Gasoline physical properties
05-22-2013, 10:31 PM
#1
Drifting
Thread Starter
Gasoline physical properties
I'll start a new thread, this once morphed from my FI questions and someone asking why I hadn't posted about gasoline specs.
BTW I find this subject fascinating but difficult as it was my bread and butter for so many years.
Gasoline has many specs having to do with vapor pressure or how light or heavy it is.
Three properties are used to measure gasoline volatility:vapor pressure,
distillation profile, and vapor-liquid ratio. A fourth property, driveability index, is
calculated from the distillation profile.
Vapor pressure, the pressure of a closed bomb of gasoline with a pressure gauge on the top in a 100F water bath.
There are distillation specs - the temperature at which a given % are boiled away in an atmospheric pressure distillation flask
10% distilled maximum of 158F
Important for cooler temperatures, must be low enough to help vaporize the gasoline
50% distilled minimum of 170F maximum of 250F.
This is a tricky one for super as the high octane components also happen to be the heavier ones in general. Hard to get high octane for Super and low 50% point
90% distilled maximum of 374F
This insures gasoline is not too heavy, like having too much high boiling naphtha in it.
FBP final boiling point, maximum of 437F
This one is to prevent too much heavy kerosene boiling material in gasoline that can cause dieseling. You want to maximize it to get more
yield of gasoline but not too high. It only takes a very small % of heavy stuff to raise the FBP.
T V/L-20 90F-140F
This is the temperature when the vapor to liquid ratio is 20.
This has to be a higher temperature in the summer than the winter. You wouldn't want to have mostly vapor at a low temperature in the summer. This temperature needs to be higher for the hot Southwest than cooler Midwest. This is the primary reason the gasoline you buy in Texas is different than what sells in Chicago and what you buy in winter is different than what you buy in summer.
Here is a typical distillation curve for gasoline. There is stuff that boils from less than 30F(butane) to 400F+ in it!
This is a very good writeup from Chevron about gasoline specs that should be understandable to many Corvette enthusiasts:
http://www.chevronwithtechron.com/pr...ech_review.pdf
Taken from the link:
VOLATILITY
Driveability describes how an engine starts, warms up, and runs. It is the assessment
of a vehicle’s response to the use of its accelerator relative to what a driver expects.
Driveability problems include hard starting, backfiring, rough idling, poor throttle
response, and stalling (at idle, under load, or when decelerating).
The key gasoline characteristic for good driveability is volatility – a gasoline’s tendency to
vaporize. Volatility is important because liquids and solids don’t burn; only vapors burn.
When a liquid appears to be burning, actually it is the invisible vapor above its surface that
is burning. This rule holds true in the combustion chamber of an engine; gasoline must
be vaporized before it can burn. For winter weather, gasoline blenders formulate gasoline
to vaporize easily. Gasoline that vaporizes easily allows a cold engine to start quickly and
warm up smoothly. Warm-weather gasoline is blended to vaporize less easily to prevent
engine vapor lock and other hot fuel handling problems and to control evaporative
emissions that contribute to air pollution.
It is important to note that there is no single best volatility for gasoline. Volatility must be
adjusted for the altitude and seasonal temperature of the location where the gasoline will be
used. Later, this chapter will explain how gasoline specifications address this requirement.
Three properties are used to measure gasoline volatility in the United States: vapor pressure,
distillation profile, and vapor-liquid ratio. A fourth property, driveability index, is
calculated from the distillation profile. Instead of a vapor-liquid ratio, a vapor lock index
is used outside the U.S. to control hot fuel handling problem
Distillation Profile
Gasoline is a mixture of hundreds of hydrocarbons, many of which have different boiling
points. Thus gasoline boils, or distills, over a range of temperatures, unlike a pure compound;
water, for instance, boils at a single temperature. A distillation profile, or distillation curve, is
the set of increasing temperatures at which gasoline evaporates for a fixed series of increasing
volume percentages (5 percent, 10 percent, 20 percent, 30 percent and so on) under specific
conditions (see page 48). A distillation profile is also shown for a summer reformulated gasoline (RFG) containing ethanol.
Various ranges of a distillation profile correlate with specific
aspects of gasoline performance.
Front-end volatility is adjusted to provide:
• Easy cold starting.
• Easy hot starting.
• Freedom from vapor lock or other hot fuel handling problems.
• Low evaporation and running-loss emissions.
Midrange volatility is adjusted to provide:
• Rapid warm-up and smooth running.
• Good short-trip fuel economy.
• Good power and acceleration.
• Protection against carburetor icing and hot-stalling.
Tail-end volatility is adjusted to provide:
• Good fuel economy after engine warm-up.
• Freedom from engine deposits.
• Minimal fuel dilution of crankcase oil.
