Fuel Economy Merged Threads

[Kuboshi]

Erm... it was really hard using the search wit the more then 4 letter limit... My IS 250 is currently at 2,400 miles and I drive it 100% city in Irvine by UCI. I've been trying to squeeze as much as I can from it in terms of mileage - ie: I would drive and whenever possible would let off the gas and let inertia take over... however I've only been getting 17miles per gallon! Is this right? EPA said 24 city... and I know its off by some 10-15% because of old measuring standards... and I know that Irvine is somewat hilly... but still 17mpg only? Is there something wrong wit my IS? Is it still in "Break in"? or am I just unlucky? Thanx for any help!

Also, I did one fuel up where I rev it a lot to 4k-5k whenever possible. and leave ECT Power on... and I got 16mpg from that... which was expected but the 17mpg is when I drive VERY conservatively.

[Scott M]

Erm... it was really hard using the search wit the more then 4 letter limit... My IS 250 is currently at 2,400 miles and I drive it 100% city in Irvine by UCI. I've been trying to squeeze as much as I can from it in terms of mileage - ie: I would drive and whenever possible would let off the gas and let inertia take over... however I've only been getting 17miles per gallon! Is this right? EPA said 24 city... and I know its off by some 10-15% because of old measuring standards... and I know that Irvine is somewat hilly... but still 17mpg only? Is there something wrong wit my IS? Is it still in "Break in"? or am I just unlucky? Thanx for any help!

Also, I did one fuel up where I rev it a lot to 4k-5k whenever possible. and leave ECT Power on... and I got 16mpg from that... which was expected but the 17mpg is when I drive VERY conservatively.

I agree... It's hard to search for MPG threads with that limitation.

I knew a thread existed, so I went spelunking and found it for you.

http://us.lexusownersclub.com/forums/index...showtopic=29944

[EnginePassion]

My IS 250 is about two months old. The first time i filled up the tank, the range said about 320, but each time i fill up it lowers more and more, This morning i filled up and the range said 293... Is this because the car is getting use to how you drive the car and making a more accurate estimate for the range?

Thanks

Need help on this topic.

what is250 do you have? I mean they may vary from AWD to RWD.

[chughtaijr]

Erm... it was really hard using the search wit the more then 4 letter limit... My IS 250 is currently at 2,400 miles and I drive it 100% city in Irvine by UCI. I've been trying to squeeze as much as I can from it in terms of mileage - ie: I would drive and whenever possible would let off the gas and let inertia take over... however I've only been getting 17miles per gallon! Is this right? EPA said 24 city... and I know its off by some 10-15% because of old measuring standards... and I know that Irvine is somewat hilly... but still 17mpg only? Is there something wrong wit my IS? Is it still in "Break in"? or am I just unlucky? Thanx for any help!

Also, I did one fuel up where I rev it a lot to 4k-5k whenever possible. and leave ECT Power on... and I got 16mpg from that... which was expected but the 17mpg is when I drive VERY conservatively.

My 350 got 15 mpg, winter and city only driving when I first got it, it has climbed over time and now with 6K miles, and 10 months old, it is up to 20mpg city only driving, and I park and start my car alot, typically 6 times in the about 14 miles I drive on a typical day. If I jump on the highway right after I fill up I can pull 31mpg if I take it easy and run for max gas miles. I would say give it 7-10K miles and see what happens, I'll bet it loosens up.

[tex2670]

Erm... it was really hard using the search wit the more then 4 letter limit... My IS 250 is currently at 2,400 miles and I drive it 100% city in Irvine by UCI. I've been trying to squeeze as much as I can from it in terms of mileage - ie: I would drive and whenever possible would let off the gas and let inertia take over... however I've only been getting 17miles per gallon! Is this right? EPA said 24 city... and I know its off by some 10-15% because of old measuring standards... and I know that Irvine is somewat hilly... but still 17mpg only? Is there something wrong wit my IS? Is it still in "Break in"? or am I just unlucky? Thanx for any help!

Also, I did one fuel up where I rev it a lot to 4k-5k whenever possible. and leave ECT Power on... and I got 16mpg from that... which was expected but the 17mpg is when I drive VERY conservatively.

My 350 got 15 mpg, winter and city only driving when I first got it, it has climbed over time and now with 6K miles, and 10 months old, it is up to 20mpg city only driving, and I park and start my car alot, typically 6 times in the about 14 miles I drive on a typical day. If I jump on the highway right after I fill up I can pull 31mpg if I take it easy and run for max gas miles. I would say give it 7-10K miles and see what happens, I'll bet it loosens up.

