2021 Toyota Sienna

Discussion in 'Toyota' started by Jay, Oct 28, 2020.

  1. Jay

    Jay Well-Known Member

    Next year all the major mini-van manufacturers have updated or new wares. Toyota has a completely new Sienna with major changes to the drivetrain that set it apart from the competition. Gone is the V6; replaced by a 2.5L naturally aspirated inline-4 mated to their power-split hybrid transmission. It's very similar to the engine and drivetrain used on Highlander. It's the only engine/transmission option available. The traction battery is a 1.9kwh NiMH pack located under the driver/front passenger seats. The cherry on top is an optional electric motor for the rear axle making it 4wd.

    So we have a 7-passenger minivan now that has a hybrid drivetrain, optional 4wd, a tow rating of 3500lbs (!) and a standard payload of 3500 lbs with an EPA rating of...wait for it...36mpg city/36mpg hgwy/36mpg combined! Let that sink in! One autovlogger reports well over 40mpg on the road! The fuel economy absolutely smashes the competition which get about 25mpg if that.

    The fly in the oinkment is that the 2nd row seats do not stow or remove (Toyota doesn't want customers removing the 2nd row seats because of airbags located in them). This really hurts cargo-hauling utility. Also, the styling is ahem...polarizing. The 240hp rating, with all the electric motors helping, makes it the weakest and slowest in the segment. Nevertheless, I am amazed that this ~4500lb, 7-passenger vehicle can get fuel economy that abolutely punks my poor, aging 2700lb Acura RSX.

    Last edited: Oct 28, 2020
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  2. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    I have some experience driving the RAV4 Hybrid , with essentially the same powertrain ,
    and it's excellent. Minivans are for hauling humans. Yota will be happy to sell you an
    SUV or pickup if you need to haul large cargo.
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  3. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    But many of us resemble said cargo. :D

    I'm very happy that Toyota is putting this excellent powertrain in the bigger/heavier vehicles. How about the Tacoma and Tundra? The Tundra may require a slightly less efficient but larger engine since it competes against more powerful vehicles that handle heavier payloads. These trucks need a lot of help as well, to reduce their thirst.

    These hybrids are not the EV future, but the more quickly we can get 10-15 MPG trucks off the road, the better.
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  4. Jay

    Jay Well-Known Member

    I seriously doubt that I would be able to tolerate the hybrid funkiness of the Sienna. Most people have no trouble adapting, but I'm extremely sensitive to how a vehicle handles and feels in my hands. I've never driven a hybrid that I would buy because of rubberbanding transmissions, or some other non-linear throttle response and weird non-linear hybrid brakes. I'll certainly test drive the new Sienna though.

    You're right about minivans being primarily people movers and secondarily cargo haulers and my needs are the opposite. What I need is something like the Mercedes Benz Metris which is a mid-size cargo van--similar in size to the minivans. The Metris has no plastic or carpeting in the back. It has a bare, flat, steel floor with tie-downs, etc. Perfect. The problem with the Metris is that it's very crude. Want cruise control? That's an option. I read that it's noisy on the road. And it's FE won't touch the Sienna. I'd have to drive both.
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  5. Jay

    Jay Well-Known Member

    FCA is taking an interesting tack with the 4xe Wrangler. They are marketing a PHEV to folks that would never consider a hybrid by leveraging the low-speed, high-torque capability of the electric motors for off-road superiority. It's working. I've visited the forums and enthusiasm for the new hybrid Wrangler is high. Even the Ford Bronco enthusiasts are asking Ford for a hybrid. Of course, I don't think FCA has announced a price yet...
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  6. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    re: Jeep - Fun reading about planned charging stations along some trails like the Rubicon in CA and some trails in Moab, UT. Poor use of resources, but good marketing maybe.
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  7. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    competition of sorts... The Chrysler Pacifica Hybrid (plug-in) has enjoyed its spot as an efficient people hauler though I don't know how successful it was in adoption by families. Some were sold to the self-driving car companies. But if not plugged in, the Pacifica Hybrid is only rated 30 MPG overall so the Sienna Hybrid would be a clear winner in the efficiency department.
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  8. Jay

    Jay Well-Known Member

    Car and Driver really panned their long-term PHEV Pacifica. They had a laundry list of failures after 40,000 miles, including the traction battery. Their most damning criticism was that the non-hybrid Pacifica got better FE on the road. They called the PHEV a science experiment and not practical transportation. The PHEV Pacifica 2nd row seats don't fold into the floor because Chrysler chose that area for the traction battery. No 4wd version is available and the tow rating is 0 lbs.

