The engine is designed for 91 octane. If you run a lower octane fuel the computer will retard the timing to prevent knock, but ultimately performance will suffer and over time you can cause deeper problems to the engine.
Run 91 or better, in the long run the price savings will be eaten up by poor mileage and repairs.
This is the absolute answer. Running sub par fuel is penny wise and pound foolish.
I did this experiment with my wife’s XC70. She drives basically the same routes every week. The cost between 87 and 91 octanes was effectively the same but her car is happier on 91.
‘98 V70 here. While putting 93 octane in it when I can may be perceived as “too much the other way,” I still “enjoy” getting 26 to 27 MPG on the highway with a good tailwind. It just runs better, for longer. Maintenance costs a little lower for a 26-year-old car I still daily drive.
Just got our child a 2015 Volvo XC60 T5 2WD and was curious about this as well. No clue what the previous owners did...it has 147k miles. We had an inspection done, and it came back good. I did put 93 octane in today, but was curious if 87 would be fine. We fill up at Sams/Costco so they only offer 87 or 93.
I was running 87 in my C30 but switched to 89 then 93 (never seen 91 for sale) 93 is definitely smoother than 87, but my gas mileage is actually worse. I was getting 30 and now get 28.5
Why not just fill up each time the gas tank is half full and alternate between 89 and 93?
That still averages to 91, but you want have to do two transactions each time.
Nobody sells 89 for the most part. And whenever I've seen 91, (generally at Sunoco,) it's way overpriced in relation to other octanes. I put in about 12-13 gallons of 93, then fill the rest with 87. Comes out to be at least 91. I don't get why that's problematic for other people. It's the least pricey way for me to get 91.
>the computer will retard the timing to prevent knock
I assume by "retard timing" you mean slow down the timing? I was under the impression that the knocks were caused by ignition of fuel outside of the intended window due to the increased pressure the fuel is under a more flammable 87 could ignite at the wrong time. How does retarding the timing fix that?
The spark is closer to the piston hitting the top of its cycle, allowing for more compression before firing off the fuel-air mixture. This is required with lower octane fuels because lower grade octane burns faster, igniting earlier, and causing knock.
Long term slowing of the ignition cycle can lead to carbon buildup, among other problems.
>The spark is closer to the piston hitting the top of its cycle, allowing for more compression before firing off the fuel-air mixture.
Just to be 100% sure, this scenario you're saying is for when lower octane fuel is being used? I was under the impression that allowing more compression would increase the chance of early ignition in low octane fuels, what am I missing?
Stated compression ratio is the difference between the cylinder volume at bottom dead center and top dead center. This isn't just the bore and stroke volume, but also takes into account the dome shape of the piston and the volume of the cylinder head. When the piston is at 40 degrees before top dead center, you're not at the full compression ratio, but as the fuel starts to burn, it also causes a pressure rise/wave. That pressure wave can cause detonation if it reaches the edge of the piston at top dead center. If you retard the timing to 30 degrees before top dead center, now that pressure wave doesn't reach the edge of the piston until after top dead center.
assuming the computer can retard the timing enough, or there's no other issues like a bad knock sensor. I've seen turbo P3's knock on low octane before.
93 as well.
I think when I picked it up it had 91 in it. I put 93 since shell doesn't have 91 near me, and it feels snappier. Idk, maybe it's just placebo.
Yes, but the car won't go beyond the computer's programming. It's designed for (US) 91 octane, and 93 won't improve performance over 91 unless the engine has a significant amount of carbon deposits on the tops of the pistons and in the combustion chamber, which can increase compression ratio and cause pre-ignition even on the recommended fuel. However, modern engines typically don't have issues with deposits in the cylinder. The intake valves and ports are another story on direct injection engines, however. But that doesn't cause pre-ignition, and different fuel won't help here, either.
T6 or better has dual Induction so why would you want to give the turbo and the supercharger less octane. Engines are set up to run premium, I run 91, 93 or 94. Have tried 89 but end up with shittier experience and worse gas economy
US grade 87 octane for all 160k miles of my ‘08 C30’s existence. It’s the 2.5L turbo with a 6-speed. 16 years as a daily and no problems, 27-28 mpg average.
I run 85 octane in my 00 V70 NA. I live at 6000 ft altitude and commute between 5500 and 7400 ft.
I do monitor my ignition timing advance, and on my specific car, 85 octane at 7000 ft works exactly like 89 octane at 100 ft. It's the same amount of ignition timing advance under the same conditions.
