SickBeast's Fuel Economy Guide

[DrPizza]

OP, why do you think coasting in neutral is illegal in many states? Do you think it's because there's a conspiracy and the states want you to purchase a minuscule amount more fuel (in your estimation; I believe the posters here are correct that it would use more fuel to coast in neutral.) Maybe many jurisdictions made it illegal because it's dangerous enough to legislate against? So again, you're suggesting that people put themselves more at risk for absolutely no real benefit and only a minimal perceived benefit.

Also, for the most part, gas is gas. The vast majority of stations in this area are consignment stations - the gas is provided by the same company to most of them. And, that company drives their big truck from station to station, filling up the underground tanks - the same truck goes from brand to brand. There's no difference other than the label on the sign in front of the station.

Re: #3 air filter - change it according to the car manufacturer guidelines. And the frequency of changes depends on the area you drive in. I drive on dirt roads fairly often, so I'm on the low end for changing the filter. Still, unless you have a carburetor, the air filter is not going to affect your gas mileage.

Here's my tip: I get more mileage in a Dodge Grand Caravan when I have two longer kayaks on the roof upside down. It must effect the aerodynamics positively enough to compensate for the additional 80 pounds. It's something I wouldn't have expected.

 

[BassBomb]

Originally posted by: DrPizza
OP, why do you think coasting in neutral is illegal in many states? Do you think it's because there's a conspiracy and the states want you to purchase a minuscule amount more fuel (in your estimation; I believe the posters here are correct that it would use more fuel to coast in neutral.) Maybe many jurisdictions made it illegal because it's dangerous enough to legislate against? So again, you're suggesting that people put themselves more at risk for absolutely no real benefit and only a minimal perceived benefit.

Also, for the most part, gas is gas. The vast majority of stations in this area are consignment stations - the gas is provided by the same company to most of them. And, that company drives their big truck from station to station, filling up the underground tanks - the same truck goes from brand to brand. There's no difference other than the label on the sign in front of the station.

Re: #3 air filter - change it according to the car manufacturer guidelines. And the frequency of changes depends on the area you drive in. I drive on dirt roads fairly often, so I'm on the low end for changing the filter. Still, unless you have a carburetor, the air filter is not going to affect your gas mileage.

Here's my tip: I get more mileage in a Dodge Grand Caravan when I have two longer kayaks on the roof upside down. It must effect the aerodynamics positively enough to compensate for the additional 80 pounds. It's something I wouldn't have expected.

The reason it is illegal in jurisdictions is because you are taking a major element of control away from the driver.

 

[fleabag]

Originally posted by: Ronstang
Please do not tell people to over inflate their tires. It is a very bad idea. The heat generated driving increases the pressure inside and can cause them to explode. Not all tires are created equal and although some may be able to handle the extra pressure some definitely will not. My dumbass friend learned this the hard way. When the tire exploded it blew the fender apart. He was damn lucky he wasn't killed.

First of all, you're wrong. Why? Here is why:
1. Because "overinflated" (this is relative) tires actually run cooler, not hotter.
2. Tires are capable of handling well over 200psi
3. Stunt drivers when they want to drive on two wheels inflate their tires to 100psi without issue
4. Raising a tire to the PSI of its sidewall rating most certainly will NOT cause it to burst because you were driving it on the highway
5. Most blowouts on the highway are caused by UNDERINFLATED tires, not overinflated.
6. Tire pressures are relative, some manufacturers ask to run low pressure because their vehicles aren't smooth riders and don't want their passengers to have to experience that, even if it means risking their lives (Ford exploders rolling over).

Obviously there are some negative side effects to driving with your tires at sidewall PSI but since there are so many negatives and positives to driving at that psi, I'm not going to get into it as I really just wanted to address your misinformation.

 

[JulesMaximus]

Originally posted by: fleabag

Originally posted by: Ronstang
Please do not tell people to over inflate their tires. It is a very bad idea. The heat generated driving increases the pressure inside and can cause them to explode. Not all tires are created equal and although some may be able to handle the extra pressure some definitely will not. My dumbass friend learned this the hard way. When the tire exploded it blew the fender apart. He was damn lucky he wasn't killed.

First of all, you're wrong. Why? Here is why:
1. Because "overinflated" (this is relative) tires actually run cooler, not hotter.
2. Tires are capable of handling well over 200psi
3. Stunt drivers when they want to drive on two wheels inflate their tires to 100psi without issue
4. Raising a tire to the PSI of its sidewall rating most certainly will NOT cause it to burst because you were driving it on the highway
5. Most blowouts on the highway are caused by UNDERINFLATED tires, not overinflated.
6. Tire pressures are relative, some manufacturers ask to run low pressure because their vehicles aren't smooth riders and don't want their passengers to have to experience that, even if it means risking their lives (Ford exploders rolling over).

Obviously there are some negative side effects to driving with your tires at sidewall PSI but since there are so many negatives and positives to driving at that psi, I'm not going to get into it as I really just wanted to address your misinformation.

