i tried to search it but seeing how half of haf is down its a lil hard, simple enough question is putting chevron plus "the middle grade gas" in my car bad? some dude at work said i was killing my car.

 

Uhhh....tell that guy to go soak his head. Technically, you are treating your car since it is designed for 87 octane. mid-class is 89 i believe.

 

yeah, I agree...
Just to add on the octane topic, if your car is stock, 93 octane will be a waste of $$$. your car is designed to work w/ 87/89...so that said... mmmmmm.... im done writing now...

 

Your car was designed to run on 87. 89 may not hurt it, but it is a big waste of $ since it does not help anything. You will actually get worse gas mileage too.

 

Very tiny difference in my experience. Still a waste of money.

 

^ yeah I know. One thing that has been making me mad about gas recently: almost every gas station I have gone to has a sign on the pump that says "Contains 10% Ethanol". That means I will get worse gas mileage correct?

 

Correct-o-mundo. "/

 

Energy content (LHV for the geeks)

Iso-octane = 110k BTU/gallon
Ethanol = 76k BTU/gallon

A 90/10 mixture should be about 106k or 107k, so thats about 3% worse.

 

HAF is pissing me off... octane means nothing about performance, but rather anti-knocking...
read this: http://www.howstuffworks.com/question90.htm
and: http://en.wikipedia.org/wiki/Octane_rating

 

just to add on this ...(BTW i did not read the link) ... Its funny for some1 to mention this knocking issue .... when I had my M3 (imported high performance model) i had this chick fill me up on fuel for some $$$ she owed and the biatch put 87-octane ...
the car started knocking.....? I know it was because of that...If I remember correctlythe M3 i had required a minimum of probably the 93 but was designed to run best on even higher? (i think octane rating might be higher in Europe?)