Gasoline
Team Owner
Joined: Sep 2010
Posts: 32,042
Likes: 4,610
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,932
Likes: 12,345
From: NE South Carolina
I'll stick with fuel economy to make it clear about why using 87 octane is false economy!
The best fuel economy is achieved with the most timing advance (ignition before top dead center) possible and with the leanest mixture (higher air to fuel ratio) before preignition occurs.
You may NOT want to read it but quoting: "An octane rating of 93 is highly recommended for best performance and fuel economy."
Yep "87 octane can be used in a pinch if 91/93 octane is not available."
Last edited by JerryU; Apr 20, 2018 at 03:48 PM.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,932
Likes: 12,345
From: NE South Carolina
Suggest you buy an electric car next go around! One of the Tesla models will out accelerate a Vette!
PS: On second thought if you buy a Tesla I'd have to describe how and why they use AC power and what a pulse width modulated drive is all about!
Last edited by JerryU; Apr 20, 2018 at 03:20 AM.
Race Director
Joined: May 2001
Posts: 15,323
Likes: 2,077
From: Guelph, Ontario
Skid Mark Joe just believes what he wants to believe. I've given up trying to set him straight, he lives in his own little world. Running 87 octane on a hot Texas day is a recipe for disaster, the knock sensors probably won't be able to pull out enough timing to avoid detonation. Eventually he can kiss his pistons goodbye.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,932
Likes: 12,345
From: NE South Carolina
^^^
In fairness it can be done with some careful restrictions!
I'm reminded some years ago of my Communications Manager who bought a large 4 passenger car that came with a 4 cylinder turbocharged engine. He liked the look and the price was right.
However he was appalled when he found out and said he would not use the high test gas it required! He told me he was using regular! He was not an aggressive driver and we have no hills in Eastern SC so I suggested he not use more than half throttle and never try to accelerate rapidly! That was no problem for him or the way he drove. He did everything slow!
SIDE BAR
He was a great guy and retired ~10 years before me. He loved playing golf but no one liked to play with him because he was so slow. I played a lot of golf when in college but gave it up when in R&D. But was forced to take it up again when I got in Marketing. My boss, who became President of our Division, had a 1 handicap and was the country club champ in the town we both lived in CT. I did not enjoy golf as I was having to worry about my score!
Back to my Communication Manager years later. When I retired he wanted to play so I said fine but I will only keep track of pars and birdies not stokes! I refuse to be mad at myself when that little white ball goes where I had not intended! We played twice a week, in the hot summer starting at 8 AM! I had a great time as I enjoyed him and could care less how much time he took! He didn't care that we were often driving the cart to the trees where my ball went! Great guy, great time. Unfortunately he is no longer with us! Have not played golf since!
In fairness it can be done with some careful restrictions!
I'm reminded some years ago of my Communications Manager who bought a large 4 passenger car that came with a 4 cylinder turbocharged engine. He liked the look and the price was right.
However he was appalled when he found out and said he would not use the high test gas it required! He told me he was using regular! He was not an aggressive driver and we have no hills in Eastern SC so I suggested he not use more than half throttle and never try to accelerate rapidly! That was no problem for him or the way he drove. He did everything slow!
SIDE BAR
He was a great guy and retired ~10 years before me. He loved playing golf but no one liked to play with him because he was so slow. I played a lot of golf when in college but gave it up when in R&D. But was forced to take it up again when I got in Marketing. My boss, who became President of our Division, had a 1 handicap and was the country club champ in the town we both lived in CT. I did not enjoy golf as I was having to worry about my score!
Back to my Communication Manager years later. When I retired he wanted to play so I said fine but I will only keep track of pars and birdies not stokes! I refuse to be mad at myself when that little white ball goes where I had not intended! We played twice a week, in the hot summer starting at 8 AM! I had a great time as I enjoyed him and could care less how much time he took! He didn't care that we were often driving the cart to the trees where my ball went! Great guy, great time. Unfortunately he is no longer with us! Have not played golf since!
Last edited by JerryU; Apr 20, 2018 at 08:29 AM.
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Race Director
Joined: May 2001
Posts: 15,323
Likes: 2,077
From: Guelph, Ontario
The only time I think 87 would be perfectly safe in a C7 would be if it was below the freezing mark outside, and you were doing a highway trip on a perfectly flat road that puts virtually no load on the engine, and you never went more than 25% throttle at any point during that tank.
Team Owner
Joined: Apr 2005
Posts: 35,747
Likes: 148
From: Northern NYs Adirondack Mountains,http://www.visitsacandaga.com.
