when to shift on LX engine to get the best gas milage?
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From: Wapakoneta, ohio, USA
when to shift on LX engine to get the best gas milage?
i have been wondering this for a while now and after reading the other thread, i thought i would start my own. i was keeping it in the gear until i got to 3000 and then shift up. this week i have been short shifting at 2500. its almost a pain to shift this earlier but i just wanted to see what would happen. is it better to short shift or rev it up a little.
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From: Eldersburg, MD, U.S.A.
Re: when to shift on LX engine to get the best gas milage? (coot_er)
For better mileage, short shifting helps. That's why people whine about automatic "economy" cars not being able to get out of their own way! The trick is to get it into the highest gear without having to rev the engine so much. Everyone behind you will get red in the face, but you won't have to stop for gas as much! I've managed to get 42.3 mpg from my 07 EX on a long highway trip. Use hills to your advantage too. coast down them with the clutch disengaged,(Pedal in) engine speed will be at idle. When your speed JUST starts dropping, engage the clutch again! (Pedal out) I picked up a Scan Gauge 2 from linear logics. They're about 170.00, but they help if you're trying to improve your knowledge about what's going on with your car!
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Re: when to shift on LX engine to get the best gas milage? (AirTech)
what is the car is bogging? is that using excess gas?
im just trying to find if there is a range that is too low.
im just trying to find if there is a range that is too low.
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Re: when to shift on LX engine to get the best gas milage? (AirTech)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">For better mileage, short shifting helps. That's why people whine about automatic "economy" cars not being able to get out of their own way! The trick is to get it into the highest gear without having to rev the engine so much. Everyone behind you will get red in the face, but you won't have to stop for gas as much! I've managed to get 42.3 mpg from my 07 EX on a long highway trip. Use hills to your advantage too. coast down them with the clutch disengaged,(Pedal in) engine speed will be at idle. When your speed JUST starts dropping, engage the clutch again! (Pedal out) I picked up a Scan Gauge 2 from linear logics. They're about 170.00, but they help if you're trying to improve your knowledge about what's going on with your car!</TD></TR></TABLE>
Actually, no. Holding in the clutch down a hill is dumb for two reasons. For one, all you're doing is wearing out the clutch spring holding down the clutch for an extended time. Secondly, coasting in gear uses NO gas, vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas. So keep it in gear next time you roll down a hill.
Actually, no. Holding in the clutch down a hill is dumb for two reasons. For one, all you're doing is wearing out the clutch spring holding down the clutch for an extended time. Secondly, coasting in gear uses NO gas, vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas. So keep it in gear next time you roll down a hill.
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Re: when to shift on LX engine to get the best gas milage? (elohel)
i think the car coasts better when it is in neutral than in gear. although its not really engine braking it is engine slowing.
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Re: when to shift on LX engine to get the best gas milage? (coot_er)
shift at 3000-3500 rpm to get good gas mileage while still keeping your car enjoyable to drive.
you drive an LX you should be getting pretty good mpgs anyways. i dont think your shift points will make a huge difference unless your going from continual 5-6k shifts to 3k shifts
you drive an LX you should be getting pretty good mpgs anyways. i dont think your shift points will make a huge difference unless your going from continual 5-6k shifts to 3k shifts
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Re: when to shift on LX engine to get the best gas milage? (pd0019)
think of it this way .. when you ride a bike and you change your gear to a smaller one you have to work way harder to get up to speed same thing for a car i think when you shift to soon and you push on the gas your puting more load on the engine i would say check out you owners manual
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From: Eldersburg, MD, U.S.A.
Re: when to shift on LX engine to get the best gas milage? (elohel)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by elohel »</TD></TR><TR><TD CLASS="quote">
Actually, no. Holding in the clutch down a hill is dumb for two reasons. For one, all you're doing is wearing out the clutch spring holding down the clutch for an extended time. Secondly, coasting in gear uses NO gas, vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas. So keep it in gear next time you roll down a hill.</TD></TR></TABLE>
Sorry elohel,
Not trying to fight. I'm just going to point something out. First, the theory that "coasting in gear uses NO gas vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas."
I'm not sure I understand why you think this. When the car is coasting downhill at say, 3000 rpm, you are saying the car is using NO gas. So in other words, you're saying the engine isn't running?
I'm going to have to call
on that one.
For the engine to run, fuel MUST be present. It's true, you can look it up! Now, as for MORE fuel being used at idle, Gotta call on that one too.
After further thought, the throttle plate is in the same position whether you're decelerating, or at idle, so NO, you wouldn't be using more fuel at idle. It would be the same amount.
Now for ME. The clutch disengagement, you're right about. I'll call on myself for that one.
I've never personally known a spring to fail because of the practice. Technically you're correct though.
Coot_er, The Neutral coasting is a good idea. I was trying to eliminate gear drag from the equation by pushing the clutch in. Neutral will do that too. The reason coasting out of gear works, is because the cars acceleration increases when coasting downhill. (almost FREE!) Using the same amount of gas you'd use at idle. coasting with the car in gear downhill will "hold it back", as I'm sure you've discovered.
Modified by AirTech at 7:55 PM 11/19/2007
Modified by AirTech at 7:58 PM 11/19/2007
Actually, no. Holding in the clutch down a hill is dumb for two reasons. For one, all you're doing is wearing out the clutch spring holding down the clutch for an extended time. Secondly, coasting in gear uses NO gas, vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas. So keep it in gear next time you roll down a hill.</TD></TR></TABLE>
Sorry elohel,
Not trying to fight. I'm just going to point something out. First, the theory that "coasting in gear uses NO gas vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas."