Overinflated tires will wear the center of the tread more quickly than the inner and outer edges and reduce your tires contact patch. Under inflated tires will wear the edges sooner. If you want even treadwear then you should inflate them to the car manufacturers specifications.

Also, always check and adjust your tire pressures when the tire is cold.

You should never inflate your tires to the maximum pressure printed on the sidewall of the tire. That is just too high to get good treadwear and maintain a good contact patch with the road.

 

[fleabag]

Originally posted by: JulesMaximus

Originally posted by: fleabag

Originally posted by: Ronstang
Please do not tell people to over inflate their tires. It is a very bad idea. The heat generated driving increases the pressure inside and can cause them to explode. Not all tires are created equal and although some may be able to handle the extra pressure some definitely will not. My dumbass friend learned this the hard way. When the tire exploded it blew the fender apart. He was damn lucky he wasn't killed.

First of all, you're wrong. Why? Here is why:
1. Because "overinflated" (this is relative) tires actually run cooler, not hotter.
2. Tires are capable of handling well over 200psi
3. Stunt drivers when they want to drive on two wheels inflate their tires to 100psi without issue
4. Raising a tire to the PSI of its sidewall rating most certainly will NOT cause it to burst because you were driving it on the highway
5. Most blowouts on the highway are caused by UNDERINFLATED tires, not overinflated.
6. Tire pressures are relative, some manufacturers ask to run low pressure because their vehicles aren't smooth riders and don't want their passengers to have to experience that, even if it means risking their lives (Ford exploders rolling over).

Obviously there are some negative side effects to driving with your tires at sidewall PSI but since there are so many negatives and positives to driving at that psi, I'm not going to get into it as I really just wanted to address your misinformation.

Overinflated tires will wear the center of the tread more quickly than the inner and outer edges and reduce your tires contact patch. Under inflated tires will wear the edges sooner. If you want even treadwear then you should inflate them to the car manufacturers specifications.

Also, always check and adjust your tire pressures when the tire is cold.

You should never inflate your tires to the maximum pressure printed on the sidewall of the tire. That is just too high to get good treadwear and maintain a good contact patch with the road.

What ever the sidewall says. Most will suggest inflating based upon what the manufacturer says but I and most others have found no issues with running tires at max cold side wall PSI. Following max side wall pressure is better because tires are
far less likely to hydroplane, overheat, and suffer uneven tread wear then when they're inflated to the manufacturer's recommendation. Inflating to max sidewall pressure is NOT the same as over-inflating.

While most people follow the manufacturer's suggested PSI, what they don't know is that a tire's max load rating, speed rating, temperature rating and just about every other rating is not valid unless you inflate a tire to its cold PSI rating. The manuals for most performance/luxury cars, mention that when doing high speed/performance driving to add around 5psi to their listed PSI. For two different cars but with the same tires, it's common to see two very different PSI ratings.

It just goes to show how subjective the PSI ratings are for tires, that following the tire's sidewall pressure and not the car manufacturer's recommendation is not going to result in a blow out by any means. This isn't to say that the car manufacturer came up with PSI recommendations out of thin air. The manufacturer's recommendations are based upon knowing the vehicle's load capacity, its purpose (luxury, sports, family wagon or pickup truck), top speed, and a few others.

Basically if you're willing to put far larger rims with small sidewalls on a car that didn't come with them, then inflating to the max sidewall pressure is no different. Another way to think of it is like this: Your car came with 44psi tires with medium sized sidewall and 17" rims, door jam suggests 36psi in front 34 in rear, and now your rims are stolen. All you have is enough money for some cheap 15" steel rims with large sidewalls. These tires have the same ratings as your old tires yet the sidewall indicates a max cold pressure of 35psi.

Are you still going to follow the manufacturer's recommendation of 36 psi in the front and 34 psi in the rear?

It makes absolutely no sense to continue to follow the car manufacturer's suggested PSI rating on a car that was made 15 years ago, yet somehow everyone continues to suggest to do so. The same goes for those who continue to abide by the door jam PSI yet put a completely different tire and rim combination.

Tires made today are far stronger than those made 10 years ago and a world apart from those made in the 70s/early 80s. The people who've been "in the automotive field for 30 years" may have a lot experience but are also still following guidelines for tires that are far different than those made today. Rules change but stubborn habits do not and following the car manufacturer's recommendation for the sake of it is a stubborn habit that needs to go the way side.

Pros to inflating to sidewall:
Better handling-
Improved Steering Response
More Road Feedback
Much Better Fuel economy-
Much Longer Coasting
Less friction so less throttle which means less fuel
Speed, Load, Temp, etc. Ratings are now Valid
Which means the tire is less likely to blow out
Tires are less likely to hydroplane
Sometimes braking distance is decreased
Better grip in Snow/Mud if the soft part is Shallow
In the event you hit the curb going fast, you're far less likely to damage your rims than had they been inflated to manufacturer's recommendations.


