Cough, Splutter - How Much MPG?! 😱
- Thread starter GCorvette
- Start date
GCorvette
CCCUK Member
teamzr1
Supporting vendor
Answers can only come as I mentioned using a tool to measure what the exhaust makeup is as to the AFR (air fuel ratio)
If not possible, could weld an oxygen sensor bung into exhaust pipe close to engine and get a wideband O2 sensor with a meter
OR
at the least, read the spark plugs as they are now or
install new plugs at correct gap, do a testrun and pull plugs and read them new would give gut feeling if AFR is too rich
If not possible, could weld an oxygen sensor bung into exhaust pipe close to engine and get a wideband O2 sensor with a meter
OR
at the least, read the spark plugs as they are now or
install new plugs at correct gap, do a testrun and pull plugs and read them new would give gut feeling if AFR is too rich
teamzr1
Supporting vendor
For the techie thinkers as to AFR and also smog output
Concentration of combustion products in the vehicle's exhaust, most of which pollute the air, give important diagnostic clues to the vehicle's engine efficiency.
The component gases which contribute the most to air pollution are hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx).
Three of the five gases measured at the tailpipe are regulated pollutants - HC, CO and NOx.
The remaining gases, oxygen (O2) And carbon dioxide (CO2), while non-regulated, play a significant role as diagnostic aids. Omitec's four gas analyzer measures HC, CO, CO2 and O2 concentrations.
The five gas analyzer adds the measurement of NOx as well.
Following are a few general facts and tips to keep in mind when using a gas analyzer:
1) High Carbon Monoxide (CO) readings usually indicate a fuel mixture richer than ideal (rich mixture - air fuel ratio below 14.7).
In general CO is an indicator of combustion efficiency.
The amount of CO in a vehicle’s exhaust is directly related to its air-fuel ratio.
High CO levels result from inadequate O2 supply needed for complete combustion.
This is caused by a too rich mixture - too much fuel or not enough air (AFR readings below the optimal 14.7, Lambda below 1.0). Circumstances that can lead to high CO emissions:
* Low idle speed
* Improper float settings in carbureted vehicles
* Dirty or restricted air filters
*Excessively dirty or contaminated oil
*Saturated charcoal canister
*Non-functioning PCV valve system
*Improper operation of the fuel delivery system
*Improperly functioning thermactor system
*Catalytic converter intervention and CO concentrations
High CO readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an CO reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance.
Low range CO readings are possible, and not uncommon, from a malfunctioning engine equipped with a properly functioning catalytic converter.
In such circumstances, truly elevated pre-catalytic converter CO levels will be masked by the catalytic converter and the potential for an CO problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings.
NOTE: Great caution must always be exercised when dealing with CO. Concentrations of less than one percent can be lethal. Testing should always be done in a well ventilated area.
2) Normal CO readings.
If the combustion process is succeeding at or near the stoichiometric point (AFR equals 14.7, Lambda equals 1.0), CO levels during an idle test will typically measure less than 2%.
3) Low CO readings.
There is, effectively, no reading for CO that can be characterized as too low or "below optimal". CO concentrations will appear "normal" even in a lean burning environment, where AFR is above 14.7 (Lambda is above 1.0).
4) High hydrocarbon (HC) readings usually indicate excessive unburned fuel caused by a lack of ignition or by incomplete combustion. Concentrations are measured in parts per million (PPM). Common causes include a faulty ignition system, vacuum leaks, and fuel mixture problems. Circumstances that can lead to a high HC emissions are:
* Incomplete combustion due to fouled spark plugs.
* Improper timing or dwell
* Damaged ignition wires
* Poor compression
* Vacuum leak
* Ineffective or faulty air management system (ECM control of air/fuel ratios)
* Catalytic converter intervention and HC concentrations
High HC readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an HC reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance.
HC readings at or near "normal" are possible, and not uncommon. From a malfunctioning engine equipped with a properly functioning catalytic converter.
In such circumstances, truly elevated pre-catalytic converter HC levels will be masked by the catalytic converter and the potential for an HC problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings.
5) Oxygen (O2) readings.
