Do any Yaris owners use premium gas ?

[YodaBird]

So far I've been putting Octane 91 in the car at $1.38 a liter, not low cost.

[WeeYari]

Originally Posted by YodaBird

So far I've been putting Octane 91 in the car at $1.38 a liter, not low cost.

Why?

[94toy22re]

The higher the octane less prone to pre-ignite, allowing more timing and boost to be run without pre-detonation aka spark knock or pinging. Their is no reason to run anything over 87 in a stock yaris unless your engine is pinging under load. Its dousn't burn cleaner, increase hp/mpg or have more additives then 87. Im not sure about the new turbo cars running 87, i imagine that the computer is decreasing timing making it runs without any problems. But in that case 91 would have a definite power advantage over 87.

[edmscan]

Originally Posted by YodaBird

So far I've been putting Octane 91 in the car at $1.38 a liter, not low cost.

I would also ask why ? .... I did a tankful of 91 Octane recently (just to see if I would get better mileage) and there was neither any real difference in performance or fuel economy. You are just throwing your money away .. when you drive a Yaris, as the vehicle doesn't take advantage of the higher octane gasoline.

[CPALK719]

Originally Posted by edmscan

I would also ask why ? .... I did a tankful of 91 Octane recently (just to see if I would get better mileage) and there was neither any real difference in performance or fuel economy. You are just throwing your money away .. when you drive a Yaris, as the vehicle doesn't take advantage of the higher octane gasoline.

totally agree with this the car is made for fuel economy, as well as using 87 or whatever the lowest octane in your area is available. why blow at this point now close to $5 bucks a gallon for premium? i already have one car that Must use 93. i see reason the yaris needs 93 oct.

[YodaBird]

Originally Posted by edmscan

I would also ask why ? .... I did a tankful of 91 Octane recently (just to see if I would get better mileage) and there was neither any real difference in performance or fuel economy. You are just throwing your money away .. when you drive a Yaris, as the vehicle doesn't take advantage of the higher octane gasoline.

Just to burn a little cleaner, if that :)

[carolinablue]

More likely that the additives need to create the octane boost would make it burn dirtier in a low octane vehicle.

[detroiter]

Don't want to beat a dead horse but one poster said the 1nz is a low compression engine...from my understanding, our engines are actually fairly high compression. For being cheap econo cars, why would Toyota give our cars an engine on the higher side of compression? Is it possible for racing? I do know that Asia has the Vitz cup racing series and not to mention the Yaris liftback has those rear holes that you can change your trailing arms up to a higher mounting position.

It makes me wonder because I was watching a video that was an interview with one of the engineers for the Honda Fit and he had a Fit shell, of which he pointed out everything that went into designing it and it's purpose. He blatantly said that the Fit was built from the ground up with racing in mind.

[mr_miles]

I don't run premium, but there are gas stations here that advertise "no ethanol premium" so I'm curious. I don't know if I've ever ran pure gas before, and I want to see if it changes anything lol.

[edmscan]

Originally Posted by YodaBird

Just to burn a little cleaner, if that :)

I don't know if you saw it, but about 2 weeks ago on Marketplace (CBC on Friday nights) they had a show about premium gas.

They did some testing and they actually determined that premium gas did nothing for performance and was actually worse for the environment. There were more bad emissions out the tail pipe. Basically they said that the gas companies are making millions of dollars sucking people into buying premium gas when they don't need to.

You can watch the show here: http://www.cbc.ca/marketplace/episod...mpfiction.html

[HareBrained]

There are benefits to using premium if the ECU is capable of adapting. There are numerous ECUs that aren't (I suspect the Yaris isn't), and thus the engine performance is based on the lowest grade fuel in the target market. Adaptive ECUs can detect higher octane and can increase timing. These cars can produce more power and can increase fuel economy. The Sonic is one such car and 3-4 more mpg can be seen on premium.

Ethanol actually increases the octane rating and produces more power. But the air-fuel ratio for straight ethanol is 7:1. So, the more ethanol, the more fuel is required for each unit volume of air. If the ECU is tuned to work with 10% ethanol, and it's non-adaptive, not using it will result in a poor ratios and unburnt fuel. Flex-fuel cars (E85 compatible) have sensors that determine the mixture before it reaches the engine, and adapt the injectors, the timing, and how it interprets the O2 sensors.

If the ECU is non-adaptive, using anything other than what it was tuned for (lowest common denominator) is a waste of money. If it is adaptive, there are benefits to be had.

[DeathBeard]

interesting

[mirapatec]

I tried the different octanes in my previous vehicicle. There was no noticible differernce in fuel mileage. Therefore, I have stuck with the 87 octane since then.

[why?]

Originally Posted by Rockstar

Over here we only got 91, premium is 98.

lucky. I am pretty sure the only octane japan uses is 100.

