89 vs 91 octane.
 

Hey guys,
Well out here in California our premium gas has been diluted down to 91 and that's going for $3/gal. Can the adaptive fuel curve on a S80 T6 handle 89 vs 91? If we had 92-93 octane I wouldn't even think of 89, but given the price of gas, every penny counts. Any advice or comments would be appreciated.

RE: 89 vs 91 octane.
 

Yes you can run the 89 in your car safely!!

RE: 89 vs 91 octane.
 

I operate my high pressure turbo on 87octane............'regular' and have no detonation issues!! The turbo has a low compression ratio and premium is not necessary at all!!

RE: 89 vs 91 octane.
 

I just got a 2004 S80 2.5T and I believe 91 is recommended and the minimum is 87 (I think).

So, is it ok to use 87 (regular), because I sure would like to save the $.

RE: 89 vs 91 octane.
 

Yes, yes, and yes 28 more times!!! The need for high octane is 'generally' related to compression. Your Volvo turbo is a low compression engine..............for the most part all turbos are low compression because of heat and detonation. At any rate, I have driven several turbos over the years (going back to the 60's) and with the new engine managment systems that preclude detonation I am not hesitant at all to using 87 octane and have done so since my high pressure c70 was new.

RE: 89 vs 91 octane.
 

From what I have heard (and read), using premium 91 octane is highly recommended for the twin turbo T6. I live in California as well and yes, the gas can be pricey, but in the long run, these pennies will be worth it for your car. It will partly help ensure that your engine and transmission live a longer & better life. If you are really serious about this ordeal, you can try mixing 100 octane racing fuel with 91 for about 93-95 octane gas.

RE: 89 vs 91 octane.
 

How does using higher octane gas make your transmission last longer?

I very rarely use anything more than 87 octane. It's because I am too cheap to pay for the more exensive gas and when I have tried it, I see no difference in gas mileage or how the car runs.

RE: 89 vs 91 octane.
 

In the long run, I guarantee you will see the difference. Turbo charged engines, such as those in the T6 (twin charged) work much better with 91+ octane fuel. Found this FYI on another site as well:

Q: Why bother to boost octane at all since my engine can run just fine on lower octane fuel?

A: For a high compression engine to run on low octane fuel, the engine management system will need to retard the ignition timing to prevent preignition or pinging. Retarding the ignition timing means that the firing of the spark plug is delayed until a later moment in the compression stroke. It does not take much to see that a later onset of combustion means that the combustion is less complete, which in turn mean less power and poorer fuel economy. It is possible that the casual driver will still come out ahead in terms of saving money by using low octane fuel, but the retarded ignition advance also means a rougher running engine and a much duller throttle response. Thus octane boosting is not necessarily of interest to all motorists but rather the enthusiasts.

For turbocharged or supercharged engines, insufficient octane will also lead the engine management system to curtail the amount of boost which in turn defeats the purpose of these engines.

RE: 89 vs 91 octane.
 

Read our prior posts re: this issue. It is a moot point regarding high compression!!! Volvo does not make a high compression engine.......indeed.................a turbo has to have low compression....................BMW uses low compression pistons in their turbo conversions. Yes indeedy............if you have a "hot" turbo, then yes you will need high octane...............but...............Volvo does not have high compression and so as so many of us have found over the years..................regular 87 octane works just dandy!!!! Lastly, I spoke with the service mgr. of my Volvo dealership and he agreed with using lower octane.

RE: 89 vs 91 octane.
 

I live in Colorado. We have 91, 87 and 85. What's the lowest octane the 2000 S80 T6 can run at Denver altitude. Anyone know.

RE: 89 vs 91 octane.
 

I would not use 85 octane.................you should find that 87 will serve you well.

RE: 89 vs 91 octane.
 

I lived in Colorado and never used the 85 octane. I used the 87 and when I moved back east I stuck with 87. I don't even remember them having 91. Thought the highest I could get was 89.

RE: 89 vs 91 octane.
 

I tested my 2000 S80 T6 and if I use 87 vs 89 octanes my fuel consumption with 87 is 17l/100 km vs 13l/100 with 89 (quite a difference) and accelerator response is slower with 87 octanes.

RE: 89 vs 91 octane.
 

I have a 99 s80 non turbo. I ran 87 on the first tank and 93 after i read that the car needs 91 and higher is 89 safe for my car?

RE: 89 vs 91 octane.
 

I know that if you have not modified your original setup volvo has tuned the engine to run on pretty much anything you can throw at it. I had my chip reprogramed and they recommend that I run 91 or better now.

