94 Octane Worth It?
Racer
Joined: May 2001
Posts: 405
Likes: 0
From: Southern Illinois
I have a friend who owns a gas station. He says always buy 91 oct. Here that is the mid level gas and the one that the state always checks for octane. He says that the supplier always bumps the octane up a little to make sure they always pass the state test.
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: Jan 2005
Posts: 12,346
Likes: 4
From: New Jersey
Originally Posted by Dr. No
With 93 octane (US), you should notice a difference over 91 at WOT, but whether it's worth $4.69 a gallon is debatable. Also, if you have a chip that is looking for higher octane fuel.
Race Director
Joined: Sep 2003
Posts: 17,136
Likes: 403
From: SF Bay Area
Originally Posted by Bull
Holy Crap! $4.69 a gallon? Around here, it is around $3.19-$3.29, and they pump it for you. Most stations in this area offer 87, 89 and 93 octane, now that the remaining Sunoco 94 is dissapearing.
Sorry, $4.69 is for the 100 octane you have to use to get yourself to 93, since I can't find 93 or 94 anywhere. Average cost per gallon in CA is then about $3.65.
Addicted Specialist
Rennlist Member
Rennlist Member
Joined: Jun 2001
Posts: 6,242
Likes: 438
From: So.CA
Hi Jeff,
Remember that an engine's octane requirements are a function of their design, and the ambient conditions of temp, RH, and engine load. A Toyota Corolla will never see any benefit from 91 as it was designed for lower octane: putting prem here is literally flushing money down the drain. In high-compression performance engines with modern electronics, however, the engine IS designed for high octane, but will retard timing if lower-grade fuel leads to preignition to protect itself from damage. So yes, our cars will gain HP from higher octane as it was designed from the get-go for it. BUT, will you, and your driving habits, be able to discern the difference? Depends. For street driving and the occasional fast fwy onramp, it's a waste of money when pump 91/92 will be perfectly fine. If you're on a track and the ambient temps are high, I'd put in 94 if I could get it. As you've defined a street NA 993 with OE mapping, anything more than 91/92 is wasted dough.
Edward
Remember that an engine's octane requirements are a function of their design, and the ambient conditions of temp, RH, and engine load. A Toyota Corolla will never see any benefit from 91 as it was designed for lower octane: putting prem here is literally flushing money down the drain. In high-compression performance engines with modern electronics, however, the engine IS designed for high octane, but will retard timing if lower-grade fuel leads to preignition to protect itself from damage. So yes, our cars will gain HP from higher octane as it was designed from the get-go for it. BUT, will you, and your driving habits, be able to discern the difference? Depends. For street driving and the occasional fast fwy onramp, it's a waste of money when pump 91/92 will be perfectly fine. If you're on a track and the ambient temps are high, I'd put in 94 if I could get it. As you've defined a street NA 993 with OE mapping, anything more than 91/92 is wasted dough.
Edward
Race Director
Joined: Jun 2003
Posts: 15,122
Likes: 337
From: Los Altos, CA
Dr. Wattenburg (a real rocket scientist and a car nut), who is a local talk show host, had always advocated that 91 Octane is a waste of money, as we basically have 87, 89, and 91 octane gas in CA.
However, his only exeptions are high compression engines (11.4:1 in the NA 993 surely qualifies) and air-inducted engines (turbos and superchargers). I run 87 in all my cars except for my RUF.
I once posted a thread on the subject on the Boxster board (long-term planning for the Cayman S, wanting to run 97 in that as well), and everyone there called me a cheap-skate bastard.
CP
However, his only exeptions are high compression engines (11.4:1 in the NA 993 surely qualifies) and air-inducted engines (turbos and superchargers). I run 87 in all my cars except for my RUF.
I once posted a thread on the subject on the Boxster board (long-term planning for the Cayman S, wanting to run 97 in that as well), and everyone there called me a cheap-skate bastard.
CP
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: Jan 2005
Posts: 12,346
Likes: 4
From: New Jersey
Originally Posted by Dr. No
Sorry, $4.69 is for the 100 octane you have to use to get yourself to 93, since I can't find 93 or 94 anywhere. Average cost per gallon in CA is then about $3.65.