I'm not sure I understand why you think this. When the car is coasting downhill at say, 3000 rpm, you are saying the car is using NO gas. So in other words, you're saying the engine isn't running?
I'm going to have to call
on that one.For the engine to run, fuel MUST be present. It's true, you can look it up! Now, as for MORE fuel being used at idle, Gotta call
on that one too. After further thought, the throttle plate is in the same position whether you're decelerating, or at idle, so NO, you wouldn't be using more fuel at idle. It would be the same amount.
Now for ME. The clutch disengagement, you're right about. I'll call
on myself for that one. I've never personally known a spring to fail because of the practice. Technically you're correct though.
Coot_er, The Neutral coasting is a good idea. I was trying to eliminate gear drag from the equation by pushing the clutch in. Neutral will do that too. The reason coasting out of gear works, is because the cars acceleration increases when coasting downhill. (almost FREE!) Using the same amount of gas you'd use at idle. coasting with the car in gear downhill will "hold it back", as I'm sure you've discovered.
Modified by AirTech at 7:55 PM 11/19/2007
Modified by AirTech at 7:58 PM 11/19/2007
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Re: when to shift on LX engine to get the best gas milage? (AirTech)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">
Sorry elohel,
Not trying to fight. I'm just going to point something out. First, the theory that "coasting in gear uses NO gas vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas."
I'm not sure I understand why you think this. When the car is coasting downhill at say, 3000 rpm, you are saying the car is using NO gas. So in other words, you're saying the engine isn't running?
I'm going to have to call on that one.
For the engine to run, fuel MUST be present. It's true, you can look it up! Now, as for MORE fuel being used at idle, Gotta call on that one too.
After further thought, the throttle plate is in the same position whether you're decelerating, or at idle, so NO, you wouldn't be using more fuel at idle. It would be the same amount.
Now for ME. The clutch disengagement, you're right about. I'll call on myself for that one.
I've never personally known a spring to fail because of the practice. Technically you're correct though.
Coot_er, The Neutral coasting is a good idea. I was trying to eliminate gear drag from the equation by pushing the clutch in. Neutral will do that too. The reason coasting out of gear works, is because the cars acceleration increases when coasting downhill. (almost FREE!) Using the same amount of gas you'd use at idle. coasting with the car in gear downhill will "hold it back", as I'm sure you've discovered.
Modified by AirTech at 7:55 PM 11/19/2007
Modified by AirTech at 7:58 PM 11/19/2007</TD></TR></TABLE>
Nope, you've got everything backwards and wrong. This is the topic about engine braking and safety. How you drive is incorrect and will yield worse fuel efficiency and puts you, as well as others, at risk.
1. Fuel injectors are cut off when the clutch pedal is disengaged, and your wheels are keeping the engine running. Wheels spins driveshaft > spins clutch > spins flywheel > spins crankshaft > spins pistons. Therefore fuel DOES NOT have to be present to keep the engine running.
2. Whenever you and Cooter coast in neutral, you clutch is not in contact with your flywheel meaning your engine must resort to its fuel source to keep the pistons moving.
3. Engine braking also saves your brakes because it is a form of deceleration that uses none of your cars natural resources. There are arguments about this wearing your clutch out, but you have to understand that the forces involved with your clutch and engine braking are only the forces against the compression of your engine. Your clutch its put under a more strenuous load when it's accelerating where it must act against the weight of your car.
Coasting in neutral is extremely hazardous to you and others sharing the road with you. In an instance where one must make a quick change in direction and you're in neutral, you could cause an accident. This is why it's illegal in some states to coast in neutral.
Do some homework before you start busting the on someone else.
Sorry elohel,
Not trying to fight. I'm just going to point something out. First, the theory that "coasting in gear uses NO gas vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas."
I'm not sure I understand why you think this. When the car is coasting downhill at say, 3000 rpm, you are saying the car is using NO gas. So in other words, you're saying the engine isn't running?
I'm going to have to call
on that one.For the engine to run, fuel MUST be present. It's true, you can look it up! Now, as for MORE fuel being used at idle, Gotta call
on that one too. After further thought, the throttle plate is in the same position whether you're decelerating, or at idle, so NO, you wouldn't be using more fuel at idle. It would be the same amount.
Now for ME. The clutch disengagement, you're right about. I'll call
on myself for that one. I've never personally known a spring to fail because of the practice. Technically you're correct though.
Coot_er, The Neutral coasting is a good idea. I was trying to eliminate gear drag from the equation by pushing the clutch in. Neutral will do that too. The reason coasting out of gear works, is because the cars acceleration increases when coasting downhill. (almost FREE!) Using the same amount of gas you'd use at idle. coasting with the car in gear downhill will "hold it back", as I'm sure you've discovered.
Modified by AirTech at 7:55 PM 11/19/2007
Modified by AirTech at 7:58 PM 11/19/2007</TD></TR></TABLE>
Nope, you've got everything backwards and wrong. This is the topic about engine braking and safety. How you drive is incorrect and will yield worse fuel efficiency and puts you, as well as others, at risk.
1. Fuel injectors are cut off when the clutch pedal is disengaged, and your wheels are keeping the engine running. Wheels spins driveshaft > spins clutch > spins flywheel > spins crankshaft > spins pistons. Therefore fuel DOES NOT have to be present to keep the engine running.
2. Whenever you and Cooter coast in neutral, you clutch is not in contact with your flywheel meaning your engine must resort to its fuel source to keep the pistons moving.