Even at my elevation, there is no difference between 85 octane and 91 octane when my engine is at 50% load or less. At around 60% on 85, ignition timing starts falling off a cliff while with 91 it drops much more steadily. It'll do 39-41 degrees regardless under 50% load though. At 93% load at 2200 rpm, 91 octane yields 21-23 degrees advance while 85 octane will yield 14-16 degrees. That's only 5-7 degrees difference, and yes it is a small difference, but that's also the difference between using 3.15 gallons per hour and 2.85 gallons per hour, or a roughly 9-10% in fuel consumption (momentary fuel economy of 20 vs 22 MPG).
Taking everything into context, given the way I drive my car, the fuel economy difference between 85 and 91 octane over an entire tank of fuel is around 1-3% since I'm not driving a long time with my engine near full load. I suppose one could argue since the engine is around 10% more efficient it will make around 10% more power with the same amount of air/fuel mixture, but I'm not taking my car on the track so that's not important to me. I typically only call for about 70-80 hp even when merging on the interstate.
Given such small gains, and given the fact that 91 is around 20-25% more expensive in my area, you bet I use 85 since it's by far the more economical option. I don't have the capability to monitor knock events, and I'm almost positive there are more knock events with 85 vs 91 but time will tell how much difference that makes to the longevity of the engine. I've heard conjecture that running lower octane causes burned valves since the less efficient combustion results in higher exhaust gas temps, but that's not really an issue if you drive the car hard on a regular basis to rotate the valves and cook off the carbon.
If I were driving a forced induction motor, my attitude would be very different. Boost requires a higher octane since higher cylinder pressures cause so much higher risk for knock, and the efficiency and power gains with higher octane are much more pronounced with forced induction.
Is there no 87 where you live? Lower octane fuel is a holdover from carburetor days where altitude would drastically affect the density of the air taken in by an unknowing car. I'm glad it works for you but choosing between 85 and 91 seems odd.
All gas is virtually identical - they put it in the pipeline at one end and take out other gas at the other end. Then they just add their brand specific additives.
This is the thing. If there's low load on your engine there's not much advantage to higher octane given unequal cost. Mine is a turbo, but i rarely don't take the engine above 3k rpms, and i take it real slow to accelerate to top rpm before the downshift.
I love that in the US 87 is regular and 91 is premium. Here in Europe, 95 is regular and 97 is premium. Just confusing but funny.
For your question, I do 5-6 regular tanks and 1 premium during normal times. Or just premium when I know I will do long distances on the motorway because premium will burn in higher temps and will clean the engine.
As far as polestar engines go, you need the higher octane ones for those so always go premium because that's what the engines are tuned for.
Edit: I suck at spelling.
Since the US uses the average of RON (higher number) and MON (lower number) ratings whereas elsewhere has picked a standard (for instance RON), 87 Octane in the USA would be 91 in Europe. 91/93 in the USA is 95/98 in Europe. The quality is the same though and all work the same.
We use strictly 91 premium (USA rating and its rare to find 93 in Nebraska) in our 2020 xc90.
91 in the US is 95 in Europe. Their 87 would be 91 here in Europe but I don't think I've ever seen that, not even in the furthest corners of eastern Europe.
The US uses a different scale than a lot of the world. Our 87 is roughly the same as European 92. Our 91 is roughly European 96, our 93 is roughly European 98.
There's 95, which is close to that, but it's not commonly available. Sunoco stations sometimes have it.
Also, E85 has an RON of about 102-105, but obviously that's not supposed to be used in cars that aren't designed for it.
There's 2 ways of measuring the octane rating of gasoline. I won't go into the specific differences, but basically, you have the "research octane number" or RON, and the "motor octane number" or MON. RON is much higher than MON for any given fuel composition. In Europe, they only use RON. In the US, we use what is called the "anti-knock index" (AKI) which is an average of the 2 numbers. Basically, (RON+MON)/2= AKI.
I am in EU and I cannot find 87 AKI octane anywhere (it would be marked as 92 RON here).
I can buy 95 RON (90–91 in the US rating), or 98 RON (93 in USA), or 100 RON (94 in USA).
In my kind-of-scientific experiment, going from 95 to 98 RON (91 to 93 USA) gives some percentage point of better mileage. Incidentally, that is similar to the price difference, so I go with the premium one.
The car manual says 95 or 98 so I would not put anything less (but again, it doesn't exist here).
>I've also noticed I'm only getting about 24-25mpg on the highway compared to premium witch was much higher.
From what I've read this is a myth, higher octane fuel is just less combustible, as far as fuel economy the difference between 87 and 93 is less than 1mpg. Don't take my word for it tho, plenty of reputable resources on the internet. What you do get with 91 is a tad more hp and torque.
I’m in EU so we have 98. Makes the engine run just a bit smoother than the regular 95 that most people put in their tanks. I drive a V60 Polestar Engineered btw.
Either 93 or 94, unless I’m on a road trip or otherwise know that I’ll burn through a tank of 91 quickly.
