Premium grade fuels

[Bob Dunahugh]

At our last GMCMI event. While setting at the liars table. I got in on the =
end of their discussion on premium fuels. Their thought was that it was bet=
ter. But what does the term better mean? In the last 16 years with our GMC.=
I've only used regular gas that was rated as 87 octane. Was wet, and it bu=
rned. Never cared if it had Ethanal in it. ( This isn't an Ethanal discuss=
ion. )Never had issues with it. Got gas yesterday at $1.79 a gal here in Io=
wa. Premium was at $2.59. That's a big difference in cost. So what do you g=
et for the extra cash. Premium is higher in octane. Generally at 89 octane=
. Octane helps to prevent pre detonation in the engines combustion chamb=
er. Commonly called ping. Or knock. And this knock can take out the tops of=
piston/rings. Gasoline formulations have changed over the years. Just are=
n't meant to be atomized by way of a carburetor. The carb left the stage in=
1988 for the most part. With EFI systems that have spark control, and a k=
nock sensor. Like the GM Howell. 89 octane gas just isn't needed as a preca=
ution to avoid knock. Save that $70 cents a gal. Get an EFI with a knock se=
nsor for engine safety. And that's really where the MPG improvement is. Bo=
b Dunahugh 78 403 Royale

 

[emerystora]

Don=E2=80=99t believe everything you hear. Especially at a place called the=
=E2=80=9Cliar=E2=80=99s table=E2=80=9D ! Emery Stora 77 Kingsley =
Frederick CO > On Dec 30, 2018, at 10:58 AM, Bob Dunahugh wrote: > > At our last GMCMI event. While setting at the li=
ars table. I got in on the end of their discussion on premium fuels. Their =
thought was that it was better. But what does the term better mean? In the =
last 16 years with our GMC. I've only used regular gas that was rated as 87=
octane. Was wet, and it burned. Never cared if it had Ethanal in it. ( Th=
is isn't an Ethanal discussion. )Never had issues with it. Got gas yesterda=
y at $1.79 a gal here in Iowa. Premium was at $2.59. That's a big differenc=
e in cost. So what do you get for the extra cash. Premium is higher in octa=
ne. Generally at 89 octane. Octane helps to prevent pre detonation in th=
e engines combustion chamber. Commonly called ping. Or knock. And this kno=
ck can take out the tops of piston/rings. Gasoline formulations have chang=
ed over the years. Just aren't meant to be atomized by way of a carburetor.=
The carb left the stage in 1988 for the most part. With EFI systems that =
have spark control, and a knock sensor. Like the G > M Howell. 89 octane =
gas just isn't needed as a precaution to avoid knock. Save that $70 cents a=
gal. Get an EFI with a knock sensor for engine safety. And that's really w=
here the MPG improvement is. Bob Dunahugh 78 403 Royale > ___________=
____________________________________ > GMCnet mailing list > Unsubscrib=
e or Change List Options: > http://list.gmcnet.org/mailman/listinfo/gmcli=
st_list.gmcnet.org

 

[Jim Hupy]

Premium vs lesser grades? Hmmm!
Let me see. 87 octane vs 92.
8.7 to 1 vs 9.2 to 1 compression ratio. That's the rub. Not a lot of
difference really.
But, when you factor in heavily laden vehicles, full of carbon, thin
valve edges, poorly designed combustion chambers, mass production,
incorrect gaskets retro fitted, etc., etc. the picture comes into focus a
bit better.
There is a principle here somewhere in the recesses of my head. "Rate
of flame propagation" in combustible materials, or some such obscurity. Has
to do with the variables in engines with similar designs performing
differently under nearly identical circumstances. Thermodynamics was not
one of my best subjects, many here on the net are well versed in it, so I
won't dwell upon it, other than to say, "Bad Crap Happens" to good engines
if you don't pay attention to those small, almost silent, rattling noises
that come from the engine compartment under the right set of conditions. A
bit higher octane fuel kinda serves like an insurance policy. Never know
when you are going to need it.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

On Dec 30, 2018 10:26 AM, "Emery Stora via Gmclist"
wrote:

Don’t believe everything you hear. Especially at a place called the “liar’s
table” !