Vapor-Liquid Ratio
The vapor-locking tendency of a gasoline is influenced both by the temperatures at the
front end of its distillation profile and by its vapor pressure. However, the property that
correlates best with vapor lock and other hot fuel handling problems (hard starting or
no starting after a hot soak, and poor throttle response) is the temperature at which a
gasoline forms a vapor-liquid ratio of 20 (V/L = 20). This is the temperature at which
a gasoline exists as 20 volumes of vapor in equilibrium with one volume of liquid at
atmospheric pressure. The temperature for a V/L = 20 varies with the season; the normal
range is 35°C to 60°C (95°F to 140°F). Gasolines with higher values provide greater
protection against vapor lock and hot fuel handling problems. This correlation was
developed for vehicles with suction-type fuel pumps and carburetors. Tests in later model,
fuel-injected cars with pressurized fuel systems have shown a good correlation
for hydrocarbon-only gasoline.
Driveability Index
Although each range of a distillation profile is important, the gasoline represented by an
entire profile is what the engine must distribute, vaporize, and burn. To predict a fuel’s
cold-start and warm-up driveability, a driveability index (DI) has been developed using the
temperatures for the evaporated percentages of 10 percent (T10), 50 percent (T50), and
90 percent (T90) and ethanol content:
DI°C = 1.5(T10) + 3.0(T50) + (T90) + 1.33 (ethanol volume percent)
DI°F = 1.5(T10) + 3.0(T50) + (T90) + 2.4 (ethanol volume percent)
The DI varies with gasoline grade and season. In the U.S., the normal range of DI°C is
375°C to 610°C-derived (DI°F is 850°F to 1,275°F-derived). In other parts of the world, the
range may be narrower; for example, in the Asia-Pacific region the range of DI°C is 460°C
to 580°C-derived (DI°F is 1,000°F to 1,200°F-derived). Lower values of DI generally result
in better cold-start and warm-up performance, but once good driveability is achieved, there
is no benefit to further lowering the DI.
Vapor Lock and Hot Fuel Handling Problems
Vapor lock and hot fuel handling problems
occur when excessive gasoline
vapor accumulates somewhere in the fuel
system of a vehicle and reduces or interrupts
the fuel supply to the engine. This
may take place in the fuel pump, the fuel
line, the carburetor, or the fuel injector.
When the fuel supply is reduced, the
air-fuel ratio becomes too fuel-lean (too
much air for the amount of fuel), which
may cause loss of power, surging, or backfiring.
When the fuel supply is interrupted,
the engine stops and may be difficult to
restart until the fuel system has cooled
and the vapor has recondensed. After a
hot soak (engine shutdown), it may be
difficult to start the engine if too much
vapor has formed in the fuel system.
Overheated fuel or overly volatile fuel
is the main cause of vapor lock. Fuel
temperature depends on several factors:
the ambient temperature, how hard the
vehicle is working, how well the fuel
system is isolated from the heat of the
engine, and how effectively the fuel
system is cooled.
Will oxygenated gasoline perform as well as conventional gasoline in my vehicle?
Oxygenated gasoline will perform as well as conventional gasolines in modern vehicles
with engine control systems that adjust the air-fuel ratio (A/F). Oxygenated gasoline may
cause some driveability problems in carbureted cars and fuel-injected cars without engine
control systems because the air-fuel mixture is more fuel lean. The use of oxygenated
gasoline can reduce fuel economy up to 3 percent, depending on the level of oxygenate
in the fuel.
Why did my fuel economy drop much more than 2 percent to 3 percent when I began using oxygenated RFG?
The 2 percent to 3 percent fuel economy loss for oxygenated RFG was determined by
extensive laboratory testing and has been validated by independent organizations such as
the California State Automobile Association. The fuel economy loss also is in line with
the decrease in the heating value of RFG compared to non-oxygenated conventional
gasoline. A decrease in fuel economy much greater than 2 percent to 3 percent could be
the result of a mistuned engine or of comparing fuel economy results obtained under
weather or driving conditions that differ from those encountered in testing
How can I increase the octane number of premium unleaded gasoline for
use in my 1969 high-compression-ratio engine designed to use high-test
(95 AKI) premium leaded gasoline?
Additives available in auto parts stores will increase the octane number of unleaded
premium gasoline. The products that contain high-octane aromatics with or without
MTBE do not provide much benefit because the volume being added is too small. The
products that contain a manganese antiknock additive will provide an increase in octane
number that could help solve your problem. However, the increase will probably not be
great when added to premium unleaded gasoline, as suggested on the label.
How will unleaded gasoline affect my older vehicle with an engine
designed to be operated on leaded gasoline?
Pre-1971 U.S. vehicles were designed to operate on leaded gasoline (which is banned
from sale in the U.S. and elsewhere). The original exhaust valve seats in these engines
were not hardened and not equipped with metal alloy inserts. The lead in the gasoline
not only functioned as an antiknock additive but served as a lubricant that kept the
exhaust valves from wearing away the valve seat (exhaust valve seat recession) under
certain severe operating conditions.