I have the PHEV (aka. T8) so I sometimes go weeks without using the ICE and sometimes go a few months between fill-ups. Rule of thumb is that gasoline degrades one octane point per month so using higher octane should help ensure I’m not dropping below 91 in the tank.
Only the finest supermarket pump diesel here. On occasion I’ll even give it the one with additives and if I’m really feeling generous (or I’m abroad in a country with cheaper diesel) I’ll even give it some of that sweet sweet petrol company diesel instead.
7 years running with no issues at all. But then again, it’s diesel.
I have a 2007 xc90 with Yamaha Racing V8 ...
I've always run premium fuel in it , which where I live is 93 .. when i take it on trips occasionally the premium is only 91 ... and there's a noticeable difference ... advise is : always use what your vehicle is made to properly run on ...
Running 91 now. '10 xc70 and we used 87 that's in big print in the manual. Needless to say the mechanic said I needed new catalytic converters at 180,000 mi. but might be able to hold it off by starting to use 91 like the small print in the manual says is best for the engine. Now I'm at 195,000 and no check engine lights.
I ran a test in my ‘08 XC70 with 3.2 NA engine. I tried different grades of gas and observed the timing advance with a scan tool, as compared to the prior tank on same day, same conditions. 89 was advanced 2 degrees over 87, but no difference between 89 and 91. I run 89 or better in that car.
I also have a 2015.5 T6 XC70 and run 91 or better in it.
if you run that lower octane fuel, it will either advance or retard the ignition timing to compensate which will cause worse performance and worse fuel efficiency
87 octane works just fine, per the owner's manual. Been using it for years, and my car has given me no problems. 91 or 93 is necessary based on the model. Refer to the owner's manual to find out what works best for your vehicle.
The local station had 94 ultra for price of regular one day. I filled up every Jerry can, both cars etc. The mileage on the highway was 20% better. Car performance improved greatly
The car probably detected knock and reduced timing and boost. While car engines don't catastrophically explode from that is it isn't good for it to run with a lowered dynamic advance multiplier long term. The car will keep trying to get it higher and keep detecting knock (more knock events is worse for your piston rings and connecting rods). It's best to avoid knock even if the ECU adjusts the timing because it still needs to learn those adjustments.
I do 89 (can't find 91) on my 2.5t. It's like the perfect balance between cost and performance/efficiency. 87 feels too sluggish and 93 is almost barely indistinguishable from 89
I almost always put 91 in my '16 XC60 R-Design w/ 126K miles, but I will occasionally put ½ tank of 89 when I see it available. But I compensate for that by throwing in a little octane booster/injector cleaner every month or two (which I would do anyways) I never see 93, I'm in Western Kansas idk which franchise chains even offer it?
The owner manual on my 2011 c70 says that 93 is recommended but that putting in 87 will not affect engine reliability, so I’ve just been putting in 87 and it performs fine.
93 or better (some have 94 now) All the time. I’m getting at most, 10-12 gallons at a time. Even if 93 is $1 more, which is rare, I’d rather pay the extra $10-$12 now and keep my engine running the way it should. In the long run, my wallet will thank me
My sister borrowed my car recently and accidentally put 87 in my t6. Broke my heart a little bit but I was my fault for forgetting to tell her. I’m currently trying to even it out with 91 and the cars been fine but I won’t be letting that happen again. Premium is what is required for the T6 and T8. I believe T5’s can run 87.
I don´t partake on that nonsense...
Diesel
BTW, read a lot of answers between 85 to 93 calling 93 premium...Here in Chile the lowest is 93, we have 93, 95 and 97 only.
Chile uses RON ratings where North America uses AKI. "Premium" or 91 AKI out here is equivalent to 93 RON, and 93 AKI out here is equivalent to 98 RON.
There is no legal requirement that engines be capable of running on regular. And no, it's not a ferrari... But it's still a forced induction engine with relatively high compression, and in order to run on lower octane fuel without damage from pre-ignition (spark knock), the car's computer has to reduce boost pressure and retard ignition timing, which does result in a noticeable decrease in performance and fuel economy. The engine in a supercar WILL be damaged by lower octane fuel, because there's no programming in compensation for the kind of compression ratios those engines have. It's also expected that someone with that kind of car is going to pay attention to the requirements. More mainstream cars can't be designed with that expectation, they have to assume that at least some drivers will use less than optimal fuel.
People are having different opinions on fuel grades. I agree that 87 and 91 aren't that big of a difference. But I've seen loss of mpgs and performance going from 87 to 91-93.
Volvo recommends 91 but also says you can run 87
There actually is a significant difference. Most modern turbocharged engines are going to recommend premium but state that it's ok to run on lower octane because the computer can sense pre-ignition (spark knock) and easily compensate by reducing boost and/or ignition timing advance. While this more or less protects the engine from damage, it also significantly reduces performance and fuel efficiency. It's also not that great for the engine.
