mnorris23 wrote:I had to drop back to unleaded because I couldn't afford it.
I hope you're always running unleaded, no matter the octane, buddy.
I run 95 or 98 all the time - not surprising, I suppose, since that's all we have over here, like the Swede earlier in the thread. Never had knocking or pinging or whatnot in any of my (relatively high-mileage) Volvos.
'96 855 T5, R bumper and spoiler, Koni Yellows & blue H&R springs all 'round.
chrisjm91 wrote:I drive a 95 850 turbo with about 100k miles on it and just recently switched to 93 after reading up on octanes. I have to say I've noticed a little bit smoother engine. Just wondering if I'm crazy or if other volvo enthusiasts are running 93 octane in the turbo models volvos, as well as N/A.......
I use 93 octane. In my area I only have the choice between 87, 89 and 93. Until about 2 years ago I only used 87 octane, thinking higher octane was a waste of money. Was I ever wrong! I posted the data I collected through about six full tanks with either 87 or 93 octane in them here on MVS. You do get improved mileage with octane over 91, and therefore more miles per tank. Although it costs more at the pump, the improvement in MPG almost exactly balanced out the cost. We're talking a big improvement - about 30 extra miles per tank. These particular cars are set up to run most efficiently using 91+ fuel. That post should still be here somewhere.
Trust me on this - I am a meticulous person when it comes to measuring MPG accurately - these were real improvements and not wishful thinking.
2017 Alfa Romeo Giulia Q2 - if I could marry this car and have car babies with it I would! 2011 XC60 - sold 2000 V70XC - given to a friend, wish I still had it.
+1 on that point, several people have posted that same observation about mpg.
The real point is the longevity of the engine internals. As has been beaten to death here and on other forums, over the long haul the engine is much more likely to burn an exhaust valve when running the lower octane fuels. Burnt valves are showing up more and more these days ...
Modern fuel injections engines have knock sensors to detect knocks to save the engine. If you use lower octane gas, the engine will probably knock on acceleration, computer will see the knock and pull timing, this is why power/mpg goes down.
Use whatever the factory recommended, which is usually 91 octane for turbo car. If you can't afford 91 octane, you can't afford a turbo car.
abscate wrote: ↑Tue Jul 02, 2019 4:16 am
Old thread, note that posters in EU report their octane on a scale that is 4 points higher than a North America.
So, when Swedish poster says s/he is running 97 octane it’s equivalemt to a US 93 octane.
Higher octane fuel has slightly less fuel value than regular gas, about 3%
Differences in mileage reported of less than 5% are usually in the envelope of measurement noise.
Regular over here is RON95 which is about equivalent to 89-90 in your end. But even on the euro scale the Swedish instruction booklet for the P80 says that as low as RON87 is OK to use at least for the NA though not recommended.
Octane isn't the only fuel quality parameter though.
Mine is currently running on a mix of E85 and RON 95-E10. Simple reason being that E85 is at least half the price of 95, sometimes a third.
LTFT is at 20% which sounds legit and I get a 20% worse mpg, but still make it cheaper to keep the brick on the road