What grade gas you running in 3.0's

[DINANM3]

No it will not hurt it.

[Riyad Aliyev]

Originally Posted by DINANM3

No it will not hurt it.

Thank you.

[DINANM3]

by the way what do you usually use for gas

[JCL]

Originally Posted by Riyad Aliyev

thank you JCL for explanation. but still, nobody realy answered my question, is it ok if i'm going with this "Shell V-power 100" on my little beast named X5 4.8is?

Sorry, the answer was buried in the long-winded explanation. Your 100 RON is the same as 93 pump octane in North America. It is essentially what the manufacturer recommends. Use it, it is fine. It is no better than 98 RON in theory, but if the truck runs better on it, buy all means keep on.

[Riyad Aliyev]

What do you mean what do we use for gas? Gas is gas. Didn't quite understood your question.

[DINANM3]

Well you wanted to know if it is allright to use 100. So obviously you are not currently using 100. What do you use now.

[Riyad Aliyev]

ohh excuse me. no, i do use 100. I just wanted to know, do i need to change or is it ok if i continue to use 100. My personal oppinion is that 100(European style or whatever) is exelent, cuz' the ride is just flying.

[Jiga jace1]

what do you mean by misfire?

[JCL]

Originally Posted by Jiga jace1

what do you mean by misfire?

While there are many potential reasons for a misfire, or missing, the following refers only to situations caused by fuel.

AKI refers to the resistance of the fuel to ignition, or rather uncontrolled ignition, also called predetonation. A fuel with a higher octane rating will be harder to ignite. That is a good reason to have high performance ignition systems on race cars. On a modern street car, the problem usually only shows up in cold weather, when the engine is cold; the engine can misfire, or miss. When the piston compresses the mixture, and the sparkplug does not ignite that mixture, that is missing. It can happen on one or two cylinders, usually until the engine is at operating temperature, or at least partly warmed up. The BMW fix for this is to advise the owner to move to 89 pump octane until the weather warms up. This is not a problem in Southern California, but not all of us live there.

[crosvs]

JCL- thank you for all the constructive feedback. And so I think one pressing question -- and one lesser question! -- remains:

(1) Why does our fuel door say "91 MINIMUM?"

(2) Same logic for my Dad's C4S then too, right? Don't bother with 100?

Another note: I know for a fact that, as someone mentioned earlier, turbo- or supercharged engines necessarily DO benefit from higher octane fuel. Apparently the Mitsu Evo is a RADICALLY different beast when running on 100 octane fuel.

And finally: as I mentioned earlier, 91 octane fuel *DOES* produce *SOME* knocking at low RPMs under more than 1/4-throttle position. Any thoughts?