Last post on Dec 31, 2012 at 9:33 AM
You are in the Lexus RX 400h
What is this discussion about?
Lexus RX 400h, Hybrid Cars, Car Buying, SUV
#51 of 100 Re: Love my 400h [lexus400h]
Jun 28, 2005 (2:22 pm)
Thanks, appreciate your help and suggestions.
#52 of 100 Re: Metric blues [steering issue]
Jun 28, 2005 (4:25 am)
After driving about 600 miles in my new 400h (27.5 mpg), I've decided there actually is a bit of a steering issue with the 400h. At first, I thought my alignment was off due to extreme pulling to the left on my main commute road. The road is crowned heavily, with drainage to the left. I have to hold the wheel fairly firmly to keep it going straight. Now, switching to the other lane, which drains right, I get a fairly strong pull to the right. I've driven this road for years, and have never noticed this problem with my 540i, Audi Allroad, or Explorer. The Explorer drives like a heavy truck, but doesn't pull like the 400h on the same road.
I then went out and drove on a number of flat local roads, and I'm convinced the alignment is OK. In a parking lot,for example, I can release the wheel and the car will go dead straight without any noticeable pull.
My conclusion is that the 400h steering system is "different". It feels like the electric boost or "centering power" is unsufficient at highway speed, or stated another way, that the front end is overly-sensitive to camber in the road. I noticed that letting go of the wheel on a slightly pitched road, even at very low speed, results in a fairly rapid turn -- more so than any of my other cars.
The effect does feel like misalignment to me, but it occurs in both directions depending on road camber.
In the end, I've decided it's a bit annoying, but certainly not a driveability or safety issue. I just feel like I notice small differences in road camber much more. When driving on windy roads, I notice nothing at all. On cambered straight roads, I feel the effect almost constantly...
#53 of 100 Re: Pull and crowned roads [shelt]
Jun 28, 2005 (8:41 am)
I haven't noticed anything. I'm not sure how crowned our high speed roads are, but the 25-35 mph roads in my neighborhood have a lot of crowning - enough to be annoying on a long walk. I meant to try letting the go of the wheel to see if it would go straight on our home street, but I forgot to do it this morning.
With the steering being electronic and all the electronic stability stuff, I wonder if there is a firmware adjustment for the "centering power".
#54 of 100 Re: Pull and crowned roads [rx400_owner]
Jun 28, 2005 (9:54 pm)
I am convinced that my 400h pulls to one side based on a recent drive. I am calling the dealer tomorrow to get it looked into. The following from japanesecarfans.com about the 400h's steering makes me think that my 400h shouldn't be doing this and perhaps offers some clues as to what might be wrong:
"The optimisation of the caster angle and the adoption of ‘Nachlauf’ geometry, which offsets the kingpin axis ahead of the axle centre, result in increased caster trail which enhances both straight-line stability and steering feel. The location of the kingpin axle outside the wheel, allied to the addition of a small, well-shaped sub-frame, results in excellent tight-turn performance and a compact turning circle of just 5.7 metres.
Lower arm and tie rod geometry has been further refined to suppress changes in toe angle under suspension bounce/ rebound, thus ensuring excellent straight line performance.
And the angled location of the lower arm member with the rear side higher than the front creates an anti-dive suspension geometry effectively to suppress nose-diving under braking.
In addition, the front suspension also adopts a small level of negative camber, effectively leaning the top of each front wheel inwards when the vehicle is running in a straight line. Under cornering load, the change in vehicle posture naturally reduces the ground contact camber angle of the outside front wheel, optimising contact between tyre tread pattern and road surface for enhanced, high performance cornering."
#55 of 100 Re: Pull and crowned roads [hybrat]
Jun 29, 2005 (4:00 pm)
You might check your tire pressure. On another site, a number of people have reported finding that their tire pressure excessively high when they checked it. One of them has commented correcting the tire pressure has resolved his handling problems.
I checked this morning on our fairly crowned residential (25 mph) street. My Rx400H runs straight on it (for the limited distances I can check since there are some curves on my street). It does at least as well as my Camry on this. Even if I started with the wheel turned slightly, it wanted to self-center and go straight.
On a short very steeply tilted road section (a place where they use to have another street joining from a lower level) it did want to follow the slope down, but this was way beyond any normal crown and I think pretty much any car wouldn't track straight there.
#56 of 100 Well its been a month now....
Jun 29, 2005 (3:53 am)
I have owned the 400h for a month now and just a few observations..... of course the quality is the usual Lexus "high" and the car came delivered literally with no problems whatsoever.
