Premium Gas

[fu_im_from_texas]

Originally Posted by eTiMaGo

... our humble little car has some pretty advanced systems...

+1

You dont get to design dynamic system controls at toyota without being very sharp. Toyota recommends 87 ...

[churp]

Originally Posted by fu_im_from_texas

+1

You dont get to design dynamic system controls at toyota without being very sharp. Toyota recommends 87 ...

Toyota doesn't recommend 87.....they say: Select Octane Rating 87 or higher (read the owners manual, page 178, or other posts)...in the English language this means 87 is the lowest they allow. And yes they are very sharp.

[fu_im_from_texas]

Originally Posted by churp

Toyota doesn't recommend 87.....they say: Select Octane Rating 87 or higher (read the owners manual, page 178, or other posts)...in the English language this means 87 is the lowest they allow. And yes they are very sharp.

churp,
you are right. the "or higher" means that we should all run 110 octane race fuel ... i bet you will get 87 mpg and 200 hp ... your "understanding" of the english language is revolutionizing the yaris...

[eTiMaGo]

ok maybe it should say "87 or higher, within reason"

[YarisTom73]

Well, with all the I can only draw the conlusion that we should do what we want with our own cars. If you don't like cheap gas, run something higher. If you don't like high octane, run cheap stuff. 'nuff crying about it, just split the difference and run mid-grade as I do

[fu_im_from_texas]

Originally Posted by eTiMaGo

ok maybe it should say "87 or higher, within reason"

...also the "xx or higher" is the industry standard for recommending fuel. so my lexus gs430 says "93 or higher" which really doesnt make much sence, because 93 is the highest pump gas avaliable in north america... toyota is saying "use 93"

the yaris says "87 or higher" which really doesnt make much sence because you cant get anything lower than 87 in north america

...the industry standard is to recommend the octane then add "or higher" at the end


"....using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner. Your best bet: listen to your owner's manual."
http://www.ftc.gov/bcp/conline/pubs/autos/octane.shtm

why do people insist on ignoring empirical and statistical data?

[marcus]

i find the yaris timing is right on the border of you being able to use 87 octane. slight change of slopes and temp even with its ecu adjusting..gives you a sluggish feel...89 got better outcome..its could also be just my car.. "Dont you guys notice a whirring sound when you accelerate , try driving beside a wall" i need to know if this is normal. or a slight knockin on the engine?

[eTiMaGo]

Originally Posted by fu_im_from_texas

...also the "xx or higher" is the industry standard for recommending fuel. so my lexus gs430 says "93 or higher" which really doesnt make much sence, because 93 is the highest pump gas avaliable in north america... toyota is saying "use 93"

the yaris says "87 or higher" which really doesnt make much sence because you cant get anything lower than 87 in north america

...the industry standard is to recommend the octane then add "or higher" at the end


"....using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner. Your best bet: listen to your owner's manual."
http://www.ftc.gov/bcp/conline/pubs/autos/octane.shtm

why do people insist on ignoring empirical and statistical data?

Hmmm that's quite probable too, to be understood as, 87 is just fine, but don't worry if for some reason you can only get 91, it won't damage the engine.

heheheh too much science studies is just pushing me to experiment, if only I had that toyota intelligent tester or something similar to measure actual spark advance

Or, we can find a Toyota ECU engineer from Japan to enlighten us?

[eTiMaGo]

Originally Posted by marcus

i find the yaris timing is right on the border of you being able to use 87 octane. slight change of slopes and temp even with its ecu adjusting..gives you a sluggish feel...89 got better outcome..its could also be just my car.. "Dont you guys notice a whirring sound when you accelerate , try driving beside a wall" i need to know if this is normal. or a slight knockin on the engine?

I wouldn't be knock, I pored through all I could find in the repair and technical manuals, as soon as the knock sensor feels something out of the ordinary, it will retard the spark, so unless there is something wrong with the knock sensor, you should not "feel" knock for over a second.

[jdium]

Originally Posted by marcus

i find the yaris timing is right on the border of you being able to use 87 octane. slight change of slopes and temp even with its ecu adjusting..gives you a sluggish feel...89 got better outcome..its could also be just my car.. "Dont you guys notice a whirring sound when you accelerate , try driving beside a wall" i need to know if this is normal. or a slight knockin on the engine?

Maybe if feels sluggish because it's only 105 hp going up a hill in hot weather?

As for the whirring sound, it's probably exhaust noise. As quiet as these cars are, there is still some noise. It dissipates easily normally, but a wall would reflect it back to you...

[marcus]

thanks guys hopefully its nothing...

[hystria]

Originally Posted by cleong

So we should only run the absolute minimum RON recommended and anything above is just a waste of money?

PROBABLY higher octane/RON will provide better fuel economy with this car... but the difference will be too minimal to be easily measured by just checking a mileage variation. YES, Toyota recommends using higher octane/RON for this engine in order to obtain better mixture burning, resulting in less polluting emanations. Buying 10-15% more expensive 89/91/94 gasoline won't result in 10-15% mileage increasing. Check out the black smut (?) on the exhaust when running on 87 octane, then whip it off and switch to 91 and check again.