I'm luck up here as we now have a choice of gasses to use. For many years only ethanol crap was available for sale, and that included the marinas on the lake.
I will only use none E gas in my Vette if I have a choice.! (same for all my two stroke toys and tools) In my DD Toyota 4x4 I use 89 ethanol gas.
None E is 91 and I have used the e crap type 93 and to be truthful I find more performance and most definitely better mileage using 91 none E. That statement also includes my 07 Z06, it was quite noticeable with that car!
I have made many 400+ mile trips back and forth to Carlisle and what gas is in the car is easy to make a determination.
Contrary to what at least one person has to say the only way I will put gas lower than 91 in my Vette if its a emergency and that is all that is available. His Vette I realy do not care what he puts in the tank!
I will only use none E gas in my Vette if I have a choice.! (same for all my two stroke toys and tools) In my DD Toyota 4x4 I use 89 ethanol gas.
None E is 91 and I have used the e crap type 93 and to be truthful I find more performance and most definitely better mileage using 91 none E. That statement also includes my 07 Z06, it was quite noticeable with that car!
I have made many 400+ mile trips back and forth to Carlisle and what gas is in the car is easy to make a determination.
Contrary to what at least one person has to say the only way I will put gas lower than 91 in my Vette if its a emergency and that is all that is available. His Vette I realy do not care what he puts in the tank!
Last edited by 6spdC6; Apr 20, 2018 at 10:23 AM.
Melting Slicks
Joined: Sep 2005
Posts: 2,568
Likes: 264
From: Near Charlotte NC
On pages 213-214 of my '17 OM(LT1),it states that "93 is highly recommended" and "as low as 87 can be used".
https://my.chevrolet.com/content/dam...s%20Manual.pdf
In a pinch,once I bought a few gals of 89 PURE GAS when the station was out of 93.I would not do it often.
\db2
https://my.chevrolet.com/content/dam...s%20Manual.pdf
In a pinch,once I bought a few gals of 89 PURE GAS when the station was out of 93.I would not do it often.
\db2
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,932
Likes: 12,345
From: NE South Carolina
^^
In a pinch BUT as I stated in Post 20, 22 and 24 the full statement in the Owner's Manual is:
"An octane rating as low as 87 may be used, but it will reduce performance and fuel economy."
In a pinch BUT as I stated in Post 20, 22 and 24 the full statement in the Owner's Manual is:"An octane rating as low as 87 may be used, but it will reduce performance and fuel economy."
Last edited by JerryU; Apr 20, 2018 at 10:47 AM.
Burning Brakes
Joined: Jul 2016
Posts: 1,239
Likes: 823
From: Wilmington Ma
I use mostly Top Tier but also less expensive 93 octane from time to time. At Sam's Club their 93 octane often ~$0.40 gallon cheaper.
Use of GM Recommended Fuel Additive:
The Owner's Manual says if not using Top Tier adding the GM recommended fuel additive at each oil change can help.
Quoting: "If TOP TIER Detergent Gasoline is not available, one bottle of GM Fuel System Treatment Cleaner added to the fuel tank at every engine oil change, can help."
I was buying the GM recommended gasoline additive and using every oil change as they suggest. However it was getting expensive and now they don't list the GM part number so hard to buy on Amazon! Looked at the SDS (Safety Data Sheet) of it and Techron from Chevron. Techron is the additive many Top Tier gasolines used and/or pay Chevron a license for their patent. The GM and Techron SDS appeared to be the same and the GM bottle is identical in appearance so could be bottled for them by Chevron.
The main reason I use it is that both products say they will dissolve sulfur on the fuel level sensors. Top Tier had nothing to do with sulfur. All gasoline have it and the amount "should be low" as it's removed in the refining. However some crude oil can have 3% or more! The EPA has a new lower standard in 2017 of 10 PPM. Did the refiner get it all that low? Gasoline in our area comes in by pipeline so Sam's gas is the same as all others until the additives are put in when the delivery tank truck is filled! So sulfur is the same.
So even if using Top Tier, fuel senders failures can occur. In fact if storing Vettes for the winter it's now suggested only filling the tank ~1/3 to avoid the sender being immersed in gasoline during storage where the gas is not sloshing around.
