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RazzMaTazz 12-05-2008 09:38 AM

How to improve my MPG - Please Help.
Hello everyone, I am new to this forum, actually just discovered it while doing a search on google. I recently bought a 2009 THH, and have driven about 1300 miles so far. However, I am disappointed with MPG. From what I had read and researched for the past 9 months, almost every article/website said 26 City and 27 Highway. Well, so far I am averaging about 23-24 MPG combined:confused::(. I try to be very cautious with the way I drive (donít accelerate too quickly, let go of the pedal on down hill slopes, etc.). But it hasnít really helped much. I live in Connecticut and it is starting to get little colder these days. My driving conditions are, some of the driving has been in bumper to bumper and some just smooth sailing on the highway.

What can I do to increase the MPG, or what am I not doing. Please help!

Thank you.

Gairwyn 12-05-2008 10:34 AM

Re: How to improve my MPG - Please Help.
Cold weather and bumper-to-bumper driving are a challenge, and most likely are affecting your mpg. Another factor that I have found to decrease overall mpg is one that I have to deal with: short trips, and even worse, short trips in colder weather because the car barely warms up by the time you get to the destination.
Also, your car is relatively new and probably still needs time to "break in". I would think once the warmer weather returns, you might find some improvement in your mpg. Search the THH forum for specific advice regarding your vehicle, and continue to research the internet for subjects like eco-driving, fuel-efficient driving, or hypermiling. You will likely find some techniques you would be comfortable trying that would help improve your mpg. Keep an eye on your tire pressures, especially in colder weather, as tire pressure tends to decrease in the cold. Don't drive above the posted speed limits.
Here's a link to a rather mild article in which some suggestions are put forth that most anyone can apply to their driving to improve mpg:

wwest 12-05-2008 11:52 AM

Re: How to improve my MPG - Please Help.
The HH power train is virtually a clone of that in the RX400h series, designed for stellar performance, quick 0-60 times, NOT FE. And then to boot the HH with a third row is a much heavier than the RXh.

The 2010 RXh is getting the V6 engine revised to the Atkinson cycle so there may be improved FE on the way, especially if the GS's V6 DFI technique is also used and used properly. But I suspect the Lexus engineers will still be oriented toward 0-60 times so I'm not encouraged.

If you don't do a lot of stop and go driving then you bought the wrong vehicle.

And remember the real gain for these HSD system is in city stop and go driving when you get FREE fuel via regenerative braking, and even then only in comparison to non-hybrid vehicles.

On the highway, cruising, there will be little or even no opportunity for energy recovery and yet the hybrid battery must still be used in conjunction with the ICE for proper e/CVT operation. So the hybrid battery will often need to be recharged via the ICE. Not only not for free, but a pretty lossy path in comparison to non-hybrid without this handicap.

On the highway the new I4 Highlander would undoubtedly yeild better FE than your HH.

All that being said...

Go to the dealer and have the c-best options set that allow you to disable the A/C functionality, normal and in defrost/defog/demist and leave them disabled throughout the winter months. Those go back to '01 and now there may be other c-best options now available. The ability to prevent the system from automatically switching into cooling mode, on the coldest darkest night of winter, wherein the windshield interior surface gets no warming airflow. When in heating mode, footwell outlet airflow, a portion of airflow is diverted to the windshield.

And rather than use an engine block heater as many suggest, and maybe compromise the longivity of the catalyst, I would use a ~500 watt ceramic heater w/blower on a timer to preheat the cabin before starting out in the morning. If you opted for the leather seating option and therefore heated seats I would splice in a 12 volt power suppy and pre-heat the seats via the same timer.

wwest 12-05-2008 12:52 PM

Re: How to improve my MPG - Please Help.
One other "modification" that might be worth trying.

Disconnect the battery and then mechanically restrict the servo-driven throttle plate by say 20-30% such that it can NEVER fully open and then reconnect the battery. The engine control ECU should quickly "learn" the new throttle position travel limit and now your HH's ICE will not, cannot, burn as much fuel at WOT.

0-60 times will suffer but FE might improve quite significantly.

