You reach a point of diminishing returns though. Once the octane is sufficient to support complete combustion, determined primarily by compression ratio (unless forced induction is used), no further improvement will be obtained by additional octane. IOW, you won't turn a Harley into a Hayabusa by filling it with race fuel. It may help if you get bad fuel, and it may cool things down a bit if you're running on the ragged edge, but that's it.
Last edited by Mr. Lucky; Sep 6, 2010 at 11:50 AM.
Ultimate HDF Member
Joined: Mar 2008
Posts: 7,604
Likes: 38
From: Landrum, SC , elevation 986'
if ya want to have a blast, get some 106 octane (sometimes its higher, no matter!) and put that into your tank, I find if I mix it 50/50 with premium, its like cocaine for motorcycles!! costs around 6-7.00 a gallon but when you mix it it brings the cost down. bike starts better, runs cooler, more power, exhaust smells good, can't make it ping if ya tried to start out in 6th. downside is, just like cocaine, you get addicted to it really fast, and it starts a bad habit!! got to call my gas connection, going riding this morning!!
Hi I'm Eddie and I used to be a addict.....Sometimes I still fall off the wagon.
Sorry man but that was great.
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Ultimate HDF Member
Joined: Mar 2008
Posts: 7,604
Likes: 38
From: Landrum, SC , elevation 986'
Racing gas bought from race shops (104 to 118 octane) is leaded fuel. Lead will contaminate (kill) the Catalytic converters and 02 sensors. FI systems rely on the O2 sensors to control the amount of fuel that is injected. Vehicle won't pass emissions testing and will throw codes. I run blended fuel in my old Chevy with built 502 in it. It does make a huge difference in performance and smells sooooo good.
I have seen unleaded 100 octane at some filling stations in the past.
I have seen unleaded 100 octane at some filling stations in the past.
Road Captain
Joined: Aug 2009
Posts: 619
Likes: 3
From: In Garage
That is so true. The higher the octane the slower the burn. You dont want the burn to dump out the exhaust would you. The lower the octane the faster and more complete. I laugh at the guys that run the cam 2 fuel and think its better or makes there bike faster. Meanwhile they are burning there exhaust valves, but who cares it smells cool right?
Idiots.
I run my fuel with rocket fuel additive and shot of lead additive. as for my O2 sensors and lead well I rather replace O2 then engine parts.