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Cradle Robber
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Discussion Starter · #1 ·
I don't think so. The higher level means that the gasoline can be compressed more before igniting on its own. The compression ratio of your engine is still the same therefore no horsepower gain, right?
 

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yes and no. if you throw in high octane, but don't do anything to compensate it will do nothing and probably even slow you down. if you advance the ignition timing and/or lean out your fuel settings you can make more power though on higher octane fuel.
 

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Higher octane fuel won't do you anything unless you can burn it. The higher the octane of the fuel, the slower it burns. Basically, you want to run the lowest octane fuel you can get away with. Your cars timing is optimized for premium unleaded, but will compensate for lower octane gas (a little less performance). Now if you had high compression, advanced timing, lots of boost or nitrous you may benefit from running higher octane fuel. In the end don't waste your money if you don't have to.
 

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Boost Withdrawl... :(
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well if youre running high PSI's of boost then it will be beneficial..if you have simple bolt ons theres really no need for higher octane but at the same time you also dont want to go below the manufacturers recommended octane rating
 

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Cradle Robber
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Discussion Starter · #7 ·
Right, I was taking the case of a stock 5th gen lude, which I have.
 

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MugenPoweredLude said:
well if youre running high PSI's of boost then it will be beneficial..if you have simple bolt ons theres really no need for higher octane but at the same time you also dont want to go below the manufacturers recommended octane rating
the knock sensor will retard your timing so your motor isn't damaged, but you will run better on premium unleaded. I doubt regular gas will hurt your motor, I'm sure there are people who put regular in their ludes every fill.
 

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Even cars that come from the factory "optimized" for lower octanes benefit from higher octane. There are plenty of dyno plots that prove this. It is minimal, but it is something. I know I saw one recently on the 02 Civic Si and also one for the 350z I believe.
 

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1995 VTi-R 5spd
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The 5th gen ludes in Australia come optimised for premium unleaded (I think). I know that the RSX (Integra) Type-R is optimised for premium fuel here which means 96RON.

I run 98 RON all the time, but that more because I use BP Ultimate 98RON which has 10 times lower sulfur than regular fuel. To compensate, I have my ignition timing set to 18deg BTDC instead of 16deg. The car is factory tuned to run on 91RON regular, but now if I run on that, the engine will ping, guaranteed. I seem to get away with 96RON even in hot weather.
 

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98 RON? what's that octance?

No putting higher octane in your car does not influence performance, but it does allow you to reach higher compression ratios in your car, as well as altering your detenation timing.

The higher octance reading indicates higher burning temperature. If your your factory CR is like 10.25:1 (I don't know?) and you want to raise it to 11.00:1, then the compressed air temperature at TDC will be higher than if it were factory CR. Then you would need to use higher octane gas or your cylinders would detonate before the spark plugs ignite the mixture resulting in .... an engine replacement.

Even though I could probably get away with 89 or 91, I wouldn't want to jeoperdize my car.
 

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ryuryu said:
98 RON? what's that octance?


he lives in australia and they use a different octane rating system there along with all the other countries. that's why everyone thinks JDM motors in the US can't peform the same when infact 98 RON is 93 octane in the US.
 

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1995 VTi-R 5spd
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ryuryu said:
98 RON? what's that octance? ...B]


RON is octane level. Stands for Research Octane Number. So yes that 98 octane fuel. Really I could run about 5-6 deg more ignition advance without problems but I'm too paranoid.
 

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1995 VTi-R 5spd
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AccordSleeper said:




he lives in australia and they use a different octane rating system there along with all the other countries. that's why everyone thinks JDM motors in the US can't peform the same when infact 98 RON is 93 octane in the US.
Cool, didn't know that the US has a different way of measuring Octane rating. But found this article that explains it better.

http://www.btinternet.com/~madmole/Reference/RONMONPON.html
 
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