Jump to content

Premium gas

LM7Yukon

By LM7Yukon
in Ask A GM Technician

Recommended Posts

LM7Yukon Enthusiast

LM7Yukon

Posted
Posted

I find that using premium shell gets me better mpg, but per the owners manual it states to use 87 or higher. Yet the dealer service techs recommend only 87. In my area top tier gas is not available. Nor is it common in the North east.

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted

Premium fuel does not provide any more power, I don't see how it would improve gas mileage.

 

Octane is simply a fuel's resistance to being ignited. High compression engines need higher octane (premium) because compression alone can ignite the fuel at the wrong time, resulting in detonation.

 

Using premium fuel if your engine doesn't require it is a total waste of money.

LM7Yukon Enthusiast

LM7Yukon

Posted
  • Author
Posted
Premium fuel does not provide any more power, I don't see how it would improve gas mileage.

 

Octane is simply a fuel's resistance to being ignited.  High compression engines need higher octane (premium) because compression alone can ignite the fuel at the wrong time, resulting in detonation. 

 

Using premium fuel if your engine doesn't require it is a total waste of money.

 

 

 

 

 

The one thing your not taking into consideration is that high test has more detergent, and burns slower. Our motors are 9.5:1 compression which for a gas engine is not low. Granted some sports cars have upwards of 11:1, but my Subaru recommends high test with only 8.5:1.

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted
The one thing your not taking into consideration is that high test has more detergent, and burns slower.  Our motors are 9.5:1 compression which for a gas engine is not low.  Granted some sports cars have upwards of 11:1, but my Subaru recommends high test with only 8.5:1.

 

I won't argue that the additive package may be better in premium fuel, but I don't know where you got that premium burns slower.

 

Not sure why your Subaru would require premium. Is it turbocharged?

LM7Yukon Enthusiast

LM7Yukon

Posted
  • Author
Posted
The one thing your not taking into consideration is that high test has more detergent, and burns slower.  Our motors are 9.5:1 compression which for a gas engine is not low.  Granted some sports cars have upwards of 11:1, but my Subaru recommends high test with only 8.5:1.

 

I won't argue that the additive package may be better in premium fuel, but I don't know where you got that premium burns slower.

 

Not sure why your Subaru would require premium. Is it turbocharged?

 

 

 

 

 

 

yes my Outback XT is turbo charged.

 

If I use regular in my Yukon, do you recommend using a bottle of chevron techron every 3K?

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted
yes my Outback XT is turbo charged.

 

Which is why it requires premium even though the compression ratio is seemingly low.

 

It's cheap insurance to put a bottle of Techron in at every oil change, but personally, I don't. Then again, I work in a Chevy service department and can handle any problems with my vehicle, which for all intents and purposes, has a lifetime warranty. :banghead:

 

Fuels have improved lately, so you probably don't really need the extra additives.

PaulieK Enthusiast

PaulieK

Posted
Posted

This is what my owners manual says on the subject. I have the V6000 engine.

 

Gasoline Octane

For all except vehicles with the 6000 V8 (VIN Code N)

engine, use regular unleaded gasoline with a posted

octane of 87 or higher. If the octane is less than 87, you

may get a heavy knocking noise when you drive. If this

occurs, use a gasoline rated at 87 octane or higher as

soon as possible. Otherwise, you might damage your

engine. A little pinging noise when you accelerate or drive

uphill is considered normal. This does not indicate a

problem exists or that a higher-octane fuel is necessary.

If you are using 87 octane or higher-octane fuel and hear

heavy knocking, your engine needs service.

 

 

If you have the 6000 V8 (VIN Code N) engine, use

premium unleaded gasoline with a posted octane of

91 or higher for best performance. You may also

use middle grade or regular unleaded gasoline rated at

87 octane or higher, but your vehicle’s acceleration

may be slightly reduced. If the octane is less than 87,

you may get a heavy knocking noise when you drive.

If this occurs, use gasoline rated at 87 octane or higher

as soon as possible. Otherwise, you might damage

your engine.

 

 

Gasoline Specifications

It is recommended that gasoline meet specifications

which were developed by automobile manufacturers

around the world and contained in the World-Wide Fuel

Charter which is available from the Alliance of Automobile

Manufacturers at www.autoalliance.org/fuel_charter.htm.

Gasoline meeting these specifications could provide

improved driveability and emission control system

performance compared to other gasoline.