Oxygen, measured as a percentage of the exhaust volume, reflects the amount of gas remaining in the exhaust sample after the combustion process has taken place.
Ambient O2 readings should be about 20%, reflecting the natural amount oxygen found in the air. The ideal range for vehicles without a secondary air injection system is less than 1.5%.
If there is an air injection system, O2 levels will typically fall n the range of 3% to 4%. Pinching off the air hose of a vehicle equipped with air injection should produce O2 levels similar to those found for vehicles without air injection.
6) High oxygen (O2) readings indicate too lean an air-fuel ratio (AFR higher than 14.7, Lambda greater than 1.0). Circumstances that can lead to high O2 emissions are:
* Lean fuel mixture (AFR above 14.7)
* Vacuum leaks
* Ignition related problems causing misfires.
7) Low O2 indicates a rich fuel mixture (AFR below 14.7, Lambda below 1.0).
8) High carbon dioxide (CO2) readings indicate a nearly ideal air-fuel ratio and efficient combustion
9) Low carbon dioxide (CO2) readings indicate a fuel mixture either too rich or too lean, exhaust system leaks, or sample dilution.
10) Oxides of Nitrogen readings.
Oxides of nitrogen (NOx), including nitric oxide (NO) and nitrous oxide (NO2), are formed if the combustion temperatures within the combustion chamber exceed some 2,500 degrees F.
This can occur when the engine is under load. When excessive temperature conditions exist, the greatest amount of NOx is typically produced at the stoichiometric point (AFR 14.7 or Lambda of 1.0) as the engine is under a light load.
If the combustion process within an engine is burning fuel at or near stoichiometric point, NOx levels on acceleration will typically read significantly higher than those measured at cruise and during deceleration. Typically, the NOx readings at idle will be 0 PPM.
11) High NOx Readings. Circumstances that can lead to abnormally high NOx emissions are:
* Malfunctioning EGR valve
* Lean fuel mixture (AFR above 14.7, Lambda above 1.0)
* Improper spark advance
* Thermostatic air heater stuck in the heated air position
* Missing or damaged cold air duct
* Combustion chamber deposits
* Malfunctioning catalytic converter
* Catalytic converter intervention and NOx concentrations
High NOx readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an NOx reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance.
NOx readings at or near "normal" are possible, and not uncommon. From a malfunctioning engine equipped with a properly functioning catalytic converter.
In such circumstances, truly elevated pre-catalytic converter NOx levels will be masked by the catalytic converter and the potential for an NOx problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings.
12) Low NOx readings.
There is, effectively, no reading for NOx that can be characterized as too low or below optimal. NOx is naturally 0 ppm at idle. NOx concentrations may appear normal even in a rich burning environment where the AFR is well below 14.7 (Lambda below 1.0).
Facts to Remember
The byproducts of combustion are dependent on the air-fuel ratio.
13) O2 combines with HC to form CO2 and H2O.
14) O2 combines with CO to form CO2.
15) CO is an indicator of air-fuel mixture richness.
16) HC is an indicator of fuel mixture leanness (or richness) and misfires.
17) CO and O2 are equal at the stoichiometric air-fuel ratio.
18) O2 and CO2 are indicators of exhaust system integrity, sample hose and probe integrity, or both.
19) CO2 is an indicator of combustion efficiency that peaks at or near the stoichiometric air-fuel ratios, and decreases with lean or rich air-fuel ratio.
20) Air injection systems dilute the exhaust sample with O2.
21) O2 is essential for proper operation of the catalytic converter.
Its concentrations are essentially unchanged by the catalytic converter, providing a "window" through the converter to the engine. O2 levels are higher on vehicles with properly operating air injection systems.
22) If CO goes up, O2 goes down (inversely related)
23) If O2 goes up, CO goes down (inversely related)
24) With the air injection system disabled and the CO above 1%, the catalytic converter is oxygen-starved.
Without O2, it does not fire, allowing exhaust concentrations to be more like readings taken ahead of the converter.
If readings are within the manufacturer’s or local/state/federal allowable limits, it can generally be assumed that the fuel, ignition, and emission control systems are functioning properly.
If they exceed the limits, repairs or adjustments are probably called for.
