Miles Per Gallon

[katzjamr]

thank you mindmachine for much more eloquently explaining why premium gas used in the 400h does in fact result in better mpg, all other things being equal. (i.e. agressive driving obviously will lower mpg regardless of fuel) I understand that premium may not provide better results in other engines and in fact i use regular in our fleet of work trucks.

[RX400h]

Again, I'd like to remind everyone that the 2006 and perhaps the 2007 owner's manual clearly states that regular fuel is acceptable. Also, as I mentioned previously the intake air temperature makes a noticable difference as to how well the engine will perform with the particular grade gasolene used. Using regular gas when the ambient temperature is 40 degrees F can easily produce the same performance when ambient temperatures are 90 degrees F and premium fuel is used.

[Gryphon]

Actually for 2007 the recommendation changed to, "Premium unleaded gasoline with an octane rating of 91 (RON 96) or higher required for optimum performance."

Tom

[RX400h]

I guess I'm glad I have an 06 then!

[Gryphon]

I guess I'm glad I have an 06 then!

I think that they changed the recommendation, not the vehicle.

Tom

[400h08]

It was really cold here in Toronto in the past 2 weeks. Together with my Blizak sniw tires, I am getting 14 l/100km (17 mi/g) now instead of 9 l/100km (27.7 mi/g) back in August. In the summer, it was mixed hiway and city, but the last 2 weeks is strictly city. The ICE is running all the time, although I can still see the motors helping in start and cruising situations. Vow, 74% increase. But it still beats my old Mercedes ML320.

[SOMEONE ELSE'S GOT MY NAME]

It was really cold here in Toronto in the past 2 weeks. Together with my Blizak sniw tires, I am getting 14 l/100km (17 mi/g) now instead of 9 l/100km (27.7 mi/g) back in August. In the summer, it was mixed hiway and city, but the last 2 weeks is strictly city. The ICE is running all the time, although I can still see the motors helping in start and cruising situations. Vow, 74% increase. But it still beats my old Mercedes ML320.

Toyota part # is CO140-00644 ... if you want the block heater for the 3.3L ICE

(when it's super frosty, & you've got 90 minutes prior notice, don't leave home w/out it previously running ;) ... you'll see the mpg difference). They're about $47 USD and you'll save about $200 if you do it yourself ... just like you'll save yourself $75 by changing your own ICE air filter.

[400h08]

Thanks for your advice. I think that will really help.

[Fenton House]

Thanks for your advice. I think that will really help.

Hi//

Just wanted to add some thoughts. We have an 08 400h -- has about 25, 000 miles on it. We live in the Seattle, WA area and are happily wintering over (read Snowbirding) in the Phoenix area. While we were in Seattle the mileage varied between 25 - 27. Winter and summer - mixed driving. Did much better on hills. Changed to Mobil One 5-20 oil at 15,000 miles. Pulled a fairly heavy trailer to Phoenix through Idaho and Utah. Some significant hills. The car had no issues with the load. It's a very strong machine. We also had a Thule roof rack carrier on top. The worst mileage on the trip did not go below 22. So, now we're down in Phoenix (since Thanksgiving) and the mileage has changed considerably.

For some reason the car loves the area. I use the high octane COSTCO gas. When we're on the local highways we have to drive at 65 or risk being run over. Most of the traffic lights are not sync-ed. So, you end up getting up to speed and then braking and stopping. Not a very efficient way of driving. However, the car is averaging 30+ per gallon. Don't know why - maybe it's the oil, maybe it's the warmer weather. Whatever. I'm not complaining. Should mention that I avoid rapid acceleration.

Should also mention that the car has Michelin MXV4-S8 tires. I insisted on them after reading this forum. I kept them at 36 psi, but checked recently and found that the dealer (I think) had raised that to 38 psi. Maybe that has something to do with the mileage. Anyone have any input on tire pressure?

regards,

Fenton House

[RX400h]

My Bridgestone Alenzas seem to like 35 psi, so I recommend that you keep an eye on center wear. 38 may be a bit high, especially in warm environments.

[BillyShaft]

For some reason the car loves the area. I use the high octane COSTCO gas. When we're on the local highways we have to drive at 65 or risk being run over. Most of the traffic lights are not sync-ed. So, you end up getting up to speed and then braking and stopping. Not a very efficient way of driving. However, the car is averaging 30+ per gallon. Don't know why - maybe it's the oil, maybe it's the warmer weather. Whatever.

All of the things you are talking about, stop and go traffic, non-sync-ed lights, warm weather, high octane fuel...all contribute to your better gas mileage. Enjoy it!

[Legacy400h]

Brief question...