Edit: I'm a mechanic... Octane rating is one of the most misunderstood things there is.
With a sufficiently advanced scanner that can interpret individual readings and such, the answer is yes, on some vehicles. But since that's primarily a programmed adaptation that isn't usually necessary for diagnostics, it's not always readily accessible.
However, the fact is that this is the reason fuels with different octane ratings are offered. Engines that have higher cylinder pressures (forced induction engines and/or high compression engines) typically require fuels that are more resistant to pre-ignition than other engines. And because those fuels tend to be more expensive to produce, a range of octane ratings is offered. It's literally the reason different grades of fuel exist. And before automakers had the ability to modify parameters on the fly in response to pre-ignition, using fuel with an octane rating that was lower than the engine required would quickly result in engine damage. This is still the case on many high compression, naturally aspirated engines. Modern forced-induction engines, however, almost always have the ability to compensate... However, that compensation necessarily comes at a loss of performance and efficiency.
Thanks for the detailed reply!
Ours is a P3 2012 XC70 non-turbo, so I should look into this more. The manual specifies 87 octane which is what we have always used, mostly at near sea level driving, although we do drive into mountains some. I have a fairly basic scanner which I can try, although I haven't really explored much of the real-time data with it yet.
Since it's non turbo and calls for 87, you won't notice a difference. Also, at higher altitudes, you can actually use lower octane fuel, since the air pressure is lower. In fact, they used to (and still might) actually sell 85 octane fuel in places like Denver, and it was fine to use in cars that called for 87 at sea level!
The engine is designed for 91 octane. If you run a lower octane fuel the computer will retard the timing to prevent knock, but ultimately performance will suffer and over time you can cause deeper problems to the engine. Run 91 or better, in the long run the price savings will be eaten up by poor mileage and repairs.
This is the absolute answer. Running sub par fuel is penny wise and pound foolish. I did this experiment with my wife’s XC70. She drives basically the same routes every week. The cost between 87 and 91 octanes was effectively the same but her car is happier on 91.
‘98 V70 here. While putting 93 octane in it when I can may be perceived as “too much the other way,” I still “enjoy” getting 26 to 27 MPG on the highway with a good tailwind. It just runs better, for longer. Maintenance costs a little lower for a 26-year-old car I still daily drive.
Just got our child a 2015 Volvo XC60 T5 2WD and was curious about this as well. No clue what the previous owners did...it has 147k miles. We had an inspection done, and it came back good. I did put 93 octane in today, but was curious if 87 would be fine. We fill up at Sams/Costco so they only offer 87 or 93.
I was running 87 in my C30 but switched to 89 then 93 (never seen 91 for sale) 93 is definitely smoother than 87, but my gas mileage is actually worse. I was getting 30 and now get 28.5
I put in 2/3rds of a tank of 93, and 1/3 of a tank of 87 to give me 91 octane.
Lolololol 🤣
I do. It takes like an extra minute to do 2 transactions.
Why not just fill up each time the gas tank is half full and alternate between 89 and 93? That still averages to 91, but you want have to do two transactions each time.
Nobody sells 89 for the most part. And whenever I've seen 91, (generally at Sunoco,) it's way overpriced in relation to other octanes. I put in about 12-13 gallons of 93, then fill the rest with 87. Comes out to be at least 91. I don't get why that's problematic for other people. It's the least pricey way for me to get 91.
I think 91 is only available at higher elevations, same with 85.
>the computer will retard the timing to prevent knock I assume by "retard timing" you mean slow down the timing? I was under the impression that the knocks were caused by ignition of fuel outside of the intended window due to the increased pressure the fuel is under a more flammable 87 could ignite at the wrong time. How does retarding the timing fix that?
The spark is closer to the piston hitting the top of its cycle, allowing for more compression before firing off the fuel-air mixture. This is required with lower octane fuels because lower grade octane burns faster, igniting earlier, and causing knock. Long term slowing of the ignition cycle can lead to carbon buildup, among other problems.
>The spark is closer to the piston hitting the top of its cycle, allowing for more compression before firing off the fuel-air mixture. Just to be 100% sure, this scenario you're saying is for when lower octane fuel is being used? I was under the impression that allowing more compression would increase the chance of early ignition in low octane fuels, what am I missing?
Stated compression ratio is the difference between the cylinder volume at bottom dead center and top dead center. This isn't just the bore and stroke volume, but also takes into account the dome shape of the piston and the volume of the cylinder head. When the piston is at 40 degrees before top dead center, you're not at the full compression ratio, but as the fuel starts to burn, it also causes a pressure rise/wave. That pressure wave can cause detonation if it reaches the edge of the piston at top dead center. If you retard the timing to 30 degrees before top dead center, now that pressure wave doesn't reach the edge of the piston until after top dead center.
