Gasoline Grade Question
 

I have the X5 3.0....do I have to run Premium? If I do I will, just wondering if it is an absolute necessity.

You won't blow up if you run Regular in it, but these engines are made to run on Premium.

See, Premium fuel is burnt almost completely, and thus brings greater power and fuel economy to your engine. This, in turn, will make your engine last longer.

If you use Regular on an engine designed to run on better stuff, you will get less power, worse fuel economy, and lower engine life. Plus the engine may knock and be rougher than usual.

You're basically saving $5-10 per full fuel-up. However you will burn it faster, and cause long term damage. Not worth it at all!

Thank's Bavarian...that's the info I needed. I didn't know if it would matter as much on a 6cyl. My brother has all sorts of fun burnin' the premium up in Caddy CTS-V! Ha Ha! Thank's

Imo, premium/91+, may/will give the most performance, vis a vis, the eng mgmt sys. OTOH, I've found that on long trips, when a tank is consumed in a day or less, "mid grade" or even that cheapazz regular has offered no incidental or detectable differences. I doubt there is any "engine damage", and I suspect the 'puter simply adjusts for the less than 91 octane.

In the fiscal scheme of things though, the "savings" in using regular is slim, as is the total running cost impact in using prem. Run whatcha brung.
BR,md

PS: Question to someone that knows: whatever happened to posts that "post" just "as they are written", rather than the funky indentations, left and right 'non-justifications', and weird sentence layouts that occur when/after, I post?
Not a biggie, but I take some pride in paragraphing, etc.;
the results look like I jes'learned to type and space, :confused:

Thank's for the info MD!

Ideally you wanna run the lowest octane gas possible. You want the octane just high enough so that there is no detonation. Higher octane gas burns at a higher temperature and that is all. It isn't cleaner or anything like that. It makes it harder for the "hot spots" on pistons and valves to pre-ignite the air/fuel mixture.

So what is the ideal grade for the N62 ('04-'05) X5 4.4i ?

:rtfm: Under Fuel Specifications.

The Manual for the '03 states 91 OCT or higher.

WOW harsh smiley!

It's hard to say what the best grade is. If you had a way of reading the knock sensor you could keep going lower in octane while monitoring the sensor until the timing is retarded on a consistent basis. Generally, in hotter weather engines are more prone to detonation and vice versa. Either way, the factory tuning is probably conservative enough to allow you to run 87 all day long. If you feel a lack of power (knock sensor retarding the timing), use a higher octane.

EDIT: BTW, R8DX5, it's obvious to me from the original post that he understands 91 octane is recommended.