Results 51 to 59 of 59
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07-18-2019, 11:12 AM #51
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07-18-2019, 11:24 AM #52
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07-18-2019, 11:38 AM #53
way to put your james bond hat on
'06 Supra Launch 20SSV-gone but never forgotten
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07-18-2019, 12:24 PM #54
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08-02-2019, 03:29 PM #55Senior Member
- Join Date
- Aug 2015
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- Spokane, WA
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The HP increase comes from the timing modification not from the 93 octane fuel. The 93 octane fuel allows you to advance the timing without getting pre-ignition.
Advancing the timing is moving back from TDC, earlier in the compression cycle. Due to the length of time it takes the air/fuel to burn after it's ignited, it is ignited prior to TDC, giving it time to burn and gain peak combustion, which then forces the piston down.
As the octane number increases, it becomes harder and harder to burn. This helps prevent pre-ignition only and has nothing to do with HP gains.
This also answers the last part of your question. If you use a lower octane rated fuel in an engine not designed for that octane the engine can not run efficiently. When the “APPROPRIATE” octane rating for that engine is used, the engine runs at optimal efficiency which translates into more power output. It’s modifications which are adding the HP, not the octane.
Using higher octane fuel in an Unmodified engine gives you nothing. Once you modify the engine: advance the timing, increase compression... the higher octane fuel is needed to prevent the air fuel mixture from igniting too early in the compression stroke. That’s it. There’s nothing magic about.
Is octane important? Absolutely? But more is only better when you’re modifying the engine or designing the engine to run at higher compression ratios and combustion timing modifications. To get the full benefit of the modification you need a higher octane fuel (again, simply to make the fuel more difficult to ignite either under pressure or higher temps.
Again: The 1st octane booster was lead. Lead is not flammable. Adding lead simply made it more difficult to ignite the fuel. It reduces the fuels volatility. However, once the fuel is ignited high octane fuel and low octane fuel produce the same energy.
It’s the modification that produces the HP. The higher octane just allows you to maximize the advantage of those modifications. If there’s no modification your just wasting your money on the higher octane fuel.
There’s like 10,000 articles on the internet about this.
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08-02-2019, 03:39 PM #56Senior Member
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- Aug 2015
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- Spokane, WA
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Good article regarding Dyno test.
https://www.roadandtrack.com/car-cul...-dyno-numbers/
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08-02-2019, 03:55 PM #57Senior Member
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- Aug 2015
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- Spokane, WA
- Posts
- 262
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08-02-2019, 04:41 PM #58Senior Member
- Join Date
- Aug 2015
- Location
- Spokane, WA
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- 262
https://www.bellperformance.com/blog...Octane-Ratings
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08-02-2019, 08:04 PM #59
This dudes videos are pretty damn good. Well explained about how you can make more HP with higher octane if you add timing and how low octane will drop to lower timing tables when knock is sensed.
This is of course assuming the engine is tuned for the higher octane.
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2018 Supra SA 400 (SOLD)
Michigan