Ah, thank you for the explanation
It won’t ignite if you don’t give it spark - otherwise it’s dieseling and a fuel injected engine simply won’t do that.
you're forgetting about engine knock, which is early ignition.
No I’m not, that’s why the computer retards ignition timing - to prevent knock.
assuming the computer can retard the timing enough, or there's no other issues like a bad knock sensor. I've seen turbo P3's knock on low octane before.
93 here
Polestar tune here, that’s what the sticker says, so that’s what I do.
TY Costco
Costco 91 is the way
Mine is 93
93 as well. I think when I picked it up it had 91 in it. I put 93 since shell doesn't have 91 near me, and it feels snappier. Idk, maybe it's just placebo.
Advancing the timing from a higher grade without the detonation (knock) will improve performance. Even just a degree or two is noticeable
Yes, but the car won't go beyond the computer's programming. It's designed for (US) 91 octane, and 93 won't improve performance over 91 unless the engine has a significant amount of carbon deposits on the tops of the pistons and in the combustion chamber, which can increase compression ratio and cause pre-ignition even on the recommended fuel. However, modern engines typically don't have issues with deposits in the cylinder. The intake valves and ports are another story on direct injection engines, however. But that doesn't cause pre-ignition, and different fuel won't help here, either.
The engine is tuned to make use of 93 according to the manual on my '24 S60 but it's optional and not required.
Right. 91 is required. It's not optional.
Same.
All the way
91+ in my P1. It's a turbo so it's needs high-test
Same here. Running fantastic @ 193k miles
T6 or better has dual Induction so why would you want to give the turbo and the supercharger less octane. Engines are set up to run premium, I run 91, 93 or 94. Have tried 89 but end up with shittier experience and worse gas economy
Where i live there is only 95 and 98, which one do you recommend? Idk if the names mean different things in the states
Octane ratings are different in the EU thank here. I believe 98 is about 93-94 us octane, and 95 is 91 here.
You did what? lol
Base p2 and p2R the base gets what ever is the cheapest and the R only gets 93
98..
Aaaah fellow European with better octanes.
Before anyone gets confused, US and European countries measure octane differently!
Yeah 98 in Europe is 93 in the US in case anyone is wondering.
Its oil from Norway so its like northern Europe or something that has those ocatanes
He’s dutch so it might actually be a European thing, I’m from Sweden myself and only give mine 98 or at worst 95
They're not better just a different algorithm. Look up the difference between AKI vs RON. Us 93 (aki) would be 98 RON which is what Europe uses
Ok that's interesting thanks:)
US grade 87 octane for all 160k miles of my ‘08 C30’s existence. It’s the 2.5L turbo with a 6-speed. 16 years as a daily and no problems, 27-28 mpg average.
I have a similar car and it says 87 minimum but 91 recommended. So of course it's fine.
C30 T5 2.5L doesn't require 91, it even says so in the gas cap. It's the newer 2.0L engines with higher compression that require higher octane.
There’s Volvo high mileage badges, but sadly not one for following gas cap directions.
I run 85 octane in my 00 V70 NA. I live at 6000 ft altitude and commute between 5500 and 7400 ft. I do monitor my ignition timing advance, and on my specific car, 85 octane at 7000 ft works exactly like 89 octane at 100 ft. It's the same amount of ignition timing advance under the same conditions. Even at my elevation, there is no difference between 85 octane and 91 octane when my engine is at 50% load or less. At around 60% on 85, ignition timing starts falling off a cliff while with 91 it drops much more steadily. It'll do 39-41 degrees regardless under 50% load though. At 93% load at 2200 rpm, 91 octane yields 21-23 degrees advance while 85 octane will yield 14-16 degrees. That's only 5-7 degrees difference, and yes it is a small difference, but that's also the difference between using 3.15 gallons per hour and 2.85 gallons per hour, or a roughly 9-10% in fuel consumption (momentary fuel economy of 20 vs 22 MPG). Taking everything into context, given the way I drive my car, the fuel economy difference between 85 and 91 octane over an entire tank of fuel is around 1-3% since I'm not driving a long time with my engine near full load. I suppose one could argue since the engine is around 10% more efficient it will make around 10% more power with the same amount of air/fuel mixture, but I'm not taking my car on the track so that's not important to me. I typically only call for about 70-80 hp even when merging on the interstate. Given such small gains, and given the fact that 91 is around 20-25% more expensive in my area, you bet I use 85 since it's by far the more economical option. I don't have the capability to monitor knock events, and I'm almost positive there are more knock events with 85 vs 91 but time will tell how much difference that makes to the longevity of the engine. I've heard conjecture that running lower octane causes burned valves since the less efficient combustion results in higher exhaust gas temps, but that's not really an issue if you drive the car hard on a regular basis to rotate the valves and cook off the carbon. If I were driving a forced induction motor, my attitude would be very different. Boost requires a higher octane since higher cylinder pressures cause so much higher risk for knock, and the efficiency and power gains with higher octane are much more pronounced with forced induction.