Emery Stora
77 Kingsley
Frederick CO

>
> At our last GMCMI event. While setting at the liars table. I got in on
the end of their discussion on premium fuels. Their thought was that it was
better. But what does the term better mean? In the last 16 years with our
GMC. I've only used regular gas that was rated as 87 octane. Was wet, and
it burned. Never cared if it had Ethanal in it. ( This isn't an Ethanal
discussion. )Never had issues with it. Got gas yesterday at $1.79 a gal
here in Iowa. Premium was at $2.59. That's a big difference in cost. So
what do you get for the extra cash. Premium is higher in octane. Generally
at 89 octane. Octane helps to prevent pre detonation in the engines
combustion chamber. Commonly called ping. Or knock. And this knock can
take out the tops of piston/rings. Gasoline formulations have changed over
the years. Just aren't meant to be atomized by way of a carburetor. The
carb left the stage in 1988 for the most part. With EFI systems that have
spark control, and a knock sensor. Like the G
> M Howell. 89 octane gas just isn't needed as a precaution to avoid knock.
Save that $70 cents a gal. Get an EFI with a knock sensor for engine
safety. And that's really where the MPG improvement is. Bob Dunahugh 78
403 Royale
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[johnny]

Stations I buy from sell midgrade no alcohol, currently getting a .50/gallon premium versus regular alcoholized hovers around $2. The 23' with a
stock carb liked no alcohol in pretty much whatever octane it came. The current coach came with MSD Atomic via Miguel Mendez. I write its shitty
performance of to the engine which blew, Miguel has several out there working just fine so it's doable. I'll bother him after it's back together.

--johnny

--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[Ken B]

Premium stands for "PREMIUM PRICE" and "Premium profits". Use whatever fuel the engine calls for. On a lower compression engine there is no need for
a fuel with a higher AKI (Octane) rating.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[Jim Hupy]

If you have a 100% cylinder fill at sea level, you will have 14.7 psi in
the cylinder. If you multiply that by your compression ratio, you can come
up with what your cranking cylinder pressure should be if this were a
perfect world, which it ain't. Figure 80% of that for an engine in good
condition. If you are at high altitude, figure 70%.
Example: 14.7 psi x 8.2 = 120.54. Multiply that 10 fold for combustion
pressure. If that figure exceeds the anti knock index for the fuel you are
using, combustion irregularities may occur.
This is ONLY AN EXAMPLE. Your figures will vary. Altitude, spark
timing, air /fuel ratio, and about a jillion other factors will influence
these numbers. DO YOU NEED TO USE PREMIUM FUEL? SHORT ANSWER, NO. BUT, do
you want to use premium fuel? You can supply this answer for yourself.
Jim Hupy

Premium stands for "PREMIUM PRICE" and "Premium profits". Use whatever
fuel the engine calls for. On a lower compression engine there is no need
for
a fuel with a higher AKI (Octane) rating.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Jim Hupy]

And, if you really care who profits from the sale of a gallon of gasoline,
I will venture a clue or two. It ain't the guys who drill holes in the
ground, pump out the crude, transport it to the refinery, pays to convert
it into gasoline, blend it with government mandated amount of alcohol,
deliver it to gas stations and pump it into your motor home. If they make
$.06 a gallon, they run a tidy house. But, uncle sam, state, county, city,
all get their cuts whether or not Exxon makes a dime. But, geez, they build
such great roads and bridges with your money.
Jim Hupy

> If you have a 100% cylinder fill at sea level, you will have 14.7 psi in
> the cylinder. If you multiply that by your compression ratio, you can come
> up with what your cranking cylinder pressure should be if this were a
> perfect world, which it ain't. Figure 80% of that for an engine in good
> condition. If you are at high altitude, figure 70%.
> Example: 14.7 psi x 8.2 = 120.54. Multiply that 10 fold for
> combustion pressure. If that figure exceeds the anti knock index for the
> fuel you are using, combustion irregularities may occur.
> This is ONLY AN EXAMPLE. Your figures will vary. Altitude, spark
> timing, air /fuel ratio, and about a jillion other factors will influence
> these numbers. DO YOU NEED TO USE PREMIUM FUEL? SHORT ANSWER, NO. BUT, do
> you want to use premium fuel? You can supply this answer for yourself.
> Jim Hupy
>

