Gas Mileage Improvement

[Marine Mustang]

Just purchased a 2011 RX-350 AWD with 19,500 miles on odometer. Now at 20, 500 with several long trips planned next month. Currently getting average of 20 MPG in mixed driving (not heavy city type, but not Interstate) Used to get about 24 mpg city and 27 mpg road driving on a 2008 model, also AWD. Is there a method, adjustment, computer setting or other 'fix' for this that will improve the overall mileage? Have tried both mid-range and high octane fuels with no noticeable difference or improvement. I there an acceptable after-market product that would be beneficial? Thanks for the review.

[13IS250C]

Are you using a synthetic oil? My mileage went up a little bit on my 370Z when I switched to it. Other than that, I don't know much else to suggest.

[Marine Mustang]

The dealer swore that he put in Mobil 1 (5W30) and I'll take his word for it. I'm thinking about the Dunlop tires on it now but will likely switch to Michelin at the right time. The dealer discourages any 'after-market' gimmicks to be on the cautious side but we'll see. Thanks for your comment.

[13IS250C]

Sure!

I went from 19.7 to 19.9. Never could get over the 20 mpg mark.

[00RX300-Again]

The dealer swore that he put in Mobil 1 (5W30)...

Isn't 0W20 the correct oil vs the 5W30 your dealer used? I think it was changed since the 2010 model.

[Marine Mustang]

Bob, I just went back and looked at the work sheet on the car...and you are spot on! It calls out 0W20 oil, 7 quarts (with the filter). Good tip, thank you.

[pj8708]

As you delve into the Lexus litureature, you'l find that the proper viscosity of oil to use can vary by the choice of what your dealer thinks best suits your area/region, the various speeds incountered, i.e. lots of freeway driving or rural driving. Also climate.....range of teperature from one season to the next.

I know their are dealers who insist on Dino oil/synth blend for older Lexus, and full synthetic for 2013's.

IMO, You will never find anything better to increase the bottom line of your MPG , than your right foot. Control the rate of acceleration, the number of people you just HAVE to pass, the kind of stops where you almost put your RX in a "head Stand".

There's also the ability to leave 10 minute early so your not having to blow out 75 - 80 mph in order to get to your destination on time.

Sorry if this sounds like a "Dad" lecture.

We just added a 2013 RX350 so we'll have a chance to put our money where our mouth is.

Paul

[Rayzee]

I drive a 2010 RX 350 and was told that mileage would improve with use. Sure enough I got better mileage after about a year. In my opinion those manufacturer supplied mileage figures don't apply unless you pay religious attention to the ECO light on your dash. Also, at my last maintenance appointment two months ago the dealer installed an update to the computer firmware that supposedly improves performance.

[13IS250C]

I noticed the other day that my mileage had jumped from 24.5 to 24.7. I have just hit 8k miles. I'm pleased as punch at the mileage I am getting with my "spirited" driving habits. ;)

[IanR]

Try using a K&N lifetime replacement air filter. They not only increase horsepower but also gas mileage. I installed it in my RX330 and highway mileage went from 21 to 22.9 at an average speed of 80mph. Acceleration improvement is phenomenal. K&M claim they last 50,000 miles between cleanings. I got mine on line for $30.00 and installed it myself.

[RED HORSE]

Switching to ethanol free gas will result in about a 2mpg increase in my experience. It is hard to find but it is out there and worth it to me.

[Micah.Berry]

Make sure your tire pressures are up to spec. With colder temperatures, pressures will go down, and rolling resistance goes up, eating your fuel economy.

Micah

[IanR]

The only place I know of where you can get ethanol free gas is from a boat marina. However you'll pay a hefty premium and may not be worth it.

[RED HORSE]

I buy it at a CIGO station two blocks from the house and they don't do any boat business. I purchased it earlier this week during a 500 mile trip in Baton Rouge, Louisiana and was no where near a marina or any boats. True, many marinas have ethanol free gas, but they aren't the only ones.

http://pure-gas.org/index.jsp

[SmilingBoognish]

I'm very impressed with 27/24 on an '08 RX350 with AWD. We get around 24-25 on trips to Tahoe, with a roof mounted box and 7,000+ feet of elevation change. However, we are lucky to get more than 14 around town! I should note that the road to our house has an elevation gain of almost 400' in less than half a mile, which just kills the around town mileage.

[billtech66]

Working professionly on vehicles for almost 50 years;

Best things to improve fuel economy is:

1. a light foot. as Paul mentioned.

2. Tire Pressures. Make sure they are not low, and in fact raise them as much as is safe, but not to maximum.

3. Dropping your speed by 3mph.

4. Putting auto trans in neutral at stops, since it uses up to 50% more fuel at stops when in gear.

quote: A main way hybrid-electric cars reduce fuel consumption is by switching off their engines while stopped in traffic. For modern, fuel-injected vehicles, the break-even point for turning off the engine and then restarting it right before traffic begins to flow may be as little as 10 seconds, even when considering extra wear on the starter motor, battery and other components. END

http://www.edmunds.com/car-reviews/top-10/top-10-ways-to-waste-gas.html

RE: K&N air filters; all modern air filters are high flow, high volume. And if there WAS a minor restriction, it would not lower fuel economy in modern fuel injected vehicles. (or RAISE fuel economy if you took the Air Filter OUT.)

ECU's base fuel delivery on air volume entering the engine, engine temperature, throttle position. The air filter is BEFORE this sensor.

