Regular, Plus or Prem?

[scottwyden]

I know that the 2010 says it uses Regular gas, but coming from an Infiniti that says to use Premium I was considering using Plus in the Prius. What do you think?

I know it will make the mileage go down a bit but isn't Plus and Premium better for engines in the long run anyway?

What do you think?

[bokone]

I think Toyota spends millions of r&d dollars configuring the engine (as well as tire pressures) to give the optimum performance return for the least cost. If you want to burn plus or premium, go for it. But the only thing that will change is your wallet. Just my $.02

[stream]

Originally Posted by bokone

I think Toyota spends millions of r&d dollars configuring the engine (as well as tire pressures) to give the optimum performance return for the least cost. If you want to burn plus or premium, go for it. But the only thing that will change is your wallet. Just my $.02

+1

[morpheusx]

The Prius engine is designed for 87 octane fuel. Performance engines like what was likely in your Acura that take premium only (usually 91 Octane) have engines that have higher compression and also sometimes run at hotter temps. A quick summary the higher compression and heat makes the fuel detonate easier or quicker occassionally causing a misfire or knock. Higher octane fuel will not detonate as quickly which is why the high performance engine uses it.
In other words don't waste your money
If you want to read more on the subject try these links

Octane rating - Wikipedia, the free encyclopedia

Octane_rating

Compression ratio - Wikipedia, the free encyclopedia

Compression_ratio

[jim256]

Originally Posted by morpheusx

The Prius engine is designed for 87 octane fuel. Performance engines like what was likely in your Acura that take premium only (usually 91 Octane) have engines that have higher compression and also sometimes run at hotter temps. A quick summary the higher compression and heat makes the fuel detonate easier or quicker occassionally causing a misfire or knock. Higher octane fuel will not detonate as quickly which is why the high performance engine uses it.
In other words don't waste your money

The Prius actually has a 13:1 compression ratio, which is quite high, but because of the Atkinson, or Miller, cycle, the need for premium is negated. In fact, I've seen a number of articles that suggest regular will actually perform and maintain the car best. Any experts on fuel/Atkinson that can confirm what I've read?

[fuzzy1]

Originally Posted by jim256

The Prius actually has a 13:1 compression ratio, which is quite high, but because of the Atkinson, or Miller, cycle, the need for premium is negated. ...

The 13:1 figure is really an expansion ratio. The compression ratio is considerably less, and variable. The Atkinson cycle allows the two to be different.

[Spartane]

Premium gas is still something on my list of things to try.

In Canada, Shell Premium has no ethenol, so there might be an advantage there.

It also bothers me that Toyota originally specified 88 octane in their manual instead of 87. I know it's said to be a typo, but company politics is a powerful thing and perhaps there's more to it than what's being publicly admitted...

Anyway, since it won't hurt anything, the easiest way to tell is to try it for a few tank-fulls and see if it makes any difference in the way the car runs.

[cpatch]

Giving the oil companies more money than necessary is not the reason you bought a Prius!

[blase]

Click and Clack the NPR car guys used to say premium wasn't even necessary in cars that required it. If the engine doesn't use it why pay for it?

[fred garvin]

oh for pete's sake

it was a typo. take off your tin foil hat - there is no conspiracy. there isn't even an 88 octane option here in the states. DO NOT suggest we mix a half tank of 87 and a half tank of 89, as some have crazily suggested on these very pages.

always use the lowest octane the manual says - there will be no increased performance or avoidance of damage, especially in a prius, in fact the opposite is likely