Cars requiring 93 AKI octane and filling up

[y_p_w]

Was thinking of buying one. Currently driving a 2004 WRX and thinking of maybe the 2015 STi when it comes out. I'm pretty sure it will require 93 octane like all the other STi models before it.

I know there are quite a few performance cars that are tuned from the factory for 93. I mentioned the STi, but I've heard the Corvette, Porsches, exotics, and other high performance engines are tuned for 93. And of course some mods require higher octane to take advantage.

As far as I can tell, none the refiners producing California Air Resources Board compliant unleaded fuel actually blend a 93 or 94 octane unleaded as part of their regular stream of fuel. I've seen a few gas stations in California that sell 93 or 94 octane (and some that go 96 and 98), but I suspect that they're using blending pumps that mix 100 octane CARB-compliant race fuel with 91 octane. The prices seem to reflect that compared to when I've seen 94 octane for sale while visiting the East Coast, where it might be 20 cents a gallon more than 91 octane premium (or where 93 is the only premium grade sold at some places).

All I could find was a photo from a Canadian gas station, but I specifically remember 94 octane readily available (and only a bit more expensive) on a couple of East Coast trips:

 

[Bladecutter]

I'm sorry, I must have actually missed what your question is.
Can you clarify what you're asking?

BC.

 

[Warstud]

When did they start selling gas in the US by the litre?

 

[y_p_w]

Originally Posted By: Warstud
When did they start selling gas in the US by the litre?

I did note that I could only find a photo that showed a Canadian pump. However, I remember pumps like this on a trip to Florida with 94 octane.

 

[y_p_w]

Originally Posted By: Bladecutter
I'm sorry, I must have actually missed what your question is.
Can you clarify what you're asking?

BC.

How common is this stuff in other parts of the country? In California, we can only dream of every third gas station selling 93 or 94 octane for a miniscule price premium compared to 91. We don't even get 92 any more since it was dropped around 2000.

There are a lot of cars on the road here that can use the stuff, but a lack of places that sell it. It's gotten to the point where a lot of people are buying 100 octane race fuel (maybe $7.75/gallon now) and trying to figure how much they need to get around 93 octane when blended with 91. A few specialty places seems to sell it, but I suspect it doesn't come out of a refinery as 93/94 octane, but is blended on the spot by the pump.

 

[beanoil]

Here in the Midwest, Illinois and Missouri specifically, the majority of Premium fuel is 93 octane. Indy stations will have either 93 or 91 depending upon the supplier. But while we have the octane, we have counties with more pollution than others and have a few boutique fuels specific to geographic areas that drive up the cost of the fuel.

 

[JHZR2]

I can't say that I've ever seen a car that requires 93. I'm sure there are some, but it seems that most cars that require premium, require 91.

In many states that I traveled to you can't even buy 93 at the pump.

 

[y_p_w]

Originally Posted By: JHZR2
I can't say that I've ever seen a car that requires 93. I'm sure there are some, but it seems that most cars that require premium, require 91.

In many states that I traveled to you can't even buy 93 at the pump.

Corvettes. Nissan GT-R. Mitsubishi Lancer Evo. Subaru Impreza WRX STi. Every Porsche. Most exotics. I'm sure there are more. Then there are assorted modifications.

They won't self-destruct on 91 octane, but they need 93 for their published performance. I see a lot of those cars in California. I never really thought of this until I bought a WRX. The owner's manual included the 93 octane recommendation for the STi version.

I'd heard of 100 octane race fuel before, but I'd never actually seen a pump with 93/94 octane until I went on vacation in Florida.

 

[dparm]

Originally Posted By: JHZR2
I can't say that I've ever seen a car that requires 93. I'm sure there are some, but it seems that most cars that require premium, require 91.

In many states that I traveled to you can't even buy 93 at the pump.



Nor have I. Every car I've owned has only needed 91, even my tuned S4 and my high-strung M3. Says so right on the filler door.

And no, the STI does not need 93. In the US it is tuned to run on 91, and it says so right in the manual (my friend verified it for me). Another friend verified his 911 says 93 is preferred, but that 91 can be safely run because of the knock sensors.

So I think that the better way to phrase this is, "cars that can take advantage of 93 octane".


Only the 7.0L Vette can take advantage of 93, BTW...straight from the owner's manual:



If your vehicle has the 6.0L V8 engine (VIN Code U),
use premium unleaded gasoline with a posted octane
rating of 91 or higher.

If your vehicle has the 7.0L V8 engine (VIN Code E),
use premium unleaded gasoline with a posted octane
rating of 91 or higher. For best performance, use
premium unleaded gasoline with a posted octane
rating of 93.

 

[y_p_w]

Originally Posted By: dparm
Originally Posted By: JHZR2
I can't say that I've ever seen a car that requires 93. I'm sure there are some, but it seems that most cars that require premium, require 91.

In many states that I traveled to you can't even buy 93 at the pump.



Nor have I. Every car I've owned has only needed 91, even my tuned S4 and my high-strung M3. Says so right on the filler door.

I guess it's a matter of semantics. I used to own a '95 Acura Integra GS-R. The filler door said "PREMIUM UNLEADED FUEL ONLY", the manual said at least 91, but if you must it would still work on 87 octane (the minimum requirement).

However, I believe a car like an STi really requires 93 premium. Why else would someone get one and not use what's recommended?

And I looked up the 2013 Corvette owner's manual. Says 93 for certain versions of the 6.2L as well as the 7.0L.

http://www.chevrolet.com/content/dam/Che...k13corvette.pdf

Quote:
If the vehicle has the 6.2L V8 engine
(VIN Code T) or the 7.0L V8 engine
(VIN Code E), use premium
unleaded gasoline with a posted
octane rating of 91 or higher. For
best performance, use premium
unleaded gasoline with a posted
octane rating of 93.