I have 3600 mi ono my 250 AWD, and consistently get 20-21 mpg; mostly city/suburban driving. Even when I went to 89 octane for a few tanks--no change in MPG.

[07'IS350]

I constantly get 21 MPG in the city and I have a very heavy right foot. I mean more than 3/4 throtle at every stop.

[EnginePassion]

I have around 8k in my IS250 AWD and have this very low mileage. This blows my mind and I thought it's because of the AWD; but certianly it's un acceptable.

This is the persuit of perfection!

[bjgross]

We got our 07 IS250 AWD at the beginning of Aug 07.

We consistently get 24 mostly in town driving and 29-30 highway driving.

Very satisfied for weight and power of this car!

[EnginePassion]

We got our 07 IS250 AWD at the beginning of Aug 07.

We consistently get 24 mostly in town driving and 29-30 highway driving.

Very satisfied for weight and power of this car!

Good for you!

But if this obvious discrepancy is not a sign of bad quality issue what is it? You can't tell me that your foot is made of gold and mine is cheap stone.

[Scott M]

We got our 07 IS250 AWD at the beginning of Aug 07.

We consistently get 24 mostly in town driving and 29-30 highway driving.

Very satisfied for weight and power of this car!

Good for you!

But if this obvious discrepancy is not a sign of bad quality issue what is it? You can't tell me that your foot is made of gold and mine is cheap stone.

Well, passion, you have to understand that everyone drives differently too.

No personal affront intended, but anyone who thinks the IS250 AWD has an acceptable amount of power does not drive the car like a sports car to begin with. If driven calmly, many IS250 owners are very happy with mid 20 MPG.

My guess is that bjgross drives calmly...at least more so than you.

(anyone else laugh when thay saw that name?):whistles:

[EnginePassion]

Well, passion, you have to understand that everyone drives differently too.

No personal affront intended, but anyone who thinks the IS250 AWD has an acceptable amount of power does not drive the car like a sports car to begin with. If driven calmly, many IS250 owners are very happy with mid 20 MPG.

My guess is that bjgross drives calmly...at least more so than you.

(anyone else laugh when thay saw that name?):whistles:

Well, thanks Scott, however, the discrepancy can not be that wide unless one car got to be tuned. No matter what bad driving habbit one have it should not be that big difference. I myself never got any higher than 18; when I fill in my tank with Shell(10%Ethanol) I get 14 mpg.

[HARTY]

My IS has 7500km on the clock and I get 11.5 L /100 kms.Our best petrol is 95 octane .I don't know what this is in gallons per mile.I also don't know if my figures are any good.Quite frankly I don't really care.I do know it is far better than most of the yank tanks around .

Anyway ,if anyone can convert for me ,Thanks

[EnginePassion]

My IS has 7500km on the clock and I get 11.5 L /100 kms.Our best petrol is 95 octane .I don't know what this is in gallons per mile.I also don't know if my figures are any good.Quite frankly I don't really care.I do know it is far better than most of the yank tanks around .

Anyway ,if anyone can convert for me ,Thanks

1 mile =1.61 km

1 gal = 3.79 liters

So, 11.5 L/100 kms = 3.04 gal/62.14 mile======>i.e. 20.44 mpg

Congrats.

[Scott M]

Well, thanks Scott, however, the discrepancy can not be that wide unless one car got to be tuned. No matter what bad driving habbit one have it should not be that big difference. I myself never got any higher than 18; when I fill in my tank with Shell(10%Ethanol) I get 14 mpg.

The discrepancies are very common.

I see the same thing in the Infiniti forums.

I have an 07 G35x and I use 93 Octane, but in my area, everything is also 10% Ethanol as well.

On any given day, driving 50% City / 50% Highway with some 'spirited' driving, I'm sitting at 18.x mpg.

Behaving myself, I'm at 22.x and on the highway, 27.x.

Others are complaining about being near 13 mpg, and never above 20 on the highway.

I think some of this may be the fuel, maybe a little of it could be car related, but most of this is just driving style and habits.

My wifes drives our 06 Acura MDX and when on the higway, I feel her constantly adjusting the throttle.

She gets 18 mpg.

When I drive the exact same car with the exact same fuel on the exact same day, I get 23.