Cons to inflating to sidewall:
More Road noise
Can feel potholes and bumps far more
Suspension is theoretically more susceptible to being damaged due to rough road conditions though it does depend on the vehicle; For example if the car came with (designed for) using large rims and tires with small sidewalls then inflating to sidewall PSI will have much less of an impact than a car with large sidewalls
Worse traction in Snow/Mud if its deep (deep enough to have the tires sink in, therefore letting the chassis lay on the ground.
Sometimes the braking distance is increased


So it's your decision as to whether or not you want to inflate to your tire's Max Cold Sidewall pressure. Just remember that if you inflate to the sidewall pressure when it's cold and during the day it gets hot, exceeding the Max Cold tire pressure, you should NOT deflate the tire as this is part of its design hence the name "Max COLD". Not all sidewalls on tires are imprinted with Max Cold but instead with something along the lines "max pressure", these are one in the same.

Here is a factoid in case you're worried about your tire bursting from inflating it slightly above, near or slightly below the Max Cold tire pressure imprinted on your sidewall:

Auto manufacturers who ship their vehicles overseas routinely OVER-INFLATE their tires up to 80PSI (on a 44psi tire for example) in order to prevent the car from sitting on its rims by the time it arrives at its destination.
Source(s):
http://www.tirerack.com/tires/tiretech/t?
The Internet
Experience

 

[JulesMaximus]

Originally posted by: fleabag

Originally posted by: JulesMaximus

Originally posted by: fleabag

Originally posted by: Ronstang
Please do not tell people to over inflate their tires. It is a very bad idea. The heat generated driving increases the pressure inside and can cause them to explode. Not all tires are created equal and although some may be able to handle the extra pressure some definitely will not. My dumbass friend learned this the hard way. When the tire exploded it blew the fender apart. He was damn lucky he wasn't killed.

First of all, you're wrong. Why? Here is why:
1. Because "overinflated" (this is relative) tires actually run cooler, not hotter.
2. Tires are capable of handling well over 200psi
3. Stunt drivers when they want to drive on two wheels inflate their tires to 100psi without issue
4. Raising a tire to the PSI of its sidewall rating most certainly will NOT cause it to burst because you were driving it on the highway
5. Most blowouts on the highway are caused by UNDERINFLATED tires, not overinflated.
6. Tire pressures are relative, some manufacturers ask to run low pressure because their vehicles aren't smooth riders and don't want their passengers to have to experience that, even if it means risking their lives (Ford exploders rolling over).

Obviously there are some negative side effects to driving with your tires at sidewall PSI but since there are so many negatives and positives to driving at that psi, I'm not going to get into it as I really just wanted to address your misinformation.

Overinflated tires will wear the center of the tread more quickly than the inner and outer edges and reduce your tires contact patch. Under inflated tires will wear the edges sooner. If you want even treadwear then you should inflate them to the car manufacturers specifications.

Also, always check and adjust your tire pressures when the tire is cold.

You should never inflate your tires to the maximum pressure printed on the sidewall of the tire. That is just too high to get good treadwear and maintain a good contact patch with the road.

What ever the sidewall says. Most will suggest inflating based upon what the manufacturer says but I and most others have found no issues with running tires at max cold side wall PSI. Following max side wall pressure is better because tires are
far less likely to hydroplane, overheat, and suffer uneven tread wear then when they're inflated to the manufacturer's recommendation. Inflating to max sidewall pressure is NOT the same as over-inflating.

While most people follow the manufacturer's suggested PSI, what they don't know is that a tire's max load rating, speed rating, temperature rating and just about every other rating is not valid unless you inflate a tire to its cold PSI rating. The manuals for most performance/luxury cars, mention that when doing high speed/performance driving to add around 5psi to their listed PSI. For two different cars but with the same tires, it's common to see two very different PSI ratings.

It just goes to show how subjective the PSI ratings are for tires, that following the tire's sidewall pressure and not the car manufacturer's recommendation is not going to result in a blow out by any means. This isn't to say that the car manufacturer came up with PSI recommendations out of thin air. The manufacturer's recommendations are based upon knowing the vehicle's load capacity, its purpose (luxury, sports, family wagon or pickup truck), top speed, and a few others.

Basically if you're willing to put far larger rims with small sidewalls on a car that didn't come with them, then inflating to the max sidewall pressure is no different. Another way to think of it is like this: Your car came with 44psi tires with medium sized sidewall and 17" rims, door jam suggests 36psi in front 34 in rear, and now your rims are stolen. All you have is enough money for some cheap 15" steel rims with large sidewalls. These tires have the same ratings as your old tires yet the sidewall indicates a max cold pressure of 35psi.

Are you still going to follow the manufacturer's recommendation of 36 psi in the front and 34 psi in the rear?

It makes absolutely no sense to continue to follow the car manufacturer's suggested PSI rating on a car that was made 15 years ago, yet somehow everyone continues to suggest to do so. The same goes for those who continue to abide by the door jam PSI yet put a completely different tire and rim combination.

Tires made today are far stronger than those made 10 years ago and a world apart from those made in the 70s/early 80s. The people who've been "in the automotive field for 30 years" may have a lot experience but are also still following guidelines for tires that are far different than those made today. Rules change but stubborn habits do not and following the car manufacturer's recommendation for the sake of it is a stubborn habit that needs to go the way side.