 

[y_p_w]

Originally Posted By: beanoil
Here in the Midwest, Illinois and Missouri specifically, the majority of Premium fuel is 93 octane. Indy stations will have either 93 or 91 depending upon the supplier. But while we have the octane, we have counties with more pollution than others and have a few boutique fuels specific to geographic areas that drive up the cost of the fuel.

Like I said, 93 in every town would be a pipe dream in California, even with a lot of high performance cars tuned to use it.

Enthusiast message boards include lists of gas stations known to sell race fuel as well as what I assume are blends including this race fuel. Tosco used to sell the stuff (wasn't it what NASCAR used?) under the 76 brand, but I'm not sure what happened to it after Phillips bought them out. I've heard of specialty 100 octane street legal unleaded from Torco, but they no longer list it. What seems to be available is 100 octane StreetBlaze from VP Racing. I'm guessing the stations that sell gas between 93 and 98 octane around my neck of the woods are cutting it with 91 octane to get a linear octane blend.

 

[dparm]

You don't need 93 octane at higher altitudes, BTW. 91 would be sufficient.

 

[y_p_w]

Originally Posted By: dparm
You don't need 93 octane at higher altitudes, BTW. 91 would be sufficient.

I certainly get that, and I've heard of lower octane fuel being sold at higher altitudes. Still - people who drive in those altitudes do drive down to lower altitude where it could become and issue.

In California all the gas stations sell the same octane fuels - even the ones at high altitude. There aren't that many people living there to justify blending lower octane fuel, and it's only about 70 miles from Lake Tahoe to Shingle Springs on US-50. That goes from about 6200 ft to about 1400 ft.

Now I get selling 85 octane as regular in Denver. But if you really need to get down to lower elevation, I suppose one could fill up with 87 sold as mid-grade or even premium (still 91) if it's about half a tank.

 

[tommygunn]

ypw, that high altitude information is slightly outdated.

Modern engine management can compensate for altitude, and thus many engines must run 87 regardless of altitude. Ford has included a notice to that effect for quite some time now. Some Saabs had problems with this too.

Colorado should stop selling 85 octane.

 

[eljefino]

New Hampshire has 93 all over the place but Maine has a hard time stocking it. Saw a Sunoco bragging about it.

We used to have it, and on many pumps one can see the 91 sticker shamelessly covering the old 93.

 

[y_p_w]

Originally Posted By: tommygunn
ypw, that high altitude information is slightly outdated.

Modern engine management can compensate for altitude, and thus many engines must run 87 regardless of altitude. Ford has included a notice to that effect for quite some time now. Some Saabs had problems with this too.

Colorado should stop selling 85 octane.

My understanding is that the 85 they sell is cheap. It would probably do the trick in my old '89 Integra. I think that had an 86 octane AKI requirement, but they said that it OK down to 84 at higher altitudes.

There's an incentive for the refiners to sell as much of the low octane fuel as they can. I'm guessing a lot of it just goes to Colorado or other high altitude areas where 85 is accepted (even if not necessarily the right choice). Here's an article on the loss of available 92 octane unleaded premium in California:

Quote:
http://www.modified.com/editors/technobabble/0102scc_technobabble/

You see, when crude oil is refined into gasoline, the refinery doesn't have all that much control over what comes out. Crude oil is full of all kinds of stuff, and a refinery simply separates it, sorting all the iso-this and hepta-that in order of density. The really heavy stuff, like tar, is near the bottom, while the really light stuff, like butane, is near the top.

Somewhere in the upper ranges of the stack are the components of gasoline. There are between 10 and 15 different blend stocks, each with a different octane rating, which are mixed together to make gasoline.

The crude oil being used and little else determine the amount of each blend stock available for mixing. Generally, if you just dump all the blend stocks into a bucket, you end up with something around 88 or 89 octane. If you're selective and only mix the good stuff, you can make 92, 93 or even 95 octane. But once you take out the good stuff, you're left with [censored]--something like 85 octane. Then you have to leave enough good stuff in the bucket to bring this pee-water up to at least 87 octane. This limits the amount of 95-octane gas you can make. If you make 93-octane premium instead, you use up less of the high-octane stocks, allowing you to make a higher proportion of premium fuel.

It sounds to me as if a lot of refineries have an incentive to pass off as much of this 85 octane stuff to those willing to accept it. If it can be diverted to users who don't expect higher octane, they can sell more higher octane fuel at higher prices.

 

[rfeir]

You see, the fuel in your area likely comes from only one refinery, no matter what retail tag is attached to the fuel at retail. The different brands can add a tracer and some secret hamburger helper, but only the range of octane from the refinery will be available at retail. As you might guess, the West Coast does not sport many refineries.

 

[yonyon]

85? I thought 85 was gone since the mid-1990's.

 

[jayg]

Most ecu's used to have a tune for Federal (All other 49 states) and California for the fuel. These days with more sophisticated knock sensors, your car will adapt (pull timing usually and sometimes limit boost) to run on 91 octane swamp water.

In short, you'll be fine.

 

[Hermann]

Here in Metro KC, the only brand name stations that have 93 octane unleaded, is BP. My old BMW motorcycle loves it. If I use the E10 91 octane from the other stations I can tell the difference, especially on really hot days on long rides. I cannot get a straight answer from the BP station I frequent, as to whether the 93 octane contains ethanol. A local grocery store chain sells 91 octane non-ethanol but the bike did not run as well as when using the 93 octane BP. In Springfield, MO the Rapid Robert's chain of c-stores post that their 93 octane is ethanol free.

My main question is why so much cloak and dagger about our fuels?