01-03-2014, 08:59 AM
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#1
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Registered User
Join Date: Jun 2012
Location: Peoria IL
Posts: 529
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Octane number
I know that 93 is recommended according to the note under the gas cap lid. Around here (NW Indiana), 92 is all that I have found. I'm sure it's no problem. A buddy of mine has a premium only vehicle (Nissan 350 or 370, I can't remember which) and he alternates between 89 and 92. He just passed 100k with no problems. Also when I was in Oklahoma, I went to 6 different gas stations looking for something more than 91 and 91 was all I could find. So I wondered how much different can 89 be from 91?
I guess my question is what are your thoughts? Is 91 or 92 OK? What about 89? Is alternating between 89 and 92 OK? I'll always use the highest available octane, but it's just something I was thinking about on the drive home the other day.
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01-03-2014, 09:04 AM
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#2
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Registered User
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 6,261
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The DME in these cars is perfectly capable of adjusting ignition timing to successfully cope with fuels ranging from 83 to over 93 octane; there should not be any issues other than a slight loss of total power output.
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“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
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01-04-2014, 07:56 AM
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#3
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Registered User
Join Date: Nov 2013
Location: Emerald City
Posts: 885
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I'm in nwi and I've yet to find a station that doesn't have 93...all of the speedways do...recommend you come across the state line and hit the speedway on calumet in munster or somewhere close. They all have 93. I've used 92 in a pinch but don't make a habit of using less than 93...I figure if I wanted to save money on gas I wouldve kept my nissan sentra. Instead I bought a porsche so I do what porsche says it needs.
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01-04-2014, 08:09 AM
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#4
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Registered User
Join Date: Sep 2013
Location: Chandler, AZ
Posts: 1,796
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With we had 93 or even 92. All we have is crappy 91.
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03 Carrera
02 Boxster S Guards Red, black interior with matching hardtop
89 Carrera 4
89 944 S2
78 911SC
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01-04-2014, 08:33 AM
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#5
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Registered User
Join Date: Aug 2009
Posts: 1,466
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You could get away with the 89. I don't believe it's recmended and I would be concerned with 10% ethanol and 89 octane. In the end you should probably add a fuel injector cleaner. As soon as you do you may as well have bought the more expensive 93 octane.
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2003 Black 986. modified for Advanced level HPDE and open track days.
* 3.6L LN block, 06 heads, Carrillo H rods, IDP with 987 intake, Oil mods, LN IMS. * Spec II Clutch, 3.2L S Spec P-P FW. * D2 shocks, GT3 arms & and links, Spacers front and rear * Weight reduced, No carpet, AC deleted, Remote PS pump, PS pump deleted. Recaro Pole position seats, Brey crouse ext. 5 point harness, NHP sport exhaust
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01-04-2014, 03:49 PM
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#6
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Registered User
Join Date: Apr 2009
Location: Orlando
Posts: 1,266
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Torco Accelerator - It's not just an octane booster - Torco Race Fuels
torcoracefuel.net/pro-accelerator.html
Torco Accelerator is not just another octane booster or fuel additive, it's a race fuel concentrate.
They have mixing charts for different octanes.
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2000 S/3.2 Liter/Tiptronic/Boxster S Sport Package/Cruise Control/Slate Grey Metallic
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01-04-2014, 06:24 PM
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#7
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Porsche "Purist"
Join Date: Aug 2003
Location: Wisconsin
Posts: 2,123
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From an article in USA Today:
All Porsche engines are designed for premium, too, but it's not available everywhere. "Our cars must be able to drive all over the world, and so we are able to run on regular," says Jakob Neusser, director of powertrain development at Porsche's research and development center in Weissach, Germany. "You don't have to feel that a mechanical problem or anything else will happen" using regular gas, even in the highest-performance, regular-production Porsches.
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1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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01-04-2014, 06:34 PM
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#8
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Porsche "Purist"
Join Date: Aug 2003
Location: Wisconsin
Posts: 2,123
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__________________
1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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01-04-2014, 06:44 PM
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#9
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Beginner
Join Date: Mar 2013
Location: Houston
Posts: 1,659
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So this is old school (literally) but I had a fuels and lubes course as part of my engineering degree, and we had a lab. The lab setup was half mad scientist, and half API testing rigs. a small part of the class revolved around determining, and changing octane ratings in gasoline using a knock engine in the lab. This was a big electricallty driven rig with a single cylinder, the compression ratio of the engine could be changed by turning a crank until detonation occured. Made a h3ll of a noise, all great fun (for engineers). The upshot was that experimentally, using the octane engine, the greatest increase in octane was not obtained with off the shelf octane boosters, but by mixing different octane gas (low and high ) from different producers. Why? Because at that time different chemicals were used to boost the octane in different brands, and the octane booster level in the gas was usually slightly in excess of what was needed so there was a little booster left over in each gas blend. Mix the gas blends together and you get a synergy that uses the left over boosters in each gas brand/blend to increase the overall octane of the mix you created. Because gas blends change constantly, as do the octane boosters, this is not reliably repeatable, but we were getting blends that were between 95 and 100 octane. There was an octane booster that claimed 101 octane that wasn't even close. I've made a point to use different brands ever since for higher octane.
