98 octane petrol / fuel in Prius ?

[HSDish]

(How often) Do You fill up our Priuses with 98 octane petrol / fuel ?

Heard that it should be good for the engine. Is that right ?

Is there any differenses to different Prius models, gen 1-4 , Plug In gen 1-2 or Prius +  ?

I got one Prius Plug In 2015 and one Prius + 2017 and I use to fill them up with 98 octane about every fifth fill up time, otherwise with 95 octane.

[TheProfessor]

Putting higher octane fuel in a Prius won't hurt it (or any petrol powered vehicle for that matter), but it also won't have any effect other than making your wallet lighter... maybe with one caveat.

The Octane rating is how much the fuel resists knocking. Knocking is basically how diesel engines work, where the fuel ignites due to being compressed by the cylinder. Petrol powered cars want to compress the fuel as much as possible, then ignite it with a spark from the spark plug. So diesel cars want a very low octane rating, and petrol cars want a very high octane rating.

In a petrol fuelled car, the more you can compress the fuel before igniting it, the more power you can get out of it. However, it's hard work compressing fuel, and as you get a bigger bang (literally) out of more compressed fuel the engine needs to be designed to handle these greater forces.

Such cars that are designed to handle and take advantage of greater compression are sports cars (e.g. your typical Porsche, Ferrari, Lamborghini, etc), some "sport" versions of more typical brands, some turbo charged cars, along with some modified/"tuned" cars. When these cars are fuelled with higher octane fuel, the engine's computers gradually alter the timing to increase the compression. In other cars, the timing isn't altered as it's already at its maximum compression.

In all modern cars, there is a knock sensor in the engine that detects if premature ignition (knocking) is occurring, and alters the timing accordingly to reduce the compression.

So...

In a car that isn't designed to take advantage of higher octane fuel (nearly all cars, including the Prius), the higher octane fuel achieves nothing.

In sports/performance cars, some of them may slowly adapt to the higher octane rating and extract more power and economy from it.

In all cars, if you put low octane fuel in (up to a point), the engine will adapt and reduce the compression to prevent it knocking.

There is one caveat that I mentioned above. Higher octane fuels are often sold as a Premium/Higher quality fuel and, as such, may contain a higher quality additive package. This may, in some circumstances, in some cars, in some conditions, improve the efficiency of the engine by helping to clean it internally (e.g. removing carbon deposits).

 

[QuantumFireball]

Generally the only petrol sold in Ireland is 95 RON minimum and there's usually no premium option (what premium is sold doesn't claim to be higher octant), but anecdotal evidence suggests since we moved to using E5 the actual octane rating may be 97-98 RON anyway.

[HSDish]

Thanks to both TheProfessor and QuantumFireball.

 

You just saved me some money. Thanks again

[FROSTYBALLS]

In owners manuals, Toyota just state that fuel should be 95RON or higher.

The UK is likely to move to using E10 next year for 95RON unleaded, but 97-99RON premium unleaded will remain E5 to accommodate those cars unable to use E10. 

 

[Cjohnston1982]

There’s many reports that suggest the new E10 petrol (95RON) reduces economy by up to 10% 

[kithmo]

When I had the Gen 3 and recently with the Gen 4, I found that Shell v-power 98 actually made the fuel economy slightly worse, so I stick to 95 RON now, Esso ATM for the Nectar points.

If my economy drops with E10 then I may go back on to 98

 

[Anthony Poli]

There’s many reports that suggest the new E10 petrol (95RON) reduces economy by up to 10% 

Yes, that’s why it’s a con.
Lower emissions if you get the economy, but if the economy is reduced then your going to produce more emissions.


Sent from my iPhone using Tapatalk

[johalareewi]

A few years ago there was a detailed posting in this forum about super unleaded and toyota hybrids.

[HSDish]

7 hours ago, johalareewi said:

A few years ago there was a detailed posting in this forum about super unleaded and toyota hybrids.

Thanks.

Found those topics in this subject

 

 

 

 

 

[MyOpinionIsWorthless]

On 5/11/2020 at 12:49 PM, HSDish said:

(How often) Do You fill up our Priuses with 98 octane petrol / fuel ?

Heard that it should be good for the engine. Is that right ?

Is there any differenses to different Prius models, gen 1-4 , Plug In gen 1-2 or Prius +  ?

I got one Prius Plug In 2015 and one Prius + 2017 and I use to fill them up with 98 octane about every fifth fill up time, otherwise with 95 octane.

Found that V power effectively moved the mode up one notch with regard to fuel economy. 
so eco mode acted like normal and normal like power mode. 
that said. It was a joy to drive in power mode with v power.