Last post on Dec 14, 2012 at 3:46 PM
You are in the Toyota Sienna
What is this discussion about?
Toyota Sienna, Future Vehicle, Van
#638 of 687 Re: AWD vs FWD [wwest]
May 16, 2011 (5:23 am)
Actually if you look at Toyota's information on this system (Venza, Matrix, Sienna, RAV4) it applies various levels of amperage to the clutch pack during "acceleration, tight cornering, or when one or more wheels is spinning. If the ECU sends low amperage to the solenoid, a lesser amount of pressure is applied to the disc pack resulting in a smaller amount of torque directed to the rear wheels. Higher amperage sent to the solenoid produces a larger actuating force on the main clutch disks...... The amount of torque to the rear wheels is infinitely variable through the application of current as directed by the 4WD ECU up to a maximum of 45% rear and 55% front torque distribution".
I had read the 50% figure somewhere online as well but according the the docs I have here it says 45%. So it shouldn't be pulling much power at normal acceleration.
#639 of 687 Re: AWD vs FWD [sebring95]
May 16, 2011 (9:51 am)
Okay, consider the design problem the engineering team faces in designing a F/awd system, "this" system.
Bottom line, like an actual FWD, once a wheel slips, FWD always a front wheel, for F/awd most likely a front wheel initially, ALL is lost.
The F/awd system must now INSTANTLY switch into "RECOVERY" mode. With any level of front wheelspin/slip, even the slightest level, the threat of loss of directional control is just to great to ignore.
So the F/awd system's next action will mean nil, TC (VDIM) is now the BOSS.
So, the engineering decision is, MUST be, at the instant the vehicle begins initially moving from a full stop, use the MAXIMUM front to rear coupling coefficient (45%, I'm okay with that). Now, as the vehicle picks up speed the coupling level can, by design, decline precipitously.
MUST decline precipitously, actually. Rising speed always means sufficient roadbed traction for the level of acceleration present. Forward momentum also becomes an important part of the traction equation.
NOT reducing the coupling level cognizant with rising roadspeed would result in premature failure of driveline components due to driveline windup and/or tire scrubbing.
So, absent your "scan-guages" ability to plot a real-time curve of roadspeed vs current flow, dutycycle, you will not be able to "see" how the F/awd system is working.
#640 of 687 2011 Sienna SE quality
May 17, 2011 (9:01 am)
Getting close to purchasing a new Sienna SE. Hesitant to "pull the trigger" based on some comments that the build quality is not up to Toyota standards. My 97 T-100 and 05 Prius have been excellent long term vehicles - no rattles, no mechanical issues, etc. I have a quote for under invoice ($500) - thoughts on pulling the trigger? Thanks, Andy
#641 of 687 Re: 2011 Sienna SE quality [nmflyfish]
May 17, 2011 (10:20 am)
For me, it's now close enough to wait and see what the new model year brings....I4 AND F/awd...? and even better deals for "this year's" Sienna.
Even better yet, I4 adopts DFI, 210HP, f/awd....and...improved FE.
Toyota has to start adopting DFI fleetwide soon.
#642 of 687 Re: 2011 Sienna SE quality [wwest]
May 17, 2011 (10:22 am)
I agree...question is how will they distinguish their Lexus models? Right now most add DI to Toyota's plain engines.
#643 of 687 Re: It's really sad [drews578]
May 30, 2011 (7:42 pm)
You are correct that most lower anchors only are approved up to 45 lbs, but I'm really talking here about the tether anchors. (I should have been more clear in my original comment). I have 4 kids in convertible seats, all of which use tether anchors to improve installation and reduce head excursion, even when the seat is using seat belt path. Gee, which kid in the back row do I sacrifice since Toyota decided to eliminate one of the tether anchors back there? Sorry. I will keep my 05 awhile longer and see if they add the anchors back or I will get another brand minivan to replace this one.
#644 of 687 6 bottle/cup holders for the front seats???
May 31, 2011 (7:33 am)
This is another case of the driver's functional designs in comparison to the 2004 Sienna. Can someone at Toyota explain why they took out all the front console functionality and replaced it with four cup holders for the driver and front passenger? If I include the door bottle storage, the front seat section has places for 2 bottles and 4 cups? As stated in a previous post, this must have been designed by a man who was brain dead when it came to practical/DRIVER FRIENDLY design.
#645 of 687 Re: 6 bottle/cup holders for the front seats??? [rgcc]
May 31, 2011 (7:55 am)
Quite happy with the front console, particularly the piece that slides back to the 2nd row. Pretty much required given that the 2nd row chairs don't have any cupholders on them.....!! I like the flat surface of the console for phones, etc and the storage down on the floor is nice as well. Wife's purse no longer slides around.
#646 of 687 Re: 6 bottle/cup holders for the front seats??? [sebring95]
May 31, 2011 (7:58 am)
I have a coin holder that takes up one cup position, and often use another for my BlackBerry. I wouldn't mind having those extra slots to be honest.
#647 of 687 2011 Odyssey & 2011 Toyota Sienna
Jun 25, 2011 (10:59 pm)
Reading the forums on the new Odyssey & Sienna tells me not to buy any one of these BUT a 2008 to 2010 used edition. Reminds me of the 1977 Chrysler Aspens, etc where a great engine was made worst by changing the wrist-pin design in the motor (I did not buy one).
2002 Honda Odyssey EX (currently has 278,000 kms, bought new)
1992 Ford Taurus L 4 door 300 cu in long-stroke
1982 Ford E150 Customized by Triple-E travel Van 351 cu ins V8
1979 Mercury Zephyr 6 cylinder 4-door sedan
1972 Datsun 510 4-door automatic
1967 Plymount Valiant 2-door sedan large-v6
1965 Morris 1100
1963 Austin 850 mini