3. Engine braking also saves your brakes because it is a form of deceleration that uses none of your cars natural resources. There are arguments about this wearing your clutch out, but you have to understand that the forces involved with your clutch and engine braking are only the forces against the compression of your engine. Your clutch its put under a more strenuous load when it's accelerating where it must act against the weight of your car.
Coasting in neutral is extremely hazardous to you and others sharing the road with you. In an instance where one must make a quick change in direction and you're in neutral, you could cause an accident. This is why it's illegal in some states to coast in neutral.
Do some homework before you start busting the
on someone else. 
NO MERCY!
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From: San Antonio, TX, U.S.
Re: when to shift on LX engine to get the best gas milage? (AirTech)
I'm afraid he's right Elohel. Fuel MUST be present for a car to run. Coasting will use VERY LITTLE gas....but it will still use gas.
NO MERCY!
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From: San Antonio, TX, U.S.
Re: when to shift on LX engine to get the best gas milage? (JchanFTW)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JchanFTW »</TD></TR><TR><TD CLASS="quote">
Therefore fuel DOES NOT have to be present to keep the engine running.
</TD></TR></TABLE>
Incorrect sir.
During the INTAKE STROKE of an engine the piston moves down so that it can take in a cylinder full of gas/air mix. A very tiny amount of gasoline needs to mixed in the air for this to work.....but fuel is still required. The piston moves up to compress the mixture. When the piston reaches the top the spark plug ignites the mix forcing the cycle over again. Something that wouldn't work without gasoline.
Someone feel free to correct me if i'm missing something.
Modified by RICO_ at 10:43 PM 11/19/2007
Therefore fuel DOES NOT have to be present to keep the engine running.
</TD></TR></TABLE>
Incorrect sir.
During the INTAKE STROKE of an engine the piston moves down so that it can take in a cylinder full of gas/air mix. A very tiny amount of gasoline needs to mixed in the air for this to work.....but fuel is still required. The piston moves up to compress the mixture. When the piston reaches the top the spark plug ignites the mix forcing the cycle over again. Something that wouldn't work without gasoline.
Someone feel free to correct me if i'm missing something.
Modified by RICO_ at 10:43 PM 11/19/2007
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From: usa
Re: when to shift on LX engine to get the best gas milage? (RICO_)
Ok sorry for wording it poorly. I was under the impression while the car was moving the car required no gasoline to keep the motor running..
I still stand by what I said, mostly. Keep the car in gear is a smarter choice than putting in the clutch, regardless of whether or not the car uses any gas at all or no gas at all while in gear.
Just to add on to why I say this. I used to suffer horrific gas mileage in my SI, literally 22-24 MPG. I used to pop it into neutral EVERY damn chance I got, thinking I was doing such wonders to my gas mileage. After someone posted why this was a poor choice (It was even said on Top Gear that leaving it in gear - better gas mileage) I kept it in gear until literally 10-12 mph where I was going too slowly to keep it in gear, and then I'd disengage. I now get 27 MINIMUM, usually around 30.
I still stand by what I said, mostly. Keep the car in gear is a smarter choice than putting in the clutch, regardless of whether or not the car uses any gas at all or no gas at all while in gear.
Just to add on to why I say this. I used to suffer horrific gas mileage in my SI, literally 22-24 MPG. I used to pop it into neutral EVERY damn chance I got, thinking I was doing such wonders to my gas mileage. After someone posted why this was a poor choice (It was even said on Top Gear that leaving it in gear - better gas mileage) I kept it in gear until literally 10-12 mph where I was going too slowly to keep it in gear, and then I'd disengage. I now get 27 MINIMUM, usually around 30.
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From: Monterrey, N.L., Mex
in cars ive had with instant mileage computers...always goes to 99 mpg when coasting in gear....not so long ago, i drove my uncles 07 suzuki grand vitara, and when in 4th gear (engine braking=coasting in gear) the display topped out at 30.0 km/liter (versus 4-6-13 tops)
i would have to say that coasting in gear is better than doing it in neutral with the car idling
i would have to say that coasting in gear is better than doing it in neutral with the car idling
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Re: when to shift on LX engine to get the best gas milage? (RICO_)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RICO_ »</TD></TR><TR><TD CLASS="quote">
Incorrect sir.
During the INTAKE STROKE of an engine the piston moves down so that it can take in a cylinder full of gas/air mix. A very tiny amount of gasoline needs to mixed in the air for this to work.....but fuel is still required. The piston moves up to compress the mixture. When the piston reaches the top the spark plug ignites the mix forcing the cycle over again. Something that wouldn't work without gasoline.
Someone feel free to correct me if i'm missing something.
Modified by RICO_ at 10:43 PM 11/19/2007</TD></TR></TABLE>
That is how a engine works under acceleration and idle, but when the car is preforming engine braking, the wheels are driving the engines motion. I'm fairly sure of this, but I think someone should find some documentation on this. Not me cause I have midterms
Incorrect sir.
During the INTAKE STROKE of an engine the piston moves down so that it can take in a cylinder full of gas/air mix. A very tiny amount of gasoline needs to mixed in the air for this to work.....but fuel is still required. The piston moves up to compress the mixture. When the piston reaches the top the spark plug ignites the mix forcing the cycle over again. Something that wouldn't work without gasoline.
Someone feel free to correct me if i'm missing something.