There are a number of posts about fouled C7 senders. To remove and replace the sender the tanks have to be dropped. That requires dropping the drive train. Recall a post where the owner was horrified when he saw his drivetrain on the garage floor! In another post the owner had his erratic sender reading fixed by a dealer using two bottles on the GM gasoline additive listed in the Owner's Manual. He was charged $100 but it solved the issue. Probably out of warranty or the dealer would much rather charge GM for a replacement! Must be expensive!
Adding a ~$5 container of fuel injection cleaner every oil change is a cheap precaution to assist with sulfur issues and make up for my periodic use of none Top Tier gas at Sam's Club! In fact just changed oil and added a container of Techron at the last gasoline fill.
Use of GM Recommended Fuel Additive:
The Owner's Manual says if not using Top Tier adding the GM recommended fuel additive at each oil change can help.
Quoting: "If TOP TIER Detergent Gasoline is not available, one bottle of GM Fuel System Treatment Cleaner added to the fuel tank at every engine oil change, can help."
I was buying the GM recommended gasoline additive and using every oil change as they suggest. However it was getting expensive and now they don't list the GM part number so hard to buy on Amazon! Looked at the SDS (Safety Data Sheet) of it and Techron from Chevron. Techron is the additive many Top Tier gasolines used and/or pay Chevron a license for their patent. The GM and Techron SDS appeared to be the same and the GM bottle is identical in appearance so could be bottled for them by Chevron.
The main reason I use it is that both products say they will dissolve sulfur on the fuel level sensors. Top Tier had nothing to do with sulfur. All gasoline have it and the amount "should be low" as it's removed in the refining. However some crude oil can have 3% or more! The EPA has a new lower standard in 2017 of 10 PPM. Did the refiner get it all that low? Gasoline in our area comes in by pipeline so Sam's gas is the same as all others until the additives are put in when the delivery tank truck is filled! So sulfur is the same.
So even if using Top Tier, fuel senders failures can occur. In fact if storing Vettes for the winter it's now suggested only filling the tank ~1/3 to avoid the sender being immersed in gasoline during storage where the gas is not sloshing around.
There are a number of posts about fouled C7 senders. To remove and replace the sender the tanks have to be dropped. That requires dropping the drive train. Recall a post where the owner was horrified when he saw his drivetrain on the garage floor! In another post the owner had his erratic sender reading fixed by a dealer using two bottles on the GM gasoline additive listed in the Owner's Manual. He was charged $100 but it solved the issue. Probably out of warranty or the dealer would much rather charge GM for a replacement! Must be expensive!
Adding a ~$5 container of fuel injection cleaner every oil change is a cheap precaution to assist with sulfur issues and make up for my periodic use of none Top Tier gas at Sam's Club! In fact just changed oil and added a container of Techron at the last gasoline fill.
Melting Slicks
Joined: Jul 2004
Posts: 2,216
Likes: 284
From: Ten Mile TN
Here is straight out of the 2018 Owners manual.
So its pretty clear 93 is preferred and recommended per the manual. Its also clear if you want reduced acceleration and fuel economy 87 can be used.
Makes no sense to me to buy a performance car and use a fuel that leads to reduced acceleration.
Fuel
GM recommends the use of TOP
TIER Detergent Gasoline to keep
the engine cleaner and reduce
engine deposits. See
www.toptiergas.com for a list of TOP
TIER Detergent Gasoline marketers
and applicable countries.
Do not use any fuel labeled E85 or
FlexFuel. Do not use gasoline with
ethanol levels greater than 15% by
volume.
For the LT1 6.2L engine, premium
unleaded gasoline meeting ASTM
specification D4814 with a posted
octane rating of 93 is highly
recommended for best performance
and fuel economy. Unleaded
gasoline with an octane rated as low
as 87 can be used. Using unleaded
gasoline rated below 93 octane,
however, will lead to reduced
acceleration and fuel economy.
If knocking occurs, use a gasoline
rated at 93 octane as soon as
possible, otherwise, the engine
could be damaged. If heavy
knocking is heard when using
gasoline with a 93 octane rating, the
engine needs service.
GM recommends the use of TOP
TIER Detergent Gasoline to keep
the engine cleaner and reduce
engine deposits. See
www.toptiergas.com for a list of TOP
TIER Detergent Gasoline marketers
and applicable countries.
Do not use any fuel labeled E85 or
FlexFuel. Do not use gasoline with
ethanol levels greater than 15% by
volume.
For the LT1 6.2L engine, premium
unleaded gasoline meeting ASTM
specification D4814 with a posted
octane rating of 93 is highly
recommended for best performance
and fuel economy. Unleaded
gasoline with an octane rated as low
as 87 can be used. Using unleaded
gasoline rated below 93 octane,
however, will lead to reduced
acceleration and fuel economy.
