Mile Per Gallon

[yukdude]

I wonder whether you guys experience this before....

I got my IS250 for about half year. Most of the time, It run about 18 miles per gallon in city and 27 miles per gallon on highway.

Recently, I have travel somewhere else with it and I was able to squeeze out 30.5 miles per gallon on the highway (average speed around 75)

I got back home now, and It run more miles per gallon in city these days.

Make any sense?

[Knightshade]

Warmer weather, if not romping on the car, can improve mileage, among other things...

Is your car AWD or a stick though? Because those numbers (18/27) are awfully low for a RWD automatic 250... my 350 does better than those numbers.

[clay1]

250AWD Auto - 31,000 miles - 90% highway - 24 - 25 miles per gallon, driving like grandma 80% of the time

[CrunchySkippy]

250AWD Auto - 31,000 miles - 90% highway - 24 - 25 miles per gallon, driving like grandma 80% of the time

Mine is:

250AWD Auto - 16,000 miles - 90% City at 19 - 21 MPG. Note this is per the computer, not personally calculated - as there has been previous discussions about the variance.

[Gaugster]

I am getting between 26 - 28 mpg based on what the "TANK AVG" says when I have consumed more than 3/4's of the tank since fill-up. I like to use this as it takes into account the cold starts in the morning and other driving habits. Although it is neat to watch the tank average gauge go way up into the 30’s just after a fill up even if it is meaningless.

IS250 AWD, 5W-20 motor oil, A/C ON, Normal Tire Pressure 37/39psi, 93 octane

My daily drive is mostly expressway but there tends to be traffic so my average speed is only around 40mph.

Regards,

[yukdude]

Warmer weather, if not romping on the car, can improve mileage, among other things...

Is your car AWD or a stick though? Because those numbers (18/27) are awfully low for a RWD automatic 250... my 350 does better than those numbers.

Is an Automatic AWD.

[SailorDanH]

Warmer weather, if not romping on the car, can improve mileage, among other things...

Is your car AWD or a stick though? Because those numbers (18/27) are awfully low for a RWD automatic 250... my 350 does better than those numbers.

I have never heard that warmer weather can improve mileage. That is counter intuitive. Cold weather air is normally more dense that hot air, meaning more specific energy per cubic foot of air. Plus, efficiencies improve as the difference between intake air temp and exhaust air temp increase. Maybe the thinner air when the air is warm has less aerodynamic drag..?? Where did you hear that warmer weather can improve mileage?

By the way... my IS350 is regularly getting about 23 mpg per tank with mixed city driving. Very consistent for the past 2 years. I've never seen it go above 27 for an extended highway trip.

[smooth1]

I drive from Orlando to Miami pretty regular, and that trip, in my 350 I get a measured 24 mpg. (Not according to the display calculations.) It can vary some by a mile or two per gallon, but I would say that is a pretty fair average MPG number. So, while I don't know the efficiency specifics of the 250, it does sound like you should be able to do better than that. I don't drive my car any differently from any one day to the next. Atleast not consciously. So if your granny driving and getting those numbers, I would track how much fuel your putting in and tack your mileage on the trip odometers to find out for sure. I know my on board computer calculation is off pretty regularly. I only use it as a general idea. ( Actually I don't use it all.) I like to leave it on the outside temp or the gear display.) :)

[smooth1]

Warmer weather, if not romping on the car, can improve mileage, among other things...

Is your car AWD or a stick though? Because those numbers (18/27) are awfully low for a RWD automatic 250... my 350 does better than those numbers.

I have never heard that warmer weather can improve mileage. That is counter intuitive. Cold weather air is normally more dense that hot air, meaning more specific energy per cubic foot of air. Plus, efficiencies improve as the difference between intake air temp and exhaust air temp increase. Maybe the thinner air when the air is warm has less aerodynamic drag..?? Where did you hear that warmer weather can improve mileage?

By the way... my IS350 is regularly getting about 23 mpg per tank with mixed city driving. Very consistent for the past 2 years. I've never seen it go above 27 for an extended highway trip.

Oh, this could blow up into another huge debate........LOL!!

The temputure of the air has no bearing on fuel mileage in a modern engine as the ECU will adjust to maintain the same ratios, no matter the air temp. The only thing that may change is the amount of power the motor will produce, but even then we are talking a very small number.

[bartkat]

Warmer weather, if not romping on the car, can improve mileage, among other things...

Is your car AWD or a stick though? Because those numbers (18/27) are awfully low for a RWD automatic 250... my 350 does better than those numbers.