Modified by RICO_ at 10:43 PM 11/19/2007</TD></TR></TABLE>
That is how a engine works under acceleration and idle, but when the car is preforming engine braking, the wheels are driving the engines motion. I'm fairly sure of this, but I think someone should find some documentation on this. Not me cause I have midterms
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From: Further down the spiral, TX, usa
Re: when to shift on LX engine to get the best gas milage? (AirTech)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">
Sorry elohel,
Not trying to fight. I'm just going to point something out. First, the theory that "coasting in gear uses NO gas vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas."
I'm not sure I understand why you think this. When the car is coasting downhill at say, 3000 rpm, you are saying the car is using NO gas. So in other words, you're saying the engine isn't running?
I'm going to have to call on that one.
For the engine to run, fuel MUST be present. It's true, you can look it up! Now, as for MORE fuel being used at idle, Gotta call on that one too.
</TD></TR></TABLE>
You are wrong.
If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking). This uses less gas than at idle, period.
Go do some more reading before you graduate high school.
Sorry elohel,
Not trying to fight. I'm just going to point something out. First, the theory that "coasting in gear uses NO gas vs the engine having to give it a bit of gas to idle. When you're rolling, the motion of the car keeps the motor running, and uses no gas."
I'm not sure I understand why you think this. When the car is coasting downhill at say, 3000 rpm, you are saying the car is using NO gas. So in other words, you're saying the engine isn't running?
I'm going to have to call
on that one.For the engine to run, fuel MUST be present. It's true, you can look it up! Now, as for MORE fuel being used at idle, Gotta call
on that one too. </TD></TR></TABLE>
You are wrong.
If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking). This uses less gas than at idle, period.
Go do some more reading before you graduate high school.
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From: Eldersburg, MD, U.S.A.
Re: when to shift on LX engine to get the best gas milage? (Hawkze_2.3)
I hadn't seen the Wideband A/F meters before. Thanks! Do you know how they work? They measure Air/Fuel ratio. Not fuel flow rate.
Here is a link to describe the workings for anyone interested. (It's pretty dry reading though.)
http://www.megamanual.com/PWC/LSU4.htm
Now for your comment: <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hawkze_2.3 »</TD></TR><TR><TD CLASS="quote">
You are wrong.
If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking). This uses less gas than at idle, period.
Go do some more reading before you graduate high school. </TD></TR></TABLE>
I direct your attention to your first sentence.
Well...You've said TWO things. Which one did you want to say? 1.)"If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel."
This one would cause your engine to stop running. (NO fuel, NO run.)
Or 2.) ( "and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking).
If you're running "very lean" you're still running, which requires that pesky thing called...Oh yeah...FUEL!
Fuel is still required whether you're running "rich" or "lean. Those two words just define the ratio between fuel & air.
I DID electronically watch my Throttle position sensor today. At idle, it stays at a steady 12 once the car is warm. (I didn't look before it was operating temp.) Coasting with the clutch disengaged, it was still 12, coasting in neutral, still 12. No matter which gear I was in, when I took my foot off the throttle, and coasted in gear. I got a reading of 13. I can't find the units of measurement. I would guess percentage open rather than degrees. The larger number means the throttle is open more, thereby increasing fuel flow. 1% probably isn't enough to make a difference, but there it is.
Here's another link to explain how engines work for anyone interested: http://www.bartleby.com/65/in/intern-co.html
I don't mind insults. I'm a little abrasive too. If I'm wrong, and you can PROVE it, Have at it. But when you want to call me wrong, at least have the courtesy to back up your opinions. It helps everyone.
Thanks!
Here is a link to describe the workings for anyone interested. (It's pretty dry reading though.)
http://www.megamanual.com/PWC/LSU4.htm
Now for your comment: <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hawkze_2.3 »</TD></TR><TR><TD CLASS="quote">
You are wrong.
If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking). This uses less gas than at idle, period.
Go do some more reading before you graduate high school.
</TD></TR></TABLE>I direct your attention to your first sentence.
Well...You've said TWO things. Which one did you want to say? 1.)"If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel."
This one would cause your engine to stop running. (NO fuel, NO run.)
Or 2.) ( "and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking).
If you're running "very lean" you're still running, which requires that pesky thing called...Oh yeah...FUEL!
Fuel is still required whether you're running "rich" or "lean. Those two words just define the ratio between fuel & air.
I DID electronically watch my Throttle position sensor today. At idle, it stays at a steady 12 once the car is warm. (I didn't look before it was operating temp.) Coasting with the clutch disengaged, it was still 12, coasting in neutral, still 12. No matter which gear I was in, when I took my foot off the throttle, and coasted in gear. I got a reading of 13. I can't find the units of measurement. I would guess percentage open rather than degrees. The larger number means the throttle is open more, thereby increasing fuel flow. 1% probably isn't enough to make a difference, but there it is.
Here's another link to explain how engines work for anyone interested: http://www.bartleby.com/65/in/intern-co.html
I don't mind insults. I'm a little abrasive too. If I'm wrong, and you can PROVE it, Have at it. But when you want to call me wrong, at least have the courtesy to back up your opinions. It helps everyone.
Thanks!
NO MERCY!
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From: San Antonio, TX, U.S.
Re: when to shift on LX engine to get the best gas milage? (Hawkze_2.3)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JchanFTW »</TD></TR><TR><TD CLASS="quote">
That is how a engine works under acceleration and idle, but when the car is preforming engine braking, the wheels are driving the engines motion. I'm fairly sure of this, but I think someone should find some documentation on this. Not me cause I have midterms </TD></TR></TABLE>
How exactly do wheels drive the engine?? I was under the impression that the engine transmits power to the wheels.....not the other way around. Bottom line is fuel is REQUIRED for an engine to run. No matter what. If a car is in gear....it's still using fuel. If it's coasting or idling....it's still using fuel......very little fuel....but still using fuel.