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2003 S manual
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01-04-2014, 07:27 PM
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#10
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Engine Surgeon
Join Date: Aug 2008
Location: Cleveland GA USA
Posts: 2,425
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Quote:
Originally Posted by JFP in PA
The DME in these cars is perfectly capable of adjusting ignition timing to successfully cope with fuels ranging from 83 to over 93 octane; there should not be any issues other than a slight loss of total power output.
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As long as all your injectors are firing and the knock sensors aren't wigged out.
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IMS Solution/ Faultless Tool Inventor
US Patent 8,992,089 &
US Patent 9,416,697
Developer of The IMS Retrofit Procedure- M96/ M97 Specialist
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01-04-2014, 07:46 PM
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#11
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Registered User
Join Date: Jun 2012
Location: Milwaukee, WI
Posts: 383
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My experience is that Octane number for premium grade gasoline depends on whether it is a 10% ethanol blend or not. Usually the non-ethanol premium is 91 or 92 and the ethanol blend is 93. The ethanol blend requires a higher octane rating because the ethanol makes it a less efficient fuel.
When I was in South Dakota last June, there were several stations that had their mid-grade 89 octane gas priced 10c/gal higher than premium 93 octane b/c the mid-grade did not have ethanol while the premium did.
DBear
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01-09-2014, 04:48 PM
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#12
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Registered User
Join Date: Nov 2013
Location: Colorado
Posts: 442
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knock sensor location
Quote:
Originally Posted by Jake Raby
As long as all your injectors are firing and the knock sensors aren't wigged out.
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Where do I look to see if the knock sensors have "wiggled" out?
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01-09-2014, 06:25 PM
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#13
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Registered User
Join Date: Apr 2009
Location: Orlando
Posts: 1,266
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Quote:
Originally Posted by Jamesp
So this is old school (literally) but I had a fuels and lubes course as part of my engineering degree, and we had a lab. The lab setup was half mad scientist, and half API testing rigs. a small part of the class revolved around determining, and changing octane ratings in gasoline using a knock engine in the lab. This was a big electricallty driven rig with a single cylinder, the compression ratio of the engine could be changed by turning a crank until detonation occured. Made a h3ll of a noise, all great fun (for engineers). The upshot was that experimentally, using the octane engine, the greatest increase in octane was not obtained with off the shelf octane boosters, but by mixing different octane gas (low and high ) from different producers. Why? Because at that time different chemicals were used to boost the octane in different brands, and the octane booster level in the gas was usually slightly in excess of what was needed so there was a little booster left over in each gas blend. Mix the gas blends together and you get a synergy that uses the left over boosters in each gas brand/blend to increase the overall octane of the mix you created. Because gas blends change constantly, as do the octane boosters, this is not reliably repeatable, but we were getting blends that were between 95 and 100 octane. There was an octane booster that claimed 101 octane that wasn't even close. I've made a point to use different brands ever since for higher octane.
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I built street cars back in the 60's and I would mix premium American White 93 octane with Sunoco Blue Plus also 93 octane. These were leaded gasoline, anyway you could feel a change in how the engine ran and the mix also changed the smell of the coming out of the tail pipe. When I went to drag strip I would mix airplane fuel to gas. I was running a 327 Chevy engine, 12-1 pistons, polished and ported heads and high lift street Crane cam. My best guess was my octane was around 105. Engine screamed and it performed perfectly. If you are using racing fuel you would be disqualified. Racing fuel has very unique smell. So octane makes a big difference high performance engines.
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Old Hippie Young Heart
2000 S/3.2 Liter/Tiptronic/Boxster S Sport Package/Cruise Control/Slate Grey Metallic
Red Special Leather Interior/Red Floor Mats/Red Hand Painted Instrument Dials/Roll Bar/Windstop
Small Carbon Package/Leather Wrap Carbon Wheel/Center Console Exterior Color/Alum Carbon Shift Knob
AM/FM Radio w/CD Player & Changer/Digital Sound Package/18" Turbo Wheels/Wheel Caps w/Colored Crest
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01-10-2014, 05:41 AM
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#14
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Registered User
Join Date: Jun 2012
Location: Peoria IL
Posts: 529
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Quote:
Originally Posted by jdraupp
I'm in nwi and I've yet to find a station that doesn't have 93...all of the speedways do...recommend you come across the state line and hit the speedway on calumet in munster or somewhere close. They all have 93. I've used 92 in a pinch but don't make a habit of using less than 93...I figure if I wanted to save money on gas I wouldve kept my nissan sentra. Instead I bought a porsche so I do what porsche says it needs.
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Finally put fuel in today. I guess they are 93 around here. If it was summer, I would have remembered that. I guess all the travelling through MO and OK made me misremember.