>
> Premium stands for "PREMIUM PRICE" and "Premium profits". Use whatever
> fuel the engine calls for. On a lower compression engine there is no need
> for
> a fuel with a higher AKI (Octane) rating.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
>

 

[Jim Hupy]

Happy New Year! Rant off.!
Jim Hupy

> And, if you really care who profits from the sale of a gallon of gasoline,
> I will venture a clue or two. It ain't the guys who drill holes in the
> ground, pump out the crude, transport it to the refinery, pays to convert
> it into gasoline, blend it with government mandated amount of alcohol,
> deliver it to gas stations and pump it into your motor home. If they make
> $.06 a gallon, they run a tidy house. But, uncle sam, state, county,
> city, all get their cuts whether or not Exxon makes a dime. But, geez, they
> build such great roads and bridges with your money.
> Jim Hupy
>

>
>> If you have a 100% cylinder fill at sea level, you will have 14.7 psi in
>> the cylinder. If you multiply that by your compression ratio, you can come
>> up with what your cranking cylinder pressure should be if this were a
>> perfect world, which it ain't. Figure 80% of that for an engine in good
>> condition. If you are at high altitude, figure 70%.
>> Example: 14.7 psi x 8.2 = 120.54. Multiply that 10 fold for
>> combustion pressure. If that figure exceeds the anti knock index for the
>> fuel you are using, combustion irregularities may occur.
>> This is ONLY AN EXAMPLE. Your figures will vary. Altitude, spark
>> timing, air /fuel ratio, and about a jillion other factors will influence
>> these numbers. DO YOU NEED TO USE PREMIUM FUEL? SHORT ANSWER, NO. BUT, do
>> you want to use premium fuel? You can supply this answer for yourself.
>> Jim Hupy
>>

>>
>> Premium stands for "PREMIUM PRICE" and "Premium profits". Use whatever
>> fuel the engine calls for. On a lower compression engine there is no need
>> for
>> a fuel with a higher AKI (Octane) rating.
>> --
>> Ken Burton - N9KB
>> 76 Palm Beach
>> Hebron, Indiana
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>>
>>

 

[scott nutter1]

Amen James Hupy!! Telling it how it is %100!!!
--
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, tankless water heater, everything Lenzi. Alex Ferrera
installed MSD Atomic EFI
Houston, Texas

 

[Ernest Dankert]

I distrust large volume fuel distribution (BJ-SAM-Costco), to hold to the 10% rule, especially at the higher octane grades. Alcohol is less expensive
and higher octane than gasoline. Pulling up a grade in the Rockies with a carb is tough, you have a fuel with higher reid vapor pressure (than
design)
lower atmospheric pressure and a high burn rate. At home I have a source of 89 octane non-ethanol, last bulk delivery was $3.40/gal in the Peoples
Republic
of New Yorkistan. I get 10% better mileage (consistently) compared to ethanol adulterated non bulk fuel and about 15% better than a bulk distributor.

Editorial
For the most part ethanol is an adulterating agent that delivers poorer fuel economy. As a move towards energy independence the reward is nebulous at
best
with a flex fuel engine. The politicians have seized the ethanol card to buy the agriculture vote. Unfortunately the higher commodity corn price has
elevated
land purchase & rents, crop inputs (fertilizer, herb + insecticide, seed (Dow & DuPont consolidation). Strategically should we be be burning up our
crop land
for an inferior fuel?

I also suspect some elected officials used the ethanol solution to obsolete old equipment.

Reasons not to use ethanol:
1) 1.1 btu gain is offset by poorer fuel economy
2) Poor shelf life, the fuel separates to green sludge or water.
3) Incompatible with many elastomers, requires specialized gaskets and carb rebuilds of small engines
4) Ethanol blends can not be pipeline shipped; the ethanol must be blended locally and requires truck or rail transport. Transportation accidents
require special
foam; alcohol fires are difficult to recognize.
5) At blends >10% more frequent engine oil changes are recommended.

