Difference with high octane?

Phase separation is definitely bad and will significantly drop the octane rating of E10 gas.

http://www.fuel-testers.com/gasoline_octane_and_ethanol_E10.html

It is worth noting however that phase separation in a daily driven land vehicle is very unlikely assuming the fuel system is properly sealed. Fwiw, I regularly buy pure 93 for my current vehicle (that calls for 93) and will probably put pure 93 in my Tacoma when it arrives next week.

 

I'm thinking most contamination occurs in transport or at the station.

 

Good point. If the fuel has already phase separated in the gas station's underground tank then what you pump into your vehicle could be all kinds of messed up.

 

I'm just an electrician, but I've done a bit of work with Veeder-Root Monitoring.
It happens, quite a bit.

 

Good to know. Thanks for sharing.

 

I totally get what your saying and I have done the research from pretty much everywhere you can find information and I understand the argument. But after doing testing myself using Shell 87 and Shell 89 with identical driving patterns for thirty days alternating every other month over the coarse of six months. I get an average of 2.7 MPG more using the 89. I know this does not follow the science of it all. And maybe it's related to the ethanol mixture here in the North East. Not looking for an argument and I bow to you with more knowledge. But it is what it is from my experience.

 

So many factors go into the end result for gas mileage. On a recent 1800km trip on one fill up run I managed 29.6 IMP MPG by never exceeding 100KPH. On the next leg I lost 3 IMP MPG by travelling at the same speed but on about four occasions had to accelerate to 125KPH to pass slower vehicles. Logic sometimes does not always come into play either. Id there Ethanol in the 87 Octane and none in the 89? There is up here or can be or so says the pumps.

Then you have the little people running around.

Take Care

Bob

 

This is America

do what you want

 

5% in both 87 and 89. As for the little people that would explain why I hear someone playing a kazoo from the area of my LCA now and again.

 

OK, so I have two points to add here.

One: The suggested minimum octane provided by all car manufacturers is the lowest it will go and still function. If prospective vehicle buyers see a truck that requires a higher grade of fuel, many will look elsewhere. For many drivers fuel economy and cost of ownership is as much a selling feature as the interior amenities and color of the paint. It's to the manufacturers benefit to aim low.

Two: People on here seem reticent to acknowledge that the 3rd gen runs a dual fuel cycle system. This means that for a portion of the engine duty cycle it functions as a GDI motor. In that there are significant improvements to be seen when applying a fuel with higher knock prevention capabilities during a direct injection cycle. GDI injectors will spray in advance to cool the combustion chamber, and at this point a cheaper (more detonation prone) fuel is more likely to pre-ignite. Then the ECU will detect the pre-ignition and retard the timing or alter the fueling to address the issue. Granted our fueling concerns are not a great as those using forced aspiration, but there is a additional kink in our system beyond the traditional runner based fuel injection systems.

 

I seriously think some people on here should own a Prius.

 

Just ask the second gen folks about this...this topic has been talked to DEATH

 

Correct me if I'm wrong, but my '08 owners manual says "research octane 91."

Doesn't this mean that all dyno data and testing data was taken using 91 octane by Toyota?

I've used 91 since the day I bought the truck. A friend works for TRD's r&d department for their nascar motors and he said benefits of using top tier 91 keeps the fuel system cleaner which translates to less failure or injectors and such.

 

That inside info is all good and well. But there are thousands of high mileage 1st and 2nd gens that are 1-owner vehicles, that used 87 octane and only had routine maintenance their entire time on the road.

 

Yep, I just bought my second one (2016 Prius II).

 

Higher octane does get you better gas mileage based off my own testing.

I still don't use it.

 

87 has 10 percent.
91 has 0 percent.
89 is a mix of the 2 fuels giving it 5 percent. The pump will take fuel from both tanks when you select mid grade fuel.

 

Any way we can program ECU to run higher octane in order to push a little more performance?

 

Yes and I don't care what anyone thinks- unless they offer to pay for gas.

10 year old truck still running strong.

 

Helps offset the incorrect unattainable MPG of Tacoma, right?
#sarcasm