# Do 87 and 93 octane cost the same per mile driven **URL:** \ **Category:** Factual Questions\ **Created:** [October 20, 2013, 10:32pm UTC](https://boards.straightdope.com/t/do-87-and-93-octane-cost-the-same-per-mile-driven/671758 "2013-10-20T22:32:41Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [October 21, 2013, 12:33pm UTC](https://boards.straightdope.com/t/do-87-and-93-octane-cost-the-same-per-mile-driven/671758/21 "2013-10-21T12:33:03Z")
> [@Hail\_Ants](#): > > I always prefer to call pre-ignition ‘pinging’ rather than knocking. To me an engine ‘knock’ is a serious, physical malfunction (like a rod knock). Pre-ignition is more higher pitched and ‘tinny’ sounding than knocking. It always sounded like marbles rattling around in the engine to me, whenever a lot of throttle was applied. This was in my old conventional 1995 Civic, which is one reason I started using plus. I have to use premium in my '06 SI or it will knock like the dickens. ---
**Author:** ![zwede](https://avatars.discourse-cdn.com/v4/letter/z/ac91a4/32.png) [@zwede](https://boards.straightdope.com/u/zwede)\ **Post date:** [October 21, 2013, 12:41pm UTC](https://boards.straightdope.com/t/do-87-and-93-octane-cost-the-same-per-mile-driven/671758/22 "2013-10-21T12:41:31Z")
> [@Hail\_Ants](#): > > I always prefer to call pre-ignition ‘pinging’ rather than knocking. To me an engine ‘knock’ is a serious, physical malfunction (like a rod knock). Pre-ignition is more higher pitched and ‘tinny’ sounding than knocking. It’s not pre-ignition. Like the name suggests, pre-ignition is ignition before the spark plug makes its spark. Usually caused by a foreign object in the cylinder that is glowing. Pre-ignition is extremely destructive and will destroy an engine in seconds. Insufficient octane causes the flame front to go super-sonic (detonation rather than combustion). It always happens after the spark plug fires. It can be called “pinging”, “spark-knock” or just “detonation”. I agree “knocking” should not be used. ---
**Author:** ![JerrySTL](https://avatars.discourse-cdn.com/v4/letter/j/e274bd/32.png) [@JerrySTL](https://boards.straightdope.com/u/JerrySTL)\ **Post date:** [October 21, 2013, 2:55pm UTC](https://boards.straightdope.com/t/do-87-and-93-octane-cost-the-same-per-mile-driven/671758/23 "2013-10-21T14:55:40Z")
> [@Southern\_Yankee](#): > > Slight hijack: someone told me that using 92/93 octane once in awhile was the rough equivalent of using a bottle of gas treatment. I gather that’s not true? Some premium gasoline’s do have a better additive package. However you can ensure that your regular gasoline has an adequate additive package by buying from a Top Tier manufacturer. I recommend that you read the information at the web site below and consider buying from the listed companies. > **[TOP TIER - High-quality Fuel Performance Standard - TOP TIER™](https://www.toptiergas.com/)** > > TOP TIER is developed and enforced by some of the leading automotive manufacturers and supplied by participating fuel retailers. I find it interesting which companies do and which do not meet the Top Tier standards. ---
**Author:** ![Southern\_Yankee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/southern_yankee/32/2800_2.png) [@Southern\_Yankee](https://boards.straightdope.com/u/Southern_Yankee)\ **Post date:** [October 21, 2013, 3:31pm UTC](https://boards.straightdope.com/t/do-87-and-93-octane-cost-the-same-per-mile-driven/671758/24 "2013-10-21T15:31:55Z")
> [@JerrySTL](#): > > Some premium gasoline’s do have a better additive package. However you can ensure that your regular gasoline has an adequate additive package by buying from a Top Tier manufacturer. I recommend that you read the information at the web site below and consider buying from the listed companies. > > [http://www.toptiergas.com/](http://www.toptiergas.com/) > > I find it interesting which companies do and which do not meet the Top Tier standards. Very interesting. Thanks. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [October 21, 2013, 4:00pm UTC](https://boards.straightdope.com/t/do-87-and-93-octane-cost-the-same-per-mile-driven/671758/25 "2013-10-21T16:00:21Z")
> [@kanicbird](#): > > While this may be true somewhere, I have only seen ethanol free gas sold as ethanol free gas, without regard to a octane rating. Further ethanol in gas increases the octane rating, and some stations have complained that they can actually sell higher octane gas by blending it themselves with ethanol then the ‘normal’ regular grade. Where I am, gas stations very frequently advertise ethanol free premium, and it’s usually something like 50 cents more than the regular gas. I’m guessing it’s just that they don’t want to miss out on the regular old cheap gas crowd by going all ethanol-free, but having the premium gas ethanol free snares people who are willing to pay more for “pure” gas. > [@JerrySTL](#): > > Some premium gasoline’s do have a better additive package. So I think I was slightly misremembering earlier when I said this was illegal per se, but I believe the issue is that they’re not allowed to make claims that premium gas is better for a car that doesn’t require it. As such, even if they do have a better additive package in their premium gas than their regular gas, they’re not allowed to advertise it anymore. I would think this would mean that there’s no motivation for anyone to put better additives in premium, but I guess I could be wrong. [Previous page](https://boards.straightdope.com/t/do-87-and-93-octane-cost-the-same-per-mile-driven/671758.md?page=1)