And even if cars equipped with digital gas mileage readouts see their mpg shoot up to 100mpg...it doesn't mean you have an infinite supply of fuel. You're still burning gas.....just at a very slow rate.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hawkze_2.3 »</TD></TR><TR><TD CLASS="quote">
You are wrong.
If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking). This uses less gas than at idle, period.
Go do some more reading before you graduate high school. </TD></TR></TABLE>
No actually YOU are wrong sir. If the ECU fully cut the fuel the car would die in mid-motion....even if it were in neutral. You just said two things that contradict themselves. An engine can't "run lean" without fuel. Engines don't run on air alone. They need a mixture of the two as AirTech mentioned.
That is how a engine works under acceleration and idle, but when the car is preforming engine braking, the wheels are driving the engines motion. I'm fairly sure of this, but I think someone should find some documentation on this. Not me cause I have midterms </TD></TR></TABLE>
How exactly do wheels drive the engine?? I was under the impression that the engine transmits power to the wheels.....not the other way around. Bottom line is fuel is REQUIRED for an engine to run. No matter what. If a car is in gear....it's still using fuel. If it's coasting or idling....it's still using fuel......very little fuel....but still using fuel.
And even if cars equipped with digital gas mileage readouts see their mpg shoot up to 100mpg...it doesn't mean you have an infinite supply of fuel. You're still burning gas.....just at a very slow rate.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hawkze_2.3 »</TD></TR><TR><TD CLASS="quote">
You are wrong.
If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking). This uses less gas than at idle, period.
Go do some more reading before you graduate high school.
</TD></TR></TABLE>No actually YOU are wrong sir. If the ECU fully cut the fuel the car would die in mid-motion....even if it were in neutral. You just said two things that contradict themselves. An engine can't "run lean" without fuel. Engines don't run on air alone. They need a mixture of the two as AirTech mentioned.
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From: usa
Re: when to shift on LX engine to get the best gas milage? (RICO_)
Jeez I didn't mean to start a fight 
Anyways, I'm curious why no one has been able to explain yet why my gas mileage went up tremendously when I started leaving it in gear while coasting vs. putting it in neutral. Ideas are all nice and swell here, but nothing proves a point more than actually SEEING it happen.
Anyways, I'm curious why no one has been able to explain yet why my gas mileage went up tremendously when I started leaving it in gear while coasting vs. putting it in neutral. Ideas are all nice and swell here, but nothing proves a point more than actually SEEING it happen.
NO MERCY!
Joined: Dec 2006
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From: San Antonio, TX, U.S.
Re: when to shift on LX engine to get the best gas milage? (elohel)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by elohel »</TD></TR><TR><TD CLASS="quote">Jeez I didn't mean to start a fight
Anyways, I'm curious why no one has been able to explain yet why my gas mileage went up tremendously when I started leaving it in gear while coasting vs. putting it in neutral. Ideas are all nice and swell here, but nothing proves a point more than actually SEEING it happen.</TD></TR></TABLE>
The argument wasn't about dramatic improvements in gas mileage.....just about the issue of engines requiring fuel to run. Which they do.
I honestly don't know why your gas mileage went up soo much by coasting in gear vs. neutral since they are technically the same thing since fully depressing the clutch drops the rpms to their idle position.
Anyways, I'm curious why no one has been able to explain yet why my gas mileage went up tremendously when I started leaving it in gear while coasting vs. putting it in neutral. Ideas are all nice and swell here, but nothing proves a point more than actually SEEING it happen.</TD></TR></TABLE>
The argument wasn't about dramatic improvements in gas mileage.....just about the issue of engines requiring fuel to run. Which they do.
I honestly don't know why your gas mileage went up soo much by coasting in gear vs. neutral since they are technically the same thing since fully depressing the clutch drops the rpms to their idle position.
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Re: when to shift on LX engine to get the best gas milage? (AirTech)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">I hadn't seen the Wideband A/F meters before. Thanks! Do you know how they work? They measure Air/Fuel ratio. Not fuel flow rate.
</TD></TR></TABLE>
If the ratio goes lean the ECU is adding less fuel...why are talking about 'fuel flow rate'? Google hasn't made you any smarter.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">Well...You've said TWO things. Which one did you want to say? 1.)"If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel."
This one would cause your engine to stop running. (NO fuel, NO run.)
</TD></TR></TABLE>
I shouldn't have used the word 'fully' since it seems to be exciting everyone...it wasn't meant to mean zero fuel, just cut as low as it goes under driving conditions. Like if you said the ECU 'fully' adds fuel it would mean the most that it can add...
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">Or 2.) ( "and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking).
If you're running "very lean" you're still running, which requires that pesky thing called...Oh yeah...FUEL!
Fuel is still required whether you're running "rich" or "lean. Those two words just define the ratio between fuel & air.
</TD></TR></TABLE>
So you just said the same thing again? Good job.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RICO_ »</TD></TR><TR><TD CLASS="quote">No actually YOU are wrong sir. If the ECU fully cut the fuel the car would die in mid-motion....even if it were in neutral. You just said two things that contradict themselves. An engine can't "run lean" without fuel. Engines don't run on air alone. They need a mixture of the two as AirTech mentioned.</TD></TR></TABLE>
Sorry to get you all excited also, just a misunderstanding. I mean it cuts the fuel as far as it can.