 

 

 

California Fuel

If your vehicle is certified to meet California Emission

Standards (see the underhood emission control label), it

is designed to operate on fuels that meet California

specifications. If this fuel is not available in states

adopting California emissions standards, your vehicle

will operate satisfactorily on fuels meeting federal

specifications, but emission control system performance

may be affected. The malfunction indicator lamp may

turn on and your vehicle may fail a smog-check test. See

Malfunction Indicator Lamp on page 3-44. If this

occurs, return to your authorized GM dealer for

diagnosis. If it is determined that the condition is caused

by the type of fuel used, repairs may not be covered

by your warranty.

LM7Yukon Enthusiast

LM7Yukon

Posted
  • Author
Posted
California Fuel

If your vehicle is certified to meet California Emission

Standards (see the underhood emission control label), it

is designed to operate on fuels that meet California

specifications. If this fuel is not available in states

adopting California emissions standards, your vehicle

will operate satisfactorily on fuels meeting federal

specifications, but emission control system performance

may be affected. The malfunction indicator lamp may

turn on and your vehicle may fail a smog-check test. See

Malfunction Indicator Lamp on page 3-44. If this

occurs, return to your authorized GM dealer for

diagnosis. If it is determined that the condition is caused

by the type of fuel used, repairs may not be covered

by your warranty.

 

 

 

 

This california fuel statement is bothersome. I live in PA, we don't have a Calif emission requirement, yet the Yukon I bought has Calif emissions because NYS which is nearby has calif emissions, so the dealer orders some this way. What criteria do I fall into, as here in PA we do not use calif spec fuels?

n5xl Enthusiast

n5xl

Posted
Posted
I find that using premium shell gets me better mpg, but per the owners manual it states to use 87 or higher.  Yet the dealer service techs recommend only 87.  In my area top tier gas is not available. Nor is it common in the North east.

 

 

 

 

I routinely monitor fuel economy in my 01 Silverado, and I notice the same thing.

 

For yours and my vehicle, when using 87 octane and based on our driving habits, the computer has adjusted the timing...retarded it...to prevent knocking which could over time damage the pistons. When we burn a grade of fuel that allows the computer to use normal timing advance, we get better economy.

 

As reference for you, for my driving habits, using 87 octane yields between 16.5 to 17.5 mpg. When I use 89 octane, I routinely get 18.5 to 19.5 mpg. This is fuel from the same station in my town. You have to monitor mpg each fuel up for months and months to get a good average of numbers. This smooths out driving habits and weather influences that could skew the results. Based on my testing, I started burning 89 exclusively. Its a hard habit to break when you pull into a station and are so used to grabbing the 87. FYI, I do not get any extra mpg when burning 91 octane.

 

 

According to my information, Shell is a top tier fuel.

Gasoline Brands That Currently Meet Top Tier Detergent Gasoline Standards

 

As of February 23, 2005, the following gasoline brands meet the Top Tier Detergent Gasoline Standards:

• Chevron Chevron has markets in 29 states in the West, Southwest and South, as well as in Alaska and Hawaii. ALL grades of Chevron with Techron gasoline meet Top Tier Detergent Gasoline Standards.

• QuikTrip (not to be confused with Kwik Trip) QuikTrip operates convenience stores and travel centers in a number of metropolitan areas:

- Tulsa, OK

- Springfield, MO

- Kansas City, MO and Kansas City, KS

- Wichita, KS

- Des Moines, IA

- Omaha, NE

- St. Louis, MO and St. Louis, IL

- Atlanta, GA

- Dallas-Ft. Worth, TX

- Phoenix, AZ

- Bartlesville, OK

- Miami, OK

- Vinita, OK

- Columbia, MO

• Conoco has over 4,000 stations located in 33 states.

• Phillips 66 has locations in 32 states across the nation.

• 76 has over 2,700 stations located throughout the country.

• Shell Shell Oil Products has a network of nearly 7,000 branded gasoline stations in the Western United States. Shell Oil Company markets branded products through more than 10,000 stations in the Eastern and Southern United States.

• Entec Stations offer gasoline through stations located in the greater Montgomery, Alabama area.

