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What's the difference between gasoline octanes?
- Thread starter dpk777
- Start date
Octane level indicates the fuel's resistance to detonation. The lower the number, the easier it detonates. Conversely, the higher the number the more it resists detonation.
WinkOsmosis
Banned
More octane makes your Honda faster.
LOL.
Bignate603
Lifer
Bingo, you should read your owner's manual and see the reccomended minimum octane, and use that or higher. It's my understanding that you won't see any performance difference if you use higher octane.
WinkOsmosis
Banned
Wtf? That's illegal.
If I ever found out the 93 octane I put in my car is 87...
Not really, if your car doesn't require higher octane gas you'll not gain anything from running it and if anything might get immeasurably lower gas mileage from it. If you're not running a hot spark advance (set or computer induced) or have forced induction (or high compression for another reason) or something you probably don't need it. If I don't run it in my car I'd probably break a ring land or something.
FrustratedUser
Lifer
It is both an experimental and theoretical value describing the equivalent percentage of Octanol in the gas.
100 Octane fuel has the same detonation properties as 100% Octane. 87 Octane has the same properties as if 87% of the fuel were Octanol.
Gas is made of HydroCarbons with between 6 and 8 carbon atoms in the molecule. (8 = Octagon = 8 sides <=> 8 carbon atoms)
In the old days gas were produced by distilling oil and in the 20's / 30's the Octane rating were around 30 (pleae correct me). Nowadays the long hydrocarbons are 'cracked' very accurately to produce more of the 8 fold HC.
100 Octane fuel has the same detonation properties as 100% Octane. 87 Octane has the same properties as if 87% of the fuel were Octanol.
Gas is made of HydroCarbons with between 6 and 8 carbon atoms in the molecule. (8 = Octagon = 8 sides <=> 8 carbon atoms)
In the old days gas were produced by distilling oil and in the 20's / 30's the Octane rating were around 30 (pleae correct me). Nowadays the long hydrocarbons are 'cracked' very accurately to produce more of the 8 fold HC.
WinkOsmosis
Banned
What about 110 octane?
HappyPuppy
Lifer
Stuff.
FrustratedUser
Lifer
The higher Octane fuel can deliver more power only if you increase the compression ratio or use forced induction.
Higher Octane = less prone to detonate ---> you can run higher compression which in turn gives more power.
Slightly OT but the main reason some racing series use Methanol as fuel is that Methanol has higher Octane rating (it does not contain any Octane), well above 100, so they can run higher boost and compression. At the same time the Methanol is an excellent coolant for the engine. The fresh fuel cools the intake (and the rest of the engine). The exhaust gas temperaturte is also cooler (around 300C).
If you dont believe the cooling part there is an easy way to show this. Wet your finger in alcohol. It feels really cold right!?
Do the same with gasoline. Not as cold right!?
Octane level increases were made by adding tetra-ethyl lead to gasoline back in the day. That is why some of us remember the phrase "fill it up with ethyl".
Not only did TEL increase octane, it had the effect of lubricating the valve seats and valves.
Sunoco 210 was/is the shnitz - 108+ octane for those hi-compression V8's.
Not only did TEL increase octane, it had the effect of lubricating the valve seats and valves.
Sunoco 210 was/is the shnitz - 108+ octane for those hi-compression V8's.
FrustratedUser
Lifer
It corresponds to 110% Octanol. Sounds stupid right. The scale is extrapolated, probably linear (I am out on a limb here).
Methanol has +100 Octane, yet it contains no Octanol.
Actually, despite WinkOzzie's facetious comment, it's actually true for some Honda engines. My friend's H22A Prelude drinks premium only... he was a clueless consumer and put regular in it... got horrible mileage, bad power, etcetc. Same deal with a friend that had bought a 2k Eclipse GT... I was like :Q
in both cases... I run only 93 in my GST, don't have the need for 94 or race gas on the tiny hairdryer.
110 Octane rating fuels such as race gasolines and other fuels (ie C-16) basically are 10% more resistant to detonation in comparison to 100% Octane fuel.
FrustratedUser
Lifer
Well, actually Methanol is an alcohol too. Try it with etanol or methanol, the cooling effect feels the same and is the same effect.
The 'ol'at the end means that the HC chain contains an OH molecule instead of an H atom.
H H
| |
H-C-C-OH <--- Ethanol.
| |
H H
H
|
H-C-OH <--- Methanol.
|
H
For the sake of it we can make an alcohol with Octane, called Octanol.
H H H H H H H H
| | | | | | | |
H-C- C- C- C- C- C- C- C- OH <--- Octanol
| | | | | | | |
H H H H H H H H
Well you didn't say "stick your fingers in an alcohol" you said "stick your fingers in alcohol". What is commonly referred to as alcohol is actually ethyl alcohol, or ethanol.
And yah, I know that any basic alkyl with a hydroxyl as its major functional group is an alcohol - i owned orgo!!! I'm just being nit-picky.
😛
Edit: you should've used shorthand notation! look at how the quote got messed up!
FrustratedUser
Lifer
Well, in this case Methanol or alcohol (etahnol) doesn't matter in this case. We both know what we meant 😉
WTH is shorthand notation. I used the magic trick of the
floating 😀
smiley!
WTH is shorthand notation. I used the magic trick of the
floating 😀
smiley!
I don't doubt that alcohol cools the engine better than gasoline, as you seem to know what you are talking about...however, (and correct me if I'm wrong), isn't the reason wetting your finger with alcohol will make it cold, is because it evaporates more quickly than gasoline, thus taking energy from your finger? And how would this have any effect inside an engine? Unless it's evaporating while it's inside...😕
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