I've searched and I can't find anything, I know it's kind of a dumb question, but I've read that turbo engines are supposed to use premium gas, however, my 850 has had regular running through it even before we got it. If I switched to premium now would I see a difference or would it be a waste of money?

 

I next to never run premium in mine. Most everybody says you should though. If it made it run better or gave me better gas mileage I would use premium, but there is no noticeable difference so I don't use it. I am probably in the minority though.

 

Yeah, I've never had any problems with it or anything, my performance is just fine. I guess we'll see if anyone else says anything.

 

I'm sure you may already know but the idea is that regular unleaded will combust at much lower pressure than premium. Most turbocharged cars run premium because the cylinders are full of compressed air (from the turbo), which is compressed even more by the pistons.

I don't know if the Volvo 850's 7-8 psi of boost is enough to combust regular gasoline but if it does it will definantly lead to knocking.

I am assuming it is probably a habit that will wear out engine parts faster such as the head gasket, etc.

I also learned the other day that some states have different octane levels for their gasoline. I think Missouri is 87 regular, 93 premium. The octane is the difference and if your octane is around 90 or above for regular gasoline it is probably sufficient considering the turbo will not boost over 8 psi.

 

I don't have any knocking or anything what so ever. It runs fine on regular, I'm just wondering that if I put in premium, will I get an upgrade in performance or anything like that?

 

If there is an upgrade in performance, it is minimal. I have tried both and noticed nothing. They are meant to burn the same way.

My local Phillips 66 offers "Racing Fuel" (yes they do call it that) for $5.00/gal. The good thing is the price never changes. I would be frightened to put that in a 14 year old car though.

 

Haha. Agreed. I don't think that would end well. I'll stick with my regular gas then seeing as how that's what's been in it for as long as I can remember. Four and a half more years and I can put Collector Plates on my car.

 

wouldnt hurt if once in a while you let your tank reach near empty add a bottle off fuel additive and fill up on premium just to clean up the system a little...i try and do this at least once a month with the lucas fuel additive

 

What does that do?

 

My 850 I always ran "regular" and never really noticed any pinging, etc... Then I read that turbo models should run the premium. I then found 93 and filled up on an empty tank and added injector cleaner... I did notice a better pickup and somewhat better performance out of it. I had also just done a complete stage o prior to running 93. I never looked back and get 93. I do also go to Sams club where premium is the price of regular everywhere else..

 

Hmm, maybe next time I'm close to empty I'll have to try something like that, I'm sure my car could use it. What does the injector cleaner do exactly?

And not to change the subject, but what did you all do for a stage 0?

 

The ecu will adjust for lower octane fuel, like 87. I have run 87, 89, and 93. A lot of time I would put 1/2 89 and 1/2 93 which my mind tells me = the 91 they recommend.

Now I use 93 all the time. Car seems to run a little peppyier when I want it to. If you are not heavy on the foot it probably does not matter. I think I get about 10% better gas milage with the 93 which makes up for the difference in price. So, why not run 93 if the cost is the same???

I also put a bottle of lucas in every now and then. I would guess every 10,000 miles.

Oh yea, my buddy that use to sell Volvos goes crazy every time he finds out I put 93 in. He insist that I should run 87.

 

Lucas is suppose to clean the injectors, causing them to spray a smooth even pattern. Gets rid of deposits and stuff like that. They auto parts store will have it and show pictures.

A lot of gas stations claim they put detergent additives in the gas which is suppose to do the same thing. If you have never done the LUCAS, go pump the same gas as normal and put a bottle in. Only pump about 12 or 15 gallons. I think 1 bottle is suppose to treat between 12 and 18 gallons. Read the bottle.

 

Sounds like it could go either way then. I think next time I fill up I am going to try 93 and add a bottle of Lucas to it. I think that would be good for my engine.

 

OK, so if I do the Lucas, put in the same gas. Sounds good. And then put in 93 if I want to after that tank is gone?

 

Well, I would add the lucas and go through 2 tanks to try to see the difference. Then go with 2 tanks of the 93. Do you have a trip computer to check your gas milage? Or do you have to check the long way?

 

Yeah, I have the computer in the dash that tells me my average and current mpg if that's what your talking about, otherwise my odometer doesn't work anymore, so that would be the only way I'd be able to check.

 

I believe the 11 O'clock possition is the average gas milage. Write down what you have now, put the paper in the glove box, hold the reset button for 5 seconds or what ever it takes to reset the thing, fill the tank, add the lucas, go 2 tanks and write down the difference.

Do the same thing when you go to 93 and let us know what your 3 averages are after you burn through the two 93 tanks.

Again, write it down and put it in the glove box.

 

Also, if you turn the trip dial all the way counter clock you will see the average mph. You may want to add a colum for this as well. Most city driving is about 28 mph while more highway driving is around 40 mph. This can effect your average mpg.

 

I'm going on and on here. But if you go 1 click pass the temp (clockwise) you will see the short trip milage. You can reset that as well for the 2 tank fulls. Add a colum for that.