I live by the airport in Lansing so the BP on Ridge and Calumet is my spot. I just like BP for no reason at all. Unfortunately, they seem to have run out of premium or broke something. Anyway, Hopefully I have my winter car fixed tomorrow so I can clean and park the Boxster and maybe I'll see ya on the roads this summer.
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01-10-2014, 06:25 AM
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#15
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Registered User
Join Date: Oct 2008
Location: Colorado
Posts: 317
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In the US, available octane in the various gasoline grades changes with altitude. Since the air is less dense at higher elevation you don't need as much octane to prevent detonation. That's why all 3 grades have less octane as you climb in elevation. I assume the 93 number recommended by Porsche is based on seal level elevation. You can't even buy 93 where I live at 8700 ft.
__________________
Dave S.
2003 Boxster S
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01-10-2014, 07:41 AM
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#16
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Registered User
Join Date: Oct 2008
Location: O.C. CA
Posts: 3,709
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Quote:
Originally Posted by CoBeerToad
Finally put fuel in today. I guess they are 93 around here. If it was summer, I would have remembered that. I guess all the travelling through MO and OK made me misremember.
I live by the airport in Lansing so the BP on Ridge and Calumet is my spot. I just like BP for no reason at all. Unfortunately, they seem to have run out of premium or broke something. Anyway, Hopefully I have my winter car fixed tomorrow so I can clean and park the Boxster and maybe I'll see ya on the roads this summer.
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Maybe because BP diluted Mobil 1 oil & our Gulf of Mexico.
__________________
OE engine rebuilt,3.6 litre LN Engineering billet sleeves,triple row IMSB,LN rods. Deep sump oil pan with DT40 oil.
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01-10-2014, 07:57 AM
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#17
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Registered User
Join Date: Oct 2008
Location: O.C. CA
Posts: 3,709
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Quote:
Originally Posted by jcb986
I built street cars back in the 60's and I would mix premium American White 93 octane with Sunoco Blue Plus also 93 octane. These were leaded gasoline, anyway you could feel a change in how the engine ran and the mix also changed the smell of the coming out of the tail pipe. When I went to drag strip I would mix airplane fuel to gas. I was running a 327 Chevy engine, 12-1 pistons, polished and ported heads and high lift street Crane cam. My best guess was my octane was around 105. Engine screamed and it performed perfectly. If you are using racing fuel you would be disqualified. Racing fuel has very unique smell. So octane makes a big difference high performance engines.
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I built muscle car engines in the '80s & the best pump gas was Amoco 93 which was white/clear. If cylinder pressure was high enough to cause preignition or detonation I would add 130 octane low lead "blue" aviation fuel. Avgas lacked some lubrication additives that road gas has, so I also added Marvel Mystery oil. Experimented with the Cox model fuel & mothballs that were 100% Naptha. The Amoco 93 had a very distinctive exhaust smell, & so does the Avgas. I'm guessing the American White 93 became Amoco later.
__________________
OE engine rebuilt,3.6 litre LN Engineering billet sleeves,triple row IMSB,LN rods. Deep sump oil pan with DT40 oil.
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01-11-2014, 04:15 PM
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#18
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Registered User
Join Date: Apr 2009
Location: Orlando
Posts: 1,266
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Quote:
Originally Posted by BYprodriver
I built muscle car engines in the '80s & the best pump gas was Amoco 93 which was white/clear. If cylinder pressure was high enough to cause preignition or detonation I would add 130 octane low lead "blue" aviation fuel. Avgas lacked some lubrication additives that road gas has, so I also added Marvel Mystery oil. Experimented with the Cox model fuel & mothballs that were 100% Naptha. The Amoco 93 had a very distinctive exhaust smell, & so does the Avgas. I'm guessing the American White 93 became Amoco later.
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Great, muscle cars where a lot of fun. American White was the best, but it is no longer the same because all fuels are now unleaded. The aviation fuel was fantastic add to the mixture, but you still destroy an engine if you weren't careful. Chevy man here. Owned a 55, 56, 57, 58. A 67, 68, 69 Camaro's. My new one off the lot in 64 was a Chevelle, built in June as a half year version. Had a 327, 300hp vette engine, Munice close ratio 4 speed and positraction. I changed the side flags to the 283 flags. So now I had a sleeper. Had a buddy with 64 Plymouth Valiant, 2 door and was the cheapest body style made. But, it had a V8, 4 speed and positraction too. Another sleeper looking for a pray.
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Old Hippie Young Heart
2000 S/3.2 Liter/Tiptronic/Boxster S Sport Package/Cruise Control/Slate Grey Metallic
Red Special Leather Interior/Red Floor Mats/Red Hand Painted Instrument Dials/Roll Bar/Windstop
Small Carbon Package/Leather Wrap Carbon Wheel/Center Console Exterior Color/Alum Carbon Shift Knob
AM/FM Radio w/CD Player & Changer/Digital Sound Package/18" Turbo Wheels/Wheel Caps w/Colored Crest
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