• MFA Oil Company offers gasoline at "Break Time" convenience stores located throughout Missouri.

alvocado Enthusiast

alvocado

Posted
Posted

I worked as an engineering intern for BP Oil in college and spent time in both refineries and R&D. Gasolines with different octane levels do not necessarily have different detergents. The supply chain works as follows:

 

- Refineries supply refined gasoline to a nationwide pipeline network

- Local terminals have scheduled times when they pull supply off the pipeline network. These terminals are based in market areas and serve as the supplier to gas stations within the market. They supply both their own stations, e.g. BP, in addition to independents who aren't big enough to have their own terminals

- Detergents and additives are blended at the terminals. In my experience, the additives were pretty consistent across the grades

 

What most people don't realize is that companies draw the refined gasoline in the piplelines regardless of who refined it. It's based on when they take their deliveries. The difference comes with the blended additives.

 

If your vehicle is designed to run on 87 octane, there is no benefit to using 91 or 93 octane. High octane fuels are hugely profitable for the oil companies because of their higher margin. Buying the when your vehicle requires 87 octane means you are wasting your money.

LM7Yukon Enthusiast

LM7Yukon

Posted
  • Author
Posted
If your vehicle is designed to run on 87 octane, there is no benefit to using 91 or 93 octane.  High octane fuels are hugely profitable for the oil companies because of their higher margin.  Buying the when your vehicle requires 87 octane means you are wasting your money.

 

 

 

 

The manual doesn't state that my 05 Yukon is designed to run on 87. It says to use 87 or higher. Doesn't that imply that 87 is the minimum requirement?

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted
The manual doesn't state that my 05 Yukon is designed to run on 87.  It says to use 87 or higher.

 

That's kind of mincing words, don't you think? If it can run on 87 octane, and it can since it says to use 87 octane or higher, then it is in fact designed to run on 87 octane. No one said it's designed to run on 87 octane ONLY.

 

If your manual didn't have the "... or higher" statement, we'd get the customers that would have a little ping come in and say, "But my manual says to use 87 octane, nothing else." No offense, but from your comments, I think you would probably be one of those customers. :shakehead:

LM7Yukon Enthusiast

LM7Yukon

Posted
  • Author
Posted
The manual doesn't state that my 05 Yukon is designed to run on 87.  It says to use 87 or higher.

 

That's kind of mincing words, don't you think? If it can run on 87 octane, and it can since it says to use 87 octane or higher, then it is in fact designed to run on 87 octane. No one said it's designed to run on 87 octane ONLY.

 

If your manual didn't have the "... or higher" statement, we'd get the customers that would have a little ping come in and say, "But my manual says to use 87 octane, nothing else." No offense, but from your comments, I think you would probably be one of those customers. :shakehead:

 

 

 

 

 

How is gasoline regulated in the US? How do I know that when the local shell station brings in a local distributer to fill their tanks that the gas is in fact 87?

 

What disadvantage other than a few cents would hurt to buy Mid grade or above? Is it cheap insurance, or is their a disadvantage in ruining the motor?

Supurban Enthusiast

Supurban

Posted
Posted

On these big V8s? Pffft.....87 is fine. The high-strung motors like turbo-4 cylinders beg for higher octane. But for day to day driving on lumpy V8s, I cannot justify paying more for gas than I already have to.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • mysery1
      What have you done to your K2 today?

      By mysery1 · Posted

      I have a 2018 Silverado Custom with 156k on the odometer. In the last month I've replaced the plugs, wires and the driver side engine mount. My wife just returned from a trip of about 1500 miles and told me the brakes are making a grinding noise when applied. I drove it and looked it over and this is what I found with the driver's side rear rotor.   I'm going to order new pads and check about having the rotor resurfaced. Hopefully this is easier than the last 2 jobs.   Peace  
    • FiLo
      5.3 / 6.2 valve covers / oil burning

      By FiLo · Posted

      Any update if the new valve cover help with the oil consumption?  I have a 2014 GMC sierra and my truck is consuming a lot of oil so I’m wondering if replacing the driver side valve cover will stop some of the oil consumption. Thanks 
    • Deadwood
      primary drive belt tensioner

      By Deadwood · Posted

      I bought belts and pulleys for my '20 L5P at Rock Auto a couple years ago. I have used them for many years, and almost always save significant money, especially when I buy maintenance stuff ahead of time.   They carry many OEM parts, which is all I use unless an aftermarket is shown to be same/superior, or if it is an insignificant part or unavailable OEM part anywhere else. RA is usually lower priced, often by a bunch, but parts are sometimes unavailable or out of stock, and I do shop around and sometimes find better prices at other sites.   Be aware that you pay shipping, and if you buy multiple items and they are coming from different warehouses, the shipping can kill the advantage. Planning ahead is best if possible.   If you have a transmission service in the near future, check out their OEM (AC Delco ULV) fluid, usually MUCH less than anywhere else.
    • Deadwood
      10L1000 anyone with High Mileage ? I hate Damocles....