</TD></TR></TABLE>
If the ratio goes lean the ECU is adding less fuel...why are talking about 'fuel flow rate'? Google hasn't made you any smarter.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">Well...You've said TWO things. Which one did you want to say? 1.)"If you had ever looked at an accurate wideband A/F gauge you would see that the ECU fully cuts fuel."
This one would cause your engine to stop running. (NO fuel, NO run.)
</TD></TR></TABLE>
I shouldn't have used the word 'fully' since it seems to be exciting everyone...it wasn't meant to mean zero fuel, just cut as low as it goes under driving conditions. Like if you said the ECU 'fully' adds fuel it would mean the most that it can add...
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">Or 2.) ( "and causes you to run very lean if you leave the car in gear going down a hill or slowing down (engine braking).
If you're running "very lean" you're still running, which requires that pesky thing called...Oh yeah...FUEL!
Fuel is still required whether you're running "rich" or "lean. Those two words just define the ratio between fuel & air.
</TD></TR></TABLE>
So you just said the same thing again? Good job.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RICO_ »</TD></TR><TR><TD CLASS="quote">No actually YOU are wrong sir. If the ECU fully cut the fuel the car would die in mid-motion....even if it were in neutral. You just said two things that contradict themselves. An engine can't "run lean" without fuel. Engines don't run on air alone. They need a mixture of the two as AirTech mentioned.</TD></TR></TABLE>
Sorry to get you all excited also, just a misunderstanding. I mean it cuts the fuel as far as it can.
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Re: when to shift on LX engine to get the best gas milage? (Hawkze_2.3)
Ok i tried following this thread as best i could, but had turn away before my simple little brain exploded. To hell with explanations since you all seem to be speaking different languages. I'm over it. Gimme the Cliffs.
Coast down hills or not??
Coast down hills or not??
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Joined: Dec 2006
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From: San Antonio, TX, U.S.
Re: when to shift on LX engine to get the best gas milage? (jaepalm)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jaepalm »</TD></TR><TR><TD CLASS="quote">
Coast down hills or not??</TD></TR></TABLE>
Not. Unless you're consistently going downhill on a frequent basis.....the amount of gas you would save would be unnoticeable.
Coast down hills or not??</TD></TR></TABLE>
Not. Unless you're consistently going downhill on a frequent basis.....the amount of gas you would save would be unnoticeable.
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Re: when to shift on LX engine to get the best gas milage? (Hawkze_2.3)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hawkze_2.3 »</TD></TR><TR><TD CLASS="quote">
I shouldn't have used the word 'fully' since it seems to be exciting everyone...it wasn't meant to mean zero fuel, just cut as low as it goes under driving conditions. Like if you said the ECU 'fully' adds fuel it would mean the most that it can add...
</TD></TR></TABLE>
I'll quote you like everyone else, but I will point out that you (were) exactly right.
Most modern engines (and their assoc. control systems) are programed to completely cut fuel when coasting in gear above idle speed.
There are a couple ways I could explain this ....To explain, ill quote another statement that's been made here,
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">
For the engine to run, fuel MUST be present. It's true, you can look it up! Now, as for MORE fuel being used at idle...
</TD></TR></TABLE>
That's only because you have decided to define 'running,' in that way. Who says that the the definition of running has to be 'buring fuel?'
Let's try a different way.
There are obviously an infinite number of ways we could define 'running,' Here's a few off the top of my head.
-Burning/using fuel
-In a state of self-sustained motion, i.e. producing at least enough work to overcome it's own friction.
-In a state such that the motor is capable of responding immediatly (i.e. producing power) to throttle inputs, and the crankshaft is spinning.
Let's instead choose #3 to define running, seeing that's all we care about anyways: we want the car to go when we press the throttle and we want the motor spinning to drive the alternator, a/c and power steering.
Now, there is no mention of fuel in this definition, so, ask yourself again, why would the motor need fuel in a situation where the car is coasting down in gear...?
-the engine is not needed to produce any power (the car is slowing down/coasting!)
-the engine is already spinning, and has another source of work to keep it spinning: the kinetic energy of the vehicle.
The simple answer is that ECU's these days are programmed to cut 100% fuel to the motor when the throttle position is closed and the engine speed is above idle. If the engine speed approaches idle, the ECU will add fuel to stableize the speed around the usual idle setpoint.
Now onto the the argument of coasting in gear vs coasting out of gear... that's another issue.
I shouldn't have used the word 'fully' since it seems to be exciting everyone...it wasn't meant to mean zero fuel, just cut as low as it goes under driving conditions. Like if you said the ECU 'fully' adds fuel it would mean the most that it can add...
</TD></TR></TABLE>
I'll quote you like everyone else, but I will point out that you (were) exactly right.
Most modern engines (and their assoc. control systems) are programed to completely cut fuel when coasting in gear above idle speed.
There are a couple ways I could explain this ....To explain, ill quote another statement that's been made here,
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AirTech »</TD></TR><TR><TD CLASS="quote">
For the engine to run, fuel MUST be present. It's true, you can look it up! Now, as for MORE fuel being used at idle...
</TD></TR></TABLE>
That's only because you have decided to define 'running,' in that way. Who says that the the definition of running has to be 'buring fuel?'
Let's try a different way.
There are obviously an infinite number of ways we could define 'running,' Here's a few off the top of my head.
-Burning/using fuel
-In a state of self-sustained motion, i.e. producing at least enough work to overcome it's own friction.
-In a state such that the motor is capable of responding immediatly (i.e. producing power) to throttle inputs, and the crankshaft is spinning.
