Is it worth it to use premium fuel?

[dikidera]

The information is out there. However let's not forget that premium fuel is more expensive per liter than ordinary. So whatever mpg(or km per l) increase it has, may be offset by the cost of it and even being worse.

In my country premium fuel is 100 octane or equivalent to 93 premium fuel in the US, roughly. But it's actually blended with 8-10% of ethanol, I don't think I've seen fuel not blended with ethanol. According to wiki, E10 or Gasohol has a lower energy density than regular petrol, but suprise, our regular ordinary fuel is 95 octane, this is roughly equivalent to American 91, so in my country we've not had lower octane fuel for more than 20 years. And additionally it's still blended with ethanol. More ethanol = more fuel consumption.

So maybe it's best to be sure what fuels you guys use. It may be possible that not only would you lose some power but also increase the expenditure overall with higher octane fuel.

[MoVolvos]

The fuel is not more stable but just combust better. .
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Your information in not correct. Instead of two idiots arguing something we are not experts in, I will simply site source from the. U.S. Energy Information Administration

https://www.eia.gov/energyexplained/gas ... -depth.php

Second paragraph:
"'Octane ratings are measures of fuel stability"

""These ratings are based on the pressure at which a fuel will spontaneously combust (auto-ignite) "

https://www.fuelfreedom.org/what-is-octane/

The short answer is that octane is the measure of how much compression a fuel can withstand before igniting. Or, in layman’s terms, the higher the octane rating, the less likely the fuel is going to pre-ignite (read: explode unexpectedly) at higher pressures and damage your engine

I could site hundreds more, that explain the same.

The site you quote is more marketing focuses than science but is does say what octane is in the first question.

"octane rating, which is the level at which your vehicle’s fuel will combust"

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"My understanding is high octane is a "more stable" fluid, when under high compression and heat there is reduced pre-ignition.

Our i5 have a compression ratio of 10.3:1. Is that high enough to cause pre-ignition under certain conditions and are you driving under those conditions. Either way it's not better gas mileage or horse power, but whether you're losing horse power and mileage due to pre-ignition not using 91."


You started well about stable fuel. You then end with "Either way it's not better gas mileage or horse power, but whether you're losing horse power and mileage due to pre-ignition not using 91".

I don't agree with your definition of Stable Fluid which included it's not about better mileage and power. Regardless of how you worded it, you gain mileage and power when using 91. You happened to choose the cup half full of losing power and losing better mileage due to pre-ignition from not using 91. Regardless, it's all about mileage and HP in the end. The potential engine damage from using 87 when 91 is required is a given.

OP 02V70 ask about mileage gains and increase power and whether it's worth it. "What are the advantages of using premium fuel? I have read conflicting information about it. Does it actually increase MPG? If so, is it enough to justify its higher cost? What kind of performance gain does it give? More horsepower?"

The answer is yes! What kind of gains depends on the driver and the car. Some may be worst off in mileage because the car becomes more fun to drive so the car is driven harder thereby even losing MPG. Regardless, with all thing equal the result of using 91 is more mileage and power which no one disagrees with including you. Everyone on MVS is at a different stage in learning and sometimes relearning so there are no idiots here.
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[MoVolvos]

The information is out there. However let's not forget that premium fuel is more expensive per liter than ordinary. So whatever mpg(or km per l) increase it has, may be offset by the cost of it and even being worse.

In my country premium fuel is 100 octane or equivalent to 93 premium fuel in the US, roughly. But it's actually blended with 8-10% of ethanol, I don't think I've seen fuel not blended with ethanol. According to wiki, E10 or Gasohol has a lower energy density than regular petrol, but suprise, our regular ordinary fuel is 95 octane, this is roughly equivalent to American 91, so in my country we've not had lower octane fuel for more than 20 years. And additionally it's still blended with ethanol. More ethanol = more fuel consumption.

So maybe it's best to be sure what fuels you guys use. It may be possible that not only would you lose some power but also increase the expenditure overall with higher octane fuel.

.
It's true, depending on the cost the mileage gains could be a wash. However, it's a much better driving experience not to mention cleaner burning for the benefit of the car and the environment.
.

[P80GLT]

I used regular fuel in my diesel cars for over 25 years without any problems, often doing up to 40,000 miles a year. I changed to Shell V-Power when I bought my diesel XC90 which was fitted with a DPF. Apparently V-Power burns cleaner and keeps the internals cleaner and during my 5 year ownership I never had a single DPF problem with the car. Petrol in the UK consists of e10 (95 Ron) 10% ethanol or e5 (99Ron) 5% ethanol. I use the e5 (99Ron) in both the 850 and the V70 as it contains less water in the hope it causes less corrosion of my fuel system. I also put a bottle of Forte fuel cleaner in my tank a couple of times every year

[vtl]

Fuel system is pretty much all plastic, at least in P2.

[ignatz]

I'll be the odd duck and say, I use premium fuel in my 01, 02 and 05 turbo Volvos as insurance to keep the car happy and not burn a valve. A burnt valve might be rare but, I just want to keep the cars happy.
My 01 had an oil pickup problem years back and not long after I fixed the oil pickup o-ring, I saw there was an updated oil pickup pipe available. Now at 226K, I'll drop the pan again and fit the updated oil pickup. New Volvo rod bearings and bolts too.
I just want to keep my 01 happy and it gives a retired mechanic something to do.

[vtl]

I'll be the odd duck and say, I use premium fuel in my 01, 02 and 05 turbo Volvos as insurance to keep the car happy and not burn a valve. A burnt valve might be rare but, I just want to keep the cars happy.
My 01 had an oil pickup problem years back and not long after I fixed the oil pickup o-ring, I saw there was an updated oil pickup pipe available. Now at 226K, I'll drop the pan again and fit the updated oil pickup. New Volvo rod bearings and bolts too.
I just want to keep my 01 happy and it gives a retired mechanic something to do.

Pull the head and replace the piston rings. It would make more sense than replacing rod bearings (which most likely will be fine).

[velorider]

I don't agree with your definition of Stable Fluid which included it's not about better mileage and power.

Not my definition, I included sites, that know better then we do, that use the same term. Octane is a measurement, not an ingredient. It's a measurement of fuels ability to withstand pre-ignition under high pressure and heat, i.e stability.

So saying it improves gas mileage is very misleading. In our engines, higher octane maybe prevents loss of mileage because the engine isn't retarding timing to avoid damage.

To the OP, if you run regular fuel and you car is not retarding timing, then you will receive the same gas mileage. If your car is losing mileage on regular your engine is retarding timing to protect itself from damage due to knock. If your Volvo requires 91/93 octane, that is because there is concerns the engine will have to retard timing to prevent knock or pre-ignition, aka engine damage. You can run a regular octane as long as the car can retard timing enough to prevent knock. Under these condition you will see a loss of mileage and performance, but if timing can't be retarded enough to prevent knock, it will damage your engine. This is why saying high octane improve gas mile is very misleading. The engine is retarding time to prevent knock, knock is very damaging to the engine. The loss of mileage is a side effect of retarding timing. Octane has no impact on mileage, any change in mileage is a side effect of the engine trying to prevent damage.

Octane is only a measurement of the fuel stability, any mileage gains/lose is a side effect of the reason stated above.

[abscate]

There was a fairly decent data mining exercise here to correlate octane use with burnt valves, I’ll try to find and link

[dikidera]

There was a fairly decent data mining exercise here to correlate octane use with burnt valves, I’ll try to find and link

Kind of no need.

Just these days this is kind of discussed here and specifically about Volvo http://nefariousmotorsports.com/forum/i ... c=340.2490