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: Jan 2005
Posts: 12,346
Likes: 4
From: New Jersey
Originally Posted by Edward
Hi Jeff,
Remember that an engine's octane requirements are a function of their design, and the ambient conditions of temp, RH, and engine load. A Toyota Corolla will never see any benefit from 91 as it was designed for lower octane: putting prem here is literally flushing money down the drain. In high-compression performance engines with modern electronics, however, the engine IS designed for high octane, but will retard timing if lower-grade fuel leads to preignition to protect itself from damage. So yes, our cars will gain HP from higher octane as it was designed from the get-go for it. BUT, will you, and your driving habits, be able to discern the difference? Depends. For street driving and the occasional fast fwy onramp, it's a waste of money when pump 91/92 will be perfectly fine. If you're on a track and the ambient temps are high, I'd put in 94 if I could get it. As you've defined a street NA 993 with OE mapping, anything more than 91/92 is wasted dough.
Edward
Remember that an engine's octane requirements are a function of their design, and the ambient conditions of temp, RH, and engine load. A Toyota Corolla will never see any benefit from 91 as it was designed for lower octane: putting prem here is literally flushing money down the drain. In high-compression performance engines with modern electronics, however, the engine IS designed for high octane, but will retard timing if lower-grade fuel leads to preignition to protect itself from damage. So yes, our cars will gain HP from higher octane as it was designed from the get-go for it. BUT, will you, and your driving habits, be able to discern the difference? Depends. For street driving and the occasional fast fwy onramp, it's a waste of money when pump 91/92 will be perfectly fine. If you're on a track and the ambient temps are high, I'd put in 94 if I could get it. As you've defined a street NA 993 with OE mapping, anything more than 91/92 is wasted dough.
Edward
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
9 Features and Characteristics That Only Porsche People Understand
Verdad Gallardo
I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way
Joe Kucinski
10 Most Unnecessary Porsches Ever Built (And Why We Love Them)
Verdad Gallardo
Porsche 911 GT3 S/C vs 718 Spyder RS: 10 Categories, One Winner
Joe Kucinski
This Builder Is Turning Heads With Its Slantnose 911 Creation
Verdad Gallardo
Porsche 911 GT3 Artisan Edition Pays Homage to Japanese Culture
Verdad Gallardo
Porsche Reveals Coupe Variant of the Electric Cayenne With a Fresh Look
Verdad Gallardo
10 Porsche Colors That Have More Personality Than Most People
Verdad Gallardo
Guntherwerks' Final Speedster Creation Is the Ultimate Porsche Restomod
Verdad Gallardo
Thread Starter
Nordschleife Master
Joined: Jun 2005
Posts: 5,351
Likes: 9
From: Neither Here Nor There
Great discussion guys. I appreciate the input.
Perhaps I'll need to "experiment" a bit with regard to my street driving habits. A part of me is willing to pay for higher octane, even if it is only beneficial on that occassional freeway onramp--the car is a toy, so I'm conditioned to be willing to pay for the game.
I definitely won't go below 91, but the real decision will be between 93 and 91. Maybe just "splitting the baby" is the right answer in my case--93.
Perhaps I'll need to "experiment" a bit with regard to my street driving habits. A part of me is willing to pay for higher octane, even if it is only beneficial on that occassional freeway onramp--the car is a toy, so I'm conditioned to be willing to pay for the game.
I definitely won't go below 91, but the real decision will be between 93 and 91. Maybe just "splitting the baby" is the right answer in my case--93.
Addicted Specialist
Rennlist Member
Rennlist Member
Joined: Jun 2001
Posts: 6,242
Likes: 438
From: So.CA
Originally Posted by Bull
The stock 993 engine will adjust the timing for octane that is lower than the design octane, but won't change anything for octane above the design octane.
Our 993s and other high-performance NA/turbocharged cars ARE designed for high-octane Pump gas; not 93+ octane. So yes, one can reach the design parameters of a high-compression engine with good pump stuff, and the DME will conpensate for lower-grade fuel so as to prevent grenading. But they are not designed form the factory to benefit from anything higher than pump ...which is why chip makers try and capitalize on this variable.
Edward