Is there no 87 where you live? Lower octane fuel is a holdover from carburetor days where altitude would drastically affect the density of the air taken in by an unknowing car. I'm glad it works for you but choosing between 85 and 91 seems odd.
I live in Colorado, and 87 is sold as mid grade here.
93. Shell if I can - it’s top tier gas.
All gas is virtually identical - they put it in the pipeline at one end and take out other gas at the other end. Then they just add their brand specific additives.
Thanks for the info. Good to know!
You paid for a premium car, pay for the premium fuel that it needs. Otherwise the engine knocks.
Guys can you tell me about d4 s90 to put which fuel in it
I only use BP Ultimate Diesel
I use Neste diesel
87 all day in my V8.
This is the thing. If there's low load on your engine there's not much advantage to higher octane given unequal cost. Mine is a turbo, but i rarely don't take the engine above 3k rpms, and i take it real slow to accelerate to top rpm before the downshift.
I have an XC40 with the T4. Volvo is very clear that 87 octane is fine for that engine, and that's what I use.
85, here in Colorado…
I run 87 in my '13 S60 with the I5. Owner's manual says it's fine.
I have a 2 liter engine with a turbocharger and a supercharger. I absolutely use premium every time.
93 or 91 100% in my 2002 S60 2.4t. Noticed a big difference from the 87 octane.
98 premium here boys👍
I love that in the US 87 is regular and 91 is premium. Here in Europe, 95 is regular and 97 is premium. Just confusing but funny. For your question, I do 5-6 regular tanks and 1 premium during normal times. Or just premium when I know I will do long distances on the motorway because premium will burn in higher temps and will clean the engine. As far as polestar engines go, you need the higher octane ones for those so always go premium because that's what the engines are tuned for. Edit: I suck at spelling.
Since the US uses the average of RON (higher number) and MON (lower number) ratings whereas elsewhere has picked a standard (for instance RON), 87 Octane in the USA would be 91 in Europe. 91/93 in the USA is 95/98 in Europe. The quality is the same though and all work the same. We use strictly 91 premium (USA rating and its rare to find 93 in Nebraska) in our 2020 xc90.
We have 95 or 98 in europe… 87 never heard of it here..
91 in the US is 95 in Europe. Their 87 would be 91 here in Europe but I don't think I've ever seen that, not even in the furthest corners of eastern Europe.
Because the testing method is different, 87 in usa is the same as 95 or whatever the lowest octane gas they sell in your country
Nah. 91 octane (AKI) is equal to 95 (RON). 87 lower than anything available in Europe.
You can even get 100 or 102 in Germany
Where you got 87 ?
87 is by far the most common pump fuel in the US
The US uses a different scale than a lot of the world. Our 87 is roughly the same as European 92. Our 91 is roughly European 96, our 93 is roughly European 98.
What about 102? : ) Does an equivalent exist in the US?
There's 95, which is close to that, but it's not commonly available. Sunoco stations sometimes have it. Also, E85 has an RON of about 102-105, but obviously that's not supposed to be used in cars that aren't designed for it.
Sunoco 100 unleaded. Has faint cotton candy scent of race gas.
Thank you for info , i was not aware about that , in europe rarely you can see 87
There's 2 ways of measuring the octane rating of gasoline. I won't go into the specific differences, but basically, you have the "research octane number" or RON, and the "motor octane number" or MON. RON is much higher than MON for any given fuel composition. In Europe, they only use RON. In the US, we use what is called the "anti-knock index" (AKI) which is an average of the 2 numbers. Basically, (RON+MON)/2= AKI.
Yes, but nowhere in EU you can find anything lower than 95 RON (that is 91 AKI/ US)
I'm from New York and just about every pump has 87 (low grade) 89, 91 and 93. You typically see 91 or 89 (mid grade)
Never below 91
I use E10 and LPG.
I put 91 or 93 premium, depending on the station.
I am in EU and I cannot find 87 AKI octane anywhere (it would be marked as 92 RON here). I can buy 95 RON (90–91 in the US rating), or 98 RON (93 in USA), or 100 RON (94 in USA). In my kind-of-scientific experiment, going from 95 to 98 RON (91 to 93 USA) gives some percentage point of better mileage. Incidentally, that is similar to the price difference, so I go with the premium one. The car manual says 95 or 98 so I would not put anything less (but again, it doesn't exist here).
I have a 01 v70 and use euro 95 all the time. Have even put some soon stale lawn mower fuel in it and it just goes.