I have never heard that warmer weather can improve mileage. That is counter intuitive. Cold weather air is normally more dense that hot air, meaning more specific energy per cubic foot of air. Plus, efficiencies improve as the difference between intake air temp and exhaust air temp increase. Maybe the thinner air when the air is warm has less aerodynamic drag..?? Where did you hear that warmer weather can improve mileage?

By the way... my IS350 is regularly getting about 23 mpg per tank with mixed city driving. Very consistent for the past 2 years. I've never seen it go above 27 for an extended highway trip.

Oh, this could blow up into another huge debate........LOL!!

The temputure of the air has no bearing on fuel mileage in a modern engine as the ECU will adjust to maintain the same ratios, no matter the air temp. The only thing that may change is the amount of power the motor will produce, but even then we are talking a very small number.

Baloney! Don't you unsderstand how a car works? Besides, air doesn't drive the car, the rear tires do. :huh:

[bartkat]

I got 29 MPG from my IS350 from Southern Kentucky to Colubus Ohio. Top that dudes. :D

[Knightshade]

Check the drag journals on the 350, it's not an insignificant difference in power... air temp has been shown to have a larger impact on drag times than nearly anything else anyone has done to the car so far.

At WOT colder air provides more power.

Most folks drive around at part throttle though, where they'll see better mileage in warmer weather than cold.

Even on a modern car.

In colder weather, especially early in starting the car, fluids are thicker, friction is higher, so economy is worse.

In colder weather it takes longer for the car to reach operating temp, and fuel economy is worse until it does. In general up to a point your engine works more efficiently when it's warme

In colder weather rolling resistance is higher because the PSI in your tires drops as the temp does

Warmer air, being less dense (bad for power at WOT) provides less air resistance to push the car against than cold denser air.

Plus, summer blends of fuel have more energy than winter mixes of fuel.

While none of these is a HUGE factor they certainly add up, and all of them lead to better mileage in the summer than the winter.

And I sure hope it doesn't blow into a huge debate, otherwise someone might sneak in the last word and close the thread!

[Knightshade]

I got 29 MPG from my IS350 from Southern Kentucky to Colubus Ohio. Top that dudes. :D

Not sure if you're using indicated or "actual"

If it's actual Lance has you beat-

http://www.clublexus.com/forums/showthread...ghlight=mileage

29.197 once, over 30 twice

(not the exact same route of course but that'd be kinda tough as a test)

[bartkat]

w00t w00t

If I used indicated I'd say so. When I say MPG I mean MPG.

Thread got closed because your repetitive, redundant, rehashed posts were killing it. Make anothe snyde backhanded remark and deal with the consequences. I have grown rather tired of your catty little trolling attempts. Be forewarned.

[Knightshade]

Ah, so you're allowed to openly insult me but I can't remark on your doing so? I'm unclear how posting acurate facts backed by a slew of experts and sources that happen to point out a moderator is wrong is trolling, but, Ok, consider it noted.

[playcaller]

I got 29 MPG from my IS350 from Southern Kentucky to Colubus Ohio. Top that dudes. :D

30 MPG from Medina OH to Columbus and back - cruse set at 75

[playcaller]

Check the drag journals on the 350, it's not an i

In colder weather it takes longer for the car to reach operating temp, and fuel economy is worse until it does. In general up to a point your engine works more efficiently when it's warme

The warm up period is what impacts me... I start the car and go inside until she is warm... I always drop 3-5 MPG during winter because of this. I never thought that driving had too much impact but IMO Summer sees the use of the A/C which also reduces MPG... Love the spring and fall

[bartkat]

I got 29 MPG from my IS350 from Southern Kentucky to Colubus Ohio. Top that dudes. :D

30 MPG from Medina OH to Columbus and back - cruse set at 75

Cool. When I71 first opened it was just from Medina to Columbus. I think there were maybe only a couple of exits and little traffic. I had a 64 Ford 390. We got on at Medina and ran 100MPH all the way to Columbus. LOL

[CrunchySkippy]

Baloney! Don't you unsderstand how a car works? Besides, air doesn't drive the car, the rear tires do. :huh:

Bartkat - I have to say you are out of line with the initial antagonistic comment...and then you threaten Knightshade for responding the same. Sounds like an abuse of power to me.

If you dish it out, be willing to accept some.

[bartkat]

Baloney! Don't you unsderstand how a car works? Besides, air doesn't drive the car, the rear tires do. :huh:

Bartkat - I have to say you are out of line with the initial antagonistic comment...and then you threaten Knightshade for responding the same. Sounds like an abuse of power to me.

If you dish it out, be willing to accept some.

