wildta

I just read this article about the Prius getting 80-100 MPGs. The RX400h isn't much different so I'm wondering if anyone will create a mod for our cars. Wish I had some engineering experience to apply this to my RX400h:

http://www.autobeyours.com/HighSpeedStealth.htm

LEXveryG8

Hmmm....that looks interesting...thanks for sharing!

herbvdh

Here is a link that has a Toyota Highlander with solar panels on the roof. They claim up to a 29% increase in gas milage. http://www.solarelectricalvehicles.com/products.shtml I know nothing of this company at all.

I also remember that someone took four 12 volt batteries in series and used a DC to DC converter to raise the voltage to the traction battery voltage. Then at night they would charge the 12 volt batteries. Who or where this was done I do not remember. My engineering background seems to say this can be done but there has to be more to it than this. (If you try this it is at your own risk!)

oldcajun

Consumer Reports had a review of a modified Prius. It was done at a Toyota Dealer with batteries by A123 Systems. Worked fine but did not get near the 100 mpg claim. It would, however, allow short trips on just electric power. The downside is that when it is on electric power only, there is no cabin heat and if you run the A/C the range is greatly reduced. The cost was $9800 so you could never get it back in gas savings alone.

The 2010 RX450h has taken some steps to improve the mileage of the IC engine and to reduce the amount of time it runs.

The biggest improvement in mileage on my RX400h came when I adapted my driving style to the hybrid system. I consistantly got over 30 mpg in town and over 25 on the Interstate at 80 mpg. Remember, the RX is much heavier and dragier than the Prius plus it is much more powerful.

Steve

GQD_GS4

hmmm dont want to void my warranty!

but i did remove the roof rack crossbars and keep our car as empty as possible to save a few pounds...

tod071

I've lowered my RX with Eibach springs (about 1.5" drop) and have noticed about 2-3mpg more than before. I also want to nix the roof racks soon

derekchiou

wow, that sounds like a good investment! better MPG, better handling, better look and maybe lower wind noise.

I checked on eBay and it looks like Eibach pro-kit has the same parts number for both 400h and 330,350. Does it sounds right? I know 400h is heavier than the 330, 350.

I am also considering the H&R lowering spring, has anyone heard anything good about it?
Thanks

Dbryant

I too am having trouble getting more than 23.6 MPG on the highway. Can you share with me what adaptations you made to drive more in line with the hybrid style? I would like to try something to boost by mpg's.

Thanks much.

Teacherman

I'm looking at changing the springs out as well. tod071, do you have any photos after you lowered it? derekchiou, I too noticed that the H & R are specific to the 400h. Did you ever install them? Please share your experience. Thanks

hoonami

does anyone know why our 06 rx400h is getting bad gas mileage? i mean same driver, same roads, same miles per day, same driving habbits but we used to get 29mpg(computer) but now we only get 20mpg(computer).... anything that we can do to improve gas mileage??

rcy

If you've replaced your 12 volt auxilliary battery at any time (or run it down below 7 volts by leaving a light on) you will need to reset the idle speed control. There is a TSB from Lexus advising this. Apparently only applies to 2006 models. Google ISC learning procedure or search here and at www.lexusownersclub.com where there is a DIY posted. Alternatively, you could take it to the dealer with a copy of the TSB and ask them to do it.

The other possibility is winter gas and cold weather, both of which will negatively affect mileage. However, as stated in the TSB, IF you've replaced or run down your battery you must do the ISC learning procedure.

herbvdh

Winter gas and that cold weather will do it my gas milage dropped 20% maybe more. This tank started at 25MPG now it is running lucky 23 MPG I am licky I see 22 MPG now with this bitter cold and the ICE does not warm up driving 17 miles to work either. NORMAL

SLegacy99

Proper tire pressure is frequently a factor in decreased fuel economy.

Someone short ram their 400h and see if it makes a difference in fuel economy.

jrb77

There aren't ANY reputable tuners who do programs for the 400h to increase mileage and/or add performance??

okc329

something that is already very good?