anyone run under 91 octane??? 1.8t in particular, i believe the 3.0 is the same. I was reading the manual and it says i can run regular (87) with loss of power? anyone do this to conserve fuel cash???

 

I accidently put 87 in my 2.8 and i got **** for fuel economy you can do it but it sucks just put in 91 or higher and you will get better fuel economy

 

^ BS

I've NEVER seen better or worse fuel economy from octane... I've tried 87, 89 and 92 in my car, NO difference. Maybe your foot was heavier?

 

The only reason it says that in your owners manual is to say its ok to use lower octane fuelfor a little while, if premium fuel is not available. Constantly running 87 octane will lower the engines power output yes, but will also lower the engines life span due to detonation in hot climates or long distance driving.
So if you wann run 87 octane be my guest just don't cry about your engine having no compression at 150k.

 

Just another example of post counts meaning ****.

The higher the octane the more volatile the fuel is. The more volatile the easier it can evaporate. Higher octane is harder to combust than lower ones. Just like auditech said, it will cause detonation which is not good.

 

the different octane will prevent engine knocking..so if you use a loser octane and you hear engine knocking than you need a high one...

i have heard tho that the lower the octane will get better gas mileage because it is slightly thinner or something..dont know if its proven or not..

 

 

Uhm, did you even READ my post? I was talking about FUEL ECONOMY. Maybe you should take a second to read a post before posting yourself.

Octane = resistance to ignition, NOT an increase in fuel consumption (ie: lower mileage). The knock sensor retards timing a little with lower octane, so you lose performance but rarely fuel economy. Different grades of gas can vary widely from station to station too.