Noise in gas tank when using low octane gasoline

http://en.wikipedia.org/wiki/Engine_knock

Less little octanes filling up the space. Causes things to be sloppy.

Seriously though, there should be no difference. The viscosity would change so minutely by the difference in octane. The higher the rating, the less chance of pre-ignition occuring thus causing better detonation at desired time and compression.

I think you mean ignition not detonation. Detonation is synonymous with pre-ignition and would be prevented by higher octane.

If your engine requires 93 and does not have an antiknock sensor, then you could be damaging your bearings, why not just use the correct grade of petrol?

Then you won't kill your motor and the "sound" will be gone!! Two fixes with one change!

By the way, you usually get less MPG with the cheaper petrol, so your saving on that score will usually be "Zero" anyway.....as the engine is optimized for a specific Octane value....give it that Octane value only.....

Andy,

Unless it is a high performance (Si) model, it is most likely that the recommended octane is 87, at least for US cars.

If high octane is recommended, the car would have a knock sensor to change the timing to be able to run on lower octane, unless the car is ancient.

You don't necessarily get better gas mileage with higher octane gas. In fact, here in the US, you would get noticeably lower gas mileage with higher octane gas if the engine is not designed for it. Here in the US, octane enhancers are added to increase the octane rating, and these additives have lower energy content. This may not be true in Europe.

I had a car that was designed for 87 octane. Every once in a while I would put 93 octane in. I consistently got lower mileage with the higher octane.

Tad

I've got a general question about octane levels in use in the USA. A few years ago, I went to Utah/Idaho/Wyoming area on a vacation. Rented an automobile similar to the one I owned and regularly drove in Ohio. In Ohio, 87 octane was specified, but the car I rented specified 86 octane. As the average elevation is quite a bit greater in the Western states, I wondered whether it was advisable to use the lower octane (marginally) than the higher octane (and why).

According to some sources, lower octane is OK at higher altitudes:

http://www.chevron.com/products/prodserv/fuels/gas_qanda/api_octane.shtml

Tad, if you had read and understood what I wrote, then you will realize that all you did was that you wrote exactly the same, in a different way.......nothing more, nothing less, sorry!

If you don't believe me, read my post again, slowly.

The difference was that I went from the position that the car needed 93 Octane.....you went from the position that it needed 87.

The poster did not declare which he required, or better said, what his engine required.....but if the noise was Pinking, then I suspect that either it is set up for and needs 93....or it is wrongly set up in the first place!!

Using a high Octane car on low Octane, even with a Knock sensor is not correct, as we both said (me first!) mileage will suffer......or the other way round.

Using the wrong Octane is just a "get you home trick", nothing more....

Have a great day!

I hate when that noise happens. And it usually happens under load. If you persist in sponsoring wrestling matches in your vehicle, you may find yourself the recipient of an honorary Darwin award and a large repair bill.

HEY FOLKS!

HE SAID THE WRESTLING NOISE WAS COMING FROM THE GAS TANK! - no mention of the engine making noise

maybe pre-ignition in the fuel pump? (Joking)

or something to do with additives making fuelpump work harder (if its in the tank on a civic) - I would assume the volitality (sp) of the fuel would change with the additives mixed into the base fuel.....

sounds like a challenge to me -

Your question is a little vague. But octane should have nothing to a malfuctioning fuel pump or any other device in your fuel tank. I think you have a timing problem. Have a mechanic check for pre- ignition problem which will ping when you accelerate. Honda Civics are made to run on 87 octane unless you buy your gas in another country like Mexico.

Hi Slong,

if it is really in the gas tank, either you have water already in the tank from the station you loaded last.

it is very weird but you it is the only noise that you hear, or maybe something was detached, maybe a baffle in the tank, those divisions that eliminate waves inside

Edgar

Thanks for your reply. My Honda Civic is from year 2000 with 95,000 miles on it. A fuel gas with 87 octane is recommended in the manual. I still don't understand why only a lower octane gas would give a wrestling noise in the gas tank.

Could it be that the vent line on the gas tank is partially plug perhaps in combination with a higher volatility of the higher octane gas it prevents the wrestling noice?

Look octane has nothing to do with noises in your fuel tank. Thats like water with clorine or without. By wieght means nothing measureble. By performance Yes there is a difference. Your engine has a performance problem when running on 87 and may rattle or ping or make wierd noises. Take your tank apart and check for golf balls,footballs,soccer balls, or mayde a hampster running on a wheel. or I suggest taking it to a Honda dealer.

Your engine may be out of time. It will change the way it runs and can damage the engine if it's out of time. Get a cheap timing light and check it or take it in for service. I see no way lower octane gas can actually rattle your gas tank except from pre-ignition rattling your tail pipe which is hitting your gas tank. Otherwise I would think the knock is coming from the engine and just sounds like it's coming from the gas tank.

With the limited infos we have been given, your comment would appear to be a very good one indeed....thanks. It also fits in with my take.

We could be wrong, but we are doing our best!!

hey Andy My kids stayed in Frankfort in june 07 and said it SUCKED. They rather see Polland then go back to an old distress town like Frankfort

I must admit Frankfurt is not like a tourist center, the museums (if you like them as I do) mostly situated along the Main are probably the best feature....

If you have a car, there are much more interesting things to see within 50 miles of Frankfurt....

You are not the first and you won't be the last to say that......I personally prefer Gießen and as I live halfway between the two, I have a better choice for most things there.....

Although I say that I live near Frankfurt, its about 40 miles away, I actually live in an old Farm house in a very tiny village that even Germany 50 miles away have never heard of!!

I say old, my house in England was over 550 years old, and this one is only 99, so maybe I should say "young"!! It was previously owned by a Jewish family till about 1941......!

They traveled Europe for a month and a half and had a trip of a lifetime. They landed in Frankfurt and traveled to Berlin and Poland ..... then off to Austria and ended up in Bibione Italy. Out all those towns Austria ranked the best. Not bad for a bunch of teenagers from California.

Sorry to correct you, but Austria is a country......not a town!!