You'd be wise to stay out of it. The old brake dust thread has a flame or insult in almost every post. Things like that are cumulative. It's not up for discussion though since no power has been exercised and therefore has not been abused.

Have a problem? Take it to PM.

Stick to the topic here.

[smooth1]

Check the drag journals on the 350, it's not an insignificant difference in power... air temp has been shown to have a larger impact on drag times than nearly anything else anyone has done to the car so far.

At WOT colder air provides more power.

Most folks drive around at part throttle though, where they'll see better mileage in warmer weather than cold.

Even on a modern car.

In colder weather, especially early in starting the car, fluids are thicker, friction is higher, so economy is worse.

In colder weather it takes longer for the car to reach operating temp, and fuel economy is worse until it does. In general up to a point your engine works more efficiently when it's warme

In colder weather rolling resistance is higher because the PSI in your tires drops as the temp does

Warmer air, being less dense (bad for power at WOT) provides less air resistance to push the car against than cold denser air.

Plus, summer blends of fuel have more energy than winter mixes of fuel.

While none of these is a HUGE factor they certainly add up, and all of them lead to better mileage in the summer than the winter.

And I sure hope it doesn't blow into a huge debate, otherwise someone might sneak in the last word and close the thread!

This is incorrect. Sorry.....

Of course tire pressure and the obviuos things can effect your gas mileage, but warm or cold air coming into the engine has no effect on fuel mileage.

That's why there is an IAT AND a Mass air flow sensor.

Warm air does not result in a leaner mixture of fuel. If a mass ratio of 14.7 to 1, air to fuel, needs to be maintained, then the engine will keep it there. A lean mixture is a mixture with more air (flip side of the coin, less fuel) than the stoich mix requires. To run a richer or leaner A/F mixes, you would have to reprogram the ECU and that is not available yet.

Cruising at 2200 rpm, in warm air, the engine is pulling in less oxygen, and so it is making 10 units of power, and runs at 53 mph. In order to cruise at 55mph, the engine needs to run faster, at 2250 rpms to achieve 11 units of power. Likewise, in a cold air scenario, cruising at 2200 rpm, the engine is pulling in more air, and so it is making 12 units of power, and runs at 57 mph. In order to cruise at 55mph, the engine needs to run slower, at 2150 rpms to achieve 11 units of power.

The differences your seeing at WOT are in the amount of power the engine is capable of making with the RPM range it is limited to, not in fuel efficiency. In colder air, the motor would still be able to produce more power and hence run faster, but it would still use the same amount of fuel.

[Knightshade]

Check the drag journals on the 350, it's not an insignificant difference in power... air temp has been shown to have a larger impact on drag times than nearly anything else anyone has done to the car so far.

At WOT colder air provides more power.

Most folks drive around at part throttle though, where they'll see better mileage in warmer weather than cold.

Even on a modern car.

In colder weather, especially early in starting the car, fluids are thicker, friction is higher, so economy is worse.

In colder weather it takes longer for the car to reach operating temp, and fuel economy is worse until it does. In general up to a point your engine works more efficiently when it's warme

In colder weather rolling resistance is higher because the PSI in your tires drops as the temp does

Warmer air, being less dense (bad for power at WOT) provides less air resistance to push the car against than cold denser air.

Plus, summer blends of fuel have more energy than winter mixes of fuel.

While none of these is a HUGE factor they certainly add up, and all of them lead to better mileage in the summer than the winter.

And I sure hope it doesn't blow into a huge debate, otherwise someone might sneak in the last word and close the thread!

This is incorrect. Sorry.....

Of course tire pressure and the obviuos things can effect your gas mileage, but warm or cold air coming into the engine has no effect on fuel mileage.

That's why there is an IAT AND a Mass air flow sensor.

Warm air does not result in a leaner mixture of fuel. If a mass ratio of 14.7 to 1, air to fuel, needs to be maintained, then the engine will keep it there. A lean mixture is a mixture with more air (flip side of the coin, less fuel) than the stoich mix requires. To run a richer or leaner A/F mixes, you would have to reprogram the ECU and that is not available yet.

Cruising at 2200 rpm, in warm air, the engine is pulling in less oxygen, and so it is making 10 units of power, and runs at 53 mph. In order to cruise at 55mph, the engine needs to run faster, at 2250 rpms to achieve 11 units of power. Likewise, in a cold air scenario, cruising at 2200 rpm, the engine is pulling in more air, and so it is making 12 units of power, and runs at 57 mph. In order to cruise at 55mph, the engine needs to run slower, at 2150 rpms to achieve 11 units of power.