Concentration of combustion products in the vehicle's exhaust, most of which pollute the air, give important diagnostic clues to the vehicle's engine efficiency.
The component gases which contribute the most to air pollution are hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx).
Three of the five gases measured at the tailpipe are regulated pollutants - HC, CO and NOx.
The remaining gases, oxygen (O2) And carbon dioxide (CO2), while non-regulated, play a significant role as diagnostic aids. Omitec's four gas analyzer measures HC, CO, CO2 and O2 concentrations.
The five gas analyzer adds the measurement of NOx as well.
Following are a few general facts and tips to keep in mind when using a gas analyzer:
1) High Carbon Monoxide (CO) readings usually indicate a fuel mixture richer than ideal (rich mixture - air fuel ratio below 14.7).
In general CO is an indicator of combustion efficiency.
The amount of CO in a vehicle’s exhaust is directly related to its air-fuel ratio.
High CO levels result from inadequate O2 supply needed for complete combustion.
This is caused by a too rich mixture - too much fuel or not enough air (AFR readings below the optimal 14.7, Lambda below 1.0). Circumstances that can lead to high CO emissions:
* Low idle speed
* Improper float settings in carbureted vehicles
* Dirty or restricted air filters
*Excessively dirty or contaminated oil
*Saturated charcoal canister
*Non-functioning PCV valve system
*Improper operation of the fuel delivery system
*Improperly functioning thermactor system
*Catalytic converter intervention and CO concentrations
High CO readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an CO reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance.
Low range CO readings are possible, and not uncommon, from a malfunctioning engine equipped with a properly functioning catalytic converter.
In such circumstances, truly elevated pre-catalytic converter CO levels will be masked by the catalytic converter and the potential for an CO problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings.
NOTE: Great caution must always be exercised when dealing with CO. Concentrations of less than one percent can be lethal. Testing should always be done in a well ventilated area.
2) Normal CO readings.
If the combustion process is succeeding at or near the stoichiometric point (AFR equals 14.7, Lambda equals 1.0), CO levels during an idle test will typically measure less than 2%.
3) Low CO readings.
There is, effectively, no reading for CO that can be characterized as too low or "below optimal". CO concentrations will appear "normal" even in a lean burning environment, where AFR is above 14.7 (Lambda is above 1.0).
4) High hydrocarbon (HC) readings usually indicate excessive unburned fuel caused by a lack of ignition or by incomplete combustion. Concentrations are measured in parts per million (PPM). Common causes include a faulty ignition system, vacuum leaks, and fuel mixture problems. Circumstances that can lead to a high HC emissions are:
* Incomplete combustion due to fouled spark plugs.
* Improper timing or dwell
* Damaged ignition wires
* Poor compression
* Vacuum leak
* Ineffective or faulty air management system (ECM control of air/fuel ratios)
* Catalytic converter intervention and HC concentrations
High HC readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an HC reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance.
HC readings at or near "normal" are possible, and not uncommon. From a malfunctioning engine equipped with a properly functioning catalytic converter.
In such circumstances, truly elevated pre-catalytic converter HC levels will be masked by the catalytic converter and the potential for an HC problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings.
5) Oxygen (O2) readings.
Oxygen, measured as a percentage of the exhaust volume, reflects the amount of gas remaining in the exhaust sample after the combustion process has taken place.
Ambient O2 readings should be about 20%, reflecting the natural amount oxygen found in the air. The ideal range for vehicles without a secondary air injection system is less than 1.5%.
If there is an air injection system, O2 levels will typically fall n the range of 3% to 4%. Pinching off the air hose of a vehicle equipped with air injection should produce O2 levels similar to those found for vehicles without air injection.
6) High oxygen (O2) readings indicate too lean an air-fuel ratio (AFR higher than 14.7, Lambda greater than 1.0). Circumstances that can lead to high O2 emissions are:
* Lean fuel mixture (AFR above 14.7)
* Vacuum leaks
* Ignition related problems causing misfires.
7) Low O2 indicates a rich fuel mixture (AFR below 14.7, Lambda below 1.0).
