What Gas Octane do you use ?

[duanelaugh]

<div class='quotetop'>QUOTE(viking31 @ Aug 20 2007, 01:55 PM) [snapback]499218[/snapback]</div>

Engine problems with higher octane? What problems?

Rick
#4 2006
[/b]

For starters, burned exhaust valves. It's never been mentioned here, but it can do just that. The slower burning higher octane fuel will still be burning when the exhaust valve opens.

[JimN]

<div class='quotetop'>QUOTE(mastermason11 @ Aug 19 2007, 03:42 AM) [snapback]498587[/snapback]</div>

I just got my 05 Prius the other day and was just wondering. Do you use 87, 89 or 91 octane gas ? Your info will be appreciated.
[/b]

It runs fine on 87. Anything higher is a waste of money.

[icarus]

<div class='quotetop'>QUOTE(prius2go @ Aug 20 2007, 11:59 AM) [snapback]499255[/snapback]</div>

surely it has knock sensors to use higher or lower grade?
how new is this engine design?
[/b]

It has always been my experiance that knock (preignition) occurs with lower octane than spec. Higher octane is just wastful. My question about low octane (83-85) remains. I assume that the ecu/knock sensor in a engine as advanced as a prius should retard the timing and allow it to run safely, but the real question is what happens to mpg/performance. (My 1986 vw westfaila ran fine on 83-85 but once I discovered that it was that I low I always bought the more expensive 87 just to make sure) Question is how will the Prius do? I guess I will have to do a test next week when we drive across Montana end to end. I'll do one tank on 83, the next on 87 and report the results.

Icarus

[rwhoyle]

<div class='quotetop'>QUOTE(bapajack @ Aug 19 2007, 07:45 AM) [snapback]498619[/snapback]</div>

I'm brand new at this and haven't yet read through the manual for the '07 we just got... I asked the dealer rep the same question and he said "either 87 or 89 is OK" My impression of most of the posts I've seen here since I started my pre-purchase surfing is that PriusChat is a great source of good information!!

I certainly agree with Duane that the cost of gas is a bottom line thing, but then so is engine wear & tear... Here in Nebraska, because 89 octane is ethanol-added, and because we grow corn and produce the stuff, it's subsidized and therefore less expensive that 87.

So, aside for the politics of all this, how, specifically, is ethanol better, worse or the same? (for the Prius... let's not talk environment yet). Thanks!
[/b]

bapajack,

Ethanol has a high affinity for water and usually, in an older car, will clean out your fuel system and carry all of the debris into the fuel filter causing possible plugging problems. Last, but, not least, ethanol can soften and, over a period of time, damage/destroy some rubber and rubber seal and o-ring compounds. Thus, causing leaking gasoline seals and o-rings wherever they come into contact. Does anyone know the rubber compound used in the Prius fuel system o-rings, seals and elastomers? In the petroleum industry, we normal specify Viton "A" seals for all ethanol handling uses. It is a higher grade of rubber than Buna "N", which many non-critical seals and made from because it is a cheaper rubber compound. This is why some cars are specified as okay for Ethanol blended gasolines and some are not. Does the Pruis Owners Manual specify ethanol blended fuels as okay for use? Hope this helps!!

[tripp]

<div class='quotetop'>QUOTE(Sliderule @ Aug 20 2007, 08:21 PM) [snapback]499518[/snapback]</div>

Does the Pruis Owners Manual specify ethanol blended fuels as okay for use?
[/b]

I think it says up to E10, like most other cars out there.

[patsparks]

E10 is good in mine, I ran my Camry on E10 and it ran better and got better economy than on standard petrol. E10 is cheaper than standard, it has slightly lower calorific value than standard unleaded but in my camry it stopped the pinging and improved economy.

I'm getting about 4.4l/100km which is the rated estimated consumption city cycle from the Prius on it so economy isn't suffering.

Ethanol in Australia is made from sugar cane waste.

[devprius]

<div class='quotetop'>QUOTE(mastermason11 @ Aug 19 2007, 11:24 PM) [snapback]499018[/snapback]</div>

Shhot.. When I took it from the dealer, the dealer was too cheap to put a full tank of gas, so I filled it up myself with 91 octane.. Next time, I will use 87.. Thanks guys...
[/b]

They were supposed to give you a full tank of gas. Says so on the sticker price. I'd complain to Toyota about it, or go back to the dealership. And I'd probably be less inclined to take my car for service to that dealership. If they forgot to do that as part of the PDI, god knows what else they forgot to do.

[SureValla]

Is E10 required now I cant seem to find any regular 87 in MA

[alanh]

E10 is required in many urban areas due to pollution issues, and that MTBE is no longer allowed.

Anyway... all the octane does is resist knocking. If you're not knocking, extra octane will do nothing for you.

[Winston]

Regarding the Montana Gas question; At higher altitudes, the air is less dense, so your cars engine takes in less mass of air. That makes it harder to ignite the fuel. In order to help with the fuel ignition, they reduce the octane of gasoline sold at higher altitudes. The gas you are talking about must have been sold at a high altitude gas station.