With rising gas prices I find myself wondering if my 2004 Xfire really needs $3.45 a gallon high test! Is anyone running regular in your crossfire? If so are you seeing any engine ping or knock? Does anyone want to educate me on why I should continue - I do not run the car hard so I don't care about performance.

 

I would stick with Premium gas, cost verses possible damage and warranty issues, the higher cost is not that bad...IMHO.

 

You're only saving at most $3 on a full tank of gas (~ $.20 difference * 15 gallons) and that's if you stretch it to the end. If you can't afford $3 I don't see how you can even afford the oil changes.

Go ahead and use it if you want, it's not our car but typically when it says PREMIUM ONLY on the cap there's something to be said. Some people haven't had problems but they've actually seen a drop in MPG when using regular which will make you fill up more, taking more out of your pocket in the end.

You could always sell it if you don't want to pay high gas prices (which really aren't that high on a global scale).

 

I always use 93, is premium considered 91 or 93 octane?

 

Well just did an entire read through of my manual last night before bed. It just so happens the owner manual's recommended octane rating is 91! I fill up with premium 93 always. However sometimes the plus can be 90 or 91. But often times its only 89 depending on the gas company. Anyways as previously stated the difference in price is so insignificant its worth it. Think of it as if you were buying something for your kid, you want the best of everything right? In order to keep them happy and healthy!

 

Here's a link to a British site on the subject of petrol (gas)...

http://www.petrolprices.com/about-fuel.html

Our regular petrol is rated at RON 95.

 

it says minimum 91. so 93 is perfect.

 

In California, 91 octane is a high as it gets, and that's our "premium"... no 93 octane out here.

I agree, if it calls for 91 octane minimum, use 91...

 

Maximum octane is different due to altitude. 93 give our cars a little more umph here at sea level.

 

93 is a must for me. Here is a good site to find local gas prices in the good ol USA http://gasbuddy.com/ although 93 is always expensive, cost a lot to look this good.

edit: that site is good for Canada too.

 

The car runs fine on crap gas (Regular), but your mileage will suffer, Premium fuel gives the best mpg, so you're not really saving money using Regular gas.

If you live near a station that sells E85, this will boost your octane rating but only fill 25% of the tanks total capacity, the rest should be filled with Premium fuel, then record your mileage and see what you gain.

 

I use 93+ (SI Tune for 94)...

Sure the car can run at lower Octane levels, but why would you want to?

I reviewed this car for what it was; before I purchased it, I test drove it, fully inspected it, reviewed at the MPG, and knew exactly what Octane level the manufacturer suggested, and after careful consideration I bought it!

After that, all hope of returning to a normal conventional world just seemed to fade away!

XFH

 

Or lose. The mileage will go down.

 

stick with premium i know it hurts and believe me on a soldiers salary the budget is not big. i have an sr-20 that is premium also but that the price you pay to have a good car IMO.

 

i'm wondering exactly how accurate the ratings really are? do you really trust the refiners and the rest of the gas supply racket to have quality controls? i don't. but i always buy the premium, and a little stp gas treatment every 500 miles.

 

Like most brits - I get tickled pink by any American 'moaning' over fuel prices...

We pay about 95 p/ltr in the UK.

That said - we do get 95 Octane as regular... so not all bad.

I used to run a Ferrari on race fuel (106 oct) where ever possible - very expensive, but did make a dramatic difference.

 

It may not make a difference right now, but on down the road at tune up time it may make a big difference to your budget. I had a Mercedes mechanic tell me one time with my old ML320 that had the same engine that our cars do, to be very careful of the fuel you use. The problem comes during tune up time when you pull the spark plugs. The heads are made of Aluminum. If the plugs have a lot of carbon build up on them, the threads could be stripped when the spark plugs are removed. Stripped threads are expensive to repair. The cars are factory tuned to run on premium grade fuel, not regular grade. If you decide to run regular grade fuel, you may want to change the spark plugs much sooner than what the owners manual says (which I think is 100K). Or at least run a few good tanks of fuel through the XF and drive it hard before the tune up... This just may clear out the carbon from the plugs. Just for kicks, I pulled the plugs out of the ML @ 70,000 miles. They were hard to get out without much carbon buildup. I was concerned that I was going to be stripping threads even with fairly clean plugs. Just my .02

 

In france the gallon on ron 98 would be $6 the gallon !
It's 1,35 euros by litter.

And I use Ron 98 or ron 95 depending on the stations...

Knowing that the crossfire can run on Ron 91 (Meaning that it can't run on Ron below 91 but easily on more than ron 91) because the lower the ron is, the more easily it explodes with low compression (meaning it can self ignite before the piston went all the way up) The higher the octane is the more compression ratio is required for self ignition.
(But, even with that, it's not easy to self ignite petrol, that is why petrol engine needs spark plugs)...

 

I run 99 ron in the UK. Inside the petrol cover it says 93 ron. Mine runs just brill, so I wouldn't change and only ever fill up with Shell VPower (never put anything else in the Xfire).

It's really funny hearing you lot over the "big lake" moan about petrol prices......Shell Vpower is about £1.01 per litre, thats about £4.59 per gallon at $1.99 to the £1 that is about $9.13 per gallon !!!!!!!!!!

so have a good laugh at us in the UK and I would swap petrol prices with you any day !!!

Si