Driving around town or at normal highway speeds with unleaded gasoline in a pre-1971
vehicle will not result in exhaust valve seat recession. However, travel that raises the
engine’s operating temperature will. This includes heavy towing and high-speed and uphill
driving for extended periods. If a trip is going to involve one or more of these situations and
the pre-1971 vehicle hasn’t been equipped with metal alloy exhaust valve seats, consider
using a lead-substitute aftermarket additive. Consult the engine manufacturer before using
the additive. In some countries, a lead-replacement gasoline (petrol) is offered that contains
protective additives.
Will premium gasoline give better fuel economy than regular?
Will one brand of gasoline give better mileage than another?
Gasolines with higher heating values can improve fuel economy. Mileage differences may
exist, but they will be small compared to the benefits to be derived from the maintenance
and driving tips mentioned earlier.
Traditionally, premium gasoline has had a slightly higher heating value than regular, and,
thus, provided slightly better fuel economy. Its mileage difference, less than 1 percent
better, is not large enough to offset premium’s higher cost. The difference is likely to be
less or nonexistent between grades of RFG.
There can be variance in heating value between batches of gasoline from the same refinery
or between brands of gasoline from different refineries because of compositional differences.
The variance is small, and there is no practical way for the consumer to identify the gasoline
with a higher heating value.
BTW I find this subject fascinating but difficult as it was my bread and butter for so many years.
Gasoline has many specs having to do with vapor pressure or how light or heavy it is.
Three properties are used to measure gasoline volatility:vapor pressure,
distillation profile, and vapor-liquid ratio. A fourth property, driveability index, is
calculated from the distillation profile.
Vapor pressure, the pressure of a closed bomb of gasoline with a pressure gauge on the top in a 100F water bath.
There are distillation specs - the temperature at which a given % are boiled away in an atmospheric pressure distillation flask
10% distilled maximum of 158F
Important for cooler temperatures, must be low enough to help vaporize the gasoline
50% distilled minimum of 170F maximum of 250F.
This is a tricky one for super as the high octane components also happen to be the heavier ones in general. Hard to get high octane for Super and low 50% point
90% distilled maximum of 374F
This insures gasoline is not too heavy, like having too much high boiling naphtha in it.
FBP final boiling point, maximum of 437F
This one is to prevent too much heavy kerosene boiling material in gasoline that can cause dieseling. You want to maximize it to get more
yield of gasoline but not too high. It only takes a very small % of heavy stuff to raise the FBP.
T V/L-20 90F-140F
This is the temperature when the vapor to liquid ratio is 20.
This has to be a higher temperature in the summer than the winter. You wouldn't want to have mostly vapor at a low temperature in the summer. This temperature needs to be higher for the hot Southwest than cooler Midwest. This is the primary reason the gasoline you buy in Texas is different than what sells in Chicago and what you buy in winter is different than what you buy in summer.
Here is a typical distillation curve for gasoline. There is stuff that boils from less than 30F(butane) to 400F+ in it!
This is a very good writeup from Chevron about gasoline specs that should be understandable to many Corvette enthusiasts:
http://www.chevronwithtechron.com/pr...ech_review.pdf
Taken from the link:
VOLATILITY
Driveability describes how an engine starts, warms up, and runs. It is the assessment
of a vehicle’s response to the use of its accelerator relative to what a driver expects.
Driveability problems include hard starting, backfiring, rough idling, poor throttle
response, and stalling (at idle, under load, or when decelerating).
The key gasoline characteristic for good driveability is volatility – a gasoline’s tendency to
vaporize. Volatility is important because liquids and solids don’t burn; only vapors burn.
When a liquid appears to be burning, actually it is the invisible vapor above its surface that
is burning. This rule holds true in the combustion chamber of an engine; gasoline must
be vaporized before it can burn. For winter weather, gasoline blenders formulate gasoline
to vaporize easily. Gasoline that vaporizes easily allows a cold engine to start quickly and
warm up smoothly. Warm-weather gasoline is blended to vaporize less easily to prevent
engine vapor lock and other hot fuel handling problems and to control evaporative
emissions that contribute to air pollution.
It is important to note that there is no single best volatility for gasoline. Volatility must be
adjusted for the altitude and seasonal temperature of the location where the gasoline will be
used. Later, this chapter will explain how gasoline specifications address this requirement.