Pros to inflating to sidewall:
Better handling-
Improved Steering Response
More Road Feedback
Much Better Fuel economy-
Much Longer Coasting
Less friction so less throttle which means less fuel
Speed, Load, Temp, etc. Ratings are now Valid
Which means the tire is less likely to blow out
Tires are less likely to hydroplane
Sometimes braking distance is decreased
Better grip in Snow/Mud if the soft part is Shallow
In the event you hit the curb going fast, you're far less likely to damage your rims than had they been inflated to manufacturer's recommendations.


Cons to inflating to sidewall:
More Road noise
Can feel potholes and bumps far more
Suspension is theoretically more susceptible to being damaged due to rough road conditions though it does depend on the vehicle; For example if the car came with (designed for) using large rims and tires with small sidewalls then inflating to sidewall PSI will have much less of an impact than a car with large sidewalls
Worse traction in Snow/Mud if its deep (deep enough to have the tires sink in, therefore letting the chassis lay on the ground.
Sometimes the braking distance is increased


So it's your decision as to whether or not you want to inflate to your tire's Max Cold Sidewall pressure. Just remember that if you inflate to the sidewall pressure when it's cold and during the day it gets hot, exceeding the Max Cold tire pressure, you should NOT deflate the tire as this is part of its design hence the name "Max COLD". Not all sidewalls on tires are imprinted with Max Cold but instead with something along the lines "max pressure", these are one in the same.

Here is a factoid in case you're worried about your tire bursting from inflating it slightly above, near or slightly below the Max Cold tire pressure imprinted on your sidewall:

Auto manufacturers who ship their vehicles overseas routinely OVER-INFLATE their tires up to 80PSI (on a 44psi tire for example) in order to prevent the car from sitting on its rims by the time it arrives at its destination.
Source(s):
http://www.tirerack.com/tires/tiretech/t?
The Internet
Experience

Why the hell would I put 15" wheels on a car that originally came with 17s? I don't think 15" wheels would clear the brakes on my car. That's the dumbest thing I've ever read.

Also, what does shipping a vehicle overseas have to do with anything?

I've put 80,000 miles on my car with two different brands of tires and I always keep them inflated to 36psi. Tire wear has always been even and handling and braking are excellent.

 

[DrPizza]

Originally posted by: BassBomb

Originally posted by: DrPizza
OP, why do you think coasting in neutral is illegal in many states? Do you think it's because there's a conspiracy and the states want you to purchase a minuscule amount more fuel (in your estimation; I believe the posters here are correct that it would use more fuel to coast in neutral.) Maybe many jurisdictions made it illegal because it's dangerous enough to legislate against? So again, you're suggesting that people put themselves more at risk for absolutely no real benefit and only a minimal perceived benefit.

Also, for the most part, gas is gas. The vast majority of stations in this area are consignment stations - the gas is provided by the same company to most of them. And, that company drives their big truck from station to station, filling up the underground tanks - the same truck goes from brand to brand. There's no difference other than the label on the sign in front of the station.

Re: #3 air filter - change it according to the car manufacturer guidelines. And the frequency of changes depends on the area you drive in. I drive on dirt roads fairly often, so I'm on the low end for changing the filter. Still, unless you have a carburetor, the air filter is not going to affect your gas mileage.

Here's my tip: I get more mileage in a Dodge Grand Caravan when I have two longer kayaks on the roof upside down. It must effect the aerodynamics positively enough to compensate for the additional 80 pounds. It's something I wouldn't have expected.

The reason it is illegal in jurisdictions is because you are taking a major element of control away from the driver.

(well, duhh!)

 

[BoberFett]

Wow, 10 is a horrible idea. Not only do you lose control of the vehicle, but accelerating 20 mph repeatedly will use more fuel than just maintaining speed.

 

[LTC8K6]

Auto manufacturers who ship their vehicles overseas routinely OVER-INFLATE their tires up to 80PSI (on a 44psi tire for example) in order to prevent the car from sitting on its rims by the time it arrives at its destination.

Why not just use nitrogen? My tires came filled with nitrogen when I bought the car and the pressure never drops. Almost a year later and they haven't lost any pressure.

Why take the time to pump them way up?

 

[jhu]

Originally posted by: BoberFett
Wow, 10 is a horrible idea. Not only do you lose control of the vehicle, but accelerating 20 mph repeatedly will use more fuel than just maintaining speed.

Don't knock what you haven't tried. The reason pulse and glide works is because it keeps the engine in it's most fuel efficient state. When pulsing, the engine is at the lowest (kg of gasoline)/(hp produced). When gliding, the engine is idling so not much fuel is being used (the other option is to turn off the engine, but you have to know what you're getting into if you do that). The net result is less fuel used vs. steady state speed.

For example, I have an MkV Jetta with the 2.5L gas engine. I can easily get 45 mpg on the highway with pulse and glide. At steady state speed, at the same average speed as pulse and glide, I really can't do better than about 35 mpg.

