Premium vs regular unleaded fuel.

Discussion in 'Chevy Truck Talk & GM News' started by stchman, Mar 11, 2013.

Newest Photos

  1. stchman

    stchman New Member 1000 Posts 100 Posts

    I got in a debate with someone that claims premium gas s better gas. I asked him to define better, he said that premium gas:

    contains better detergents
    burns cleaner
    better mileage
    give more horsepower

    He is wrong on the first three points. The more power is true ONLY if your engine requires premium fuel. He was driving a Silverdo with a 5.3L engine. I told him unless he has re-tuned his ECU with a programmer, running premium was only going to take more money out of his wallet. He refused to believe me and said that his truck just runs better on premium. I stopped the discussion as he has convinced himself of this.

    I have noticed that people that run premium gas tend to want to thump their chests a lot more about the automobiles.

    You try to tell people that octane is simply a combustion inhibitor and does not contain secret amounts of power. They won't hear of it. Ignorance at its finest.
  2. SurrealOne

    SurrealOne Former Member 1000 Posts 100 Posts

    If I could run on a half water, half gas mixture without nuking my engine and still get decent mileage ... I would!
  3. TRPLXL2

    TRPLXL2 New Member Platinum Contributor 1000 Posts 100 Posts

    The only actual difference I can honestly say I've seen between the two is "knock". I have data logged with hp tuners on all of my vehicles, 2.0 turbo, 6.0 vortec, 5.7 lt1, 5.7 ls1, and a 3.1. And when running 87 octane in each of these engines there is quite a bit of knock through out acceleration, when switched to 93 octane there is a considerablely less amount of knock in the engines.

    Certain amounts of knock can reduce timing, which could feel like less power. Your friend is not totally wrong, if you datalog your truck where you can actually see timing tables you will see what I am talking about. I use premium in them all, I drive 110 miles everyday to work and back so to me less knock is better....
  4. Enkeiavalanche

    Enkeiavalanche Moderator 1000 Posts 100 Posts

    I run Reg most of the year I switch to 93 for about 2 weeks to just clean out things along with some SeaFoam... I avg with almost 100K 14.7 MPG
  5. the phantom

    the phantom New Member 1000 Posts 100 Posts

    I agree that the Higher octane makes the engine "sound" better. Ive noticed with the AFM kicked in, the truck runs better in the 4 cyl. mode with the higher octane. Some people have complained of the AFM causing a chatter noise which I did notice using 87 octane. Not noticeable with premium. I also have increased my mpg by 1 mpg using higher octane. I am only convinced of this due to my own experiences. I will not try to convince anyone else of this because if your not trying it yourself then theres no point in arguing it. Also all vehicles and situations are different. I had a tuner and tuned it for premium gas. This may be where I gained the 1 MPG but the AFM chatter was gone when I put premium in before I tuned it.
  6. SurrealOne

    SurrealOne Former Member 1000 Posts 100 Posts

    @nakranij swore by 93 even before he tuned for it. Now with tuning I could see some benefit beyond reduced engine clatter, but I just don't get it with no tuner.

    I'm much more interested in the comparison of 87 E-10 versus 87 ethanol-free (if you can reliably find it, these days), as the cost difference could be as little as 5-7 cents/gal while the advantages to using ethanol-free are, in theory, a ~10% power improvement (i.e. better MPG) and less engine build-up. Ethanol-free could be a better choice for long term fuel consumption, but that's probably a discussion for another thread.
  7. PantheraUncia

    PantheraUncia Active Member 1000 Posts 100 Posts


    Well the basic's of it, The higher the octane, the hotter/cleaner the fuel burns. We are nit picking here, but a hotter, cleaner burn increases the rate at which the pistons fire (to some insignificant degree) increasing the speed at which your cam is spinning or recovering from cycles.

    This translates into a insignificant rate of transfer to your flywheel and into the transmission which is powering the wheels that are meeting the pavement.

    The other variables to consider include:


    • are you flooring the pedal to increase the speed at which you are traveling
    • are you running on "fresh" oil (meaning you just did an oil change and the engine is at its peak performance)
    • is your tranny fluid fresh?
    • is your rear diff. fluid fresh also, not worn out.
    • are your tires balanced and rotated and not bald :)

    Considering all of the above, is there a reason I like 93 oct over 87? lets just say between the split seconds I get from it ( which amount to nothing in reality right? ) when in situations with people that do not know how to drive down here, I have avoided tree's rear bumpers, etc because I can count on my reaction time and the enhanced reaction time of the truck with the better fuel in it. ( you know those people that don't know where they are going and then hit their breaks and decide to make a left turn right in front of you)

    That was before running the intune on my engine. After the intune, the 93oct. made a bigger difference.

    Surreal can tell you first hand that I like a certain level of performance from my truck, unfortunately the truck I have right now; I can't justify serious performance upgrades cause it ain't worth it. However he was right behind me getting on the freeway after we met up with a few other guys to hang out for a while.

    By the time he merged into the main freeway, I was about 2 miles ahead of him :). Now he also has a 6inch lift which changes things a little. He flashed his lights at me and they were like pin holes in my rear view mirror.

    That would not have happened with an un-tuned engine running 87oct.

    Now, I think there is a bigger difference in using gas that is ethanol-free. If I could get my hands on ethanol-free 93 oct, I would run it exclusively, but there is a station about 3 miles from me that sells 89oct ethanol-free gas.

    The problem is I can get diesel cheaper than 100% ethanol-free 89oct gas.
  8. SurrealOne

    SurrealOne Former Member 1000 Posts 100 Posts

    That would not have happened had I been trying to keep up, but I didn't bother and, instead, flicked my lights to wave 'bye'. :)

    But, yes, you stomp on it whereas I just cruise along; I've never had the urge to drive quickly in a lifted vehicle ... so the gains of which you speak are not ones I'd feel/notice.
  9. PantheraUncia

    PantheraUncia Active Member 1000 Posts 100 Posts

    :) I like space between me and other vehicles on the road, not that speeding is necessary....
  10. James4012

    James4012 New Member

    I run nothing but plus or premium in my V-8. Old gramps told me to when I was real little and the old fool is a Chevy guru so I'm inclined to try what he says. Honestly, my truck is a ether baby now. It's ran out of gas a couple times before (gas gauge don't work) and I've had to put a couple gallons of regular I keep for emergencies in it. Wouldn't ever crank less I sprayed the filter with starter fluid.

Share This Page