RE: 0w20 oil vs 10w40 engine oil. I've done dyno tests and fuel consumption runs comparing the two and there was zero difference.

When engine oil is hot, all oils are thin. NOT IMO enough difference to make a significant (or even noticeable) increase in fuel economy.

http://www.upmpg.com/tech_articles/motoroil_viscosity/

If there was a trick to increase fuel economy and power, Manufacturers are already using it.

for example: 4 valves per cyl; variable cam timing, close tolerances, many man hours dyno testing, computer model testing .. large or small changes in shape and smoothness of intake and exhaust ports for flow dynamics, inertia tuning, acoustic tuning, valves, combustion chamber, placement of spark plugs ... We get as much power and efficiency per cc now in an average car as we used to brag about from a highly tuned race engine decades ago.

[pj8708]

Thanks Bill for taking the time to write such an excellent posting! Great information.

A point I think some of us forget in discussing MPG statistics, is that the EPA does the testing with the manufacturer and determines what the miles per gallon estimates will be for a particular make and model. In a way, I can see where this can be good. If left to the manufacturer they may claim some results that are only possible in near perfect conditions, and only on the first Tuesday of each month!..LOL

Both the EPA and manufacturers, along with other automotive interest have established future mandates for fuel economy by the later part of this decade.

With all of these points in mind, you will see the mpg figures increase as we go along. But as Bill pointed , todays internal combustion engines are even more complicated than my first Lexus, a 2005 ES. However, we come to a point where basic enginered technology reaches it's limit of being able to provide any more efficientcy. That brings the new technologies we all see and read about.

Call me a fool, but as long as I am getting resonable gas mileage I don't worry about wether it's somewhat over or under. What I do worry about is if I will be willing to adapt to the new products after a life time love affair with the power of gasoline!!.

Paul

[J Random User]

Try using a K&N lifetime replacement air filter. They not only increase horsepower but also gas mileage. I installed it in my RX330 and highway mileage went from 21 to 22.9 at an average speed of 80mph. Acceleration improvement is phenomenal. K&M claim they last 50,000 miles between cleanings. I got mine on line for $30.00 and installed it myself.

This is called the "placebo effect". There is no way that switching to a K&N felt filter would give you a whopping 10% in MPG nor any noticeable increase in HP that a driver could discern and certainly never to the point of being anywhere near "phenomenal"increase etc.

Go look up the dyno tests done with K&N filters vs. stock and see for yourself the results are either marginally better (in the range of %0.0X!) or actually worse than stock.

[J Random User]

Working professionly on vehicles for almost 50 years;

Best things to improve fuel economy is:

1. a light foot. as Paul mentioned.

2. Tire Pressures. Make sure they are not low, and in fact raise them as much as is safe, but not to maximum.

3. Dropping your speed by 3mph.

4. Putting auto trans in neutral at stops, since it uses up to 50% more fuel at stops when in gear.

quote: A main way hybrid-electric cars reduce fuel consumption is by switching off their engines while stopped in traffic. For modern, fuel-injected vehicles, the break-even point for turning off the engine and then restarting it right before traffic begins to flow may be as little as 10 seconds, even when considering extra wear on the starter motor, battery and other components. END

http://www.edmunds.com/car-reviews/top-10/top-10-ways-to-waste-gas.html

RE: K&N air filters; all modern air filters are high flow, high volume. And if there WAS a minor restriction, it would not lower fuel economy in modern fuel injected vehicles. (or RAISE fuel economy if you took the Air Filter OUT.)

ECU's base fuel delivery on air volume entering the engine, engine temperature, throttle position. The air filter is BEFORE this sensor.

RE: 0w20 oil vs 10w40 engine oil. I've done dyno tests and fuel consumption runs comparing the two and there was zero difference.

When engine oil is hot, all oils are thin. NOT IMO enough difference to make a significant (or even noticeable) increase in fuel economy.

http://www.upmpg.com/tech_articles/motoroil_viscosity/

If there was a trick to increase fuel economy and power, Manufacturers are already using it.

for example: 4 valves per cyl; variable cam timing, close tolerances, many man hours dyno testing, computer model testing .. large or small changes in shape and smoothness of intake and exhaust ports for flow dynamics, inertia tuning, acoustic tuning, valves, combustion chamber, placement of spark plugs ... We get as much power and efficiency per cc now in an average car as we used to brag about from a highly tuned race engine decades ago.

Most of your advice is good but I have to call out the "pump up the pressure" myth!

Increasing tire pressure, even significantly is proven to have no effect on fuel economy:

http://www.popularmechanics.com/cars/news/4199963

[engnrng79]

"Most of your advice is good but I have to call out the "pump up the pressure" myth!

Increasing tire pressure, even significantly is proven to have no effect on fuel economy:

http://www.popularmechanics.com/cars/news/4199963 "

This article actually proves that higher tire inflation has a significant positive affect on mpg. The authors ignored the simple physics involved going uphill vs going downhill. If they had done the test in reverse, they would have claimed an effect much higher than reality. Why is it that people who don't know physics or math get to write these articles and why is it that the editor of Popular Mechanics prints them?

OK, I know. It is called "Popular Mechanics". It is not called "Actual Real World Mechanics". So, they only print what might be "popular" and therefore sell more copies. I used to have an expectation that this magazine had some integrity. Not any more.

Also, the "recommended tire pressure" on the tag on your door is what the manufacturer figures is the best compromise between ride comfort, handling safety, tire life, and mileage. The maximum rated safe tire pressure can be found on the side wall of the tire.