Three properties are used to measure gasoline volatility in the United States: vapor pressure,
distillation profile, and vapor-liquid ratio. A fourth property, driveability index, is
calculated from the distillation profile. Instead of a vapor-liquid ratio, a vapor lock index
is used outside the U.S. to control hot fuel handling problem
Distillation Profile
Gasoline is a mixture of hundreds of hydrocarbons, many of which have different boiling
points. Thus gasoline boils, or distills, over a range of temperatures, unlike a pure compound;
water, for instance, boils at a single temperature. A distillation profile, or distillation curve, is
the set of increasing temperatures at which gasoline evaporates for a fixed series of increasing
volume percentages (5 percent, 10 percent, 20 percent, 30 percent and so on) under specific
conditions (see page 48). A distillation profile is also shown for a summer reformulated gasoline (RFG) containing ethanol.
Various ranges of a distillation profile correlate with specific
aspects of gasoline performance.
Front-end volatility is adjusted to provide:
• Easy cold starting.
• Easy hot starting.
• Freedom from vapor lock or other hot fuel handling problems.
• Low evaporation and running-loss emissions.
Midrange volatility is adjusted to provide:
• Rapid warm-up and smooth running.
• Good short-trip fuel economy.
• Good power and acceleration.
• Protection against carburetor icing and hot-stalling.
Tail-end volatility is adjusted to provide:
• Good fuel economy after engine warm-up.
• Freedom from engine deposits.
• Minimal fuel dilution of crankcase oil.
Vapor-Liquid Ratio
The vapor-locking tendency of a gasoline is influenced both by the temperatures at the
front end of its distillation profile and by its vapor pressure. However, the property that
correlates best with vapor lock and other hot fuel handling problems (hard starting or
no starting after a hot soak, and poor throttle response) is the temperature at which a
gasoline forms a vapor-liquid ratio of 20 (V/L = 20). This is the temperature at which
a gasoline exists as 20 volumes of vapor in equilibrium with one volume of liquid at
atmospheric pressure. The temperature for a V/L = 20 varies with the season; the normal
range is 35°C to 60°C (95°F to 140°F). Gasolines with higher values provide greater
protection against vapor lock and hot fuel handling problems. This correlation was
developed for vehicles with suction-type fuel pumps and carburetors. Tests in later model,
fuel-injected cars with pressurized fuel systems have shown a good correlation
for hydrocarbon-only gasoline.
Driveability Index
Although each range of a distillation profile is important, the gasoline represented by an
entire profile is what the engine must distribute, vaporize, and burn. To predict a fuel’s
cold-start and warm-up driveability, a driveability index (DI) has been developed using the
temperatures for the evaporated percentages of 10 percent (T10), 50 percent (T50), and
90 percent (T90) and ethanol content:
DI°C = 1.5(T10) + 3.0(T50) + (T90) + 1.33 (ethanol volume percent)
DI°F = 1.5(T10) + 3.0(T50) + (T90) + 2.4 (ethanol volume percent)
The DI varies with gasoline grade and season. In the U.S., the normal range of DI°C is
375°C to 610°C-derived (DI°F is 850°F to 1,275°F-derived). In other parts of the world, the
range may be narrower; for example, in the Asia-Pacific region the range of DI°C is 460°C
to 580°C-derived (DI°F is 1,000°F to 1,200°F-derived). Lower values of DI generally result
in better cold-start and warm-up performance, but once good driveability is achieved, there
is no benefit to further lowering the DI.
Vapor Lock and Hot Fuel Handling Problems
Vapor lock and hot fuel handling problems
occur when excessive gasoline
vapor accumulates somewhere in the fuel
system of a vehicle and reduces or interrupts
the fuel supply to the engine. This
may take place in the fuel pump, the fuel
line, the carburetor, or the fuel injector.
When the fuel supply is reduced, the
air-fuel ratio becomes too fuel-lean (too
much air for the amount of fuel), which
may cause loss of power, surging, or backfiring.
When the fuel supply is interrupted,
the engine stops and may be difficult to
restart until the fuel system has cooled
and the vapor has recondensed. After a
hot soak (engine shutdown), it may be
difficult to start the engine if too much
vapor has formed in the fuel system.
Overheated fuel or overly volatile fuel
is the main cause of vapor lock. Fuel
temperature depends on several factors:
the ambient temperature, how hard the
vehicle is working, how well the fuel
system is isolated from the heat of the
engine, and how effectively the fuel
system is cooled.
Will oxygenated gasoline perform as well as conventional gasoline in my vehicle?
Oxygenated gasoline will perform as well as conventional gasolines in modern vehicles
with engine control systems that adjust the air-fuel ratio (A/F). Oxygenated gasoline may
cause some driveability problems in carbureted cars and fuel-injected cars without engine
control systems because the air-fuel mixture is more fuel lean. The use of oxygenated
gasoline can reduce fuel economy up to 3 percent, depending on the level of oxygenate
in the fuel.
Why did my fuel economy drop much more than 2 percent to 3 percent when I began using oxygenated RFG?