[lambobaby1218]

My husband drives very slowly, and that gives him a better mpg. However, when he was driving my car around town, he got around 26 mpg. Now that I have it back, I'm slowly creeping it back up to about 28 mpg, with city and highway driving. And that's with my lead foot. Although, my Prius made me drive a little better, so now I'm more aware of what my mpg is. My '06 250 had about 26 mpg, same driving, same gas. I don't know. Maybe it's the way the car is tuned?

[ethan_in_seattle]

[Well, thanks Scott, however, the discrepancy can not be that wide unless one car got to be tuned. No matter what bad driving habbit one have it should not be that big difference. I myself never got any higher than 18; when I fill in my tank with Shell(10%Ethanol) I get 14 mpg.]

The apparent discrepancy in gas mileage is likely not a function of the quality of the car, as some have suggested. There are many factors that affect the mileage of a vehicle, including but not limited to altitude, barometric pressure, type of tires installed on the vehicle (a big factor), tire pressure, condition of car, driving style, weight of vehicle (this includes the weight of the driver and passengers). Most, if not all, cars vary at least as much as has been suggested by people posting on this forum. I used to own a Nissan 350Z, and that car, even when driven conservatively, got only about 18mpg. When I would park that car in my garage I would have to leave the garage door open for about 10 minutes to let the smell of exhaust clear. By contrast, my IS350 is odorless. This demonstrates its efficiency (exhaust odor is due to unburnt hydrocarbons which causes poor fuel economy). The IS's engine is truly an incredible machine; it meets federal ultra-low emission standards, gets 307hp (18 more than my Z), and gets an average of around 20mpg, combined driving (I do not have a light foot). Anyone who questions this car's quality or efficiency simply doesn't have enough experience with cars. As far as internal combustion engines go, this one is top-notch.

[CrunchySkippy]

There are many factors that affect the mileage of a vehicle, including but not limited to altitude, barometric pressure, type of tires installed on the vehicle (a big factor), tire pressure, condition of car, driving style, weight of vehicle (this includes the weight of the driver and passengers).

Ethan - don't forget topography as well (think San Francisco vs Topeka). But you've listed some good variables that aren't always obvious to some.

[Scott M]

The apparent discrepancy in gas mileage is likely not a function of the quality of the car, as some have suggested. There are many factors that affect the mileage of a vehicle, including but not limited to altitude, barometric pressure, type of tires installed on the vehicle (a big factor), tire pressure, condition of car, driving style, weight of vehicle (this includes the weight of the driver and passengers). Most, if not all, cars vary at least as much as has been suggested by people posting on this forum. I used to own a Nissan 350Z, and that car, even when driven conservatively, got only about 18mpg. When I would park that car in my garage I would have to leave the garage door open for about 10 minutes to let the smell of exhaust clear. By contrast, my IS350 is odorless. This demonstrates its efficiency (exhaust odor is due to unburnt hydrocarbons which causes poor fuel economy). The IS's engine is truly an incredible machine; it meets federal ultra-low emission standards, gets 307hp (18 more than my Z), and gets an average of around 20mpg, combined driving (I do not have a light foot). Anyone who questions this car's quality or efficiency simply doesn't have enough experience with cars. As far as internal combustion engines go, this one is top-notch.

Thanks Ethan... You're absolutely correct.

The point I was trying to add is that MPG can come right down to the driver's habits as well.

Comparing 2 different models or even 2 cars of the same make brings new variables to the equation, as you have mentioned.

Comparing only the driver, I get 5 MPG more than when the wife is driving.

Here, the tires, location, altitude, barometric pressure, type of road, fuel, tires and tire pressure, gross weight, moon's phase... all the variables are the same.

The only variable that changes in my example is who's driving the car.

The wife loves to constantly adjust her throttle. It's very slight, but I notice it every time she drives.

I'm more of a throttle featherer. (is that even a word? )

My point is that when comparing one person's model to another's same make/model... driver habit can and will make a big difference in MPG ratings, even with the slightest difference in driving habits.

[ethan_in_seattle]

"Ethan - don't forget topography as well (think San Francisco vs Topeka). But you've listed some good variables that aren't always obvious to some."

As I originally stated, "there are many factors that affect the mileage of a vehicle, 'including but not limited to'...". There are of course more factors than what I mentioned, such as topology, type of fuel used (formulations varies by region and throughout the year), and maintenance (air filter, oil, etc.). The importance of what I was trying to say is that people need to consider the many factors that influence gas mileage when considering the numbers and not compare directly with other people's numbers when all factors are certainly not equal.