[fu_im_from_texas]

Originally Posted by hystria

PROBABLY higher octane/RON will provide better fuel economy with this car... but the difference will be too minimal to be easily measured by just checking a mileage variation. YES, Toyota recommends using higher octane/RON for this engine in order to obtain better mixture burning, resulting in less polluting emanations. Buying 10-15% more expensive 89/91/94 gasoline won't result in 10-15% mileage increasing. Check out the black smut (?) on the exhaust when running on 87 octane, then whip it off and switch to 91 and check again.

"....using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner. Your best bet: listen to your owner's manual."
http://www.ftc.gov/bcp/conline/pubs/autos/octane.shtm

why do people insist on ignoring empirical and statistical data?

[bearda]

This is one of those discussions that just doesn't go away. I've seen the same thing on almost every non-premium fuel car forum I've seen. The signal to noise ratio tends to vary, but you've always got a couple people clinging to numbers and reports, a couple people clinging to their anecdotal evidence, and a couple people clinging to some hope that they can improve performance.

Just to add fuel to the fire, though, I don't think higher octane gas is going to do much of anything for you (nothing good, at least). Higher octane gas doesn't give you higher performance; it just resists pre-detonation. If you're at the point where the ECU is retarding timing due to pinging it'll keep you from losing performance. Unless the ECU is really designed for performance it isn't going to keep advancing the timing on it's own unless it's already retarded the timing (There are some that do do this. The WRX actually starts with a very conservative timing advance then ramps it up until it knocks, then pulls it back a little).

Higher octane gas CAN give you better mileage if the car can take advantage of it. Octane rating is basically a measurement of how long it takes fuel to burn. If the fuel burns longer you don't need to burn quite as much of it in the optimal case. You've got to get the ECU to realize that, though. If the ECU keeps the same ignition timing/AFR/whatever you're not going to see any benefit.

One thing I have seen with higher-octane fuel on a car factory-tuned for 87 is starting delay. From what I can tell (and this is coming almost entirely out of my ass, as this goes right past my league) since higher octane gas is more resistant to predetonation sometimes it's also a little too resistant to initial detonation. You try to start the car and the ECU finds the gas a little harder to light than it thought. Not a big deal at all, but at times an indicator that lower octane gas can actually run better than high-octane.

If you're looking for the best gas for your car just buy GOOD gas, not higher-octane gas. Go with a station that stocks gas with additives and detergents in it's 87. Chevron is a great example of this; they put their Techron additive in all the gas they sell. Once again, it's isn't going to add any more performance or gas mileage the car didn't have at one point. Maybe it'll keep it running a little cleaner, though, and it's my personal opinion that you're more likely to see a benefit from that than running high-octane gas.

[Kioshi]

Originally Posted by fu_im_from_texas

...also the "xx or higher" is the industry standard for recommending fuel. so my lexus gs430 says "93 or higher" which really doesnt make much sence, because 93 is the highest pump gas avaliable in north america... toyota is saying "use 93"

the yaris says "87 or higher" which really doesnt make much sence because you cant get anything lower than 87 in north america

...the industry standard is to recommend the octane then add "or higher" at the end

They say some number and higher because say if you are driving in a foreign country....than something higher than whatever number they tell you can be used. But who would spend the money to be driving a U.S. car in Europe or Africa anyway ~

Like Tom said, just use mid grade. If its used car use cheap stuff. If its a new car in your first hands, use mid grade. If its hp is 173+ use premium~

[cm07yaris]

This topic always comes up on every forum that has to do with something that uses gas. It also turns into a huge debate taking up several pages and ending with the same result. The same goes for the big debate between using synthetic or natural oil.

[hystria]

Originally Posted by fu_im_from_texas

"....using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit.

TRUE. As per Yaris manual, it recommends 87 or higher. Why "or higher" ? Ever wonder why Toyota recommends wasting your money ? With NO REASON ? Is Toyota in business with Shell ? Well, if not, there should be a reason, unless there are places on Earth that sell only 89 or higher octane gasoline... don't think so...

Engines are optimized to run with a precise level of octane. If an engine requires 87 and the owner put 89 or higher, there will be absolutely no benefit for the engine. On the other hand, if and engine is optimized to run with 89 and the owner uses 87, the engine will not run at 100% performance. It will knock more or little because the mixture ignites before the optimum moment during compression, thus leading to hot points on the piston/ring surface. Because the mixture ignites before the moment when the engine compression is optimal, it produces less overall performance. But not by much, one will not be able to feel any difference.

To resume... if using 87 the engine starts knocking, try changing the brand... the Yaris engine should not be knocking to an audible/damageable level while using good quality 87 octane gasoline.

[WRBlue]

Originally Posted by Kioshi

Like Tom said, just use mid grade. If its used car use cheap stuff. If its a new car in your first hands, use mid grade. If its hp is 173+ use premium~

That makes no sence...

If anything, an older car needs higher grade gas because of bad maintance, wrong plugs, carbon buildups in the combustion chamber, etc. But, if a car is maintaned, there is no reason what so ever to use anything but 87 octane. I have been to gas stations that don't sell less than 89, and I've been to some that sell 86...

There are a great many cars that make more than 170hp that only use regular. For example: My last truck was a V6 S10 that made 200-ish, and ran best on 86. The Jeep I traded in for the WRX made 235hp on 87.