Let's instead choose #3 to define running, seeing that's all we care about anyways: we want the car to go when we press the throttle and we want the motor spinning to drive the alternator, a/c and power steering.
Now, there is no mention of fuel in this definition, so, ask yourself again, why would the motor need fuel in a situation where the car is coasting down in gear...?
-the engine is not needed to produce any power (the car is slowing down/coasting!)
-the engine is already spinning, and has another source of work to keep it spinning: the kinetic energy of the vehicle.
The simple answer is that ECU's these days are programmed to cut 100% fuel to the motor when the throttle position is closed and the engine speed is above idle. If the engine speed approaches idle, the ECU will add fuel to stableize the speed around the usual idle setpoint.
Now onto the the argument of coasting in gear vs coasting out of gear... that's another issue.
NO MERCY!
Joined: Dec 2006
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From: San Antonio, TX, U.S.
Re: when to shift on LX engine to get the best gas milage? (okashira)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by okashira »</TD></TR><TR><TD CLASS="quote">
I'll quote you like everyone else, but I will point out that you (were) exactly right.
Most modern engines (and their assoc. control systems) are programed to completely cut fuel when coasting in gear above idle speed.
There are a couple ways I could explain this ....To explain, ill quote another statement that's been made here,
That's only because you have decided to define 'running,' in that way. Who says that the the definition of running has to be 'buring fuel?'
Let's try a different way.
There are obviously an infinite number of ways we could define 'running,' Here's a few off the top of my head.
-Burning/using fuel
-In a state of self-sustained motion, i.e. producing at least enough work to overcome it's own friction.
-In a state such that the motor is capable of responding immediatly (i.e. producing power) to throttle inputs, and the crankshaft is spinning.
Let's instead choose #3 to define running, seeing that's all we care about anyways: we want the car to go when we press the throttle and we want the motor spinning to drive the alternator, a/c and power steering.
Now, there is no mention of fuel in this definition, so, ask yourself again, why would the motor need fuel in a situation where the car is coasting down in gear...?
-the engine is not needed to produce any power (the car is slowing down/coasting!)
-the engine is already spinning, and has another source of work to keep it spinning: the kinetic energy of the vehicle.
The simple answer is that ECU's these days are programmed to cut 100% fuel to the motor when the throttle position is closed and the engine speed is above idle. If the engine speed approaches idle, the ECU will add fuel to stableize the speed around the usual idle setpoint.
Now onto the the argument of coasting in gear vs coasting out of gear... that's another issue. </TD></TR></TABLE>
Thank you for that extensive post. Too bad it's all crap.
To answer the question in bold.....the motor needs fuel even when it's coasting in gear because the pistons are still operating....even at idle. And part of the operating cycle dictates that fuel and air are compressed in the cylinder and then ignited via the spark plug to force the cycle over again. You can't ignite compressed air without fuel being mixed in.
You would know this if you had read my previous post.........
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RICO_ »</TD></TR><TR><TD CLASS="quote">
During the INTAKE STROKE of an engine the piston moves down so that it can take in a cylinder full of gas/air mix. A very tiny amount of gasoline needs to mixed in the air for this to work.....but fuel is still required. The piston moves up to compress the mixture. When the piston reaches the top the spark plug ignites the mix forcing the cycle over again. Something that wouldn't work without gasoline.
</TD></TR></TABLE>
Fuel is not cut 100% when a car is idling because the car would die instantly. Fuel cut happens during over-rev/over-boost situations to help prevent damage to the motor.....so the ECU cuts the fuel for a split second to drop the RPMs back down within the programmed limits.
I'll quote you like everyone else, but I will point out that you (were) exactly right.
Most modern engines (and their assoc. control systems) are programed to completely cut fuel when coasting in gear above idle speed.
There are a couple ways I could explain this ....To explain, ill quote another statement that's been made here,
That's only because you have decided to define 'running,' in that way. Who says that the the definition of running has to be 'buring fuel?'
Let's try a different way.
There are obviously an infinite number of ways we could define 'running,' Here's a few off the top of my head.
-Burning/using fuel
-In a state of self-sustained motion, i.e. producing at least enough work to overcome it's own friction.
-In a state such that the motor is capable of responding immediatly (i.e. producing power) to throttle inputs, and the crankshaft is spinning.
Let's instead choose #3 to define running, seeing that's all we care about anyways: we want the car to go when we press the throttle and we want the motor spinning to drive the alternator, a/c and power steering.
Now, there is no mention of fuel in this definition, so, ask yourself again, why would the motor need fuel in a situation where the car is coasting down in gear...?
-the engine is not needed to produce any power (the car is slowing down/coasting!)
-the engine is already spinning, and has another source of work to keep it spinning: the kinetic energy of the vehicle.
The simple answer is that ECU's these days are programmed to cut 100% fuel to the motor when the throttle position is closed and the engine speed is above idle. If the engine speed approaches idle, the ECU will add fuel to stableize the speed around the usual idle setpoint.
Now onto the the argument of coasting in gear vs coasting out of gear... that's another issue. </TD></TR></TABLE>
Thank you for that extensive post. Too bad it's all crap.
To answer the question in bold.....the motor needs fuel even when it's coasting in gear because the pistons are still operating....even at idle. And part of the operating cycle dictates that fuel and air are compressed in the cylinder and then ignited via the spark plug to force the cycle over again. You can't ignite compressed air without fuel being mixed in.
You would know this if you had read my previous post.........