Reasons to use ethanol:
1) Better mileage for 100% fueled engines specially designed for 12:1 compression
2)
--
1977 Eleganza II
Ogden NY

 

[Bob Dunahugh]

Ernest. I wouldn't say that we are burning up our crop lands here in Iowa =
because of ethanal. The amount of corn, and soybean grown here is way be o=
n anyone's possible comprehension. Cedar Rapids is a town just over 100,00=
people. Over a half million bushes of corn get processed into food product=
s each 365 day of the year. Then think about the fact that Cedar Rapids is =
a small processor in this country. Over half of the soybean crop did go to =
China till the tariffs hit. That cost Iowa about 14 billion in lost income.=
But the FED is going to subsidies our lost. ( So thanks to all you taxes=
payers out there.) Yes. Corn prices have gone up in the last 15 years. But=
the food you eat everyday is still the cheapest in the entire world as to =
the cost of living. So with the increases in the price corn/beans. There's=
more money for R&D for hybrid seeds being developed. Thus being able to p=
roduce even more corn/beans for the world. More trucks, tractors, and other=
equipment being ordered for production. Iowa also produces more pork then =
any other state because of the crops. 1/3 of the population is employed in=
agriculture. A third of our electrical power comes from the winds in those=
fields. Their working for 100% renewable power in 9 years. Their closing =
a nuclear plant next year because of reducing need. I 2008. And the rest of=
the country saw a recession. We saw none of it. Our state government runs =
in the black. Yes. Iowa sets at the edge of the Earth. You can see the edg=
e from here. Most of the country sees us as just a spacer between the coas=
t. If they know of us at all. That's perfectly fine. From the edge. Bob D=
unahugh

 

[johnny]

My experience has been, when the nice places get touted, ever body goes there and directly they aren't nice anymopre. You should whisper

=--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[george beckman]

> If you have a 100% cylinder fill at sea level, you will have 14.7 psi in
> the cylinder. If you multiply that by your compression ratio, you can come
> up with what your cranking cylinder pressure should be if this were a
> perfect world, which it ain't. Figure 80% of that for an engine in good
> condition. If you are at high altitude, figure 70%.
> Example: 14.7 psi x 8.2 = 120.54. Multiply that 10 fold for combustion
> pressure. If that figure exceeds the anti knock index for the fuel you are
> using, combustion irregularities may occur.

One cravat about 100% cylinder fill. That only happens at wide open throttle. Most of the time we drive around with a much lower compression pressure.
The old time vacuum gauge helps get better mileage because much less air is getting in, meaning less gas at the same time due to the air-fuel ratio.
But it is not efficient. It is a way to detune your engine by lowering the working compression pressure.

This is the main problem with spark engines. We starve them for air thus lowering the compression pressure. Diesel take a full charge of air. And
higher compression pressures yield more bang for your buck.

--
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George

 

[Jim Hupy]

Pistons don't suck air into cylinders. Atmospheric pressure, present around
the engine, senses the pressure differential between inside the cylinders
vs and atmospheric pressure, and fills the cylinders as much as is possible
given flow restrictions and time constraints. That's why you use a
correction factor of 75% or so at sea level, less than that at higher
altitudes where atmospheric pressure is less.
Jim Hupy (Happy New Year)

> > If you have a 100% cylinder fill at sea level, you will have 14.7 psi in
> > the cylinder. If you multiply that by your compression ratio, you can
> come
> > up with what your cranking cylinder pressure should be if this were a
> > perfect world, which it ain't. Figure 80% of that for an engine in good
> > condition. If you are at high altitude, figure 70%.
> > Example: 14.7 psi x 8.2 = 120.54. Multiply that 10 fold for
> combustion
> > pressure. If that figure exceeds the anti knock index for the fuel you
> are
> > using, combustion irregularities may occur.
>
> One cravat about 100% cylinder fill. That only happens at wide open
> throttle. Most of the time we drive around with a much lower compression
> pressure.
> The old time vacuum gauge helps get better mileage because much less air
> is getting in, meaning less gas at the same time due to the air-fuel ratio.
> But it is not efficient. It is a way to detune your engine by lowering the
> working compression pressure.
>
> This is the main problem with spark engines. We starve them for air thus
> lowering the compression pressure. Diesel take a full charge of air. And
> higher compression pressures yield more bang for your buck.
>
> --
> '74 Eleganza, SE, Howell + EBL
> Best Wishes,
> George
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[chris tyler]

