Just filled up with new Mobil "Synergy" gasoline

Sounds like you're ex RAF, if I'm not mistaken.

 

I couldn't find the on/off gas warning setting. The Two Eco may not have this feature or I was looking in the wrong place.

 

Certainly works on my Four. I've seen it on each of my 20 tanks.

 

I keep my big screen off so that may be why I never see it

 

well not ever seeing it, didn't know if it appeared up in the screen area where the yeller light comes on, or in the bottom big screen

 

Top Tier testing. https://s3.amazonaws.com/associationcommunicationfiles/PDF/Fuel-Quality-Full-Report-FINAL-1.pdf

 

Thank you for posting this. It was extremely informative.
Clearly the Top Tier detergents not only work, but prevent up to 90% of the deposits on intake valves--huge difference! I was relieved to see that deposit formations can be largely if not completely reversed by subsequent normal driving with a Top Tier gasoline as I have experimented with some E0 fuels that were definitely not Top Tier just last summer.

Interesting that the old 100,000 mile test cycle has been replaced by a much easier to conduct , roughly 5,000 mile test cycle using a Ford engine prone to accumulating deposits:

"At the time of this report, the preferred method for evaluating fuel deposits is the ASTM D6201 test [8], which involves running the test fuel in a Ford 2.3L port fuel injected engine in a dynamometer test cell. This particular engine test has been an industry standard for more than 15 fifteen years because the orientation and temperature of the intake valves during the dynamometer test cycle accelerate intake valve deposit formation. This allows fuel marketers and vehicle manufacturers to screen different gasoline detergent additive packages in only 100 hours of testing. "

What puzzled me is no measurement of deposits on exhaust valves. IIRC, deposits on exhaust valves used to prevent good metal-to-metal seating of the exhaust valve, thus preventing heat transfer and finally causing burned exhaust valves. Does that simply not happen on modern engines? Anybody know?

 

Pretty much all of the brands are top tier?

Licensed Brands | Top Tier Gas

Looks like top tier gas is very good for reducing deposits on intake valves, so-so on cylinder top, and increases cylinder head deposits? And no mention of exhaust valves, as Robert mentioned:

 

Get a Top Tier credit card and commit to using it. Not only does it make it easy to buy and track purchases of gasoline, your car will thank you.

For the Prius, the other important aspect are the electrons. Never, NEVER go for less than top-tier electrons. The difference is shocking.

 

Not only is Costco top tier, it's cheaper to boot. You can get a little cash back with the Costco credit card too.

 

i'll be filling up at mobil tomorrow, but i haven't noticed anything about synergy when driving by the station. is it possible it isn't nationwide, or is it another button next to the octane choices?

 

Sorry folks. Imho it's simply marketing hype, aka bovine excrement of the male variety!

 

filled up with mobil this morning. same price as 3 weeks ago, but no synergy.

 

The Gen 4 Prius you own will post "Thank You" messages??
That's way better than my Gen 3; all I ever get are temperamental, nagging messages like "EV mode unavailable " and never, ever any appreciation for all I've done for it!

Those top-tier electrons would be the ones in the higher quantum states, right? And clearly the higher quantum states tend to have more energy and thus the electrons would be harder to capture, but well worth it in increasing the mpg of the Prius!