The 2 percent to 3 percent fuel economy loss for oxygenated RFG was determined by
extensive laboratory testing and has been validated by independent organizations such as
the California State Automobile Association. The fuel economy loss also is in line with
the decrease in the heating value of RFG compared to non-oxygenated conventional
gasoline. A decrease in fuel economy much greater than 2 percent to 3 percent could be
the result of a mistuned engine or of comparing fuel economy results obtained under
weather or driving conditions that differ from those encountered in testing
How can I increase the octane number of premium unleaded gasoline for
use in my 1969 high-compression-ratio engine designed to use high-test
(95 AKI) premium leaded gasoline?
Additives available in auto parts stores will increase the octane number of unleaded
premium gasoline. The products that contain high-octane aromatics with or without
MTBE do not provide much benefit because the volume being added is too small. The
products that contain a manganese antiknock additive will provide an increase in octane
number that could help solve your problem. However, the increase will probably not be
great when added to premium unleaded gasoline, as suggested on the label.
How will unleaded gasoline affect my older vehicle with an engine
designed to be operated on leaded gasoline?
Pre-1971 U.S. vehicles were designed to operate on leaded gasoline (which is banned
from sale in the U.S. and elsewhere). The original exhaust valve seats in these engines
were not hardened and not equipped with metal alloy inserts. The lead in the gasoline
not only functioned as an antiknock additive but served as a lubricant that kept the
exhaust valves from wearing away the valve seat (exhaust valve seat recession) under
certain severe operating conditions.
Driving around town or at normal highway speeds with unleaded gasoline in a pre-1971
vehicle will not result in exhaust valve seat recession. However, travel that raises the
engine’s operating temperature will. This includes heavy towing and high-speed and uphill
driving for extended periods. If a trip is going to involve one or more of these situations and
the pre-1971 vehicle hasn’t been equipped with metal alloy exhaust valve seats, consider
using a lead-substitute aftermarket additive. Consult the engine manufacturer before using
the additive. In some countries, a lead-replacement gasoline (petrol) is offered that contains
protective additives.
Will premium gasoline give better fuel economy than regular?
Will one brand of gasoline give better mileage than another?
Gasolines with higher heating values can improve fuel economy. Mileage differences may
exist, but they will be small compared to the benefits to be derived from the maintenance
and driving tips mentioned earlier.
Traditionally, premium gasoline has had a slightly higher heating value than regular, and,
thus, provided slightly better fuel economy. Its mileage difference, less than 1 percent
better, is not large enough to offset premium’s higher cost. The difference is likely to be
less or nonexistent between grades of RFG.
There can be variance in heating value between batches of gasoline from the same refinery
or between brands of gasoline from different refineries because of compositional differences.
The variance is small, and there is no practical way for the consumer to identify the gasoline
with a higher heating value.
Last edited by mrtexas; 05-22-2013 at 10:51 PM.
05-23-2013, 10:44 AM
#3
Racer
05-23-2013, 01:16 PM
#4
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 26,118
Received 1,843 Likes
on
1,398 Posts
I'll start a new thread, this once morphed from my FI questions and someone asking why I hadn't posted about gasoline specs.
BTW I find this subject fascinating but difficult as it was my bread and butter for so many years.
Gasoline has many specs having to do with vapor pressure or how light or heavy it is.
Vapor Lock and Hot Fuel Handling Problems
Vapor lock and hot fuel handling problems
occur when excessive gasoline
vapor accumulates somewhere in the fuel
system of a vehicle and reduces or interrupts
the fuel supply to the engine. This
may take place in the fuel pump, the fuel
line, the carburetor, or the fuel injector.
When the fuel supply is reduced, the
air-fuel ratio becomes too fuel-lean (too
much air for the amount of fuel), which
may cause loss of power, surging, or backfiring.
When the fuel supply is interrupted,
the engine stops and may be difficult to
restart until the fuel system has cooled
and the vapor has recondensed. After a
hot soak (engine shutdown), it may be
difficult to start the engine if too much
vapor has formed in the fuel system.
Overheated fuel or overly volatile fuel
is the main cause of vapor lock. Fuel
temperature depends on several factors:
the ambient temperature, how hard the
vehicle is working, how well the fuel
system is isolated from the heat of the
engine, and how effectively the fuel
system is cooled.
BTW I find this subject fascinating but difficult as it was my bread and butter for so many years.
Gasoline has many specs having to do with vapor pressure or how light or heavy it is.
Vapor Lock and Hot Fuel Handling Problems
Vapor lock and hot fuel handling problems
occur when excessive gasoline
vapor accumulates somewhere in the fuel
system of a vehicle and reduces or interrupts
the fuel supply to the engine. This
may take place in the fuel pump, the fuel
line, the carburetor, or the fuel injector.
When the fuel supply is reduced, the
air-fuel ratio becomes too fuel-lean (too
much air for the amount of fuel), which
may cause loss of power, surging, or backfiring.