Dirty little secret is that often you dont get what you pay for. Its common to substitute lower octane and 90% will not know the difference.
But the 10 % who actually need the octane will.
The state checks volume but not octane levels at least here
Its also common to have independant stations buying non branded gas- So what you were getting wasnt nessesarily ammoco because it was an ammoco
station.
Had a relative who was an ammco distibtor in FL for many years

--
76 Glenbrook

 

[Bob Dunahugh]

Chris Tylor is absolutely correct. I do a fair amount of road race track ev=
ents. Running engines that are in the range of 13.5 to 1 compression. Our G=
MC's are about 7 to 1. I use 110 octane leaded fuel. Listings on the pump=
s aren't always what you get. That's why the GM timing recommendations are =
lower for safe operation. With our GMC's. To avoid these variations. And g=
et the maximum performance. I'll buy 50 to 100 gals ( at $7,50 a gal ) fo=
r the weekend track event. Then I'll tune the engine based on that fuel, a=
ltitude, temps expected, and humidity. But we can't do this for every fill =
up in our GMC's. Then on top of that. Modern fuels now are meant to be ato=
mized with EFI systems. The GM Howell EFI system with spark control. Will a=
djust spark timing if you end up with lower octane level. That's why you ca=
n run lower octane fuel then what's posted. Bob Dunahugh 78 Royale _=
_______________________________ From: Bob Dunahugh Sent: Monday, Decemb=
er 31, 2018 5:49 PM To: gmclist Subject: RE: Premium gr=
ade fuels Ernest. I wouldn't say that we are burning up our crop land=
s here in Iowa because of ethanal. The amount of corn, and soybean grown he=
re is way be on anyone's possible comprehension. Cedar Rapids is a town j=
ust over 100,00 people. Over a half million bushes of corn get processed in=
to food products each 365 day of the year. Then think about the fact that C=
edar Rapids is a small processor in this country. Over half of the soybean =
crop did go to China till the tariffs hit. That cost Iowa about 14 billion =
in lost income. But the FED is going to subsidies our lost. ( So thanks t=
o all you taxes payers out there.) Yes. Corn prices have gone up in the las=
t 15 years. But the food you eat everyday is still the cheapest in the enti=
re world as to the cost of living. So with the increases in the price corn=
/beans. There's more money for R&D for hybrid seeds being developed. Thus =
being able to produce even more corn/beans for the world. More trucks, trac=
tors, and other equipment being ordered for production. Iowa also produces =
more pork then any other state because of the crops. 1/3 of the population=
is employed in agriculture. A third of our electrical power comes from the=
winds in those fields. Their working for 100% renewable power in 9 years.=
Their closing a nuclear plant next year because of reducing need. I 2008. =
And the rest of the country saw a recession. We saw none of it. Our state g=
overnment runs in the black. Yes. Iowa sets at the edge of the Earth. You =
can see the edge from here. Most of the country sees us as just a spacer b=
etween the coast. If they know of us at all. That's perfectly fine. From t=
he edge. Bob Dunahugh

 

[Matt Colie]

> Dirty little secret is that often you dont get what you pay for. Its common to substitute lower octane and 90% will not know the difference.
> But the 10 % who actually need the octane will.
> The state checks volume but not octane levels at least here
> Its also common to have independant stations buying non branded gas- So what you were getting wasnt nessesarily ammoco because it was an ammoco
> station.
> Had a relative who was an ammco distibtor in FL for many years

Chris,

You are right about most of this, but most states require that motorfuel octane be certified by the distributor. Doing that is not simple. It
requires a laboratory knock engine and a skilled technician. But, just because the fuel is certified does not mean it ended up in the right tank.
Not long ago we had a local station get busted. The owner would order mid grade and have the driver drop most of it into the premium grade tank.
This is more common than one might suspect. I have had cars that needed high octane, but the best was the '87 TurboCoupe. I could have made
calibrations on the boost gauge for pump grade. I did file a few complaints with the state.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[mark sawyer]

> Not long ago we had a local station get busted. The owner would order mid grade and have the driver drop most of it into the premium grade tank.
> This is more common than one might suspect.
> Matt

I worked at a gas station for a while and there was no "Mid-Grade" tank... Mid-Grade was just a blend of 87 and 93... Always thought mid-grade was a
ripoff, cause the price was always halfway between regular and premium, but 89 is not half way between 87 and 93..... That would be what, 90 and a
half, right?

