What Octane gas do you use for your Buick Encore?

ThatsNotABuick!

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Mojave Desert is not regular driving.​


We are trying to do day to day comparison. Octane has no effect
It probably has less effect in cold climates where you are, but in hot climates here like Arizona, Nevada, lower California, lower Florida, Texas, etc. it does make a difference. At least 1/5 of the states have seen temperatures above 120F at some point. I think anything over 100F you will notice a significant difference between fuel octanes. Every state except for Hawaii has seen above 100F.
 
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mshultz

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I can't seem to find it right now - but there was a review/road test of a buick encore a few years ago by a reputable publisher. e.g. car and driver, edmunds, etc.. I don't recall.

They drove the encore in high heat across a desert - it might have been death valley. They had very poor fuel mileage.

They contacted GM and they told them to try again with premium fuel as it was reverting to the low octane tables in the ECU. When they repeated this road test with 92 octane fuel - the mileage jumped up dramatically.

Also, look here to get a better understanding of why this vehicle can do much better on premium fuel - it keeps you in the high octane advance table in the ecu...

https://store.badnewsracing.net/Which-fuel-should-I-use-in-my-LUVLUJ-Does-it-matter_b_1.html

From the blog post above....

"There are a number of articles published by so-called "Experts" that state that there is no benefit to running premium fuel on any car that does not specifically require it. This information is FALSE. "

It's not that it just pulls timing for very short period of time - it will move you over to the less efficient timing map and leave you there until you refuel the vehicle. (which resets the selection of the table).

jeff
Let us know if you find the article. Car and Driver's official fuel has been Shell V-Power Nitro+ Premium Gasoline since at least 09/15, when they tested the Chevrolet Trax in a comparison test, so it must be some other publisher. I remember when I could buy Shell alcohol-free premium gas, but alas, they pulled out of my area decades ago.

That's an interesting link. Are they talking about the regular engine, or the direct injection engine? It is more efficient to reduce the compression ratio for a given octane than it is to retard timing.
 

oregon_rider

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Let us know if you find the article. Car and Driver's official fuel has been Shell V-Power Nitro+ Premium Gasoline since at least 09/15, when they tested the Chevrolet Trax in a comparison test, so it must be some other publisher. I remember when I could buy Shell alcohol-free premium gas, but alas, they pulled out of my area decades ago.

That's an interesting link. Are they talking about the regular engine, or the direct injection engine? It is more efficient to reduce the compression ratio for a given octane than it is to retard timing.

The blog that I referenced in my previous post was for the "more mature" port injected LUV engine (not the newer direct injected motor.

jeff
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DocBrown

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From the blog post above....

"There are a number of articles published by so-called "Experts" that state that there is no benefit to running premium fuel on any car that does not specifically require it. This information is FALSE. "


jeff
It's not entirely true either. In fact in most climates and conditions for the average driver it makes no discernable difference. The only times I've found a difference between premium and regular is on so-called premium optional cars that called for 87 but could run on 93. In my 2.4 in my HHR I found enough of an increase in mileage when gas was $4.00 and premium was only $.20 cents more that I saved about $200 a year using premium. Premium is now $.80 more per gallon where I live. It would be a total waste of money. On my old Cadillac Catera there was no difference in mileage but a noticeable difference in power, especially at freeway speeds. Again, at $.20 cents more it was worth it for the fun factor. That car was a blast to drive.

My wife averages 29 mpg in the city with her Encore and puts on about 10-12k mile per year. At $.80 more per gallon she'd have get 40+ in the city to make premium worth while. Of course that isn't even going to be close to reality.

The old saying, "your mileage may vary" is exactly true here. What I've always told people is to try a couple of tanks of each and run the numbers based on the actual gallons pumped vs actual miles driven (not the DIC!). It might be worthwhile. More likely it's not going to be.
 

mshultz

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The blog that I referenced in my previous post was for the "more mature" port injected LUV engine (not the newer direct injected motor.

jeff
That's what I thought. I did not want to spend much time looking at the blog if it was not for my direct injection engine.
 

oregon_rider

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That's what I thought. I did not want to spend much time looking at the blog if it was not for my direct injection engine.

I'll drop an e-mail to the company to see if the direct injected motor has same tables for ECU - I don't see any reason why it wouldn't...

jeff
 

oregon_rider

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Let us know if you find the article....

I found the article - it was actually for a cruze with the same luv motor that is standard equipment in the buick encore.


"Subsequent discussions with GM powertrain bigwigs and our own Jay Kavanagh revealed that small turbo engines are especially octane sensitive, which means their computers may agressively dial back the engine calibration in order to ward off knock in high load situations or in very hot weather."
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mshultz

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I found the article - it was actually for a cruze with the same luv motor that is standard equipment in the buick encore.


"Subsequent discussions with GM powertrain bigwigs and our own Jay Kavanagh revealed that small turbo engines are especially octane sensitive, which means their computers may agressively dial back the engine calibration in order to ward off knock in high load situations or in very hot weather."
Thank you.
 

mshultz

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Way back in the day, Consumer Reports used to harp about premium gas engines. If their "engineers" were familiar with the Carnot Cycle, they never mentioned it. I spent an afternoon in 1975 at the University of Akron library looking through all of the Consumer Reports from 1964-1970. I chose that range because I wanted to compare modern pre-emission engines. The only useful comparison I found was a Chevrolet Chevelle with the 283 V8 and 3.08 axle along with a Chevrolet Impala with the premium gas 275 HP 327 V8 and 2.78 axle. Both had the 2-speed Powerglide transmission. Despite weighing 500 pounds more, the 327 V8 got better fuel mileage, and had much better acceleration.
 