 

[fleabag]

Originally posted by: JulesMaximus

Originally posted by: fleabag

Originally posted by: JulesMaximus

Originally posted by: fleabag

Originally posted by: Ronstang
Please do not tell people to over inflate their tires. It is a very bad idea. The heat generated driving increases the pressure inside and can cause them to explode. Not all tires are created equal and although some may be able to handle the extra pressure some definitely will not. My dumbass friend learned this the hard way. When the tire exploded it blew the fender apart. He was damn lucky he wasn't killed.

First of all, you're wrong. Why? Here is why:
1. Because "overinflated" (this is relative) tires actually run cooler, not hotter.
2. Tires are capable of handling well over 200psi
3. Stunt drivers when they want to drive on two wheels inflate their tires to 100psi without issue
4. Raising a tire to the PSI of its sidewall rating most certainly will NOT cause it to burst because you were driving it on the highway
5. Most blowouts on the highway are caused by UNDERINFLATED tires, not overinflated.
6. Tire pressures are relative, some manufacturers ask to run low pressure because their vehicles aren't smooth riders and don't want their passengers to have to experience that, even if it means risking their lives (Ford exploders rolling over).

Obviously there are some negative side effects to driving with your tires at sidewall PSI but since there are so many negatives and positives to driving at that psi, I'm not going to get into it as I really just wanted to address your misinformation.

Overinflated tires will wear the center of the tread more quickly than the inner and outer edges and reduce your tires contact patch. Under inflated tires will wear the edges sooner. If you want even treadwear then you should inflate them to the car manufacturers specifications.

Also, always check and adjust your tire pressures when the tire is cold.

You should never inflate your tires to the maximum pressure printed on the sidewall of the tire. That is just too high to get good treadwear and maintain a good contact patch with the road.

What ever the sidewall says. Most will suggest inflating based upon what the manufacturer says but I and most others have found no issues with running tires at max cold side wall PSI. Following max side wall pressure is better because tires are
far less likely to hydroplane, overheat, and suffer uneven tread wear then when they're inflated to the manufacturer's recommendation. Inflating to max sidewall pressure is NOT the same as over-inflating.

While most people follow the manufacturer's suggested PSI, what they don't know is that a tire's max load rating, speed rating, temperature rating and just about every other rating is not valid unless you inflate a tire to its cold PSI rating. The manuals for most performance/luxury cars, mention that when doing high speed/performance driving to add around 5psi to their listed PSI. For two different cars but with the same tires, it's common to see two very different PSI ratings.

It just goes to show how subjective the PSI ratings are for tires, that following the tire's sidewall pressure and not the car manufacturer's recommendation is not going to result in a blow out by any means. This isn't to say that the car manufacturer came up with PSI recommendations out of thin air. The manufacturer's recommendations are based upon knowing the vehicle's load capacity, its purpose (luxury, sports, family wagon or pickup truck), top speed, and a few others.

Basically if you're willing to put far larger rims with small sidewalls on a car that didn't come with them, then inflating to the max sidewall pressure is no different. Another way to think of it is like this: Your car came with 44psi tires with medium sized sidewall and 17" rims, door jam suggests 36psi in front 34 in rear, and now your rims are stolen. All you have is enough money for some cheap 15" steel rims with large sidewalls. These tires have the same ratings as your old tires yet the sidewall indicates a max cold pressure of 35psi.

Are you still going to follow the manufacturer's recommendation of 36 psi in the front and 34 psi in the rear?

It makes absolutely no sense to continue to follow the car manufacturer's suggested PSI rating on a car that was made 15 years ago, yet somehow everyone continues to suggest to do so. The same goes for those who continue to abide by the door jam PSI yet put a completely different tire and rim combination.

Tires made today are far stronger than those made 10 years ago and a world apart from those made in the 70s/early 80s. The people who've been "in the automotive field for 30 years" may have a lot experience but are also still following guidelines for tires that are far different than those made today. Rules change but stubborn habits do not and following the car manufacturer's recommendation for the sake of it is a stubborn habit that needs to go the way side.

Pros to inflating to sidewall:
Better handling-
Improved Steering Response
More Road Feedback
Much Better Fuel economy-
Much Longer Coasting
Less friction so less throttle which means less fuel
Speed, Load, Temp, etc. Ratings are now Valid
Which means the tire is less likely to blow out
Tires are less likely to hydroplane
Sometimes braking distance is decreased
Better grip in Snow/Mud if the soft part is Shallow
In the event you hit the curb going fast, you're far less likely to damage your rims than had they been inflated to manufacturer's recommendations.