Your observation about topology deserves further attention. Consider that work is defined as force times distance, and that when a car does work it consumes gas. The more work is does, the more gas it consumes. When you're driving on a flat surface, the amount of work your car does is basically equal to the sum of forces (drag, frictional losses in the drive train, tire resistance) required to propel the car at a constant speed multiplied by the distance that the car has traveled. When driving on irregular topology, the car must change elevation too. The amount of work done when climbing elevation is equal to the weight of the car multiplied by the change in elevation. Of course, roads don't go straight up or down, so the real work done by a car while traveling on hilly roads is equal to the work required to move it forward plus the work required to gain elevation. It should be obvious then that even a small change in elevation requires significantly more work, and thus consumes more gas, than driving on a flat road. Also, you don't get back the work done while climbing a hill when you go back down, though gravity does help reduce the amount of effort required to keep the car moving forward at a constant speed. In conclusion, the heavier the car or the hillier the terrain, the more gas a car is going to consume, regardless of the type of car. Our cars are relatively heavy, and so anyone who drives in a hilly area needs to understand that they will get significantly worse gas mileage than someone else who doesn't drive many hills, all other variables being equal.

[ethan_in_seattle]

Thanks Ethan... You're absolutely correct.

The point I was trying to add is that MPG can come right down to the driver's habits as well.

Comparing 2 different models or even 2 cars of the same make brings new variables to the equation, as you have mentioned.

Comparing only the driver, I get 5 MPG more than when the wife is driving.

Here, the tires, location, altitude, barometric pressure, type of road, fuel, tires and tire pressure, gross weight, moon's phase... all the variables are the same.

The only variable that changes in my example is who's driving the car.

The wife loves to constantly adjust her throttle. It's very slight, but I notice it every time she drives.

I'm more of a throttle featherer. (is that even a word? )

My point is that when comparing one person's model to another's same make/model... driver habit can and will make a big difference in MPG ratings, even with the slightest difference in driving habits.

Agreed. I don't mean to undermine the significance of driving behavior. This is undoubtedly one of the greatest factors in determining gas mileage. I've ridden with many people who seem incapable of modulating throttle response smoothly. These very same people seem to be rather vocal about their car's poor gas mileage. Coincidence?

[2008is250]

I wanted to start a slightly different angle on the mpg debate.

BTW, I get about 27.5 in mixed city/hwy driving with my 2008 is250.

What I want to discuss is the discrepancy between what the computer thinks I'm getting for the current tank and what I calculator says I'm getting. I've found the calculated mileage to be anywhere from 1-3 mpg different (the calculated figure is always lower). Anyone else doublecheck the Lexus math?

[2008is250]

I wanted to start a slightly different angle on the mpg debate.

BTW, I get about 27.5 in mixed city/hwy driving with my 2008 is250.

What I want to discuss is the discrepancy between what the computer thinks I'm getting for the current tank and what I calculator says I'm getting. I've found the calculated mileage to be anywhere from 1-3 mpg different (the calculated figure is always lower). Anyone else doublecheck the Lexus math?

[lambobaby1218]

My car's average right now is 27.1, and going up since I got the car back from my husband. My last tank average was 29.9. When I input my last three tanks into my GasBuddy site, it says I'm getting 28 mpg. I'm working on getting it back up to 30 mpg. But I guess that means I should stop driving 75 on the freeway, huh???!!! ;)

[pheelgood]

Got my 08' IS250 rwd, about a month ago. got 3k miles on it.

NOT very good on mpg, im getting abot 19-23 city driving, and 21-27 hwy... OH WELL, its an IS ...

My everyday car. about 35-40mi./day.

Anyway, is the gas tank range decline everytime I fill the tank?

1st time it was 384

2nd time it was 362

3rd time it was 348

does that happen to you guys?

[tex2670]

Got my 08' IS250 rwd, about a month ago. got 3k miles on it.

NOT very good on mpg, im getting abot 19-23 city driving, and 21-27 hwy... OH WELL, its an IS ...

My everyday car. about 35-40mi./day.

Anyway, is the gas tank range decline everytime I fill the tank?

1st time it was 384

2nd time it was 362

3rd time it was 348

does that happen to you guys?

I never even remember to check--it's all based on estimates anyway.