# Premium-quiet engine - better? **URL:** \ **Category:** Factual Questions\ **Created:** [December 20, 2006, 9:55pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974 "2006-12-20T21:55:36Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [December 20, 2006, 9:55pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/1 "2006-12-20T21:55:36Z")
Recently, to try to cure something that sounded like it was an air filter problem but I didn’t have time for a mechanic to check it due to it being the middle of the night on a long distance trip, I switched to premium gas to see what would happen. Well, it did cure the problem (or perhaps it went away on its own?), and as a bonus, my car’s engine runs _much_ quieter. As in, before, when I got it up to highway speed, it (a 2002 Kia Rio) made a godawful din until my ears got used to it. Now that no longer happens, and I have noticably better acceleration on the streets. Does this mean that highway travelling like this is better for my car’s engine on premium than on regular? I don’t get better gas mileage, if anything it’s a bit worse, but that might be explained by taking advantage of the better acceleration 😉 ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [December 20, 2006, 10:05pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/2 "2006-12-20T22:05:05Z")
Sounds (heh) like your car wants the extra octane. Didn’t think Kia made anything that could be considered high-performance, but the proof is in the driving - you’re getting better acceleration and the engine’s not knocking itself to death. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [December 20, 2006, 10:09pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/3 "2006-12-20T22:09:49Z")
Well… you may want to check the owner’s manual and make sure that it’s not intended for higher octane gas than the usual 87. If that’s not the case, then I might have it checked out- it sounds like you may be getting some knocking and/or pinging, although the knock sensors in today’s cars should retard the timing enough to keep it from causing damage. Essentially, with regular gas, it is being ignited too early or late, and causing noise, and potential damage. Using the higher octane stuff will allow it to ignite at the right time, which means that it won’t make so much racket. Believe it or not, the octane number measures the resistance to pre-ignition, and is only useful as far as keeping cars that are tuned for it from knocking or pinging. In most engines intended for regular gasoline, it doesn’t give any more power or anything- you’re just blowing money out your tail pipe. ---
**Author:** ![duality72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duality72/32/3910_2.png) [@duality72](https://boards.straightdope.com/u/duality72)\ **Post date:** [December 20, 2006, 10:14pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/4 "2006-12-20T22:14:16Z")
[QUOTE=bump] Believe it or not, the octane number measures the resistance to pre-ignition, and is only useful as far as keeping cars that are tuned for it from knocking or pinging. In most engines intended for regular gasoline, it doesn’t give any more power or anything- you’re just blowing money out your tail pipe. [/QUOTE] From [Wikipedia](http://en.wikipedia.org/wiki/Octane_rating), for what it’s worth: > [@](#): > > It might seem odd that fuels with higher octane ratings burn less easily, yet are popularly thought of as more powerful. The misunderstanding is caused by confusing the ability of the fuel to resist compression detonation (pre-ignition = engine knock) as opposed to the ability of the fuel to burn (combustion). However, premium grades of petrol often contain more energy per litre due to the composition of the fuel as well as increased octane. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 20, 2006, 10:17pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/5 "2006-12-20T22:17:05Z")
[QUOTE=bump] Essentially, with regular gas, it is being ignited too early or late, and causing noise, and potential damage. [/QUOTE] Too early. Knocking (also called predetonation) is caused by the fuel/air mixture in the cylinder igniting before it’s supposed to; the earlier it ignites, the worse the problem becomes. Octane is a measure of a gasoline’s ability to resist preignition. The higher the octane number, the harder the gas is to ignite and the better it resists igniting too early. ---
**Author:** ![duality72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duality72/32/3910_2.png) [@duality72](https://boards.straightdope.com/u/duality72)\ **Post date:** [December 20, 2006, 10:17pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/6 "2006-12-20T22:17:26Z")
Arg, should have read a bit more first. As to **bump** ’s point: > [@](#): > > The power output of an engine depends on the energy content of its fuel, and this bears no simple relationship to the octane rating. A common myth amongst petrol consumers is that adding a higher octane fuel to a vehicle’s engine will increase its performance and/or lessen its fuel consumption; this is mostly false—engines perform best when using fuel with the octane rating they were designed for and any increase in performance by using a fuel with a different octane rating is minimal. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [December 20, 2006, 10:22pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/7 "2006-12-20T22:22:29Z")