Cons to inflating to sidewall:
More Road noise
Can feel potholes and bumps far more
Suspension is theoretically more susceptible to being damaged due to rough road conditions though it does depend on the vehicle; For example if the car came with (designed for) using large rims and tires with small sidewalls then inflating to sidewall PSI will have much less of an impact than a car with large sidewalls
Worse traction in Snow/Mud if its deep (deep enough to have the tires sink in, therefore letting the chassis lay on the ground.
Sometimes the braking distance is increased


So it's your decision as to whether or not you want to inflate to your tire's Max Cold Sidewall pressure. Just remember that if you inflate to the sidewall pressure when it's cold and during the day it gets hot, exceeding the Max Cold tire pressure, you should NOT deflate the tire as this is part of its design hence the name "Max COLD". Not all sidewalls on tires are imprinted with Max Cold but instead with something along the lines "max pressure", these are one in the same.

Here is a factoid in case you're worried about your tire bursting from inflating it slightly above, near or slightly below the Max Cold tire pressure imprinted on your sidewall:

Auto manufacturers who ship their vehicles overseas routinely OVER-INFLATE their tires up to 80PSI (on a 44psi tire for example) in order to prevent the car from sitting on its rims by the time it arrives at its destination.
Source(s):
http://www.tirerack.com/tires/tiretech/t?
The Internet
Experience

Why the hell would I put 15" wheels on a car that originally came with 17s? I don't think 15" wheels would clear the brakes on my car. That's the dumbest thing I've ever read.

Also, what does shipping a vehicle overseas have to do with anything?

I've put 80,000 miles on my car with two different brands of tires and I always keep them inflated to 36psi. Tire wear has always been even and handling and braking are excellent.

That's great that your tires wear evenly but that isn't the case for everyone. I see many many vehicles that have their tires at door jam inflation and still see uneven wear, indicating that it's underinflated. On the Volvo S60, I keep the tires at 55psi cold even though the tires are rated 51psi cold and I can't tell you how amazed I am to see the tires wear so perfectly even. As for the rims, it was just an example and not all cars with large rims have equally sized brakes..

Originally posted by: BoberFett
Wow, 10 is a horrible idea. Not only do you lose control of the vehicle, but accelerating 20 mph repeatedly will use more fuel than just maintaining speed.

Actually you're incorrect. Go visit some hypermiling websites and you'll quickly find out that pulse and glide are indeed the way to improve mileage, though it is cumbersome and could prematurely wear out your clutch and transmission.

 

[JulesMaximus]

Originally posted by: fleabag
That's great that your tires wear evenly but that isn't the case for everyone. I see many many vehicles that have their tires at door jam inflation and still see uneven wear, indicating that it's underinflated. On the Volvo S60, I keep the tires at 55psi cold even though the tires are rated 51psi cold and I can't tell you how amazed I am to see the tires wear so perfectly even. As for the rims, it was just an example and not all cars with large rims have equally sized brakes..

That is way too high. I seriously doubt that you're getting any benefit at all by running that much pressure in your tires. You are probably getting less grip in fact because your contact patch is smaller than tires running lower pressure. 5-6psi over I can see but 20psi over? That's waaaay too much.

 

[Mide]

I don't know about #10. I pulse drive but I don't really know if it will really benefit much over that of keeping your speed constant with your foot on the gas.

 

[BoberFett]

Originally posted by: jhu

Originally posted by: BoberFett
Wow, 10 is a horrible idea. Not only do you lose control of the vehicle, but accelerating 20 mph repeatedly will use more fuel than just maintaining speed.

Don't knock what you haven't tried. The reason pulse and glide works is because it keeps the engine in it's most fuel efficient state. When pulsing, the engine is at the lowest (kg of gasoline)/(hp produced). When gliding, the engine is idling so not much fuel is being used (the other option is to turn off the engine, but you have to know what you're getting into if you do that). The net result is less fuel used vs. steady state speed.

For example, I have an MkV Jetta with the 2.5L gas engine. I can easily get 45 mpg on the highway with pulse and glide. At steady state speed, at the same average speed as pulse and glide, I really can't do better than about 35 mpg.

I'll believe that you saw what you want to see. I'd like to see it scientifically proven however. How did you measure 45 MPG?

The engine will use the least amount of fuel when it's running at it's lowest RPMs. It all depends on how your vehicle is geared and what speed you're attempting to maintain at. Running in your final gear at the lowest speed possible without the vehicle shifting back a gear should give you your best MPG. If your vehicle is running 55MPH at 1000 RPMs, then going between 45 and 65, and the possible shifting back to a lower gear, cranking up your RPMs to accelerate, shouldn't give you better mileage than just maintaining 55.

 

[IcePickFreak]

First, accelerating as slow as possible is not going to net you better mpg. Engine efficiency isn't linear, ie running the engine at 1500rpm vs 3000rpm isn't going to cut gas consumption in half. If your accelerating like grandma from every stop the engine isn't running as efficient since your nowhere near acceptable power output. Lugging the engine isn't doing anything good for efficiency. And no, I'm not saying to floor it to get better mileage.

Also, when cruising generally the best mpg on an automatic will occur right when the torque converter locks up. But again lugging the engine won't help out efficiency, so if your in a hilly area a low rpm isn't necessarily the best thing.

 

[jhu]

Originally posted by: BoberFett

I'll believe that you saw what you want to see. I'd like to see it scientifically proven however. How did you measure 45 MPG?

