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Does everyone use premium gas with the turbo?

57K views 49 replies 27 participants last post by  Enigma 
#1 ·
Just purchased a Denali. Actually have not got gas yet. What is everyone's thoughts on using Premium Vs mid-grade gas? Thanks
 
#2 ·
We use 89 for around town driving and 92/93 when we're going to do mostly hwy driving. Haven't noticed any problems when using 89, but the wife drives most of the time and wouldn't notice anything unless it was really noticeable.
 
#3 ·
From my understanding you need the recommended 92/93 only when you want to use it at its limit of tow or hp capabilities...
Carrying a few passengers in city and highway should be fine with 87.

there are threads here about how the new engines/ECM etc deals with the different octane values...so no fear of knocking etc.
 
#6 ·
I got the 1.5 with the turbo and I run 87 regular without exception. I have all the power I need (especially compared to the slug that was my old Rav4) and my lifetime fuel mileage is 30.8 mpg.


Tim
 
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#7 ·
We have a 2018 SLT with 2.0T. For the first 9K miles we used 93 octane gas. The last 6K miles we have used 89 octane.
Our average MPG on 93 was 24/25 and the MPG on 89 octane has been 25/26. We haven't noticed and difference in performance and our gas mileage has been slightly better. Our driving has been fairly even between city, highway, and interstate. Our next fill up will be 87 octane and we will try that for awhile.
 
#9 ·
I've been using 87 in my 2.0 Turbo after the first two tanks. Overall fuel mileage is at 25.8, with mostly short trips with stop and go. When I do need to accelerate quickly, I haven't noticed any real difference from the first two tanks.
 
#11 ·
I just drove 1300 miles (NE to AZ) in our '18 2.0L Equinox. Due to the big price difference between 87 and 91, coupled with the varying octane numbers in various states, I ended up filling up with either 87 or 88. Not counting driving through the 3 inches of slush in NE, our highway mileage was consistently at 30 mpg + or - .
At home, I fill up at Costco with 91, but then most of the driving is local with little interstate driving.
I a couple weeks I'll make the return trip, so I'll see if there's a difference going uphill :)

So far I am very happy with the mileage on this vehicle. For trips I wish it had a. bigger tank, but by the time it's needing a fill-up, I need a drain down:)

I noticed that the spread between diesel and gas at interstate gas stations is huge compared to at home.
 
#14 ·
Other than the first tank that the dealer presumably put in at 91 we have not on our 18 Terrain SLT with 2.0 used anything but 87. My wife averages about 7.1 to 7.9l per 100km but with the crummy winter gas it has since gone to 8.6 or so still pretty respectable. The only vehicle I ever drove that really you could tell works great on 91 was a 97 Pontiac GTP with Supercharger, wow did that thing ever bog with 87 in it but did ok with the 91. In my area, the price of Premium 91 and up was 45 cents more than 87 or roughly a little more than the spread between Diesel and Regular. They must be trying to hose all those audi and Mercedes folks.
 
#16 · (Edited)
.

This is regarding the 2.0 turbo; the recommended fuel for the 1.5 turbo is regular grade 87 octane.

So far all that I use is Top Tier Phillips 91 octane, no ethanol or BP 93 octane, with ethanol.

I'm just a little gun shy of using 87 octane because of a potential LSPI issue with these direct injected turbo engines: Just not willing to gamble with an engine failure if better fuel can potentially avoid it.

Remember, LSPI is an issue among various manufacturers using small displacement, direct injected, boosted induction engines, and the cause hasn't been completely understood or resolved yet.

I also use a Dexos1, Gen2, certified oil: Mobil1 Extended Performance 5W-30 in my 2019, 2.0 Equinox, to also aid in preventing the LSPI phenomenon.

If the GM powertrain engineers recommend premium fuel, I'm going with that recommendation.

.
 
#20 ·
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If the GM powertrain engineers recommend premium fuel, I'm going with that recommendation.
.

I would tend to agree. Even though its "only recommended" and not required, I fill with 91 octane Premium 10% ethanol. Our gas here is Oregon is 87, 89, and 91 octane. Stations offering non-ethanol are few and far between and it's significantly higher priced.
 