8) High carbon dioxide (CO2) readings indicate a nearly ideal air-fuel ratio and efficient combustion
9) Low carbon dioxide (CO2) readings indicate a fuel mixture either too rich or too lean, exhaust system leaks, or sample dilution.
10) Oxides of Nitrogen readings.
Oxides of nitrogen (NOx), including nitric oxide (NO) and nitrous oxide (NO2), are formed if the combustion temperatures within the combustion chamber exceed some 2,500 degrees F.
This can occur when the engine is under load. When excessive temperature conditions exist, the greatest amount of NOx is typically produced at the stoichiometric point (AFR 14.7 or Lambda of 1.0) as the engine is under a light load.
If the combustion process within an engine is burning fuel at or near stoichiometric point, NOx levels on acceleration will typically read significantly higher than those measured at cruise and during deceleration. Typically, the NOx readings at idle will be 0 PPM.
11) High NOx Readings. Circumstances that can lead to abnormally high NOx emissions are:
* Malfunctioning EGR valve
* Lean fuel mixture (AFR above 14.7, Lambda above 1.0)
* Improper spark advance
* Thermostatic air heater stuck in the heated air position
* Missing or damaged cold air duct
* Combustion chamber deposits
* Malfunctioning catalytic converter
* Catalytic converter intervention and NOx concentrations
High NOx readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an NOx reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance.
NOx readings at or near "normal" are possible, and not uncommon. From a malfunctioning engine equipped with a properly functioning catalytic converter.
In such circumstances, truly elevated pre-catalytic converter NOx levels will be masked by the catalytic converter and the potential for an NOx problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings.
12) Low NOx readings.
There is, effectively, no reading for NOx that can be characterized as too low or below optimal. NOx is naturally 0 ppm at idle. NOx concentrations may appear normal even in a rich burning environment where the AFR is well below 14.7 (Lambda below 1.0).
Facts to Remember
The byproducts of combustion are dependent on the air-fuel ratio.
13) O2 combines with HC to form CO2 and H2O.
14) O2 combines with CO to form CO2.
15) CO is an indicator of air-fuel mixture richness.
16) HC is an indicator of fuel mixture leanness (or richness) and misfires.
17) CO and O2 are equal at the stoichiometric air-fuel ratio.
18) O2 and CO2 are indicators of exhaust system integrity, sample hose and probe integrity, or both.
19) CO2 is an indicator of combustion efficiency that peaks at or near the stoichiometric air-fuel ratios, and decreases with lean or rich air-fuel ratio.
20) Air injection systems dilute the exhaust sample with O2.
21) O2 is essential for proper operation of the catalytic converter.
Its concentrations are essentially unchanged by the catalytic converter, providing a "window" through the converter to the engine. O2 levels are higher on vehicles with properly operating air injection systems.
22) If CO goes up, O2 goes down (inversely related)
23) If O2 goes up, CO goes down (inversely related)
24) With the air injection system disabled and the CO above 1%, the catalytic converter is oxygen-starved.
Without O2, it does not fire, allowing exhaust concentrations to be more like readings taken ahead of the converter.
If readings are within the manufacturer’s or local/state/federal allowable limits, it can generally be assumed that the fuel, ignition, and emission control systems are functioning properly.
If they exceed the limits, repairs or adjustments are probably called for.
teamzr1
Supporting vendor
Where most in the UK and their C3s as not liking the electronics of modern Corvettes
Look at the much higher HP & Tq but also how fuel mileage really went way up
While its thrilling brothers the Z06 and ZR1 have hogged most of the Corvette glory over the past few years, one could argue that the plain, old base-model Corvette has the greatest range of talents. It's blisteringly quick (0 to 60 mph in about 4.5 seconds), mild-mannered around town (quiet and reliably untemperamental in traffic), rides pretty well (stiff, not painful), and starts at a modest (for a 436-hp sports car) $48,565.
But the most amazing talent of them all is its astonishing fuel economy.
According to the EPA, the base Corvette is good for 16 MPG in the city and 26 MPG on the highway. But with a feathery touch on the throttle and conservative speeds, we figured we could stretch the fuel economy on a Corvette beyond 30 mpg. Easy.