I don’t know why everyone keeps mentioning that the octane rating has no bearing on its energy content: I am aware of that and even mentioned that I am not getting better gas mileage in my post. The louder sound at highway speeds, however, wasn’t really a “ping” unless I was misunderstanding it: it’s just a louder version of what’s happening at lower speeds. So I was wondering if a premium gas _that doesn’t_ give you better gas mileage but _nonetheless_ makes the engine quieter could be better _for the engine_. I could see it going either way: – Yes, a quieter engine is a sign that there is less wear on the engine despite the same mileage. – No, the engine is working just as hard, but the fact that it’s burning the fuel at a different point in the cycle just makes it _sound_ like there’s less wear. But thanks for your inputs everyone so far. ---
**Author:** ![lowbrass](https://avatars.discourse-cdn.com/v4/letter/l/dc4da7/32.png) [@lowbrass](https://boards.straightdope.com/u/lowbrass)\ **Post date:** [December 20, 2006, 10:33pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/8 "2006-12-20T22:33:36Z")
If your car was PINGing before, it would have sounded like a sort of fast “ticking” noise. You would hear it more under load - accelerating and going uphill. Higher octane gas would help that, but it still leaves the question of what’s wrong with the engine that it’s PINGing in the first place. The only reason to use high-octane that I’m aware of is to eliminate pre-ignition, which is damaging to the engine. My understanding is that using it with the belief that it does anything else is just wasting your money. ---
**Author:** ![MrFloppy](https://avatars.discourse-cdn.com/v4/letter/m/43a26b/32.png) [@MrFloppy](https://boards.straightdope.com/u/MrFloppy)\ **Post date:** [December 20, 2006, 10:55pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/9 "2006-12-20T22:55:56Z")
Ditto everything Bump said above. A Kia Rio should run fine on regular. What gas are you buying? Branded or non-branded? Maybe you were just using bad gas. The knock sensors and your car’s engine management system should adjust the timing to compensate for low octane but if it is pinging (always sounds to me like ping pong balls are rattling around the air intake) on the recommended gas, you should have your car checked out. ---
**Author:** ![brad\_d](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@brad\_d](https://boards.straightdope.com/u/brad_d)\ **Post date:** [December 20, 2006, 11:46pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/10 "2006-12-20T23:46:54Z")
Are _pinging_ and _knocking_ just two names for the same thing, or are they distinct phenomena? If they don’t refer to the same thing, could somebody explain the difference? ---
**Author:** ![Princhester](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Princhester](https://boards.straightdope.com/u/Princhester)\ **Post date:** [December 21, 2006, 12:20am UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/11 "2006-12-21T00:20:21Z")
I have my doubts about the whole scenario. Get someone else to fill up the car and not tell you what they put in. Do this a few times. See if you can still pick the quietness/better acceleration etc when you don’t know what to expect. ---
**Author:** ![lowbrass](https://avatars.discourse-cdn.com/v4/letter/l/dc4da7/32.png) [@lowbrass](https://boards.straightdope.com/u/lowbrass)\ **Post date:** [December 21, 2006, 12:40am UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/12 "2006-12-21T00:40:30Z")
[QUOTE=brad\_d] Are _pinging_ and _knocking_ just two names for the same thing, or are they distinct phenomena? If they don’t refer to the same thing, could somebody explain the difference? [/QUOTE] I think they’re the same thing, although Wikipedia says it can refer to two different phenomena: pre-ignition and detonation. That’s something I didn’t know. Apparently pre-ignition means the fuel is burning _before_ the spark plug fires. ---