RE: 89 vs 91 octane.
 

89 can be used, although to be even more safe, 91 is strongly recommended. The T6 is a twin turbo and turbos necessitate 91 or higher. If 89 is used, the car will run fine but 91 will maximize the output performance and if V-Power is used, the engine will also be cleaned. Basically, 91 is better in the long run because it will offset the costs if problems should arise.

RE: 89 vs 91 octane.
 

What octane fuel should I use for a S80?

The answer is 91 AKI (RON+MON/2). This fuel will cover all daily driving conditions. The only reason to use higher octane is when you increase the power of the engine substantially or racing. To increase the power, you would have to increase the size of the turbo charger on the T6 model, add a larger turbo charger on a non T6 model or introduce nitrous oxide.

Why?

A brief introduction of modern fuels is in order. The number “91” represents that the fuel contains 91% octane and 9% other. This is a very basic description and is not the whole truth. There are other chemicals added to gasoline to increase octane “behavior” a perfect example is TEL or aka “lead”. Aviation and racing gasoline contain TEL “lead” and is not a suitable for legal street cars (cars with catalytic converters). Octane has a lot of potential energy and is very cost effective which make it perfect for cars. Alcohol is also cost effective but is inefficient because it does not have enough potential energy so a lot of alcohol is needed and thus becomes not cost effective. Nitro methane has far more potential energy than octane but is far too dangerous to use.

The greater the octane the more stable the fuel is during combustion. In order to increase the power of an engine more fuel and air is needed. This can be achieved by adding more fuel and air via: adding cylinders, increasing the size of cylinders, forced induction (turbo and super charging) or chemicals (nitrous oxide or alcohol injection). Combustion efficiency is when the air/fuel mixture is burned completely utilizing all the potential energy. If the fuel exploded too early (detonation) the fuel will not completely burn and engine damage can occur as well as lower kinetic energy (less power). The more “power” the greater the octane requirement of the engine.

How to Saving Money.

Fuel efficiency is achieved by utilizing the full potential of the engine and using less air/fuel. This can be accomplished by: keeping the engine running peak efficiency (proper maintenance), driving less, driving slower (not speeding or hard acceleration) and proper tire pressure. A very simple solution is to pay less for gas but that is very hard to do. Most of the cost of gasoline is taxes and the service stations do not mark-up gasoline much (pennies per gallon).

You could drive 50 miles to buy cheap gas but when you add the cost of purchase you loose money. The trick is to find cheaper gasoline where you are driving. Rebate credit cards are also another way to purchase discounted fuel. Brand loyalty is nice but gasoline is gasoline so why pay a premium for brand gasoline when non brand gasoline is 9 times out of 10 the same product. Here is a site for people who share price knowledge. http://www.gasbuddy.com/


You can create your own custom blend by mixing 89 and 93 to make 91 octane gasoline. These are common gasoline grades but they are not available throughout the entire US. If you live in a high altitude area you will notice lower grades of gasoline. If your vehicle is turbo or super charged you still need at least 91 octane gasoline. Fuel additives control deposits which form during combustion. The more incomplete combustion is the more deposits form. Premium gasoline has more deposit control additives and is better for your engine. Fuel injection cleaning will also increase gas mileage by cleaning the injectors, intake ports, valves and pistons. I have left a lot of information out but the length of this message would be pages. If you want more information or disagree let me know?

Happy motoring

RE: 89 vs 91 octane.
 

Note: If you want to run a high quality gasoline then here is a list of retailers. This is for the United States only. If you live in Europe or Japan then you have a much higher quality petro than in the US.

TOP TIER Detergent Gasoline Retailers

Gasoline retailers must meet the high TOP TIER standards with all grades of gasoline to be approved by the automakers as providing TOP TIER Detergent Gasoline.

In addition, all gasoline outlets carrying the brand of the approved retailer must meet the TOP TIER standards.

Additional gasoline retailers are added to the TOP TIER list as they meet the standards. The retailers known to be on the TOP TIER list are shown below.

TOP TIER Gasoline Retailers:

QuikTrip
Chevron
Conoco
Phillips
76
Shell
Entec Stations
MFA Oil Company
Kwik Trip/Kwik Star
The Somerset Refinery, Inc.

RE: 89 vs 91 octane.
 

91 (premium) Shell V-Power.

RE: 89 vs 91 octane.
 

Note: The Big 3 (GM, Ford and Chrysler) use Cheveron to help their new engines pass the US EPA 100,000 mile emissions system durability tests.