So we borrowed a new base model Corvette coupe equipped with the standard six-speed manual transmission from Chevrolet, picked a road unlikely to be crammed with traffic, and set out to eke every last mpg out of this world-class sports car.
Yeah, it's sort of like judging a thoroughbred racehorse on its plow-pulling prowess. But tomorrow's sports cars will need to be as efficient as they are quick. Turns out, our Chevy might be ahead of the curve.
The Test
We chose a straightforward trip from a Shell station in Santa Barbara, Calif., north along U.S. Route 101 to the city of Santa Maria about 70 miles away, and back again to the same gas station.
We ran the Vette on the freeway at 55 mph (10 mph below the posted speed limit) using cruise control with the Corvette's windows up, the air conditioning off and vents open. The late-May weather was a cloudless 72 degrees with no appreciable wind.
With the 18-gallon fuel tank filled with 91 octane premium, we entered the flow of traffic on the 101 using as light a touch on the throttle as we dared, and shifting at a mere 2200 rpm. When the car hit 55, we shifted into sixth and engaged the cruise control.
No frustration matches spending a couple of hours on a wide-open freeway in a new Corvette, traveling at a crawl, while being passed by semis, ancient Buicks and several aggressively driven vehicles that should have met their fate in the boneyard a decade ago.
The Results
At 55 mph, the Corvette's tachometer registered a perfectly poised 1300 rpm. That's barely off-idle, but the engine never bogged down or hiccupped.
Even when climbing the rather long grade near Nojoqui Falls, the 6.2-liter LS3 V8 produced plenty of torque to maintain the 3217-pound fiberglass sports car's modest velocity. The trip was completely undramatic, uneventful, and totally boring.
According to the Corvette's onboard trip computer, we averaged 30.5 MPG with an average speed of 52.8 mph over the 142.8 miles.
But it only took 4.358 gallons to refill the Vette's tank (using the same pump we filled up on), and works to just a bare fraction shy of 32.8 MPG.
That's 32.8 MPG from a sports car that will top out at over 180 mph.
That is a parsimonious performance that likely can't be duplicated by any other car with anywhere near the performance.
There's no big secret as to how the Corvette can pull this trick off.
The great trick here is sixth gear in the transmission, which is an aggressive 0.50:1 overdrive that, when combined with the 3.42:1 final drive ratio, allows the engine to turn slowly at modest cruising speeds.
More subtly, the great well of low-end torque produced by the large-displacement V8 engine means that the engine doesn't have to spin to high revs to ensure there are enough lb-ft on tap.
For instance, it's unlikely the high-revving Ferrari F430 (EPA rated at 11 mpg in the city and 16 on the highway) could make the trip without at least one downshift. Throw in the Corvette's relatively low-rolling-resistance Goodyear Eagle F1 run-flat tires and some smart aerodynamic tweaks, and the good economy makes sense.
The Lessons
Anyone who buys a Corvette has already decided to trade off ultimate fuel economy in favor of high performance and visual aggression. But this quick, back-of-the-envelope test bears real-world lessons.
First, driving conservatively will pay off in better mileage, no matter what car you're piloting. Zipping through holes in traffic and ripping along at high velocities have their obvious attractions, but they will literally cost you money at the pump.
Driven hard and recklessly, even a Prius will suck down dead dinosaurs at a furious rate.
Driven carefully and with precision, you will find that a Hummer H2 can return something approaching reasonable mileage.
Furthermore, the big advantage the Corvette had during this exercise was a clear and open road. Starting and stopping kills fuel economy, and road design and traffic management may well be the public policy areas where some tweaks would pay off in reduced fuel cost.
Designating more streets as one-way thoroughfares, having fewer traffic lights and enforcing rules that emphasize efficient traffic flow should be considered by every governing body with road responsibility.
Finally, the Corvette really is what General Motors does best.
No matter what the financial condition of the company, this is an amazing machine that delivers spectacular performance without throwing aside all considerations of economy.
Rerunning this test at 65 mph, we're sure we'd get something close to 30 MPG from the Corvette.
