Type of Fuel

87 octane. Back in the ol' days (20 years ago?) when you could hear an engine knock, it was when you were putting the petal to the metal. With the Prius, the high torque electric motor kicks in helping the ICE out. I'm not worried about octane because I know the electric boost takes most of the torque strain off the gas engine.

 

eighty seven

 

87 all the way.

 

87, though I did spend 20 extra cents a gallon today to get ethanol free up in Greenville SC.

I figured why not, thats what our normal gas here costs.

 

I use regular (lowest octane--not sure what it is in CA).

 

Regular, which is 87 here, but could be 86 or 85 west from Mississippi.

 

87 octane (Regular)
E10 (No choice)

 

Well, I'll get sucked into this discussion:

At work I drove a 2005 Buick AWD van with a large v6 engine, and averaged between 5,000 and 6,000 miles a month. I have had time to 'experiment' with octane ratings. For two months I used premium grade gasoline and averaged 21.8 mpg. For two months I used the lowest grade and averaged 21.9 mpg. My trips were mostly highway miles with about 5% city driving. I cover the state from corner to corner so all my trips were about the same. I used mostly the same brand of fuel. The weather conditions were about the same when I 'experimented.' I drove fairly conservative with the work car just as I would with my own car.

I saw no real difference between mileage and octane rating. The van must have compensated for the octane and adjusted accordingly. I noticed no knock on any of the gasoline changes.

JUST my 2 cents worth.

So octane 85 is my choice from here on out.

 

I agree with this assumption. The only time you would get spark knock from a low octane fuel would be in a full "under load" condition. That's the brilliancy of having an electric motor to do the hard work, and having the ICE as the backup.

 

87 makes sense, Toyota recommends it . Higher octane does not give more power as the Fuel Companies used to claim-back in the day.

octane (ktn) Any of several hydrocarbons having eight carbon atoms connected by single bonds. It is commonly added to gasoline to prevent knocking from uneven burning of fuel in internal-combustion engines. Octane is the eighth member of the alkane series. Chemical formula: C8H18.

The American Heritage® Science Dictionary Copyright © 2005 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

 

Wonder if the ICE has an "anti-knock" sensor? Most cars do nowdays.

 

I can only get gas with 10% ethanol in California. Did you notice any difference in FE with the ethanol free?

 

Dealer told me 87, so 87 it has been for over 9000 miles. Averaging right at 50 mpg.

 

This car is made to run on 87, anything more would be a waste IMHO seeing how this is a fuel saving hybrid and not a performance vehicle of any type.

 

87.

 

I use 87.

Just for fun, I've run a couple of tanks of E0 through my car and I didn't notice a difference that justifies the added price....maybe 2MPG.

I'll give BW's advice to use 89 for longer trips a read...but I haven't yet seen a reason to use anything but the cheap stuff.

 

An additional contraversy is using a Top Tier manufacturer. When auto makers first started with port injection and all aluminum construction, they found the intake area around the valves building up with deposits. The auto makers response was to band together to create a higher standard. Here is an excerpt from Wikipedia both pro and con.
According to its marketers, all vehicles will benefit from using Top Tier Detergent Gasoline over gasoline meeting the basic EPA standard. Deposits will reputedly be minimized on fuel injectors, intake valves, and combustion chambers.[7]
New vehicles will supposedly benefit by keeping their engine clean and running optimally, older vehicles may benefit with increased engine performance and prolonged vehicle life.
Using this gas is purported to have the following benefits over gasolines just meeting the EPA standard:
Improved fuel efficiency
Reduced driving upsets (rough idle, stalling and surge)
Improved acceleration
Increased engine power
Reduced emissions
Criticism
Several car manufacturers believe that using top tier detergent gasoline has an impact on all vehicles. Some critics believe that using top tier detergent gasoline is only critical on high-end vehicles; otherwise, using engine cleaner every 100,000 miles should clean up any carbon buildup.[8][9] Other critics say that top tier detergent gasolines cause little or no decrease on the amount of buildup on a car's engine.[10]
Before a standard used was the BMW Unlimited Mileage Test. Arco claims to meet this. BMW now mentions Top Tier gas in its owner's manuals but not the unlimited mileage test. Arco is not listed as a Top Tier gas.
Ford recommends BP fuels and mentions it on Ford car gas caps. BP is not on the Top Tier gas list.[11