**Author:** ![Schuyler](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@Schuyler](https://boards.straightdope.com/u/Schuyler)\ **Post date:** [December 21, 2006, 12:46am UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/13 "2006-12-21T00:46:39Z")
[QUOTE=Princhester] I have my doubts about the whole scenario. Get someone else to fill up the car and not tell you what they put in. Do this a few times. See if you can still pick the quietness/better acceleration etc when you don’t know what to expect. [/QUOTE] Pardon me **Ludovic** if you’ve already done this - but have you also eliminated other things it could be (i.e., you’re sure it’s the engine). Like tire inflation, what road surface you are driving on, whether the doors/windows/sunroof/hatch are sealed properly, overdrive on/off, that kind of thing. [QUOTE=brad\_d] Are _pinging_ and _knocking_ just two names for the same thing, or are they distinct phenomena? [/QUOTE] Same thing - pinging, knocking, pinking, pre-ignition - see [wiki](http://en.wikipedia.org/wiki/Engine_knocking) for an explanation, although what’s been said here so far is generally accurate. ---
**Author:** ![brad\_d](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@brad\_d](https://boards.straightdope.com/u/brad_d)\ **Post date:** [December 21, 2006, 5:57am UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/14 "2006-12-21T05:57:53Z")
Thanks for the info, guys. 🙂 ---
**Author:** ![FRDE](https://avatars.discourse-cdn.com/v4/letter/f/e68b1a/32.png) [@FRDE](https://boards.straightdope.com/u/FRDE)\ **Post date:** [December 21, 2006, 10:56am UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/15 "2006-12-21T10:56:11Z")
I’m just wondering whether the cylinder heads were coked up, or maybe even the spark plugs. The Premium should give you a hotter burn which might have cleaned things up. ---
**Author:** ![Mr.Slant](https://avatars.discourse-cdn.com/v4/letter/m/c57346/32.png) [@Mr.Slant](https://boards.straightdope.com/u/Mr.Slant)\ **Post date:** [December 21, 2006, 4:05pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/16 "2006-12-21T16:05:44Z")
[QUOTE=FRDE] I’m just wondering whether the cylinder heads were coked up, or maybe even the spark plugs. The Premium should give you a hotter burn which might have cleaned things up. [/QUOTE] If your idea is right, he should probably run a bottle of Chevron Techron additive in along with his next tank of gas… only mass-market fuel additive worth 5 cents. Actually, it probably isn’t a bad idea to make that part of your annual preventive maintenance routine with _ANY_ car. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [December 22, 2006, 2:39am UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/17 "2006-12-22T02:39:41Z")
Some brands (Chevron & Shell come to mind) intentionally put more of their cleaning agents in their premium blends, so that may have been what did it. ---
**Author:** ![FRDE](https://avatars.discourse-cdn.com/v4/letter/f/e68b1a/32.png) [@FRDE](https://boards.straightdope.com/u/FRDE)\ **Post date:** [December 22, 2006, 10:19am UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/18 "2006-12-22T10:19:39Z")
[QUOTE=Mr. Slant] If your idea is right, he should probably run a bottle of Chevron Techron additive in along with his next tank of gas… only mass-market fuel additive worth 5 cents. Actually, it probably isn’t a bad idea to make that part of your annual preventive maintenance routine with _ANY_ car. [/QUOTE] A good point, I was tentatively thinking of suggesting that. My mechanic swore by Redex, while I’ve heard people laugh at additives, I’m inclined to take advice from experienced mechanics. Incidentally a long time ago a garage owner told me that if you were out of 4\* you could stick a couple of gallons of oil into the 2\* storage tank - I’m not sure I fancy doing that - but it makes a bit of sense. ---
**Author:** ![Common\_Tater](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/common_tater/32/13846_2.png) [@Common\_Tater](https://boards.straightdope.com/u/Common_Tater)\ **Post date:** [December 22, 2006, 11:48am UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/19 "2006-12-22T11:48:27Z")
As several have pointed out, high octane fuel is of no benefit if the engine timing is not sufficiently advanced to take advantage of it. It’s entirely possible that the car runs smoother and has more pep using premium fuel if the engine knock sensors are advancing the timing. Read the owners manual to see what the manufacturer recommends. ---
**Author:** ![Mr.Slant](https://avatars.discourse-cdn.com/v4/letter/m/c57346/32.png) [@Mr.Slant](https://boards.straightdope.com/u/Mr.Slant)\ **Post date:** [December 22, 2006, 12:00pm UTC](https://boards.straightdope.com/t/premium-quiet-engine-better/384974/20 "2006-12-22T12:00:41Z")
[QUOTE=Common Tater] As several have pointed out, high octane fuel is of no benefit if the engine timing is not sufficiently advanced to take advantage of it. It’s entirely possible that the car runs smoother and has more pep using premium fuel if the engine knock sensors are advancing the timing. Read the owners manual to see what the manufacturer recommends. [/QUOTE] He has an '02 Kia Rio, perhaps the cheapest and slowest car an American can buy. I guarantee it says 87 octane. [Next page](https://boards.straightdope.com/t/premium-quiet-engine-better/384974.md?page=2)