#18 ·
Dealer said when filling up to only put the nozzle in half way....and if ever need to use a gas can to push nozzle all the way in....what's all this about...?...this is on our 19 Terrain with capless fuel filler....wife cant seem to totally fill up the tank before it auto stops...
 
#19 ·
13000 miles, 90% on 87 gas, lots of power, lifetime 25.8 mpg. That includes 2018 and half 2019 Canadian winter with some -30F temps. Highway trips below freezing at 30 mpg in the COLD. Best was 35 in summer. No issues at all.
 
#21 ·
FWIW, we live at 7,500 ft elevation... even with a turbo I kinda doubt that octane makes much difference but I'm not sure about it. This is my first turbo so I've been using mid grade fuel and it seems to do fine. Premium costs about 90 cents/gal more than regular around here.
 
#22 ·
Inside your engine, with the turbo spooled up, it's virtually the same as being at sea level. The turbo boosts to a given pressure, regardless of outside atmospheric pressure--that's why turbos and superchargers were put on aircraft when they used recip engines: to maintain power and increase the ceiling altitude. Therefore, high octane is essential regardless of your elevation, in accordance with manufacturer's suggestions, to prevent damage to the engine at high boost/high compression.
 
#24 ·
Stick with the recommended fuel for a turbo charged motor. It has nothing to do with each individuals mileage and everything to do with the life of the turbo and valves as well. Running a lower octane works with the advanced computer control but it also is sending false signals and may be retarding or advancing your timing incorrectly. In turn this can lead to an overheated turbo.

I have seen one on an Audi red hot and then catching fire. It was not pretty.

I am so glad to have the V6. But please people run the correct fuel in your beautiful GM automobile.
 
#26 ·
Well Said. I'm a retired ASE Master Tech. It goes as tharvey57 sort of says. If you have to ask how to save pennies, you bought the wrong vehicle. This reminds me of the guys who buy supercharged jet skis and won't buy the proper fuel. They get towed in off the lake or ocean, motor blown. The computer in the car can only make up for issues for so long, then the possibility of "Kaput" increases. Put your big boy panties on and suck it up!
 
#27 · (Edited)
Well Said. I'm a retired ASE Master Tech. It goes as tharvey57 sort of says. If you have to ask how to save pennies, you bought the wrong vehicle. This reminds me of the guys who buy supercharged jet skis and won't buy the proper fuel. They get towed in off the lake or ocean, motor blown. The computer in the car can only make up for issues for so long, then the possibility of "Kaput" increases. Put your big boy panties on and suck it up!
That is a pretty lame response.

I have commercial heavy trucks. I tweak out even one tenth of a mile better fuel economy when I can. Each tenth nets me a savings of $600-$700 a year is fuel cost savings per truck. Imagine just 1 mpg better mpg. And i always look for the best value is fuel I can get.

Just because someone wants to save some scratch on the operation of their vehicle doesn't mean they bought the wrong one or they have the wrong mindset. As much as ego inflated morons would like to make them think so.

I don't have a turbo engine that is part of this discussion. My personal vehicles are all NA, but I use E85 in my various vehicles since they are flex fuel. 100 Octane and half the price of premium fuel. The 11.2:1 ratio 2.4L LEA in my Nox runs silky smooth on the stuff. The 6.0L in my 2500 can push snow, haul, and tow with the best of them while using E85. And even the diesel 2500 with its better fuel economy cannot come in as low of fuel cost on a per mile basis that I get with E85. And even though E85 delivers lower fuel economy, it also has such a low price in my area that there is not a similar Nox out there that can beat the low cost per mile of operation if they use regular, mid grade, or premium. Now that is putting big boy panties on and sucking it up...... and engaging the brain instead of the ego.
 
#29 ·
That latter is especially important with a turbo gasser.... preventing LSPI. And that does indeed call for a very good oil. The additive package in that oil is paramount. LSPI is terrible for an engine. Will destroy pistons and valves. And it has been found that the oil plays a part in preventing it.
 
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#30 ·
I run 91 in mine most of the time but, if I come across a station without it I run 93... I bought the 2.0T for it's performance so I want to get the most out of it AND I want to keep this car for the long haul so I want to put the recommended fuel..
 