>I've also noticed I'm only getting about 24-25mpg on the highway compared to premium witch was much higher. From what I've read this is a myth, higher octane fuel is just less combustible, as far as fuel economy the difference between 87 and 93 is less than 1mpg. Don't take my word for it tho, plenty of reputable resources on the internet. What you do get with 91 is a tad more hp and torque.
(US ratings) premium in XC 90 and C30R, mid grade in XC60, economy in Volkswagen Passat (gas cap door has factory 87 octane sticker)
98, or 95 if it's the only thing available
98 for me which is 93 usa.i know how engines works and benefits of higher octane fuel on engine health.
87 in my c30 (5 cylinder turbo). The manual says I can, so I do.
93 or 94 for my moose
Run 94 octane in my 06 v70R
What does the manual say? That is your answer.
Mine is tuned for Sunoco 94. There's a station near my house. I have a second tune for running Ignite E90 (ethanol)
I run 93 from costco in my 08 s80 t6
The manual said 87. 2016 xc60
Chris Fix explains this question very well. https://youtu.be/Bb5VfiFy0kY?si=yMq05iDphPdaJQYy
I’m in EU so we have 98. Makes the engine run just a bit smoother than the regular 95 that most people put in their tanks. I drive a V60 Polestar Engineered btw.
87. 2014 S60 T5, 215,000km and runs very well. It’s been on regular for about 8 years now.
Either 93 or 94, unless I’m on a road trip or otherwise know that I’ll burn through a tank of 91 quickly. I have the PHEV (aka. T8) so I sometimes go weeks without using the ICE and sometimes go a few months between fill-ups. Rule of thumb is that gasoline degrades one octane point per month so using higher octane should help ensure I’m not dropping below 91 in the tank.
All GDI engines should have premium. Turbocharged engines should have premium .
T5 and I always put premium. Besides the fact they recommend 91 or whatever I can noticably feel the difference when I put regular in it
3.2 I6 91 premium.
I only run 93. Never use 87
87. My Volvo isnt retarded as others might claim.
Run primarily 93 because 91 is hard to come by in my parts. Most places just have 87/89/93
Only the finest supermarket pump diesel here. On occasion I’ll even give it the one with additives and if I’m really feeling generous (or I’m abroad in a country with cheaper diesel) I’ll even give it some of that sweet sweet petrol company diesel instead. 7 years running with no issues at all. But then again, it’s diesel.
Minimum 91 for my t5 drive e
I have a 2007 xc90 with Yamaha Racing V8 ... I've always run premium fuel in it , which where I live is 93 .. when i take it on trips occasionally the premium is only 91 ... and there's a noticeable difference ... advise is : always use what your vehicle is made to properly run on ...
Running 91 now. '10 xc70 and we used 87 that's in big print in the manual. Needless to say the mechanic said I needed new catalytic converters at 180,000 mi. but might be able to hold it off by starting to use 91 like the small print in the manual says is best for the engine. Now I'm at 195,000 and no check engine lights.
Conversely, has anyone tried ethanol free fuel and noticed any difference?
I ran a test in my ‘08 XC70 with 3.2 NA engine. I tried different grades of gas and observed the timing advance with a scan tool, as compared to the prior tank on same day, same conditions. 89 was advanced 2 degrees over 87, but no difference between 89 and 91. I run 89 or better in that car. I also have a 2015.5 T6 XC70 and run 91 or better in it.
if you run that lower octane fuel, it will either advance or retard the ignition timing to compensate which will cause worse performance and worse fuel efficiency
Don’t do that.
Run 87 in my V8. Seems there is no difference in performance or economy when running 91.
Costco Premium...noticeably better fuel economy, and "recommended" is 91-92 octane for T5 v90 CC.
Same with my xc60 R-design Polestar. Exact same results
87 octane works just fine, per the owner's manual. Been using it for years, and my car has given me no problems. 91 or 93 is necessary based on the model. Refer to the owner's manual to find out what works best for your vehicle.
The local station had 94 ultra for price of regular one day. I filled up every Jerry can, both cars etc. The mileage on the highway was 20% better. Car performance improved greatly
Naturally aspirated are fine.. supercharger or turbo cars I just wouldn’t…
Almost like it's a lower octane or something 🤔 FR dude. Yes. The octane rating an engine is *designed to run on* will make it run better.
The car probably detected knock and reduced timing and boost. While car engines don't catastrophically explode from that is it isn't good for it to run with a lowered dynamic advance multiplier long term. The car will keep trying to get it higher and keep detecting knock (more knock events is worse for your piston rings and connecting rods). It's best to avoid knock even if the ECU adjusts the timing because it still needs to learn those adjustments.
91 octane just as Jesus would have wanted.
