My wife filled up her CF with 87 octane last fill up. I only put 93 octane in
it when I fill it up. I did not notice any difference with the 87 octane in it.

What do you guys normally burn?

thanks!

XfireStan
http://www.stanarseneaux.com/crossfire/

 

Here in Phoenix, the highest available is 91. They quit selling 93 years ago.

You should be able to tell the difference between 93 and 87. Most engines these days have knock sensors that tell the computer to retard the timing a bit when knocking occurs, and what you notice is a bit less power. The knock sensor will pick up the knocking before you hear it, so you won't hear it if you put in 87.

I suspect that you should feel a power difference during part throttle acceleration, since that is when knock is most likely (because that is when the engine experiences the highest load). Full throttle should feel different as well, but unless your engine is fully broken in, you may not be able to tell there.

There really is no harm in using lower octanes fuels, you just get a reduced performance out of your engine.

Why you feel no difference is beyond me. You really should!

 

I run 93 octane. But 91 is also acceptable. Anything higher than 93 (ie, CAM2 racing fuel) and you are just waisting your money. It will not give you any better performance. The ECU has the fuel scheduling setup to be efficient with 91. Anything less than 91 and you will probably experience "pinging" (predetonation) that can, and will, damage your pistons and valves.

 

we only have 93, no 91 so that is what I have to use. I don't want my engine to ping and know better from other family members experiances.

-marc

 

Here in the UK we can get 95 as standard, and 97/98 as super. When I had my BMW M Coupe I user to fill up 3 out of 4 times with 98 and then the other time with 95.

The crossfire isn't that high performance and although I did notice a slight increase in MPG with the 97, I'm sticking with 95 for the moment.

 

Only 94 after ECU... hard to find in Mi though

 

Heed the warning WMichaels put in his post. My former managers wife used nothing but 87 Octane in her Mercedes SUV (an ML 350, I believe) and it killed the cat converter. It took a while to do it, but it did. Well, that's what the mechanics told him anyway and it cost several thousand to fix. It seems possible, if there is a lot of predetonation, then the engine will be burning fuel less efficiently, leading to higher amounts of impurities in the exhaust.

 

Is 87 octane considered "premium fuel" where you live? The sticker inside the fuel fill door, and your owner's manual, say to use only "premium fuel".

 

87 octane. You can't even get that anymore can you?

 

Yep, here in Phoenix all we have is 87, 89 and 91... And then on top of that we have blended formulas mandated by the EPA to improve air quality here, summer and winter blends. :wink:

 

Same in Las Vegas. And 91 was $2.13 at our "cheap" Arco station yesterday.

 

I'm using 95 Octane at the moment. I can't justify the extra 7p per litre for 97.

 

What is the minimum the UK cars call for? Here in the US it's 91....

 

You can't get any less than 95 in the UK.

 

Wow! Upsolute and crew should make an ECU remap especially for you folks and your higher RON, can probably get a bit more out of the car. I know PowerChip sells two different upgrades for the Crossfire, one if you have 91 RON in your area, the other if you have 93 or better. But seems if you can get 95 or 97 a few more horsies lie under the hood waiting to be tapped.

 

Those in the UK are actually using fuel with similar octane to that which is used in the US. The UK uses the RON octane rating. The US uses the CLC rating which is an average between RON and MON. Therefore, 95 RON (UK) = 91 CLC (US). 91 RON = 87 CLC and 98 RON would be comparable to 93 or 94 CLC.

 

I didn't know that! thanks.

 

I'm supposed nobody has raised the red flag on this one!

Most of you guys are making it sound like 87 octane is totally acceptable in this engine, when in fact it is not! The car REQUIRES premium fuel only, that's not a recommendation or an opinion. You might get by on 87 for a while, but it certainly isn't good for an engine made only to run on premium.

You can't fault women though, they just don't understand this stuff, but I'd have her put some octane booster in it asap.

 

Read the thread again, NJ.... I don't think anyone said or even suggested that 87 octane was okay. In fact most all know that it's bad news.

You were very right about adding an octane booster, like "104 Octane Plus". It's available at any autoparts store.

The key is that we have 10.0:1 compression. That's what dictates the higher octane fuel. Even retarding the spark won't change the octane requirement with a compression ratio that high. Lower octane fuel will predetonate (ping) and can and will do severe damage to your valves and pistons (burn and pit them). Lower compression engines can use lower octane fuels.

 

Wes,

But there are always exceptions. My wife has an 01 Ford Escape with a 3L V6 engine. The compression ratio is 10.0:1. The recommended octane is 87!