Look at the much higher HP & Tq but also how fuel mileage really went way up
While its thrilling brothers the Z06 and ZR1 have hogged most of the Corvette glory over the past few years, one could argue that the plain, old base-model Corvette has the greatest range of talents. It's blisteringly quick (0 to 60 mph in about 4.5 seconds), mild-mannered around town (quiet and reliably untemperamental in traffic), rides pretty well (stiff, not painful), and starts at a modest (for a 436-hp sports car) $48,565.
But the most amazing talent of them all is its astonishing fuel economy.
According to the EPA, the base Corvette is good for 16 MPG in the city and 26 MPG on the highway. But with a feathery touch on the throttle and conservative speeds, we figured we could stretch the fuel economy on a Corvette beyond 30 mpg. Easy.
So we borrowed a new base model Corvette coupe equipped with the standard six-speed manual transmission from Chevrolet, picked a road unlikely to be crammed with traffic, and set out to eke every last mpg out of this world-class sports car.
Yeah, it's sort of like judging a thoroughbred racehorse on its plow-pulling prowess. But tomorrow's sports cars will need to be as efficient as they are quick. Turns out, our Chevy might be ahead of the curve.
The Test
We chose a straightforward trip from a Shell station in Santa Barbara, Calif., north along U.S. Route 101 to the city of Santa Maria about 70 miles away, and back again to the same gas station.
We ran the Vette on the freeway at 55 mph (10 mph below the posted speed limit) using cruise control with the Corvette's windows up, the air conditioning off and vents open. The late-May weather was a cloudless 72 degrees with no appreciable wind.
With the 18-gallon fuel tank filled with 91 octane premium, we entered the flow of traffic on the 101 using as light a touch on the throttle as we dared, and shifting at a mere 2200 rpm. When the car hit 55, we shifted into sixth and engaged the cruise control.
No frustration matches spending a couple of hours on a wide-open freeway in a new Corvette, traveling at a crawl, while being passed by semis, ancient Buicks and several aggressively driven vehicles that should have met their fate in the boneyard a decade ago.
The Results
At 55 mph, the Corvette's tachometer registered a perfectly poised 1300 rpm. That's barely off-idle, but the engine never bogged down or hiccupped.
Even when climbing the rather long grade near Nojoqui Falls, the 6.2-liter LS3 V8 produced plenty of torque to maintain the 3217-pound fiberglass sports car's modest velocity. The trip was completely undramatic, uneventful, and totally boring.
According to the Corvette's onboard trip computer, we averaged 30.5 MPG with an average speed of 52.8 mph over the 142.8 miles.
But it only took 4.358 gallons to refill the Vette's tank (using the same pump we filled up on), and works to just a bare fraction shy of 32.8 MPG.
That's 32.8 MPG from a sports car that will top out at over 180 mph.
That is a parsimonious performance that likely can't be duplicated by any other car with anywhere near the performance.
There's no big secret as to how the Corvette can pull this trick off.
The great trick here is sixth gear in the transmission, which is an aggressive 0.50:1 overdrive that, when combined with the 3.42:1 final drive ratio, allows the engine to turn slowly at modest cruising speeds.
More subtly, the great well of low-end torque produced by the large-displacement V8 engine means that the engine doesn't have to spin to high revs to ensure there are enough lb-ft on tap.
For instance, it's unlikely the high-revving Ferrari F430 (EPA rated at 11 mpg in the city and 16 on the highway) could make the trip without at least one downshift. Throw in the Corvette's relatively low-rolling-resistance Goodyear Eagle F1 run-flat tires and some smart aerodynamic tweaks, and the good economy makes sense.
The Lessons
Anyone who buys a Corvette has already decided to trade off ultimate fuel economy in favor of high performance and visual aggression. But this quick, back-of-the-envelope test bears real-world lessons.
First, driving conservatively will pay off in better mileage, no matter what car you're piloting. Zipping through holes in traffic and ripping along at high velocities have their obvious attractions, but they will literally cost you money at the pump.
Driven hard and recklessly, even a Prius will suck down dead dinosaurs at a furious rate.
Driven carefully and with precision, you will find that a Hummer H2 can return something approaching reasonable mileage.