I am of course now more observant of my MPG's. Its natural with all the emphasis on why the car was purchased in the first place. A SUV vehicle with a smaller car MPG rating. I am getting in the low 20's right now in combined MPG's. Most of my driving has been local (still under 1000 miles) and here where there has been a bit of disappointment so far. I notice that upon acceleration no matter how slight it might be the engine will "kick in" and not rely on electric power for that up to 30 mph start. I have babied the gas pedal to the point I could probably run faster off the starting line than the car. I do get electric only usage if I get up to a speed of 30 mph steady and put it on cruise control. As soon as I touch the gas again the engine will turn on. I was expecting something a bit different like normal acceleration with stop and go driving in that 20- 30 mph range and then use the engine for that boost to highway speed. Essentially, use the electric around town (live in a somewhat congested area) for speeds under 30 and only use the engine in that speed range when the batteries needed to be charged or that quick acceleration was needed.
I was wondering if others have experienced the same. Also is anyone aware of a computer setting that could be made by LEXUS that would tune the vehicle on when the engine would kick in. I will be reporting this information to the dealership when I see then in a few weeks.
#57 of 100 Re: Well its been a month now.... [joed2]
Jun 29, 2005 (8:59 pm)
It sounds like you didn't do a lot of research on how these work before you bought. It would be a good idea to read at least the little hybrid overview you got with your manual. That clearly says that the motors are used for acceleration up to about 10-15 mph. Even that depends on other factors like how much charge is in the battery, how heavily you lean on the accelerator, etc. After that you might read some of the history on this forum.
For instance message 1570 contains a nice analysis of the battery capacity that Dylan Hixon did. The batteries store about the equivalent of about a tenth of a gallon of gas or a couple of miles worth (and of course most of the time you don't start with a full battery and you don't want to run the battery down to zero). These aren't meant to be a main power source for running around town.
The batteries are meant for supplying power when you need less than the engine can produce efficiently and for supplementing the power from the engine when you need more than the engine can produce efficiently. This allows the engine to be tuned for more efficiency in the range that it is normally used and then to stay in that range most of the time it runs. There are always losses in moving energy around so when the engine can efficiently produce what you need, it is most efficient to take the energy directly from it.
I find I get good mileage with this car by:
Accelrate normally - not jack rabbit but not trying to keep the ICE off
Once up to cruising, drive smoothly
Keep an eye on the lights and traffic ahead so that brakes are applied early enough for maximum regeneration or drop speed a little to arrive at the light when it is green.
Short trips with a cold engine get reduced mileage so combining errands helps too. My first tank was a bit below 25 mpg. Since then I've been running between 25 and 27.5 mpg (depending mainly on amount of AC needed and how much I have short trips).
#58 of 100 RX400H
Jul 13, 2005 (4:01 am)
I traded in a 2003 Audi Allroad 2.7T with low mileage for the RX400H. I've had 5 Lexuses in the past and the quality and reliability were always top notch. Morever the trade in values were always very good. With my last Audi and one previous one (an Audi for an Audi) I took a beating on trade-in. The substantially lower depreciation rate on Lexuses make them a better buy. It's only one week in the new Lexus but I find it vastly superior to the Audi Allroad.
The Audi had air suspension and I didn't think the Lexus suspension would be as good but it is. Fuel economy is superior and inline with reports posted here. I've taken one measurement: with airconditioning constantly on 24.9 mpg. The Lexus to my surprise corners as well as the Audi squealing tires et al. The Lexus corners more flatly probably due to the VDIM system. Steering is very precise and alignment perfect. The smooth flow of power is unmatched; hillclimbing is a joy. This hybrid offers a great deal more than fuel economy and super low emissions and in an excellent value
#59 of 100 Re: RX400H [idele]
Jul 13, 2005 (4:32 am)
I owned an Audi allroad too (2002) and I changed the chip to make it 330hp and also the tires. That car could eat the RX and RH for breakfast. As far as reliability is concerned, well it's obvious. The Audi needed brakes and rotors at 10,000 miles. It was mainly suburban/highway miles too!! If I had to make a choice I'd say the allroad is definitely the better looking car. The Rh/Rx is just so damn ubiquitous but it IS a great vehicle. No more Audis for me.. way too high maint. Enjoy the Lexus... I am sure it will give you years of enjoyment!!
#60 of 100 Re: RX400H [falconone]
Jul 13, 2005 (5:21 am)
The Audis have a different look and are very handsome. I don't like the current grill. I thought about the A6 and also about BMW but hybrid technology and my desire to try it together with excellent Lexus experience was decisive. Lexus offers single pay two year leases and so for the first time I'm leasing. I expect to be in a Lexus LS600H two years from now. The instantaneous torque boost by the electric motors of a hybrid is immensely superior to a turbo with its lag. I also find the rear view TV terrific. I'm still learning about the car but there's no doubt in my mind the value is there.. To me the considerable improvement in fuel economy and environmental impact is just a bonus As far as ubiquity goes, I much prefer a popular car to a rare one.