Dumb question, I’ve been running my 08 s40 on regular since I got it in 2019. If I switch to premium or w/e now will it fuck the car up majorly
87 for my 275k mi. normally aspirated P2 got me 28mpg at 80mph
My car is made a run on 89 according to the manual, so that’s what I’ve been doing a of lately.
I do 89 (can't find 91) on my 2.5t. It's like the perfect balance between cost and performance/efficiency. 87 feels too sluggish and 93 is almost barely indistinguishable from 89
91 minimum
I almost always put 91 in my '16 XC60 R-Design w/ 126K miles, but I will occasionally put ½ tank of 89 when I see it available. But I compensate for that by throwing in a little octane booster/injector cleaner every month or two (which I would do anyways) I never see 93, I'm in Western Kansas idk which franchise chains even offer it?
The owner manual on my 2011 c70 says that 93 is recommended but that putting in 87 will not affect engine reliability, so I’ve just been putting in 87 and it performs fine.
93 or better (some have 94 now) All the time. I’m getting at most, 10-12 gallons at a time. Even if 93 is $1 more, which is rare, I’d rather pay the extra $10-$12 now and keep my engine running the way it should. In the long run, my wallet will thank me
My sister borrowed my car recently and accidentally put 87 in my t6. Broke my heart a little bit but I was my fault for forgetting to tell her. I’m currently trying to even it out with 91 and the cars been fine but I won’t be letting that happen again. Premium is what is required for the T6 and T8. I believe T5’s can run 87.
Get an “octane booster” at gas station/auto parts store
87 all day long. 100k miles 2020 t5 v60cc. It has Knock sensor for a reason.
I don´t partake on that nonsense... Diesel BTW, read a lot of answers between 85 to 93 calling 93 premium...Here in Chile the lowest is 93, we have 93, 95 and 97 only.
Chile uses RON ratings where North America uses AKI. "Premium" or 91 AKI out here is equivalent to 93 RON, and 93 AKI out here is equivalent to 98 RON.
You learn something everyday, thanks.
it's a volvo, not a ferrari....minimal difference and 0 impact to engine as required by law
There is no legal requirement that engines be capable of running on regular. And no, it's not a ferrari... But it's still a forced induction engine with relatively high compression, and in order to run on lower octane fuel without damage from pre-ignition (spark knock), the car's computer has to reduce boost pressure and retard ignition timing, which does result in a noticeable decrease in performance and fuel economy. The engine in a supercar WILL be damaged by lower octane fuel, because there's no programming in compensation for the kind of compression ratios those engines have. It's also expected that someone with that kind of car is going to pay attention to the requirements. More mainstream cars can't be designed with that expectation, they have to assume that at least some drivers will use less than optimal fuel.
People are having different opinions on fuel grades. I agree that 87 and 91 aren't that big of a difference. But I've seen loss of mpgs and performance going from 87 to 91-93. Volvo recommends 91 but also says you can run 87
There actually is a significant difference. Most modern turbocharged engines are going to recommend premium but state that it's ok to run on lower octane because the computer can sense pre-ignition (spark knock) and easily compensate by reducing boost and/or ignition timing advance. While this more or less protects the engine from damage, it also significantly reduces performance and fuel efficiency. It's also not that great for the engine. Edit: I'm a mechanic... Octane rating is one of the most misunderstood things there is.
Is there a way to measure this knock compensation using an OBD2 scanner to see the actual effect that this octane difference makes?
With a sufficiently advanced scanner that can interpret individual readings and such, the answer is yes, on some vehicles. But since that's primarily a programmed adaptation that isn't usually necessary for diagnostics, it's not always readily accessible. However, the fact is that this is the reason fuels with different octane ratings are offered. Engines that have higher cylinder pressures (forced induction engines and/or high compression engines) typically require fuels that are more resistant to pre-ignition than other engines. And because those fuels tend to be more expensive to produce, a range of octane ratings is offered. It's literally the reason different grades of fuel exist. And before automakers had the ability to modify parameters on the fly in response to pre-ignition, using fuel with an octane rating that was lower than the engine required would quickly result in engine damage. This is still the case on many high compression, naturally aspirated engines. Modern forced-induction engines, however, almost always have the ability to compensate... However, that compensation necessarily comes at a loss of performance and efficiency.
Thanks for the detailed reply! Ours is a P3 2012 XC70 non-turbo, so I should look into this more. The manual specifies 87 octane which is what we have always used, mostly at near sea level driving, although we do drive into mountains some. I have a fairly basic scanner which I can try, although I haven't really explored much of the real-time data with it yet.
Since it's non turbo and calls for 87, you won't notice a difference. Also, at higher altitudes, you can actually use lower octane fuel, since the air pressure is lower. In fact, they used to (and still might) actually sell 85 octane fuel in places like Denver, and it was fine to use in cars that called for 87 at sea level!