When the fuel supply is interrupted,
the engine stops and may be difficult to
restart until the fuel system has cooled
and the vapor has recondensed. After a
hot soak (engine shutdown), it may be
difficult to start the engine if too much
vapor has formed in the fuel system.
Overheated fuel or overly volatile fuel
is the main cause of vapor lock. Fuel
temperature depends on several factors:
the ambient temperature, how hard the
vehicle is working, how well the fuel
system is isolated from the heat of the
engine, and how effectively the fuel
system is cooled.
It was I who requested you comment on gasoline specs. Nice bit of information you posted there but unfortunately for me, that info didn't answer a few questions I have and I'm sure many others have. Maybe I just don't understand enough of what you posted. I have no technical background on the subject.
Me being a simple person have three simple questions:
a) Since alcohol was introduced into gasoline in this country, many owners of non-pressurized fuel systems have complained of "hot" driveability problems. Hard starting, stumbling, percolation, etc. What effect or how much of the burden of these claims can be placed directly to the use of alcohol or is it a combination of alcohol and other additives, i.e., if there was no alcohol mandate, and it wasn't blended into the gasoline, would the reported problems go away or????????????
b) The majority of driveability complaints I see posted seem to be coming mostly from Calif., Texas and other Gulf coast states (I don't recall any Canadian complaints). Not saying others don't have problems just reporting what I see most of. Where I live in Indiana, it gets as hot here as it does any place in the country for the most part, just doesn't stay hot for as long so why have different blends that may cause driveability problems and/or is the blending mix really the difference in one part of the country to the other?
c) Is there a practical thing a car owner can do for fuel besides use racing gasoline or maybe avgas?
05-23-2013, 05:03 PM
#5
Drifting
Thread Starter
It was I who requested you comment on gasoline specs. Nice bit of information you posted there but unfortunately for me, that info didn't answer a few questions I have and I'm sure many others have. Maybe I just don't understand enough of what you posted. I have no technical background on the subject.
a) Since alcohol was introduced into gasoline in this country, many owners of non-pressurized fuel systems have complained of "hot" driveability problems. Hard starting, stumbling, percolation, etc. What effect or how much of the burden of these claims can be placed directly to the use of alcohol or is it a combination of alcohol and other additives, i.e., if there was no alcohol mandate, and it wasn't blended into the gasoline, would the reported problems go away or????????????
b) The majority of driveability complaints I see posted seem to be coming mostly from Calif., Texas and other Gulf coast states (I don't recall any Canadian complaints). Not saying others don't have problems just reporting what I see most of. Where I live in Indiana, it gets as hot here as it does any place in the country for the most part, just doesn't stay hot for as long so why have different blends that may cause driveability problems and/or is the blending mix really the difference in one part of the country to the other?
a) Since alcohol was introduced into gasoline in this country, many owners of non-pressurized fuel systems have complained of "hot" driveability problems. Hard starting, stumbling, percolation, etc. What effect or how much of the burden of these claims can be placed directly to the use of alcohol or is it a combination of alcohol and other additives, i.e., if there was no alcohol mandate, and it wasn't blended into the gasoline, would the reported problems go away or????????????
b) The majority of driveability complaints I see posted seem to be coming mostly from Calif., Texas and other Gulf coast states (I don't recall any Canadian complaints). Not saying others don't have problems just reporting what I see most of. Where I live in Indiana, it gets as hot here as it does any place in the country for the most part, just doesn't stay hot for as long so why have different blends that may cause driveability problems and/or is the blending mix really the difference in one part of the country to the other?
a) Looks like the corn gas would contribute to vapor lock. Look at the distillation curve for corn gas vs conventional. At 40% distilled the corn gas has a boiling point of 150F vs 200F for conventional. Seems to me lots of stuff under the hood could get close to 150F and cause some partial boiling vs not so much for the 200F of conventional gas.
b) Gasoline specs are regional. The gasoline in Texas in summer is not a light as the gasoline in Indiana no matter how hot is gets in Indiana. You didn't expect the bureaucrats at the EPA to be logical in how they regulate did you?
c) NO
Last edited by mrtexas; 05-23-2013 at 05:17 PM.
05-23-2013, 05:31 PM
#6
Drifting
Thread Starter
There used to be cracked gasoline components that were yellow but now that the sulfur level has been dictated to be 15ppm, the yellow stuff has been treated to remove the sulfur and isn't yellow anymore as a result.
However, Florida has it's own peculiar gasoline specs...
05-23-2013, 05:58 PM
#7
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
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05-23-2013, 06:03 PM
#8
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 26,118
Received 1,843 Likes
on
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I think I have read the gasoline vapor pressure spec in the summer is the same in Texas as Indiana. Could be wrong. In any case, what is the result of the gasoline being blended differently between Texas and Indiana? Otherwise, what does not as "light" mean for driveability?