Don R 12-06-2008 10:05 AM

Re: How to improve my MPG - Please Help.
2 Attachment(s)
As others have noted, ambient air temperature greatly affects fuel efficiency of a Hybrid. This is increasingly true as the trip distance becomes shorter than 10 miles. See the MPG charts below for my 2006 Highlander Hybrid typically driven 9 miles to work and back.

These charts use miles-driven/gallons-used calculations for all tanks of gas I consumed since the vehicle was new. In the summer I can easily get 30 MPG and in the dead of winter I get 24 MPG or even less for the exact same driving routine.

Attachment 3290

Attachment 3291

RazzMaTazz 12-08-2008 08:57 AM

Re: How to improve my MPG - Please Help.
Thank you all. I will definitely try some of the techniques you have mentioned and see if it improves the MPG. I guess I will also wait and see how the MPG improves as I break in the car a little more. Maybe since this is our first hybrid vehicle, we just need to understand the vehicle a little more.

Thanks a bunch.

gumby 12-12-2008 09:38 PM

Re: How to improve my MPG - Please Help.
Yes, do not be discouraged. ALL vehicles get poorer gas Mileage in cold weather.
Most people don't know this or notice. Now that you have a hybrid, you notice, as better MPG is one of the things you are now interested in.
My lifetime average is near 47 MPG, but in the winter I get 40-44. And Dallas-area winters are not severe :). Nothing like in CN.

08hybridok 12-16-2008 09:01 AM

Re: How to improve my MPG - Please Help.
Sorry I have no ideas on how to optimise the HH as I understand the technology is different then the FEH. But one factor besides cold weather is winter blends of gas. That can affect FE. Have you ever met EPA estimates? How long have you been driveing, weeks/months? [to see if you can compare warmer weather, and various gas blends].

I don't know about CT, but here in OK the 2 major differecens at the pump are 10% Ethenol or not [yes I'm sure the technical side there's more varations, but to K.I.S.S. we call it 100% & E10]. Now I know from experience of using E10 (wasn't labeled as such at the time, laws have changed so now it is labeled) affected mt FE by ~10% ~4Mpg

If this is still a new purchase, it does take time to re-learn to drive and adapt to the new technology. The FEH board has some great members that have posted many a message on how to break EPA estimates, and I read and follow a few tips, so I can't or won't follow; but you get the point see what others with your technology have done, maybe impliment 1 change at a time. For me fake/force shifting was the easiest tip to start doing, not sure if the HH has a eCVT or not tho.

Don't give up, just keep tring differnt things.

Check Tire Pressure!

RazzMaTazz 12-17-2008 09:00 AM

Re: How to improve my MPG - Please Help.
Just an update from this past weekends driving.

My wife and I drove the THH quite a bit this past weekend, and I used some of the techniques others have mentioned and tried some of my own. By just doing some basic and above mentioned techniques, I was able to improve the MPG by about 1 Ė though not much, but I guess still an improvement and encouraging. Hopefully I can hit the 25/26+ threshold with more practice, understanding of the weaknesses and strengths and warmer months. By the way, we really love this vehicle.

08hybridok 12-17-2008 10:34 AM

Re: How to improve my MPG - Please Help.
A couple things, does the THH Have an instant mpg readout? (My FEH only has a 'gauge' buit in, but once you reach about 28-30mpg it's topped out when you can still get 5+mpgs). So I bought a ScanGuage, programmed in a few key things to keep an eye on. instant and trip avg mpgs seem to help. You can see when driving, instantly what makes it go up & down!

Also, since it seems theres 2 drivers, like me as well, is to play the who's better game! My wife loves competition, and really hates losing! So that lightened her foot a bit, after a month her #'s went up a few mpgs, but she's not into the whole hypermilling thing; but even so our combined avg on a tank is a pretty consistient 30-32 (epa is 34/30 32 combined) so I'm kinda happy. But knowing by the ScanGauge on a majority of my trips to see my trip avg above 35, sometimes in the 40's it's discourging to know the avg will still only be 30 :angry:

Good luck, keep up updated!

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