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

Higher octane rate equals more boost possible, right?! well I got 100octane fuel..

Old Oct 13, 2004 | 06:07 AM
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Higher octane rate equals more boost possible, right?! well I got 100octane fuel..

title says it all... 100octane fuel is not avaible everywhere here, but its spreading fast.. but there is 98octane everywhere! any toughts? it's possible to get higher boost without risking detonation right?
even without higher boost its recomended to get higher octane cause it hold higher pressure without detonating right?
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Old Oct 13, 2004 | 07:39 AM
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......boom......do not attempt to use a higher octane fuel as simply a band-aid because the truth is that you need MORE of it, not just a higher octane, compensating with a higher octane is going to be a very short story of how you blew your motor running 18 lbs of boost.

--Fritz
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Old Oct 13, 2004 | 08:12 AM
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Originally Posted by ShIvER[PT]
title says it all... 100octane fuel is not avaible everywhere here, but its spreading fast.. but there is 98octane everywhere! any toughts?
The United States uses a more strict anti-knock rating system than other countries. The 98 RON in your country is roughly equivalent to 93 or 94 PON in the US.
http://www.btinternet.com/~madmole/R...RONMONPON.html

Originally Posted by ShIvER[PT]
it's possible to get higher boost without risking detonation right?
Yes

Originally Posted by ShIvER[PT]
even without higher boost its recomended to get higher octane cause it hold higher pressure without detonating right?
If your engine is not in danger of detonating, then higher octane fuel is just a waste of money.
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Old Oct 13, 2004 | 08:25 AM
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US gas stations rate octane with (R+M)/2 or the average of "research octane" and "measured octane".
Your 98 and 100 are most likely research octane numbers, which Evil Aviator has already pointed out.
100 RON is about 96 (R+M)/2 in the US - how much is it?
When I was in CZ a few months ago, they had 100 RON stuff that was selling about $1.50/liter.
We've got a local 76 gas station right down the street from me that pumps 100 (R+M)/2 stuff straight out of a standing pump.
$6/gallon though...yesh.


-Ted
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Old Oct 13, 2004 | 09:59 AM
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if that's so... I should put at least 98 on the car right?
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Old Oct 13, 2004 | 10:36 AM
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Originally Posted by ShIvER[PT]

if that's so... I should put at least 98 on the car right?
A stock TurboII is rated for 87 PON, which is somewhere around 90-92 RON. The problem with commercial anti-knock ratings is that the MON is the important number, but that is usually not given to the consumer. At least the US system averages the MON into its rating, so that helps some.

If your engine is modified to run higher boost levels than stock, or if your engine is in poor repair, you may need to use fuel of a higher anti-knock rating. Basically, if you notice knocking, then move up to the next higher octane. Sometimes a different brand of fuel will also make a difference, as well as the particular service station if the fuel sits too long in storage and loses its octane rating.

Last edited by Evil Aviator; Oct 13, 2004 at 10:38 AM.
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Old Oct 13, 2004 | 07:04 PM
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what do you mean with "Basically, if you notice knocking,".. what is knocking ?
sorry.. still learning :p
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Old Oct 15, 2004 | 06:14 PM
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Originally Posted by ShIvER[PT]
what do you mean with "Basically, if you notice knocking,".. what is knocking ?
sorry.. still learning :p
http://zhome.com/ZCMnL/PICS/detonation/detonation.html
http://www.motorcycle.com/mo/mcrob/rt-fuel2.html
http://www.stanford.edu/~bmoses/knock.html
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