Ok, every modern ecu is capable of adjusting everything up to a small point, either for good gas, or for bad gas.

Every new car is tested with 93 octane in the US, and i am sure the highest octane available in every other market as well. This allows the manufacturer to put out the best hp numbers the car can make. I assume it probably helps gas mileage a very little bit as well. I can almost guarantee though you could not make up the money you would spend on premium compared to the gas mileage gains.

In the US at least, the differences in cost between the octanes now vary greatly. It use to always be a 10 cent difference for each better octane, now it is always much higher. I have seen over 60 cent higher for premium gas. You can't possibly make that up in gas mileage. You would have to get 4 mpg more to just break even at 30 cents a gallon extra.

And if you are talking about additives, think about this. A new Yaris engine is around $500 or so. If you drive 10k miles a year, @ 36 mpg, assuming $3.50 regular gas, premium gas would cost $83 more if premium was 30 cents extra. So over 10 years of driving a car with premium, you'd save enough to buy another engine for the car plus some.

[Superfly]

Yeah, I run on 87. I tried the high octane but I noticed that my Yaris would fail to turn over early in the mornings. I thought it was the specific gas company but mutliple tries from multiple companies have proven my hypothesis wrong. That is why I roll on 87 octane now.

[Nigel8600]

In my yaris (which I just bought) my first tank was regular 87 from superstore, but I was noticing a pinging rattling noise right around 2200 rpm so at half a tank I filled up with premium which made my full tank midgade. I can say that the rattling definitely calmed down around the 2200 rpm area but I can still hear it slightly. I might have to go to empty and try a full premium tank next. And my premium is only .10 cents per litre more. Kinda suks that I'm saying ONLY .10 cents cause I remember in the early 90's when it was only .02 cents per litre more. :(

[Exiwolfman]

The only difference between regular fuel, mid-grade fuel, and premium fuel is the octane rating.

Octane has nothing to do with the amount of energy in the fuel. High octane fuel will not give any significant increase in performance in a low compression engine. You do not see any benefit from high octane fuel unless you have a high compression engine.

The octane rating is the fuel's resistance to spontaneous combustion under compression. The higher the octane rating, the more compression it takes to make the fuel spontaneously ignite.

A high compression engine requires higher octane fuel to prevent detonation. Detonation is a condition where the fuel air mixture ignites while being compressed before the spark plug fires. Detonation can cause serious internal damage to an engine. You can usually hear when detonation is occurring. With the engine under a load or hard acceleration, you will hear a knocking noise coming from the engine compartment. Sometimes this noise can sound like a bunch of marbles rattling around in a tin can under the hood. When you ease up on the throttle this noise goes away.

You usually won't hear this knocking noise on a modern computer controlled engines because they have a knock sensor to detect detonation. When detonation is detected, the engine management computer will adjust the fuel / air mixture and ignition timing to stop the detonation and protect the engine. When this happens, there will be a loss of power and fuel economy.

In some instances, an engine will not run as well on higher octane fuel. This is because higher octane fuel has a slower burn rate. If it is not compressed enough before it is ignited, the fuel may not completely burn in the combustion chamber of your engine. It would finish burning in your exhaust system where it does absolutely no good.

On some occasions, you may feel an improvement in performance and fuel economy when using premium fuel in an engine designed to run on 87 octane regular fuel. Most times this improvement is slight. Many times, it is a placebo effect. You may even get a slight improvement in fuel economy.

You only did half of the math. You figured miles per gallon but you falied to calculate cost of fuel per mile. It is this second calculation that makes a difference in your wallet. If you do the rest of the math you will usually find that the improvement in fuel economy is not enough to make up the increased cost of the fuel. Try this. Calculate your MPG with both fuels and keep a log. Include the price per gallon for the fuel in your log. Calculate the cost per mile for fuel by dividing the amount paid for the fuel by the miles per gallon.

You don't really need to use a higher octane fuel until you go over 10 to 1 compression or if the engine is equipped with a turbocharger or supercharger.

The higher octane fuel will not make your car run any better or last any longer. You are only giving the oil companies more money than you need to. I think they make enough money already.

If you are in doubt, follow the fuel recommendations found in your owner's manual and you won't go wrong.

The link below will tell you all about how gasoline works. The 4th page of the article explains octane.
Source(s):
http://science.howstuffworks.com/gasolin…

[gollygirl1]

Here in my part of sunny Australia (Queensland) I am just using good old Unleaded - at $1.39 a Litre here at the moment. My car cost me $20 a week to fill up and go to work and do errands (I use half a tank a week) I do about 220kms a week. I am not complaining, I have been in heaven since buying my Yaris about 3 months ago - those trips to the petrol station are much lighter than they used to be that is for sure.