The engine will use the least amount of fuel when it's running at it's lowest RPMs. It all depends on how your vehicle is geared and what speed you're attempting to maintain at. Running in your final gear at the lowest speed possible without the vehicle shifting back a gear should give you your best MPG. If your vehicle is running 55MPH at 1000 RPMs, then going between 45 and 65, and the possible shifting back to a lower gear, cranking up your RPMs to accelerate, shouldn't give you better mileage than just maintaining 55.

I have a Scangauge II. Also, I drove from San Diego to Sacramento, filled up when I got to Sacramento, and got 46.4 MPG (EPA on an MkV Jetta is 29 MPG highway for my year). There's no way I can get that kind of gas mileage at steady state speed. You should read up on brake specific fuel consumption to better understand why pulse and glide works*. That article really shows how much energy is lost due to pumping losses at partial throttle. I can understand your skepticism since I was pretty skeptical when I read about it last year too. But the results speak for themselves.

For comparison, here's my tracked gas mileage. compared with most other people driving a 2.5L.

*Pulse and glide works much better on cars with throttles. Diesel engines don't have a throttle (at least last time I checked), so steady state speed works better in that case.

 

[PlasmaBomb]

Originally posted by: SickBeast

Originally posted by: PlasmaBomb

12. Use neutral as much as possible. Coast to stop signs. Coast down hills. Again, be careful, this may not be legal in your area.

This is wrong... I concur with PhokingGuy, idling in neutral increases the fuel consumption.

Do not coast down hills in neutral! It's dangerous and may very well be illegal.

Using engine braking to coast to a stop is fine, since the car should cut the fuel to the engine.

First of all, you get the equivalent of 100+mpg when you're coasting in neutral.

Second, what I do is to coast in neutral if I want a long "glide". If I need to slow down/stop, then I leave it in gear to use engine brakes.

You are advising people to do something that is illegal in several states.

California -
21710. The driver of a motor vehicle when traveling on down grade
upon any highway shall not coast with the gears of such vehicle in
neutral.

In Great Britain, coasting in neutral or with your foot on the clutch, is illegal. If prosecuted, the driver can face a fine and points on their licence.

It is dangerous and regarded as being "Not in full control of the motor vehicle".

Originally posted by: JulesMaximus
No, you shouldn't. Modern fuel injected cars shut off the injectors completely when coasting in gear as the wheels are basically driving the engine at that point. Put it in neutral and the engine has to use fuel to keep running.

This.

100 mpg is great but when the fuel injectors are cut you get infinite mpg* (zero fuel used/distance covered). People have posted the data on the forums before.

engine brakes

:roll:

It is engine braking, or if you prefer compression braking... the engine doesn't have brakes.

If people want something to read on fuel economy try this -

AA Guide - Drive Smart

Coasting - rolling downhill or approaching a junction with the car out of gear - is inadvisable because the driver doesn't have full control of the vehicle, though it used to be quite a common practice to save fuel.

* You lose the ability to suddenly accelerate out of tricky situations.
* You lose engine braking which takes some of the load off the brakes on down hill stretches and helps to avoid brake fade - overheated brakes require harder pedal pressures to stop the vehicle.

These days, coasting is still inadvisable and changes in vehicle fuel systems mean it won't save you fuel either.

Old car with carburettor - take your foot off the accelerator pedal with the car in gear and fuel is still drawn through into the engine. Fuel savings could be made by coasting out of gear.

Modern car with electronic engine management - fuel and ignition systems are effectively combined and controlled by one Electronic Control Unit (ECU). Take your foot off the accelerator and the ECU cuts the fuel supply to the injectors anyway so there's nothing to be gained by coasting.

Modern diesel engines - these also have the ability to shut off the fuel when you take your foot off the accelerator.

*There will be times when coasting gets you further using less fuel overall, due to picking up speed going down hill vs. using no fuel and then going back to cruising mpg sooner...

Edit: Fixed quotes...

 

[Knavish]

Pulse and glide is a real MPG technique. I heard about a group testing for maximum MPG in some special prototype car at a race track. They would accelerate at full throttle to a high speed (determined by aerodynamics / engine power), shut off the engine, let it roll to a stop, and then repeat. If you're really serious about your mileage, YOU WOULD BE DOING THIS TOO!

Seriously, pulse and glide is making your highway driving more like city driving with regards to engine/transmission wear and tear. You're saving a few bucks on gas just to have to repair your engine sooner. Perhaps you'll sell your car before that point, though. I think people who hypermile are similar to people who will play an arcade game over and over just to get a higher score -- it's just a game where they want to score the most points.

 

[PlasmaBomb]

Originally posted by: fleabag
Source(s):
http://www.tirerack.com/tires/tiretech/t?
The Internet
Experience

Link fail.

 

[PlasmaBomb]

Originally posted by: LTC8K6

Auto manufacturers who ship their vehicles overseas routinely OVER-INFLATE their tires up to 80PSI (on a 44psi tire for example) in order to prevent the car from sitting on its rims by the time it arrives at its destination.

