94 octane gasoline = quieter ICE

I'm surrounded by petrol stations. I got a choice of Shell, Arco, 76, and Mobil... all within 1/16 of a mile from the house. The smell of... victory...

I noticed a new sign at the Chevron stations. "Chevron with Techron Is PROVEN to give you better gas mileage."

 

Canada is a totally different story, so I have no problem with your observations.
USA we have EPA control of gasoline formulation basically (oversimplifying slightly) takes away most of the freedom to vary formula, additives and E10 ethanol content, etc.

 

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Not sure if anyone else has any data points on this, but I saw this thread a while ago and thought I'd give it a try.

I usually get gas at the Costcos here in Orange County, CA. The two options available are 87 and 91 octane. I used a basic decibel meter app on my phone (Decibel X) for the measurements. Both times the ICE was in idle, with AC and audio off. After filling the tank with 91 gas, I drove the car about 80 miles on the ICE to make sure all the 87 gas is burned off and only the 91 is in the ICE. I filled the tank when I had only 3miles range on the 87 gas, so there is very little mixture of the different grades. The results were...

87 Octane- 72-75db inside the car. Averaging around 73.2db.
91 Octane- 68-70db. Averaging around 68.9db.

Personally, I do feel like the ICE is much quieter with 91 octane gas (not sure if its placebo effect or not), especially those times when I'm accelerating on the highway and the ICE is revving in the red zone. I think I will keep filling 91 gas in my car in the future. The one thing that I really liked about the Prime is how quiet it is (compared to my Gen3 Prius), and the 91 does feel quieter. I only fill up every 1300-1400 miles or so anyway (4 to 5 weeks), so it's worth the few extra bucks.

 

OK, now do the exact same test alternately filling it with higher then lower octane. And then repeat, repeat, repeat.
Betcha my house that the gas isn't making a 4db difference.

Posted via the PriusChat mobile app.

 

The engine (aka ICE) would likely shut off when you stopped; you just waited till it came on?

 

When you are driving in HV mode, yes. But when you drive in EV most of the time (like me), switching to HV will turn on the ICE momentarily.

 

If you lived in Palo Alto, I would take that bet

Had a duramax, chipped it, used to get 12-16mpg, after chipping got 16-22, did mostly around town driving, the ice was so much more torqued...I never touched the pedal, at idle the thing would go up Everest.

No, I don’t think the higher octane is making more torque so the motor is more silent, both measurements were taken at a stop at an idle, as I understand.

But still. A house in Palo Alto, why not

 

Not sure of the significance, but it sounds like the reading would be at fast idle, an engine just started, and warming up.

 

I've been testing various types of fuel. Most recently I tried Shell V-Power NiTRO+ 93 octane. The ICE definitely seems quieter and smoother as others have reported.

I've also tried Murphy 87 octane with ethanol (<10%) vs. Murphy ethanol-free 87 octane without any discernible effects. This seems to indicate that it's the higher octane (or possibly fuel additives) that makes the difference, not the ethanol content.

I've started tracking engine parameters using the OBDLink LX device. Does anyone know how to interpret "Ignition timing advance for #1 cylinder", "Knock Correction Learning Value", and "Knock F/B Value"? Understanding these values may help to objectively determine if there is a difference in engine performance.

 

I found that my car accelerates better on 87 octane. Definitely faster.

 

I just use 87/86 unleaded because it's recommended and cheaper. The difference in price per gallon/mile for premium is not worth having this car run any smoother or quieter than any other ICE or Hybrid, nor does it increase my mpg. The only time my mpg increased, taking in all other variables, was when I used 87 "leaded" gas twice, but the price for that also killed the cost per gallon/mile...so that wasn't even a wash.

So while this is a quaint topic, it's only 87/86 unleaded for our 2015 Prius, 2017 RAV4 HV and the 2018 Tacoma.

Now my other toy's 455 does not run 87/86 unleaded...at all, but then it doesn't get 40 something mph either.

My new Prius...not! | PriusChat

 

That's gotta be some sorta record!

 

Golly, @frodoz737! That must have taken you all afternoon to build!! Nice.

 

Maybe a little longer than an afternoon.

Of course my favorite "toy" puts out 56,000 lbs of thrust. I drive those 4-5 days a week too.

 

Wow, what toy is that?

 

Just follow the thread back to #52.

 

Not sure about how octane is measured in Canada but I’ve honestly never seen 94 octane fuel, 93 is very rare and only e10, I wonder if the ops 94 octane is really us 90 octane like Europe?


Around here we have many flavors of gas at completely random prices as follows

87 e10 $2.22
87 e0. $2.34
$2.14. 88 e15 (cheapest normal gas)
$2.80 89 e10
2.80. 89 less than e10 (unspecified)
$2.99 89e0
$2.99 90e10
$3.25 91e10
$3.99 91e0
$3.50 92e10
$3.99 92e0 (rare only at one vendor)
$3.99 93e10

I did not list e20 e30 e50 or e85 because they are very randomly priced and much much cheaper.

I do wonder though if your going for lowest noise if a higher ethanol blend wouldn’t be the cheapest way to low noise?

88 octane for me has almost the same knock counts in a Volt as e0 91 Premium (expensive stuff)
I also get better fuel economy on 88 than I do on 87, but only in the summer , non ethanol does best in the winter. (Yeah I get I am tuned for Premium but a few cars do run better on Premium without requiring it)

Maybe the Prius would work the same?

 

Wow. I filled up Friday with 87 E10 for $2.069/gallon. As in $2.06 and 9/10ths. It's been a while since it's been this low. (I never round it off because they don't round it off. )

 

Just got me curious. So what do they charge, if you buy 1 gallon of gas, no more no less? Exactly 1 gallon. I think they charge $2.07, don't they?