Furthermore, the big advantage the Corvette had during this exercise was a clear and open road. Starting and stopping kills fuel economy, and road design and traffic management may well be the public policy areas where some tweaks would pay off in reduced fuel cost.
Designating more streets as one-way thoroughfares, having fewer traffic lights and enforcing rules that emphasize efficient traffic flow should be considered by every governing body with road responsibility.
Finally, the Corvette really is what General Motors does best.
No matter what the financial condition of the company, this is an amazing machine that delivers spectacular performance without throwing aside all considerations of economy.
Rerunning this test at 65 mph, we're sure we'd get something close to 30 MPG from the Corvette.
teamzr1
Supporting vendor
Hi Roscobbc
Please explain this, is it due to using liters, rather than gallons ?
Thanks
Nassau65
CCCUK Member
A UK gallon is a fifth larger than a US gallon. So official US figures are 4 fifths different to UK figures. So, 12 mpg on a US gallon equals 15 mpg to a UK gallon.
teamzr1
Supporting vendor
OK Thanks for explaining
So 1 UK gallon is 1.2 American gallon, which is about 16% difference
or is 1 liter = 0.264 of 1 US gallon ?
Does that mean if using the UK liter that the MPG rating of a Corvette is lower,
Also does that mean you have to pay a gas guzzler tax there, where not in the USA ?
CaptainK
CCCUK Member
I just use the Google conversion to convert between US gallons and UK gallons (1 US gallon = 3.78 litres (or spelt liters I guess as we're talking US), 1 UK gallon = 4.54 litres) .
But to the thread, the one and only time I bothered recording my MPG was when I first got the car and drove it home over long distance - it was about 18 MPG (UK gallons).
But to the thread, the one and only time I bothered recording my MPG was when I first got the car and drove it home over long distance - it was about 18 MPG (UK gallons).
Stingray
CCCUK Member
Yes, the easiest approximation is that 1 lire = 1 quart US
and 4 litres = 1 gallon US .
The difference is only about 5%
None of which explains why Coke is sold in 2 litre bottles in the US....
or why beer is sold in 330 ml bottles and 440 ml cans in UK.
Roscobbc
Moderator
Going back from metric to imperial right now would mean millions of people still continuing to use metric mentally and never really fully taking on 'Imperial'...........
Much like us oldet farts who grew up with Imperial measurement, always visualising yards, feet and inches (not forgetting thou's) and doubling-up and also using metric too. Fuel measurements in litres was a governmental con to effectively hide the horror of seeing what petrol costs are in 'real' and effectively visualisable gallons.
Much like us oldet farts who grew up with Imperial measurement, always visualising yards, feet and inches (not forgetting thou's) and doubling-up and also using metric too. Fuel measurements in litres was a governmental con to effectively hide the horror of seeing what petrol costs are in 'real' and effectively visualisable gallons.
teamzr1
Supporting vendor
At least we should be spared going back to all the old Imperial measurements now that Boris is resigning.
Boris Johnson finally announced his resignation, now can we Americans convince you to take joey biden in his place ?
antijam
CCCUK Member
So we've got rid of a strong Prime Minister, who knew what he was doing and was patently dishonest. I'm not sure a weak President, who has no idea what he's doing but is probably honest is a better bet.....Boris Johnson finally announced his resignation, now can we Americans convince you to take joey biden in his place ?
James Vette
CCCUK Member
Mine doesn't get good MPH either.
CaptainK
CCCUK Member
Mine gets 70 MPH on the dually or motorway.... any more than that would be illegal officer.
Forrest Gump
CCCUK regional rep
I’ve never previously felt the urge to check my mpg, but though the run to the Nationals today would be a chance to verify the bad news.
Massive surprise …..I used 9 gallons (rounded up) for 187 miles = 20.75 mpg
This is from a 383, Holley d/p and cammed motor!
It was a fairly steady run but there were still numerous “uneconomical“ moments. Well happy with over 20mpg.
Massive surprise …..I used 9 gallons (rounded up) for 187 miles = 20.75 mpg
This is from a 383, Holley d/p and cammed motor!
It was a fairly steady run but there were still numerous “uneconomical“ moments. Well happy with over 20mpg.