DocBrown

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Way back in the day, Consumer Reports used to harp about premium gas engines. If their "engineers" were familiar with the Carnot Cycle, they never mentioned it. I spent an afternoon in 1975 at the University of Akron library looking through all of the Consumer Reports from 1964-1970. I chose that range because I wanted to compare modern pre-emission engines. The only useful comparison I found was a Chevrolet Chevelle with the 283 V8 and 3.08 axle along with a Chevrolet Impala with the premium gas 275 HP 327 V8 and 2.78 axle. Both had the 2-speed Powerglide transmission. Despite weighing 500 pounds more, the 327 V8 got better fuel mileage, and had much better acceleration.
Might be because the 327 had something like 50 bhp more, a 4.3l compared to a 5.4, the 327 was a much bigger engine. Most people don't understand the concept but more power can result is less fuel needed to do the same job simply because the engine doesn't have to work as hard.

I had a 2003 Trailblazer EXT with the 4.3 L I6. It's was 270 hp. Good engine and quite powerful. I could get 15 mpg in the city and with a little effort I could sometimes squeeze out 16. My 2008 GMC Sierra is just about 500# more than the Trailblazer, 5.3 L V8, 310 hp. I get 16 in the city without even trying, and 17 isn't a stretch either. Neither of these runs premium gas. I realize that this is very unscientific, but I've seen the same sort of results over the years and in talking to different people. More power, less work needed for the same job. Again, this is just day to day driving.

I gave up on CR many years ago. They once bashed a Corvette for not having enough luggage carrying capacity. The Toyota Matrix had a higher rating than the Pontiac Vibe did. They were both produced by Toyota on the same assembly line. When they admitted they rigged child car seat ratings, that was the end for me.
 

mshultz

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Consumer Reports also disliked larger optional engines, despite the fact that for the same power, a larger engine running at a lower rpm tended to be more efficient.
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2500 miles on my Luv motor and I'm already sold on only running 89 or better... I noticed some surging \ jerkiness when climbing hills with 87.. On 89 it runs fantastic.. And I believe it has to downshift for hills less often on 89. 89 is 30 cents more here in MD... But93 is 80 cents so ill try 91 or 93 come summer but ill stick with 89 for the most part..

GM knows what they are doing.. Yeah car can get by on 87 but ill run 89 for the better ride and to spoil the car...

The scenerio is exactly the same for my triumph tiger 800cc inline 3... Can get by on 87 but runs much much smoother and stronger on 89..

On the other hand my old 2012 v6 lfx Camaro ran fine on 87.. I shouldn't have sold that car.. I miss it.
 
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mshultz

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I bought 9 gallons of 93 octane fuel yesterday for the lawn mower & tractor. This is probably overkill for the lawn mower, but the 1968 tractor was designed for regular gas, which was about 90 octane when measured by the current (R+M)/2 standard.
 

Again

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I fail to see what you buying 90 octane for your lawn tractor has to do with an Encore but I'll bite. Your lawn tractor doesn't have variable ignition timing, the Encore does. That's why the manufacturer suggest 87 octane. Lower octane gas has more energy so you can go further on a liter. This engine under normal conditions does absolutely well on 87. I've always run 87 in my Encore and I've never reset the average fuel meter since new. I'm at 6.9 l/100k ( 34.1mpgUS ).

2020-05-24 16.55.31.jpg

Now if you live at higher elevation like Denver then I can see you needing higher octane or if you always carry four 300lbs passengers all the time, then yes.

As for your lawn tractor, yes it will run better with the highest octane possible because it has a static ignition point and detonation will be minimized.
 

mshultz

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My post had to do with the change in the US in the way they measure octane, rather than with the Encore in particular. Regular gas of the 1960s would have been about 90 octane, while premium gas would have been about 95 octane in today's measurements. Sunoco 260 would have been about 97 octane. This comes into play when you talk about running a premium gas engine from the "good old days" on today's fuels.

You did the conversion from Liters /100km to miles per gallon for me, although I also ran the numbers. This reminds me of a New Zealand member who ranted in the Mensa Bulletin decades ago about the poor mileage of American cars compared to what they drove in New Zealand. He had botched the conversion, and was promptly called out for it.
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mshultz

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While I know from memory that 1 US gallon equals 3.7854 Liters (After gasoline exceeded $1 per gallon, Shell Oil was selling it by the Liter until they were able to acquire pumps that could handle prices of over $1 per gallon), I had to look up the Imperial gallon: 4.5461 Liters or 160 fluid ounces. Easiest way to increase your miles per gallon; start buying gasoline by the Imperial gallon.
 

asdx1234

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I have noticed on cars that require premium fuel you can hear them knock if you put regular 87 octane gas in it.

I put regular 87 octane in my encore and it seems fine.
 
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89 here is now 60 cents more and Premium 80,,,,, so now I'm going to buy 87 and add stp octane booster which costs $3 per fill up instead of $10 buying 93
 
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