When all of you are stating your mph, are you resetting it to zero with each tank of gas? It may seem obvious to most, but when I see some people reporting that they couldn't get less than 25 mph if they tried, it makes me wonder. If I tried, I could easily get it down to 15-16 --- if I tried. But as averaging goes, as you get more miles racked up (250-300), it's harder to change the average.

I do, and I don't get nearly the mph you all do. I got better mileage when my '06 was newer, but it seems to have fallen. I always watch the mileage screen, as well as the little battery/ICE display above the steering wheel, and I try to keep it on battery as much as possible.

However, the winter has been -really- cold here near Chicago, and I make mostly shorter trips of less than 5 miles each. I've recently been getting 18-20 mph, and I always use premium. In warmer weather, I was getting 22-24 mph. It doesn't seem to keep the ICE off as much as it used to. Perhaps I'm not being quite as careful as I used to, but I try to use the cruise control as much as possible, which seems to help.

So, do you reset it with each tankful, or not?

[Gryphon]

Legacy, I only check my MPG by recording the data and maintaining it in an Excel spreadsheet. The onboard computer seems optimistic.

I have noticed that with moderate hypermiling (cruise control, anticipating slowdowns/stops, etc.) I can increase my mileage about 10 MPG--typically from 25-26 to 35-36. Unfortunately I get power hungry too often and end up in the mid 20s.

Tom

[Legacy400h]

Since you maintain it in a spreadsheet, you should know not only your tank-by-tank mileage, but a running average as well.

I doubt many people are that diligent, but I don't know. RX400h owners are a different breed, it seems.

You mention getting 25-35 mph when you're careful. I'd kill for mileage like that. I also anticipate stops as much as possible, yet cannot get it above 25-26 in the summer months on an occasional half hour trip, which is the longest trip I'm likely to take.

After almost 3 years, I only have 20K on it, yet it doesn't seem to stay on electric as much as it used to.

Thanks for your feedback.

[SOMEONE ELSE'S GOT MY NAME]

On the topic of spreadsheets, I believe it's on (something like) greenhybrid.com where you'll find a nifty little software program (that'll post on threads like this below your entry) for logging your mpg's ... from tank to tank, your best ever tank, and your average over all. On the oil topic, I recently switched to 0w-30 synthetic and it seems to help a bit mileage wise, on winter drives. I'm thinking it'll make a difference on cold summer mornings too, but it's a bit early to tell. Will post a follow up in a few months. so far, so good

[wildta]

I used to get around 25 mpg on the monitor prior to installing a roof rack and that was not being conservative. I even got 23mpg avgs on a couple tanks when I did trips btwn LA and San Diego avg'ing around 80 to 90 mph.

Here's the rack that I got:

http://www.orsracksdirect.com/inno-racks-b...board-rack.html

Ever since it has been on my car I've been getting around 22 mpg on the monitor (two tanks now). It doesn't appear to add a lot of wind resistance since it's looks unobtrusive, and I can only hear a slight amount of extra wind on the road when above 60mph. I'm using premium in about 60 deg weather, tires at 38 psi, 65% freeway/35% city, new oil change at 10,500 miles (at around 11,000 miles on the odo now) and tires just rotated with oil change. I just started an excel sheet and my last tank read 21.4 on the monitor but manual calculations gave me 20.5 :cries:

My last two tanks I've been relatively conservative too. I've even started using my cruise control set at 65mph, which is unbelievably slow here in socal, I swear I get passed by grandmas and their walkers.

Anyone else have similarly reduced mpg's with a roof rack?

The person above hauling a trailer and getting 22mpg... that's amazing!

Btw, my brother has a BMW 5-series and his mpg gauge is much more accurate than ours, he calculates his mpg manually and has consistently been off by only .1 from his monitor. What's the deal Lexus?

[skyfish400h]

I used to get around 25 mpg on the monitor prior to installing a roof rack and that was not being conservative. I even got 23mpg avgs on a couple tanks when I did trips btwn LA and San Diego avg'ing around 80 to 90 mph.

You have put your finger on the issue... Aerodynamic Drag.

I've never reached the 25-26 mpg numbers that many have seen. The best I've been able to achieve on the old Goodyear tires was 24 mpg. Now with the wider tires 22 mpg looks good to me. Realistically, 20-21 is my normal mileage without extensive hypermileing behavior and going without the amenities like AC, music and heated seats which all take a toll.

The "egg" shape of our RX is OK for aerodynamics below 40 mph, but wind resistance increases exponentially with speed. So when driving around on SoCal freeways at 75-80mph on a regular basis, the drag losses really have an impact. Adding even a small parasitic drag will be magnified exponentially by driving at freeway speeds, especially corridors like the I5 to San Diego or the I15 to Vegas where average speeds are even higher.

If the factory cross bars were easier to take in and out, I would just leave them off unless I'm hauling something.