#33 · (Edited)
We run mid grade 89 octane in ours...only has 6k miles no pinging what so ever, but I have not been through heat of summer with it yet. Time will tell and if I suspect any pre-ignition spark knock or ping I'll be pulling the plugs to confirm if any detonation is occurring. There is no need to guess or finalize choices based on conjecture the plugs will tell ya the story...if ya know how to read em.

PS not the same as it's naturally aspirated V8 our 07 Caddy also has the recommended premium fuel suggestion from GM, we have been running regular 87 octane in that for the last 100K miles with no ill effects :surprise:
 
#34 · (Edited)
If one really wants to know, get a OBD scanner that will display real time while driving and test things. I don't really use it for the topic at hand, but I like the BlueDriver OBD scanner. The module plugs into the port and a bluetooth hookup to my iPhone and I can see all sorts of real time stuff going on.

I think in most cases, mid grade would be a pretty balance for the average person. Many of the folks that have the Silverado 1500 with the 6.2 Ecotec use 89 regularly. And that engine has a premium 91 recommendation. In that case, if really working like hauling heavy, towing, or driving hilly terrain, it probably would be wise to use premium 91. The same thing can be said for these turbo motors we are discussing. If one is really going to put the motor thru its paces, probably best to use 91. But for average day to day stuff, 89 should do the trick. Especially if there is a substantial price difference.

And Low Speed Pre Ignition (LSPI) is a common thing with these newer high compression, direct injection motors. It is the primary reason that led to improving the API SN rating on motor oil to API SN+. One doesn't want to risk beating the snot out of their motor and killing it prematurely with LSPI. Running regular should only be used when there is no other choice.

My 2017 2.4L LEA is not turbo, but it does have DI and it has a compression ratio of 11.2:1, darn close to the ratio of the Ecotec 6.2 which GM says should use 91. I would not consider running 87 in it on a regular basis. I use E85 because of the big price advantage, and it has a killer octane rating, but if I was using gasoline it would be mid grade 89. LSPI can affect the LEA 2.4L engine too just like it can affect the 6.2L, not just the turbo engines. Anything running higher compression ratios and direct injection is fair game for LSPI.
 
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#35 ·
Copperhead--Agree completely. Regarding LSPI, seems that GM is leading us down that path with the 2.0T and 9-speed transmission that shifts into 9th at speeds as low as 60 mph and 1400 rpm. I encounter those conditions routinely in city freeway driving. Small amounts of throttle input don't always cause transmission to kick down, but does create idle situation for LSPI. I would rather err on side of caution; therefore I use premium with higher octane.
 
#36 · (Edited)
That is the reason I am fond of using manual mode for most of my driving. That includes my pickup as well as my Nox. I want a little more control on keeping the engine in the optimal power band. And in doing so, I have not seen a hit on mpg. I think that is primarily due to the fact that on the rolling hills in my area, by using manual mode and keeping RPM's as a reasonable level on the engine, it greatly reduces the shifting and gear hunting that goes on by the trans when it is left to its own. That constant shifting on every little mole hill really takes a toll on fuel economy and transmission longevity. This gear fast, run low concept is nice on a test track and makes the numbers more palatable to corporate and government interests, but is doesn't equate well to real world operation. At least there is manual mode.

Peak torque on the 2.0T is at 2500 RPM. it really rises fast below 2500 (or one could say "falls fast" below 2500 if the trans is kicking into higher gears sooner), holds it well up to 4000 RPM, then tapers downward above that. 90% torque is available at roughly 2000 RPM. That should give an indication fo were the engine should be operated. On my 2.4L, the torque curve is more gradual across the spectrum but I get 90% torque at around 2100. So for most of my rolling hill stuff, I keep the RPM's at or above 2100. Only if I am on flat ground with constant speed and low load will I let it stay below 2000 RPM for any period.

I basically use the same principle regarding torque as I use for my heavy commercial trucks. It has served me well as a good operational technique for many years.
 
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#37 ·
Copperhead--you're a man with the same philosophies as me. My father drove 18 wheelers and taught me the same principles you just wrote. Hitting that optimal part of the torque band is essential to performance, longevity, and fuel economy. thanks for sharing and reminding me of those good days of "rowing twin sticks".
 
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