05-23-2013, 06:47 PM
#9
Race Director
Member Since: Apr 1999
Location: Beverly Hills/Pine Ridge Florida
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I don't know about a yellow dye.
There used to be cracked gasoline components that were yellow but now that the sulfur level has been dictated to be 15ppm, the yellow stuff has been treated to remove the sulfur and isn't yellow anymore as a result.
However, Florida has it's own peculiar gasoline specs...
There used to be cracked gasoline components that were yellow but now that the sulfur level has been dictated to be 15ppm, the yellow stuff has been treated to remove the sulfur and isn't yellow anymore as a result.
However, Florida has it's own peculiar gasoline specs...
MikeM and I have gone round and round about this on other forums.
My 63 ran fine on "Maryland gas". When I moved to Florida, my car runs like crap..........
Chuck
05-23-2013, 07:22 PM
#11
Melting Slicks
Thanks for the great article Phil. I take it the distillation curve is manipulated in the refining process rather than with additive packages and that is why there is no practical way to make the gasoline less susceptible to vapor locking without adjusting the refining level. In other words, the bureaucrats would just as soon that carbs and low pressure fuel injection systems become extinct. Fortunately up here in the Northwest it hasn't been a critical problem yet but with the continual tweaking of the fuel regulations we are losing ground every year.
05-23-2013, 08:20 PM
#12
AMOCO white gas was sold in the 30s and 40s and maybe 50s that had no lead how come cars that ran it back then did not have valve seat problems ??? it was the only gasoline that was recommended be used in gasoline powered "blow torches" by plumbers and tinners. the reason i know this is because i was around then and i remember my dad using AMOCO white gas
05-24-2013, 06:52 AM
#13
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AMOCO white gas was sold in the 30s and 40s and maybe 50s that had no lead how come cars that ran it back then did not have valve seat problems ??? it was the only gasoline that was recommended be used in gasoline powered "blow torches" by plumbers and tinners. the reason i know this is because i was around then and i remember my dad using AMOCO white gas
I remember as a kid, I used to hike up to the Gulf station with my one gallon metal can in hand and get a gallon of white gas for $.17. My Dad also used the white gas in his blow torch and camp stove in the '40's. I know you can remember further back than that but I can't as I wasn't here.
Last edited by MikeM; 05-24-2013 at 06:56 AM.
05-24-2013, 08:12 AM
#14
Safety Car
It was I who requested you comment on gasoline specs. Nice bit of information you posted there but unfortunately for me, that info didn't answer a few questions I have and I'm sure many others have. Maybe I just don't understand enough of what you posted. I have no technical background on the subject.
Me being a simple person have three simple questions:
a) Since alcohol was introduced into gasoline in this country, many owners of non-pressurized fuel systems have complained of "hot" driveability problems. Hard starting, stumbling, percolation, etc. What effect or how much of the burden of these claims can be placed directly to the use of alcohol or is it a combination of alcohol and other additives, i.e., if there was no alcohol mandate, and it wasn't blended into the gasoline, would the reported problems go away or????????????
b) The majority of driveability complaints I see posted seem to be coming mostly from Calif., Texas and other Gulf coast states (I don't recall any Canadian complaints). Not saying others don't have problems just reporting what I see most of. Where I live in Indiana, it gets as hot here as it does any place in the country for the most part, just doesn't stay hot for as long so why have different blends that may cause driveability problems and/or is the blending mix really the difference in one part of the country to the other?
c) Is there a practical thing a car owner can do for fuel besides use racing gasoline or maybe avgas?
Me being a simple person have three simple questions:
a) Since alcohol was introduced into gasoline in this country, many owners of non-pressurized fuel systems have complained of "hot" driveability problems. Hard starting, stumbling, percolation, etc. What effect or how much of the burden of these claims can be placed directly to the use of alcohol or is it a combination of alcohol and other additives, i.e., if there was no alcohol mandate, and it wasn't blended into the gasoline, would the reported problems go away or????????????
b) The majority of driveability complaints I see posted seem to be coming mostly from Calif., Texas and other Gulf coast states (I don't recall any Canadian complaints). Not saying others don't have problems just reporting what I see most of. Where I live in Indiana, it gets as hot here as it does any place in the country for the most part, just doesn't stay hot for as long so why have different blends that may cause driveability problems and/or is the blending mix really the difference in one part of the country to the other?
c) Is there a practical thing a car owner can do for fuel besides use racing gasoline or maybe avgas?
1.) Boil your gasoline before dispensing it into your Corvette's fuel tank. This will vaporize the lighter compounds, like ethanol, leaving behind the heavier compounds. CAUTION: Your cold weather drivability may be affected.
2.) Get rid of the Rochester fuel unit and install a good carburetor, like a QF.