Why not just use nitrogen? My tires came filled with nitrogen when I bought the car and the pressure never drops. Almost a year later and they haven't lost any pressure.

Why take the time to pump them way up?

/facepalm.

Nitrogen will still leak out of tyres.

 

[jhu]

Originally posted by: PlasmaBomb

You are advising people to do something that is illegal in several states.

California -
21710. The driver of a motor vehicle when traveling on down grade
upon any highway shall not coast with the gears of such vehicle in
neutral.

In Great Britain, coasting in neutral or with your foot on the clutch, is illegal. If prosecuted, the driver can face a fine and points on their licence.

It is dangerous and regarded as being "Not in full control of the motor vehicle".

While coasting in neutral is technically illegal in some states, going over the posted speed limit is technically illegal in all states. Same with jaywalking in most jurisdictions. Yet most people view speeding and jaywalking as okay. Speeding, coasting in neutral, jaywalking - it's all about the same with regards to how much risk you're willing to take and depending on your particular situation.

With regard to fuel consumption coasting in gear vs. in neutral, I see this debate crop up all the time in other car forums. The general rule of thumb is (assuming the driver is trying to maintain a certain speed):

1) if the car can't maintain speed when coasting in gear, then coasting in neutral will use less fuel overall despite coasting in gear using no fuel.
2) if the car can maintain speed when coasting in gear, then coasting in gear will use less fuel than coasting in neutral.

 

[PlasmaBomb]

Originally posted by: jhu

Originally posted by: PlasmaBomb

You are advising people to do something that is illegal in several states.

California -
21710. The driver of a motor vehicle when traveling on down grade
upon any highway shall not coast with the gears of such vehicle in
neutral.

In Great Britain, coasting in neutral or with your foot on the clutch, is illegal. If prosecuted, the driver can face a fine and points on their licence.

It is dangerous and regarded as being "Not in full control of the motor vehicle".

While coasting in neutral is technically illegal in some states, going over the posted speed limit is technically illegal in all states. Same with jaywalking in most jurisdictions. Yet most people view speeding and jaywalking as okay. Speeding, coasting in neutral, jaywalking - it's all about the same with regards to how much risk you're willing to take and depending on your particular situation.

With regard to fuel consumption coasting in gear vs. in neutral, I see this debate crop up all the time in other car forums. The general rule of thumb is (assuming the driver is trying to maintain a certain speed):

It is not "technically illegal" it is illegal, it's just the chances of getting caught are less and the penalties aren't too harsh, but I get what you are saying...

However, there is a difference in doing something which is technically illegal, and advising someone else to do something technically illegal. Especially since the OP didn't originally state that and had no disclaimers...

1) if the car can't maintain speed when coasting in gear, then coasting in neutral will use less fuel overall despite coasting in gear using no fuel.
2) if the car can maintain speed when coasting in gear, then coasting in gear will use less fuel than coasting in neutral.

No Wai...

*There will be times when coasting gets you further using less fuel overall, due to picking up speed going down hill vs. using no fuel and then going back to cruising mpg sooner...

Perhaps I wasn't clear enough? I agree - If the coasting distance in neutral >> coasting distance in gear, then you can save gas using neutral. An alternative would be if the manufacturer has the cut in for the injectors set quite high.

It will probably be less of a problem in the future, manufacturers are implementing systems which partially open the throttle in coasting situations (i.e. when the driver has the throttle shut) to reduce pumping losses.

 

[Uhtrinity]

Originally posted by: punjabiplaya
cruise control is fail for economy, especially if any elevation change is involved.

I agree, I bought one and didn't install it based on results other Insight owner got. cruise universally dropped mpgs vs using lite contact on the gas pedal.

 

[Uhtrinity]

Originally posted by: SickBeast

Originally posted by: PlasmaBomb

12. Use neutral as much as possible. Coast to stop signs. Coast down hills. Again, be careful, this may not be legal in your area.

This is wrong... I concur with PhokingGuy, neutral fuel consumption is higher.

Do not coast down hills in neutral!

Using engine braking to coast to a stop is fine since the car should cut fuel.

First of all, you get the equivalent of 100+mpg when you're coasting in neutral.

Second, what I do is to coast in neutral if I want a long "glide". If I need to slow down/stop, then I leave it in gear to use engine brakes.

Not always. If I shift to netreul the car will then idel the engine. Depending on my speed it will show from 50 - mpg

If I leave the car in gear and coast to a stop the mpg gauge will peg beyond 150mpg + which is usually representative of fuel cut.

The only exception to this is when the engine is too cold for fuel cut and it will idle until warmed.

 

[zerocool84]

Originally posted by: Uhtrinity

Originally posted by: punjabiplaya
cruise control is fail for economy, especially if any elevation change is involved.

I agree, I bought one and didn't install it based on results other Insight owner got. cruise universally dropped mpgs vs using lite contact on the gas pedal.

I'm sure cruise control will save gas for majority of drivers since most drivers tend to not keep at a steady speed. The only ones who it won't save gas for the are ones like you who are already trying to get the most mpg out of their car.