Good evening again,
Just a quickie, my son drives a 2003 S40 and runs only premium gas, does my 850 N/A need to be run on premium?
Thanks all.

 

No, and neither does his.

 

Thank you that's what I thought, but it is nice to hear from someone else. Thanks again

 

Read the manual. Not sure about N/A cars, but turbo cars call for premium. The car runs fine on mid-grade, though.

 

They do not require premium. They will run fine on 87.

 

I don't get the connection between "requires premium" and "run fine". Just because it runs fine, you guys think that's okay? I thought we were trying not to burn a piston.

 

ES6T is correct - its a "recommendation" not a requirement. The difference in octane is the fuels ability to resist combustion by compression. Modern cars with knock sensors will adjust to compensate - ie retard the spark, enrich the mixture etc. What happens is 87 won't produce the same top HP as 93 octane, but in real world driving you are not using all the potential power of the engine so there's no gain. Also, pretty much all brands of pump gas have the same additives so its not like 93 is better for your fuel injectors than 87... Oh and ethanol that comes mixed into your pump gas effectively raises octane... which is why top end dragsters run methanol based fuels.

 

87 is not going to burn a piston in an engine that does not require 91.

 

https://volvoforums.com/forum/2001-2013-model-year-xc70-53/gasoline-grade-69726/

And you won't notice a power difference.
https://youtu.be/FPPkPAbzwbU

 

@ES6T: agree with 95% of your posts; normally you're spot on and cut through the bull crap. And I was with you here too, until you posted that youtube link. Boy, talk about mis-information!

1. That guy is an investigative reporter; gee they never sensationalize a debatable topic..
2. The question they posed was not the one posed in this thread. They are asking, does premium gas increase performance and/or mileage in a "regular car" e.g. the 2013 chevy cruze, which, as you may have guessed, its owners manual recommends regular gas. Ck the link.
3. What's interesting is this edmunds article I found, which states that even given the above info, they found increased mileage w/91 octane fuel in hot weather testing of the 2011 chevy cruze.

I've said it before and repeating it here (again..): For max performance (and possibly mileage) follow the owners manual recommendation for octane.



If you own a modern car that the owner's manual recommends higher octane than regular, but you drive like an old lady (bad stereotype; i know some lead-footed grandmas..), then run regular in your car; you most likely will not notice any difference at all. And no, you won't burn valves or pistons either.



But if you want/need max performance, then follow the owner's manual recommendation. Bingo-bango done; end of story....RTFM! again!


@bmdubya: the 850 owners manual recommends 91 octane for max performance but says 87 is the min requirement. Relevant for both N/A and turbo models.


@mt6127: what you said!

 

I still stand by my statement. You won't notice a difference in power.

I don't trust any on the road MPG tests. There is no way to drive the car exactly the same each time. Those results are surprising though. So if your commute takes you through Death Valley, run premium.

Also, comparing different cars and fuel management systems isn't exactly an equal comparison (I know that video was also a Cruze). I'm sure that little engine will run differently in extreme heat than a 2.3L or even the 1.9L. I wish someone would do a dyno test and dyno MPG test on a Volvo.

Here is another Edmunds article that also referenced the one you posted:
http://www.edmunds.com/fuel-economy/to-save-money-on-gas-stop-buying-premium.html

 

If anyone was wondering about the acceptable amount of ethanol in your gas (since some places use more than recommended), I read from my '95 Volvo manual that 10% is the max ethanol/gas mix you should put in your vehicle.

Ethanol collects moisture and puts more gunk through your fuel system if the gas sits for a while, FastTrac chain stores have ethanol free 91 (Volvo manual says 91 is the minimum octane rating for '95 turbos). Ethanol free I would recommend for anyone with a turbo but not to anyone with a non-turbo. Most non-turbo vehicles are designed to run on 87 octane with ethanol, which means your engine is designed for a fuel which takes less work to burn. Turbos knock with low octane fuel because the combustion happens earlier than the engine is designed for. The opposite could probably happen in a non-turbo: an engine taking longer to burn the fuel than it is used to.

If you are worried about moisture in your gas tank, use a dry gas additive and try to keep a lot of gas in it. A full fuel tank will mean less space for humid air full of contaminants near your gas. This is especially important in a car that is sitting, or in cold climates. Too much water in your gas can freeze overnight and cause problems, a full tank will dilute water and other contaminants in the tank.

I believe being low on gas actually caused my '93 240 to sputter out and run rough at times. From what I've been told, this is because there is a reserve fuel pump that is used rather than the main pump when the gas gets low, and mine is crappy. I am not 100% sure about that theory, but I know when I have more gas in a car, it runs better.

 

The reference to 10% is to steer people away from E85. The alcohol will mix with any water in the tank so there's no issue with gas line freezing and driving will swish the tank enough to keep it mixed. I'd think the concern is more the impact on the seals than on creating tarnish. That is a problem for small motors which can sit for extended periods (I always run my small motor's carb dry when storing -ie snow blower, generator, mower). If you still are concerned about gas line freeze ups, just note that "Heet" and similar dry gas products are just Isopropyl alcohol which can be purchased in your local chain drug store for half the cost. It won't hurt to throw a few oz with fill up - then again it probably won't help either.

 

Actually I know someone who had gas line freezing exactly as I say on a BMW K75 he was daily driving, he ran an extension cord with a hot plate to the frozen spot for hours in the winter to evaporate the water and unfreeze the iced lines so it would start. He swears by the stuff.

This is only one example, moisture will not collect most of the time when you are driving daily and fill up at a decent gas station. I mentioned that if the gas sits for a while you have reason for concern. My dry gas additive supposedly contains a type of anti-freeze, it seems to help. I know it doesn't evaporate the water, but a little bit diluted might give the lines a little more time before anything freezes. I could be subject to the placebo effect.

I run it in my crf230l enduro along with adding fresh gas to the stale and both things seem to help. The carb is currently drained on that bike since we've had some freezing nights here. I agree it is good practice to drain any unused carb when it sits or gets below freezing.

It goes far below 0 degrees here in the winter, so any cheap dry gas additive that might help with water in my gas is worth it to me. Hopefully the one bottle I bought contains more than Isopropyl.

 

I believe it is important to run quality fuels as well as the recommended octane. And for some strange reason, my car gets worse gas mileage with 100% gas (no ethanol).

Top Tier Gasoline

 

Do what the owners manual recommends and your car will drive and last longer. The only exception to this is where they recommend omitting servicing to up their JD Powers ratings, i.e. transmission service.

Link to page about fuel octane recommendations.
1996 Volvo 850

 

It will not last longer.

 

curious about Robert's comment on fuel economy on 100% petrol vs petrol/ethanol blends. Here in CT, its pretty hard to find 100% petrol - dunno if that's just an emissions thing or what (but I did see that option in upstate NY recently). The thing about alcohol fuels is they have a smaller energy density than petrol but a higher RON (ie octane rating). Energy density is the reason diesels get better fuel mileage than gas cars (each gallon of diesel has more energy than gas, and similarly gas has a greater energy density than ethanol). By the numbers, if 100% petrol gas is = 100, Diesel has 13% more energy (ED=113), and gas/10% ethanol blend is about 2% less (ED=98) - winter gas with MBTE is about 1.5% less than summer gas. Note that E85 (85% ethanol) has an energy density 30% less than gas - which all translates to your MPGs. Thus if you sense you get worse MPGs in winter, its all due to the trifecta of fuel mix, cold/winter tires and cold moving parts which add friction.