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RICO_ »</TD></TR><TR><TD CLASS="quote">
During the INTAKE STROKE of an engine the piston moves down so that it can take in a cylinder full of gas/air mix. A very tiny amount of gasoline needs to mixed in the air for this to work.....but fuel is still required. The piston moves up to compress the mixture. When the piston reaches the top the spark plug ignites the mix forcing the cycle over again. Something that wouldn't work without gasoline.
</TD></TR></TABLE>
Fuel is not cut 100% when a car is idling because the car would die instantly. Fuel cut happens during over-rev/over-boost situations to help prevent damage to the motor.....so the ECU cuts the fuel for a split second to drop the RPMs back down within the programmed limits.
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Joined: Nov 2007
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Re: when to shift on LX engine to get the best gas milage? (RICO_)
I don't need anyone to tell me how an engine works. 
No need to get defensive.
I had read your post. It seems that you didn't concepts in my explination, or didn't read all-together.
You say the engine would 'die instantly,' when fuel is cut 100% with the car at idle, yet nowhere in my post did I claim that fuel is cut at idle, in fact, I said the opposite:
Also,
Referencing your statement I placed in italics: Again, my post was not about when the engine was at idle, but in gear at a speed (and a gear) that would keep the engine above the idle speed.
Please understand that the pistons do not 'operate,' on their own, they are mechanically linked, by a bearing, to solid metal rods which are mechanically linked to a solid metal crankshaft. The crankshaft is directly linked, when in gear, to the front wheels.
If the crankshaft is spinning, the pistons will oscilliate up and down, regardless if fuel is injected and ignited. The pistons are there and move the way they do to take advantage of the pressure force created when a gas is heated suddenly at a constant volume.
If the car is in gear and coasting at a significant speed, and fuel to the engine is cut, nothing special will happen. the engine will simply stop producing torque and will continue to rotate proportional to the vehicle speed. The engine will produce a significant frictional drag, but insignificant compared to the momentum of the vehicle, especially when you consider all the engineering Honda has put into the motor to reduce bearing friction, piston/piston ring friction and pumping losses. (and these new civics are heavy!)
If fuel is cut, the car will simple continue to coast, with the engine dragging (slightly, called engine braking, used to be called compression braking.)
Fuel can and will be added again anytime you press the accelerator and the engine will fire again and produce torque to accelerate.
So, in a way, everytime you let off the gas when the car moving in gear, the engine 'dies,' in a way, and 'restarts,' so to speak as soon as you press the accelerator. Think of it like continually push-starting the car. You just don't notice it because, by your definition of 'running,' the line between not running and running is in reality a fine one. Motors in compression braking will continue to produce noise and even exhaust noise..some produce quite a bit of noise when compression braking. It is, after-all, a giant pump.
Ever heard an 18-wheeler use a Jake-Brake?
No need to get defensive.
Originally Posted by RICO_
You would know this if you had read my previous post.........
Fuel is not cut 100% when a car is idling because the car would die instantly. Fuel cut happens during over-rev/over-boost situations to help prevent damage to the motor.....so the ECU cuts the fuel for a split second to drop the RPMs back down within the programmed limits.
Fuel is not cut 100% when a car is idling because the car would die instantly. Fuel cut happens during over-rev/over-boost situations to help prevent damage to the motor.....so the ECU cuts the fuel for a split second to drop the RPMs back down within the programmed limits.
You say the engine would 'die instantly,' when fuel is cut 100% with the car at idle, yet nowhere in my post did I claim that fuel is cut at idle, in fact, I said the opposite:
Originally Posted by okashira
The simple answer is that ECU's these days are programmed to cut 100% fuel to the motor when the throttle position is closed and the engine speed is above idle. If the engine speed approaches idle, the ECU will add fuel to stableize the speed around the usual idle setpoint.
Originally Posted by RICO_
To answer the question in bold.....the motor needs fuel even when it's coasting in gear because the pistons are still operating....even at idle.[/I] And part of the operating cycle dictates that fuel and air are compressed in the cylinder and then ignited via the spark plug to force the cycle over again. You can't ignite compressed air without fuel being mixed in.
Please understand that the pistons do not 'operate,' on their own, they are mechanically linked, by a bearing, to solid metal rods which are mechanically linked to a solid metal crankshaft. The crankshaft is directly linked, when in gear, to the front wheels.
If the crankshaft is spinning, the pistons will oscilliate up and down, regardless if fuel is injected and ignited. The pistons are there and move the way they do to take advantage of the pressure force created when a gas is heated suddenly at a constant volume.
If the car is in gear and coasting at a significant speed, and fuel to the engine is cut, nothing special will happen. the engine will simply stop producing torque and will continue to rotate proportional to the vehicle speed. The engine will produce a significant frictional drag, but insignificant compared to the momentum of the vehicle, especially when you consider all the engineering Honda has put into the motor to reduce bearing friction, piston/piston ring friction and pumping losses. (and these new civics are heavy!)
If fuel is cut, the car will simple continue to coast, with the engine dragging (slightly, called engine braking, used to be called compression braking.)
Fuel can and will be added again anytime you press the accelerator and the engine will fire again and produce torque to accelerate.
So, in a way, everytime you let off the gas when the car moving in gear, the engine 'dies,' in a way, and 'restarts,' so to speak as soon as you press the accelerator. Think of it like continually push-starting the car. You just don't notice it because, by your definition of 'running,' the line between not running and running is in reality a fine one. Motors in compression braking will continue to produce noise and even exhaust noise..some produce quite a bit of noise when compression braking. It is, after-all, a giant pump.
Ever heard an 18-wheeler use a Jake-Brake?