The differences your seeing at WOT are in the amount of power the engine is capable of making with the RPM range it is limited to, not in fuel efficiency. In colder air, the motor would still be able to produce more power and hence run faster, but it would still use the same amount of fuel.

Can you point out which part of my post, specifically, is wrong?

because I list half a dozen points about when it's cold out. 0 of them have to do with the temp of the air coming into the engine. And you admit I'm correct about them causing worse mileage when it's cold.

Then you tell me I'm wrong by giving a lecture on air temps entering the engine. Which isn't at all what I was talking about.

[mr_raider]

My AWD is250 is getting 11L/100km city and I got 8.2L/100km highway on recent road trip with 4 people in the car and a full trunk driving 120km/h.

I'll let the smart people convert all that from metric to US.

[smooth1]

Check the drag journals on the 350, it's not an insignificant difference in power... air temp has been shown to have a larger impact on drag times than nearly anything else anyone has done to the car so far.

At WOT colder air provides more power.

Most folks drive around at part throttle though, where they'll see better mileage in warmer weather than cold.

Even on a modern car.

In colder weather, especially early in starting the car, fluids are thicker, friction is higher, so economy is worse.

In colder weather it takes longer for the car to reach operating temp, and fuel economy is worse until it does. In general up to a point your engine works more efficiently when it's warme

In colder weather rolling resistance is higher because the PSI in your tires drops as the temp does

Warmer air, being less dense (bad for power at WOT) provides less air resistance to push the car against than cold denser air.

Plus, summer blends of fuel have more energy than winter mixes of fuel.

While none of these is a HUGE factor they certainly add up, and all of them lead to better mileage in the summer than the winter.

And I sure hope it doesn't blow into a huge debate, otherwise someone might sneak in the last word and close the thread!

This is incorrect. Sorry.....

Of course tire pressure and the obviuos things can effect your gas mileage, but warm or cold air coming into the engine has no effect on fuel mileage.

That's why there is an IAT AND a Mass air flow sensor.

Warm air does not result in a leaner mixture of fuel. If a mass ratio of 14.7 to 1, air to fuel, needs to be maintained, then the engine will keep it there. A lean mixture is a mixture with more air (flip side of the coin, less fuel) than the stoich mix requires. To run a richer or leaner A/F mixes, you would have to reprogram the ECU and that is not available yet.

Cruising at 2200 rpm, in warm air, the engine is pulling in less oxygen, and so it is making 10 units of power, and runs at 53 mph. In order to cruise at 55mph, the engine needs to run faster, at 2250 rpms to achieve 11 units of power. Likewise, in a cold air scenario, cruising at 2200 rpm, the engine is pulling in more air, and so it is making 11 units of power, and runs at 57 mph. In order to cruise at 55mph, the engine needs to run slower, at 2150 rpms to achieve 10 units of power.

The differences your seeing at WOT are in the amount of power the engine is capable of making with the RPM range it is limited to, not in fuel efficiency. In colder air, the motor would still be able to produce more power and hence run faster, but it would still use the same amount of fuel.

Can you point out which part of my post, specifically, is wrong?

because I list half a dozen points about when it's cold out. 0 of them have to do with the temp of the air coming into the engine. And you admit I'm correct about them causing worse mileage when it's cold.

Then you tell me I'm wrong by giving a lecture on air temps entering the engine. Which isn't at all what I was talking about.

Most folks drive around at part throttle though, where they'll see better mileage in warmer weather than cold.

Even on a modern car.

This would be taken by anyone with a mechanical background as referring to the intake air temp.

In colder weather it takes longer for the car to reach operating temp, and fuel economy is worse until it does. In general up to a point your engine works more efficiently when it's warme

Again, all monitored and adjusted for by the ECU and hence, won't change the fuel mileage. The car would simply run at a higher or lower RPM to create the same amount of power. And in todays engines, tolerances levels are much tighter than say the 1980's in which piston rings would need time to warm up and flex to create the seals on the pistons, but not in todays engines.

In colder weather rolling resistance is higher because the PSI in your tires drops as the temp does

only for the first few feet of travel as they come up to temp. But even then, your really reaching here.

Warmer air, being less dense (bad for power at WOT) provides less air resistance to push the car against than cold denser air.

I don't even know what you are trying to say here, or where you are going with this.

/Plus, summer blends of fuel have more energy than winter mixes of fuel.

The term "summer blend" is shorthand for a menu of federally and locally mandated summertime fuel recipes that are designed to cut down on smog. The gasoline we use is always refined from an intricate blend of ingredients; the process combines coffee-dark crude oil with various additives that increase performance or make fuel burn more cleanly. Because overlapping federal and local requirements call for different recipes in different locales and seasons, there are approximately 20 distinct "boutique blends" of gasoline sold in the United States. Some Americans end up pumping a blend called Carb (named for the California Air Resources Board) while others burn Atlanta (named for Georgia's capital, where it's sold).