      By Deadwood · Posted

      New member here, very long time occasional guest. Saw this thread, thought it would be a good time to contribute someting. It is only my experience and not a claim that everyone will have the same.   I bought my '20 3500 L5P new and have put 99.9% (literally) of it's current ~400k miles on it myself, with over 50% of that towing loads between 4k to 15k, and to me this truck has been nothing short of amazing. For the first 235k I had zero issues, and from there until 321k I replaced a NOx sensor, two failing glow plugs, and three of the notorious injector connectors. I believe this truck is in part, a testament to good luck, but also good care and following a decent maintenance schedule (I also keep meticulous records.) As a result, it looks as good as a well cared for 70k rig, up and down, inside and out.   At some point before that 321k mile mark I began to get a little spooked about the 10L1000, especially the valve body. Word of mouth about potential issues prompted me to jump on the net to sift through all the noise and determine what all the fuss was about. I routinely take long trips, coast-to-coast and points in between, so roadside breakdowns can be '...a thousand miles from nowhere' and a bit of a challenge, and though I had no issues, my guard was up and activated.   And then I stumbled across a chance to salvage some parts off a new 2025 that had been wrecked in transport. I grabbed a few wear items (alternator, pulleys, etc.) and on a whim asked what the ten speeder would cost me. It was cheap...really cheap. I knew some changes had been made in the '24+ version 10L and were supposedly not compatible, but I called service/parts at my local Chevy dealer and asked why and they didn't know. A call to a well known aftermarket transmission outfit revealed it was very likely it would be fine, but to them not 100% sure.   Because it was cheap (really cheap) and I was spooked, I took the chance. Had it installed by a local shop and it worked like a champ, shifted just like the original. At it's first service at 37k, I had the shop put in a Next Gen valve body kit, which after some initial hiccups and rough shifts, smoothed out though with somewhat firmer shifting.   All that said, I have a very serious concern about my newer transmission as just two weeks ago it suddenly began to exhibit a strong reluctance to engage forward or reverse. It was a bit past due anyway so I took it in for service. The reason it was sticking was due to 'glitter' in the fluid clogging the filter...not good folks, often indicates a converter giving out. We ended up going ahead with the new filter and fluid, first to see if it would move and shift, and then if so buy me a little time. It did, and I've driven it over a thousand miles and it is shifting smooth, no noises or slipping. Regardless, it looks like a third gearbox is in my future so I can resume taking long trips with some confidence. In the very short term, my curiosity will have me examining the fluid to check how much glitter has reappeared.   An earlier poster had alleged, in the context of 10L100 failures, that it is another example of how we seasoned citizens somehow descend into hysteria, lose control of our senses, and react irrationally after brief encounters with the idiocy of the internet infosphere. Let me say (and I have used and abused said internet since it's infancy) there is no segment of the populace that has a corner on over-reaction to digital garbage. Just as my offering of experience in this arena is purely anecdotal and should not be considered gospel or all-encompassing, I believe it is still worthwhile information to consider, along with other relevant anecdotal experiences about things like complex transmissions, especially when balanced with other sources.   So to answer the original question, yes I got high miles out of my first 10L, trouble free for 321,000. Now I really wonder how much longer it would have went. Did I 'overreact' to the internet ghouls by replacing a 'good' one with a 'bad' one? Maybe. Who knows, the thing might have taken a puke a 100 miles later. So I'll just fix it again, then move on and start thinking about all the other stuff that will eventually wear out. It still has the original brakes (they're at ~60%), original injectors/pump, turbo, water pump, etc....pretty much original everything. Knock on wood.
    • swathdiver
      6 Speed vs 8 Speed

      By swathdiver · Posted

      At peak temperature.  They get to cool down and warm up more, especially those with the external cooler.  I have three GMT900s and one of them has over 225K on its original transmission.  Fluid gets changed about every 36K miles, all of it.     It's not the bean counters, it was the government.  They had to meet CAFE standards and other government requirements.   To get around that, we tune them and modify them to our liking.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...