Anyway, because I'm a cheap SOB, if I'm getting detonation on 87, rather than go midgrade, I fill with Regular then flip the pump off before I'm full
and add a few gallons of premium in there...

Matt: Maybe the guy got busted putting regular in the premium tank....?

--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX

 

[mark sawyer]

So glancing through this thread, I don't see any mention of "Top Tier Gas" so if I missed it, sorry, if I did not, here is a little blurb on it's
history:

Quote:
> In the late 1980s, automakers became concerned with fuel additives as more advanced fuel injection technology became widely used in new cars. The
> injectors often became clogged, and the problem was found to be inadequate levels of detergent additives in some gasoline. The automakers began to
> recommend specific brands of gas with adequate content to their customers. But some fuel marketers were still not using detergents, and in a move
> supported by the auto industry, the federal government mandated specific levels of additives. The U.S. Environmental Protection Agency (EPA)
> introduced the minimum gasoline detergent standard[14] in 1995.
>
> However, the new regulations had unintended consequences. The new EPA standards required lower levels of detergent additives than were then being
> used by a few major fuel marketers. When the new regulations came in, most gasoline marketers who had previously provided higher levels of
> detergents reduced the level of detergents in their gasolines to meet the new standard.[15] The EPA detergent additive levels were designed to meet
> emissions standards but not engine longevity standards. Automakers said they were seeing persistent problems such as clogged fuel injectors, and
> contaminated combustion chambers, resulting in higher emissions and lower fuel economy.[16]
>
> By 2002, the automakers said their repair records suggested that the EPA standard for detergents wasn't high enough, but the EPA was not
> responsive when they asked them to increase the standards. These concerns were heightened by plans to introduce a new generation of vehicles that
> would meet the EPA's "Tier Two" environmental standards for reduced emissions. These vehicles require higher levels of detergents to avoid reduced
> performance.[15] Cars with direct injection technology (GDI) have been especially prone to carbon buildup, and car makers recommend fuels with
> higher detergent levels to combat the problem.[17] At first GDI was mainly available in high-end autos, but it is now being used in mid-range cars
> and economy cars, such as the Hyundai Sonata, Ford Focus and Hyundai Accent.[18][19][20]
>
> In 2004 representatives of BMW, General Motors, Honda, and Toyota got together to specify what makes a good fuel. Using recommendations from the
> Worldwide Fuel Charter, a global committee of automakers and engine manufacturers, they established a proprietary standard for a class of gasoline
> called "TOP TIER" Detergent Gasoline The new standard required increased levels of detergents, and restricted metallic content. Volkswagen/Audi
> joined the group of automakers in 2007. Gas brands can participate and get a TOP TIER license if they meet certain standards, which includes
> performance tests for intake valve and combustion chamber deposits, fuel injector fouling, and intake valve sticking. Additive manufacturers pay for
> the testing, the cost of which varies from year to year, while gasoline companies pay an annual fee based on the number of stations it operates to
> participate in the program.[21]
>
> In addition to higher detergent levels, Top Tier standards also require that gasolines be free of metallic additives, which can be harmful to the
> emissions control systems in cars.

--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX

 

[mark sawyer]

One thing to note, in order to obtain a Top Tier certification, all grades must meet the minimum standards at all stations. As an example, for a
while, BP was not on this list. Apparently their premium met Top Tier standards, but not regular and mid-grade, so they were unable to get the
certification. Later on, they chose to update their regular to meet top tier as well, and were added.

Here is the Top Tier website with a list of approved stations:

https://toptiergas.com/licensed-brands/
--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX