4-Bangers and octane

Worked at an oil refinery for a while and chatted to one of the UOP engineers about gasoline chemistry and the benefits of using high octane gas in my car. He smiled and said
" High octane gas is a real money maker for the oil companies. It costs a fraction of a cent more to make than regular and there was actually less energy in higher octane and it was impossible to get better fuel economy in an engine designed to run on regular gas. Unless the engine is designed to run on high octane then it is a complete waste of money. He went on to say that gas rated at 87 is usually a bit higher because minimum spec. was 87 and it was easier to keep it on "spec" than risk rejection for below spec. fuel".
As for the 2.7 engine. It is designed to run or 87 or higher. Burn whatever tickles your fancy but as the UOP guy said "You are wasting money".

 

If you run 91 or 93 you may find that you get better gas mileage than running 87 so the higher octane will pay for itself. Also, if you pay attention you may notice improved performance. But if you are innumerate you won’t be able to do the calculations and if you are a typical driver you won’t be paying attention.

 

Thanks for reading the thread.

 

May is a very subjective, word. Hardly a numeration on your claimed bennies of high octane.

We're paying attention to any "real" evidence you can provide. I've only realized won't.

 

In my case I did get an increase in gas mileage to cover the cost of the higher octane. Also, most of my driving is up and down mountain passes and I noticed a difference in performance going up the hill. Somebody who drives the flatlands may have a different result. The standard yarn (mostly from the main stream media) that it is a waste of money is completely stupid. It might be or it might not be. The calculations must be done over a period of time using MPG’s not just how many total miles you got out of one tank. It was mentioned above that this will never end. However, it will end for you if you go beyond opinion and find out for yourself whether it works for your driving situation or not.

 

I did read the entire thread and found it almost completely worthless. Running two or three tanks of 87 then 91 and calculating the results would be worthwhile. Put this example in a spreadsheet to check the math then change the variables to be accurate to your situation.

20 gal tank filled with $2.00, 87gas = $40
20 gal tank filled with $2.20, 91 gas = $44

Mileage = 20mpg with 87
Mileage = 22mpg with 91

2mpg extra with 91 = 40 extra miles

40 extra miles is worth $4 of 87 gas

So it is a wash. 87 costs the same as 91

 

And of course that extra 2mpg is never achieved, why would it. Most people are driving with a light throttle under a rather light load where 87 octane is more than plenty.

If premium had less ethanol than it could improve mpg but otherwise not really, and certainly not 10% beter like your simplistic innumeration. I've found about a 5% increase in mpg with straight gas vs 10% ethanol. Around here premium is $0.35 more not $0.20.

 

Three and a half years ago, when I did my calculations, I achieved a 2mpg increase with 91 vs. 87. My entire point is to do the test yourself instead of just throwing out some worthless opinion.

 

3 and a half years ago it was much more likely the 91 had no ethanol while the 87 did. Today it almost all has ethanol, at least in my area.

Most of us did do the test ourselves and found zero or negligible improvement. I have logged every tank run through my truck and found a reduction going from 87 to 91. That's math, not opinion. YMMV but we are not pulling numbers out of our ass as you imply.

 

I also live in the mountains. I've tried 93 octane in a Tundra with the 4.7 V8 (2UZ-FE), Subaru wagon with an 2.5 boxer 4 (EJ-253), and a Tacoma 2.7 L4 (2TR-FE). No noticeable power gain. The Subaru actual dropped a couple of MPG. Was the 93 fuel the reason? Don't know. The only thing I run 93 in now is my small air cooled power equipment engines. Due to the high heat present in air cooled engines. Same reason they run 100 octane in small piston engine aircraft.

I do agree about the ethanol. It will cut 1 to 3 mpg from many engines run under similar conditions. I always buy non ethanol gas, as we have it here locally. Ethanol is another money scam, and is especially bad on small power equipment engines with openly vented tanks, and carburetors. High moisture condition operation (water craft) makes it extra bad...

 

Can anyone comment on the vast decrease in pinging noise when running higher octane.

 

No dieseling noise here with 85.

 

87 ping (since new)

91 no ping feels great good mpg

93 drank the tank, felt decrease in performance although no way to prove it and may be just my imagination.

So I run 91, not sure if it has to do with quality of gas around here or the fact that I'm close to sea level or just the hot temperature. My 3.0L Ranger was the same my friends 3.0L too and there is another local in the forum with the 2.7L running 93 due to pinging at 87 so I know is not just my truck.

 

You won't notice much difference with ethanol fuel.do your tests with non ethanol fuel. I would like to see some responses with that.has anyone else noticed a performance gain with fuel additive? It sure seems like it works for me but I want to hear other peoples thoughts

 

Which non ethanol pump fuel do you suggest? Give me E85 it's like race fuel without the price cost, yeah i know it doesn't pack the energy of regular pump fuels but it's sweet man.

 

87 octane. With upper cyl lubricant fuel additive. you don't need the higher octane since the 2.7 l compression is low