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Old 08-27-2010, 07:04 PM   #1
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Default Is premium gas still needed if SC is bypassed?

I know a few people that didnt perform routine maintanance on there GTP'* and SSEi'* and there SC bearings, ect have failed so they for some reason bought a smaller belt so they arent running their SC... do they still need to run premium fuel if the SC isnt being used?
I know they should fix the problem and run the SC...but i would just like this question answered
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Old 08-27-2010, 09:49 PM   #2
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You will have lower pressures under WOT, but still be about the same at idle and cruise. I'm sure it will be OK, but I still suggest premium. You will get a bit more mileage to off set the extra cost.
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Old 08-27-2010, 09:54 PM   #3
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If they didn't maintain the */C do you really think they will Care if they run 93 Octane ???
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Old 08-27-2010, 10:16 PM   #4
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Originally Posted by StealthGXP View Post
If they didn't maintain the */C do you really think they will Care if they run 93 Octane ???
lolzz

i think you should be fine but i also noticed that my mileage suffered quite a bit when i used 87 once instead of 93
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Old 08-27-2010, 11:14 PM   #5
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sometimes the higher heat from higher octane fuel can cause more damage the do good, i would say no */C run mid grade
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Old 08-28-2010, 01:47 AM   #6
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higher octane doesn't produce more heat, it'* just a measure of how easily it will more or less self-ignite. if you bypass the */C, you're running on a whopping 8.5:1 compression, totally within the realm of ****-water 87 octane fuel, especially if dealing with stock spark settings.
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Old 08-28-2010, 01:52 AM   #7
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Originally Posted by RobertISaar View Post
higher octane doesn't produce more heat, it'* just a measure of how easily it will more or less self-ignite. if you bypass the */C, you're running on a whopping 8.5:1 compression, totally within the realm of ****-water 87 octane fuel, especially if dealing with stock spark settings.
I second...

Higher octane simply keeps the fuel more stable at higher compression until there is spark... aka avoids detonation.

Without higher compression, there is no need for high octane fuel.
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Old 08-28-2010, 02:33 AM   #8
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If I understand correctly, the series 2 supercharger belt runs only the supercharger right? So why are they buying shorter belts? To run all the extra idler pulleys? What you have with no supercharger is a L36, that has lower compression, and a big air restriction from stopped supercharger rotors. Run regular.
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Old 08-28-2010, 03:04 AM   #9
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Quote:
Originally Posted by RobertISaar View Post
higher octane doesn't produce more heat, it'* just a measure of how easily it will more or less self-ignite. if you bypass the */C, you're running on a whopping 8.5:1 compression, totally within the realm of ****-water 87 octane fuel, especially if dealing with stock spark settings.
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I second...

Higher octane simply keeps the fuel more stable at higher compression until there is spark... aka avoids detonation.

Without higher compression, there is no need for high octane fuel.

it doesn't burn cooler than lower octane, it just take a higher temp to make it burn, it actually burns hotter. I believe it is that for every 5 octane points it takes another 100 to ignite the fuel

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High performance cars need higher-octane gasoline, because the combustion chamber environment is much hotter. Experts from the Automobile Association of America (AAA) say about five percent of cars sold in the US require premium gasoline. Yet, premium gasoline accounts for 20 percent of all gasoline sold in the US.
It burns hotter because the Temp to Detonate is higher.
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Old 08-28-2010, 03:19 AM   #10
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"because the combustion chamber environment is much hotter"

CC temps are higher because of a few factors, like higher compression or boost, which requires more octane to prevent detonation.

if higher octane fuel did burn hotter, it would have more BTUs for a given volume/weight compared to 87, but it doesn't, i've actually seen SLIGHTLY lower BTU content for higher octane gasoline before.

"I believe it is that for every 5 octane points it takes another 100 to ignite the fuel"

this may be true, but consider this: the laws of thermodynamics state that the greater the temp difference between a fuel when being oxidized compared to the state it was in beforehand, the more energy is extracted.
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