what are the pros and cons of pumping premium or regular?

this is on a totally bone stock civic

i've been pumping premium but due to the high gas prices i might want to switch over

 

Regular 87.

If you have nothing to done performance wise, it is best to stick with 87. I personally have not seen any advantages of using 89 or 91 myself on my near stock Civic, but with the way I drive, I doubt anything could boost MPG on my car.

Its really just overkill. All youre doing is putting in gas which resists detonation upon compression. If youve got stock compression, it best to just run 87 like the O.M. states.

Now if you were turbo'd or using aftermarket internal parts which push the Compression up, then yeah, you would need to step up to curve detonation in the motor.

 

I actually get WORSE gas mileage when I go from 87 to 89. My EM2 is 100% original under the hood.

The difference between Octane ratings is when the gas actually ignites, how much fire it takes to do so. If you're running a track/drag car, having a high Octane allows you to adjust for higher compression (later in the compression cycle) and thus, more hp is attained. But, in order to do so, you need to adjust the timing, spark, and air/fuel ratios to make it effective.

You'd be better off using 87.

 

You can save yourself some money by using regular in the stock engine.

 

oh i get it, im using supreme because i used to have a huge suv and dang it would cost me 70 bucks to fill that thing up! but now that i have a em2, could fill up on supreme for about 35 bucks more or less? but now that ur saying it not worth the extra cents, well i guess ill be going back to my regular 87 octane gas. but doesnt the higher octane gas have certain detergents that help keep your fuel system in tip top shape??

 

Nope.

 

do not just jump back to regular, my friend did that with his car and it started acting up. Now its ok, but maybe thats with some cars only.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Red_EMII &raquo;</TD></TR><TR><TD CLASS="quote">Regular 87.

If you have nothing to done performance wise, it is best to stick with 87. I personally have not seen any advantages of using 89 or 91 myself on my near stock Civic, but with the way I drive, I doubt anything could boost MPG on my car.

Its really just overkill. All youre doing is putting in gas which resists detonation upon compression. If youve got stock compression, it best to just run 87 like the O.M. states.

Now if you were turbo'd or using aftermarket internal parts which push the Compression up, then yeah, you would need to step up to curve detonation in the motor.</TD></TR></TABLE>

i agree with him... higher octane would only be good for higher compression vehicles or turbo charged vehicles.. on civics 87 would be perfectly fine..