2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

100 octane

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Old Jul 6, 2003 | 11:46 PM
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Question 100 octane

ive got a 90 tII running a pfcon w/ gcc. was wondering if running 100octane would make a difference or not. i did a search most of the results were for na's. just wondering if it was worth my time or not. thanks!!
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Old Jul 6, 2003 | 11:50 PM
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Not unless you tune for it. It's not that easy.
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Old Jul 6, 2003 | 11:56 PM
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Not unless you tune for it. It's not that easy.
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Old Jul 7, 2003 | 12:00 AM
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is it leaded or unleaded?

there is really no addvanage. it would let you tune further to the edge which isn't smart for a street car. just using it with no changes in your car it won't do anything.
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Old Jul 7, 2003 | 12:07 AM
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The octane rating is an anti-knock rating, so the 100 octane would lower your detonation threashold vs. lower octane gas. Since it is probably race gas, it may also have more BTU's per pound or gallon than pump gas, but you would need to ask the manufacturer. If it is leaded gas, it will ruin your cat and possibly your fuel system. Unless the 100 octane gas in question has the same specific gravity and stoich mixture as pump gas, you will need to re-tune your engine if you want to keep the same lambda.
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Old Jul 7, 2003 | 12:41 AM
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i imagine there's a system out there that could tune itself and adjust to the gas/octane, knowing it has a higher resistance to detonation. stock ecu's are smart. newer computers are damn smart, but is the operator/programmer?
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Old Jul 7, 2003 | 12:45 AM
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Unless the 100 octane gas in question has the same specific gravity and stoich mixture as pump gas, you will need to re-tune your engine if you want to keep the same lambda.
hehehehe.... you nerd.... fluid mechanics huh?
hehehe... don't worry... i'm a nerd here too.....
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Old Jul 7, 2003 | 12:52 AM
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nerds? i love nerds. tell me what the math equation on the stickers at the pump mean. wish i remembered the equation. you know it off hand? r=m/2 or something like that?
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Old Jul 7, 2003 | 12:59 AM
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north america is ron+mon / 2 so it's an avg of ron and mon..

japan only lists one. that's why there oct #'s are higher at the pump. but in real life they are not. same with eroupe.
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Old Jul 7, 2003 | 01:20 AM
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Originally posted by Howi
hehehehe.... you nerd.... fluid mechanics huh?
hehehe... don't worry... i'm a nerd here too.....
I'm just an evil aviator. Hey, I have to do something with my $100,000 worth of college.

Originally posted by casio
nerds? i love nerds. tell me what the math equation on the stickers at the pump mean. wish i remembered the equation. you know it off hand? r=m/2 or something like that?
Pump Octane Number (PON) = (R+M)/2 = (RON + MON)/2 = (Research Octane Number + Motor Octane Number)/2 = the average of mild driving anti-knock rating + high load anti-knock rating.
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Old Jul 7, 2003 | 01:33 AM
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so what about C16? its 103 or 105 and both times i blew my motor was using 1 gallon of that with the rest 93...I was dissapointed with my times both accurences and every time I lean the car out I ran faster and faster
untill the inevitble, best time it a 13.5 at 6psi on my streetport with stock turbo
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