Refineries brew their summer blends by removing hydrocarbons that are more prone to evaporate in hot weather. These chemicals, called volatile organic compounds, react with airborne pollutants in the summer sun to form ozone, one of the main components of smog. From June 1 to Sept. 15, the EPA mandates that pumps in 12 high-ozone urban areas—such as Los Angeles, New York City, and Baton Rouge—deliver gasoline that meets special low-evaporation standards. Several states have voluntarily adopted the rules, and 15 have enacted their own seasonal-blend regulations on top of the EPA's. For example, pollution-conscious California has mandated that service stations must start selling its summer blend in May.

As the BTU ratings can vary by 3-4% from one fuel company to the next, the 1.5% difference in the summer to winter blend is kinda moot.

[Knightshade]

Most folks drive around at part throttle though, where they'll see better mileage in warmer weather than cold.

Even on a modern car.

This would be taken by anyone with a mechanical background as referring to the intake air temp.

It would be taken by a basic reading of english, and the context of the sentence immediately before it (about WOT making more power in cold weather) to mean that a car sees better mileage in warm weather than cold. Which is does.

The -rest- of the post goes on to explain why, and at NO point does it mention intake air at all.

You just decided to make that -your- point, and say I was wrong about it, when I didn't say a single word about it to begin with.

In colder weather it takes longer for the car to reach operating temp, and fuel economy is worse until it does. In general up to a point your engine works more efficiently when it's warmer

Again, all monitored and adjusted for by the ECU and hence, won't change the fuel mileage. The car would simply run at a higher or lower RPM to create the same amount of power. And in todays engines, tolerances levels are much tighter than say the 1980's in which piston rings would need time to warm up and flex to create the seals on the pistons, but not in todays engines.

Not at all. The engine can not compensate for the oil being thicker when its cold by knowing that it's cold. The internals of the engine will overall experience higher friction and less efficient operation prior to reached operating temps.

Do you know what open loop and closed loop are by the way? Do you know why, and when, the car switches from one to the other? (Hint: temperature is involved, and one is more efficient than the other)

In colder weather rolling resistance is higher because the PSI in your tires drops as the temp does

only for the first few feet of travel as they come up to temp. But even then, your really reaching here.

You're suggesting that tires go from parked-in-winter-cold to "same operating temp as summer" in a couple feet of travel?

Really?

Plus, summer blends of fuel have more energy than winter mixes of fuel.

The term "summer blend" is shorthand for a menu of federally and locally mandated summertime fuel recipes that are designed to cut down on smog. The gasoline we use is always refined from an intricate blend of ingredients; the process combines coffee-dark crude oil with various additives that increase performance or make fuel burn more cleanly. Because overlapping federal and local requirements call for different recipes in different locales and seasons, there are approximately 20 distinct "boutique blends" of gasoline sold in the United States. Some Americans end up pumping a blend called Carb (named for the California Air Resources Board) while others burn Atlanta (named for Georgia's capital, where it's sold).

Refineries brew their summer blends by removing hydrocarbons that are more prone to evaporate in hot weather. These chemicals, called volatile organic compounds, react with airborne pollutants in the summer sun to form ozone, one of the main components of smog. From June 1 to Sept. 15, the EPA mandates that pumps in 12 high-ozone urban areas—such as Los Angeles, New York City, and Baton Rouge—deliver gasoline that meets special low-evaporation standards. Several states have voluntarily adopted the rules, and 15 have enacted their own seasonal-blend regulations on top of the EPA's. For example, pollution-conscious California has mandated that service stations must start selling its summer blend in May.

As the BTU ratings can vary by 3-4% from one fuel company to the next, the 1.5% difference in the summer to winter blend is kinda moot.

That was an extraordinarily long and completely irrelevant description of summer and winter fuel blends.

If you buy your gas from the same company it will have less energy in the winter blend than the summer blend. 1.5% according to you, which certainly might or might not be accurate, but the essential point was IT HAS LESS ENERGY so you will.... what?

Get worse mileage.

It's hilarious when you post 3 pages of stuff that ends up agreeing with me then somehow conclude it means I'm wrong.

It doesn't make any sense, but it's hilarious.

I will try again to get a direct answer out of you, which you seem to dislike giving-

True or false, all else being equal the same car getting fuel from the same place will experience better average mileage in the summer than in the winter?