3.) Chrome plate everything on your engine and fuel supply system which raises its emissivity, thus reflecting radiated heat rather than absorbing it.
Last edited by 65tripleblack; 05-24-2013 at 08:26 AM.
05-24-2013, 08:24 AM
#15
Safety Car
AMOCO white gas was sold in the 30s and 40s and maybe 50s that had no lead how come cars that ran it back then did not have valve seat problems ??? it was the only gasoline that was recommended be used in gasoline powered "blow torches" by plumbers and tinners. the reason i know this is because i was around then and i remember my dad using AMOCO white gas
Remember blue Sunoco too, back when Sunoco was good gas. Now its non Top Tier crap gas that sells cheap, at least in my region.
Last edited by 65tripleblack; 05-24-2013 at 08:28 AM.
05-24-2013, 09:04 AM
#16
Race Director
My 61s' FI is long gone.
For those that still have FI,
Is there any reason a small fan would not fix any perc problems? Has anyone tried one?
Been using a fan and duct to cool air since last Aug, carb is 100% happy. even with FL gas. Fan costs $3-6, so big spenders should find something more costly
For those that still have FI,
Is there any reason a small fan would not fix any perc problems? Has anyone tried one?
Been using a fan and duct to cool air since last Aug, carb is 100% happy. even with FL gas. Fan costs $3-6, so big spenders should find something more costly
05-24-2013, 09:54 AM
#17
Race Director
Thanks for the great article Phil. I take it the distillation curve is manipulated in the refining process rather than with additive packages and that is why there is no practical way to make the gasoline less susceptible to vapor locking without adjusting the refining level. In other words, the bureaucrats would just as soon that carbs and low pressure fuel injection systems become extinct. Fortunately up here in the Northwest it hasn't been a critical problem yet but with the continual tweaking of the fuel regulations we are losing ground every year.
It's probably more complicated than this, but MRTEXAS can help to clarify.
FWIW, I worked at the small chemical plant in Beaumont in the early 1970's that made the TEL that was supplied to MRTEXAS and the Mobil Refinery. We were located just across the street. I remember it well.
Larry
Last edited by Powershift; 05-24-2013 at 10:00 AM.
05-24-2013, 10:30 AM
#18
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Some people also called it "Coleman Fuel". I remember that it was clear well into the seventies. Haven't paid attention since, nor have I looked.
Remember blue Sunoco too, back when Sunoco was good gas. Now its non Top Tier crap gas that sells cheap, at least in my region.
Remember blue Sunoco too, back when Sunoco was good gas. Now its non Top Tier crap gas that sells cheap, at least in my region.
05-24-2013, 10:37 AM
#19
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a) Looks like the corn gas would contribute to vapor lock. Look at the distillation curve for corn gas vs conventional. At 40% distilled the corn gas has a boiling point of 150F vs 200F for conventional. Seems to me lots of stuff under the hood could get close to 150F and cause some partial boiling vs not so much for the 200F of conventional gas.
Since alcohol was introduced into gasoline in this country, many owners of non-pressurized fuel systems have complained of "hot" driveability problems. Hard starting, stumbling, percolation, etc. What effect or how much of the burden of these claims can be placed directly to the use of alcohol or is it a combination of alcohol and other additives, i.e., if there was no alcohol mandate, and it wasn't blended into the gasoline, would the reported problems go away or????????????
Last edited by MikeM; 05-24-2013 at 10:48 AM.
05-24-2013, 11:04 AM
#20
Safety Car
I don't think this answers my question? If no alcohol was present in the gasoline, something would have to be in it's place to meet EPA specs. Whatever would be in it's place, would it cause any more/less driveabily problems than the the alcohol? Here it is again.
Since alcohol was introduced into gasoline in this country, many owners of non-pressurized fuel systems have complained of "hot" driveability problems. Hard starting, stumbling, percolation, etc. What effect or how much of the burden of these claims can be placed directly to the use of alcohol or is it a combination of alcohol and other additives, i.e., if there was no alcohol mandate, and it wasn't blended into the gasoline, would the reported problems go away or????????????
Since alcohol was introduced into gasoline in this country, many owners of non-pressurized fuel systems have complained of "hot" driveability problems. Hard starting, stumbling, percolation, etc. What effect or how much of the burden of these claims can be placed directly to the use of alcohol or is it a combination of alcohol and other additives, i.e., if there was no alcohol mandate, and it wasn't blended into the gasoline, would the reported problems go away or????????????
Here are some alternative oxygenating compounds:
http://en.wikipedia.org/wiki/Oxygenate
Why are they not used (with the exception of the evil, doomsday compound known as MTBE) is probably price related. I would think that they would all have higher BP's than CH3CH2OH.
Last edited by 65tripleblack; 05-24-2013 at 11:10 AM.