If knocking occurs, use a gasoline
rated at 93 octane as soon as
possible, otherwise, the engine
could be damaged. If heavy
knocking is heard when using
gasoline with a 93 octane rating, the
engine needs service.
Makes no sense to me to buy a performance car and use a fuel that leads to reduced acceleration.
Team Owner
Joined: Sep 2000
Posts: 25,002
Likes: 2,703
From: Far NW 'burbs of Chicago
St. Jude Donor '13
The only time I think 87 would be perfectly safe in a C7 would be if it was below the freezing mark outside, and you were doing a highway trip on a perfectly flat road that puts virtually no load on the engine, and you never went more than 25% throttle at any point during that tank.
I can recall being in towns, rather affluent, up in the Rockies where the elevation was around 10k and the only gas available was 87. We used it in the 'vette with no problems, but needed to remember your feather-foot technique when we went down to lower elevations and still had some of the 87 in the tank.
Back in the days of big piston engines in airplanes, there were often two power setting tables, one was called "civilian gas" (100-130 octane), and one with more power for "military gas" (115-145 octane). Same concept.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,932
Likes: 12,345
From: NE South Carolina
None of this stuff works in 3 days to “clean carbon!” The concept of using Top Tier is to avoid it forming it in the first place.
Techron and the recommended GM cleaner also devolves sulfur. Both say the same thing! They do not cure arthritis or the common cold!
Best to always use Top Tier but as I said that has nothing to do with the sulfur content! Oil can have ~3% sulfur, called sour crude versus sweet crude which costs more and is limited supply dictated my Mother Nature and where those dinosaurs died! It is “mostly removed” in the refining process.
A poster noted his dealer used two bottles of the GM “stuff” and solved his irratic fuel level reading. Charged him $100. I’ll continue to use a bottle every oil change as recommended in th Owner’s Manual. I was using the GM stuff but they got cute, now have essentially did buy it from the dealer! Techron SDS Safety Data Shert) shows it is essentially same, if not identical.
Everyone can do as the wish, might not be needed. But then again even while under warranty I don’t want to see my whole rear drivetrain the the dealer’s garage floor as the tanks are dropped to replace the sender ! What are the odds it will not be installed properly? They are nor zero!
Last edited by JerryU; Apr 20, 2018 at 01:11 PM.
Drifting
Joined: Jul 2016
Posts: 1,878
Likes: 1,160
From: Keswick, Virginia
In my 2018 Honda Accord (my DD), I always use 87 octane unleaded gasoline. No problems at all and the car was designed to run on it.
My 2017 Stingray? Nothing but 93 octane - all of the time. Could I possibly use 87 in a pinch? Probably.....but why spend that kind of money for a nice car like a C7 and not give it the best diet of fuel? Since it is a weekend 'garage queen' car, the extra ducats I have to shell out for the good gasoline is a small price to pay for the good performance when I need it AND the peace of mind that comes along with it.
In my area of VA, we don't have any 'unadulturated' fuel - as every station sells gasoline that contains 10 percent ethanol. They all have it clearly marked on every gasoline pump. I always use Costco 93 octane - if I am near one of their locations when I top off the tank. They are always 20 to 30 cents cheaper per gallon than everywhere else AND their gasolines are all "top-tier" blends.
If I cannot find a Costco, I go to Valero, BP/Amoco, Shell or Exxon/Mobil.......all of which are "top tier" brands. Fortunately, there are plenty of them in my part of the state.
It's a Corvette, folks. Don't skimp on something that may affect your car in the long term.
Race Director
Joined: May 2001
Posts: 15,323
Likes: 2,077
From: Guelph, Ontario
There is one other condition where 87 would be safe- if you were using a normally aspirated engine (no supercharger or turbocharger) and above a certain elevation where the thinner air reduces your ability to pull anything close to full power from the engine. That would be pretty high, maybe around 10,000 feet. In that case, mother nature is forcing what you suggested in your post, about using reduced power.
Team Owner
Joined: Sep 2010
Posts: 32,042
Likes: 4,610
The 2017 Owner's Manual says nothing about only "using 87 in a pinch." 93 is not "highly recommended," either. Those quotes do not exist in the 2017 Owners Manual! You made them up......
ALL of these grades for sale @ my Murphy's Oil, are approved fuels for my 2017 Corvette:
Last edited by Skid Row Joe; Apr 20, 2018 at 07:10 PM.