 Octane ratings for 914 fueling, I hate to kick a horse while he's down.. |
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| davidcalvin |
 Sep 4 2004, 04:58 PM
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#1
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Member  Group: Members Posts: 200 Joined: 31-August 04 From: California Member No.: 2,662  |
Earlier I started a thread on gas. What kind should I put in my tank?
Everyone basically said, 87 is what you need. I just got my 914 and I was out and bought some gas today. And I dutifully chose 87. While I was pumping my gas, though, I looked down and there I saw a decal, in german, which read to the effect of "minimum 91 octane". So what gives? Which is better? 87 or 91? Thanks, david |
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| TimT |
Sep 4 2004, 06:21 PM
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#2
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retired Group: Members Posts: 4,033 Joined: 18-February 03 From: Wantagh, NY Member No.: 313 |
the octane rating you see at the pump is an average of two octane ratings
I believe R and M over 2= research octane over motor octane... Im to lazy now to look it all up again.. Unless you have a high compression engine.. there is no need for the higher octane. |
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| Elliot_Cannon |
Sep 4 2004, 06:25 PM
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#3
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Senior Member Group: Retired Members Posts: 1,922 Joined: 26-March 03 From: Orange County Ca Member No.: 480 Region Association: None |
Try 87. If the engine don't like it, go to 91. Simple.
Cheers, Elliot |
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| lapuwali |
Sep 4 2004, 06:34 PM
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#4
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743  |
The German label specifies 91 ROZ (aka RON, or Research Octane Number, one way to measure octane). The US system is to average RON and MON (Motor Octane Number) to get pump octane. MON is typically 8-12 numbers lower than RON (varies based on exact fuel chemsitry), so RON is always higher than US pump octane. 91 RON is roughly equivalent to US 86 octane, so using 87 by the US measure is fine. European "premium" is typically 98 RON, or about 92 by the US measure.
btw, early 1.7s required higher than 91 RON even stock, and I have to run my '71 1.7 on premium or it pings. They had higher compression than the later engines. I think the 1.8 had the lowest compression, and the lowest octane requirement. |
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| SirAndy |
Sep 5 2004, 12:45 PM
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#5
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Resident German Group: Admin Posts: 41,640 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
QUOTE(davidcalvin @ Sep 4 2004, 03:58 PM) While I was pumping my gas, though, I looked down and there I saw a decal, in german, which read to the effect of "minimum 91 octane". (IMG:style_emoticons/default/agree.gif) lapuwali is right. european specifications are different and don't translate into US octane ratings ... (IMG:style_emoticons/default/wink.gif) Andy |
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| ChrisReale |
Sep 5 2004, 09:05 PM
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#6
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Sleazy Group: Members Posts: 2,665 Joined: 20-January 03 From: San Francisco Member No.: 176 |
Ok. One last time.
I have 8:1 compression ratio. What USA octane do I need? None of this Ron, MOn shit. Say it and say it loud... (IMG:style_emoticons/default/monkeydance.gif) |
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| SirAndy |
Sep 5 2004, 09:39 PM
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#7
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Resident German Group: Admin Posts: 41,640 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
QUOTE(ChrisReale @ Sep 5 2004, 08:05 PM) Ok. One last time. I have 8:1 compression ratio. What USA octane do I need? None of this Ron, MOn shit. Say it and say it loud... start with 89 and listen to your engine. if it "knocks", go to 91, if not, call it a day and be happy with it ... altough, 8:1 is kind of unusual. are you sure about that? (IMG:style_emoticons/default/biggrin.gif) Andy |
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| ChrisReale |
Sep 6 2004, 01:00 AM
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#8
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Sleazy Group: Members Posts: 2,665 Joined: 20-January 03 From: San Francisco Member No.: 176 |
Euro pistons are 8:1, right? Nothing seems unusual about that
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| SirAndy |
Sep 6 2004, 01:06 AM
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#9
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Resident German Group: Admin Posts: 41,640 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
QUOTE(ChrisReale @ Sep 6 2004, 12:00 AM) Euro pistons are 8:1, right? Nothing seems unusual about that oops, you're right, 8.0:1 for a 2.0L, 8.2:1 for a 1.7L and 8.6:1 for a 1.8L ... my bad, (IMG:style_emoticons/default/wink.gif) Andy |
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