    In contrast, Toyota's HSD has proven itself as their most reliable power train--even more so than their conventional ones.
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  9. Dorean Clarke

    Dorean Clarke Well-Known Member

    Yes, I agreed! I wish they will add more features!
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  10. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    The one item I would add is that the Sienna with the Camry Hybrid Drivetrain, it is a class above any other minivan outside a full electric ModelX and that does not have the room or reliability of a Sienna.

    On a negative note, I had the 7-passenger Highlander Hybrid with the Camry Hybrid Drivetrain for a week and it was the first time I thought Toyota may have overloaded the drivetrain with to much mass and to much weight from the oversized tire and wheel combination. I felt the same with the RAV4 Prime. Just a little to much mass for the best efficiency and it shows in the EPA.

    2021 Toyota Highlander Hybrid


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  11. Jay

    Jay Well-Known Member

    The local dealer got a XLE trim (mid-level) in and I went out to have a look. I liked the looks better than I thought I would. The big 20" wheels really look boss. I really liked the engine bay. The packaging of everything looked very organized and it looked like you could get to things and work on them fairly easily. I liked the cargo area much less. The floor is quite lumpy and uneven with the 3rd row seats folded. The captain's-chairs 2nd row seats take up a LOT of space. They make it difficult, if not impossible, to get to your cargo from the side doors. I hadn't considered that. If I got one, the 2nd row would have to come out and probably the 3rd row too, and that means I'd need a lot of area somewhere to store them. Not good. I have an appt. to test drive an LE that's coming in the 18th. I may follow through, but it's an awful lot of money for a vehicle that isn't quite right for me.
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  12. Jay

    Jay Well-Known Member

    I took an AWD XLE for a test drive this afternoon. I was quite surprised at how good it was. The last time I test drove hybrids, it was the Ioniq and Niro, and I ran away from them. My sister's hybrid Sonata is no driver's car either, so I was expecting more of the same hybrid funkiness of those Hyundais. First, the Sienna didn't feel, in my hands, as large as it looks from the outside. That was one concern. I didn't want to drive a bus. Electric/ICE transitions were seamless. There was no pronounced rubberbanding from the eCVT or non-linear throttle response. The drivetrain was eerily smooth and quiet. At 18.8 lbs/hp the Sienna is one of the heavier/slower vehicles I'm looking at, but around-town manners were flawless and it merged onto the freeway without drama and kept wanting to go faster than the speed limit. It would be a superb cross-county vehicle. As for negatives, I really don't like that the 2nd row seats don't remove and the 3rd row doesn't fold in a way that gives a smooth cargo floor. There was a pronounced step in the braking between regen braking and friction brakes but this was not a deal killer at all. The dealer wants nearly $38k for an AWD LE. Ouch!

    All in all, props to Toyota. This thing is way more refined and polished than I was expecting. I wanted to not like it so I could cross it off my list but now it's #1. I'll be keeping my RSX but I like to have a plan B lined up in the event my 19yo Acura RSX dies.
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  13. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Jay:

    If there are two items Toyota Hybrids have over the rest, it is drivability with almost seamless transitions between modes and reliability. The Hyundai systems still have transition and ICE NVH while the Honda systems have a different set of transition and ICE NVH attributes.

    I was surprised to hear about your performance highlights. While driving the RAV4 Prime and Highlander, I felt the Camry Drivetrain was overwhelmed. This was not an issue for the lighter weight RAV4, Camry, Avalon, and ESh.

    As for hard braking from Regen to mechanical, I would guess you will only use that once very 100 braking scenarios at most.

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  14. Jay

    Jay Well-Known Member

    My test drive was about 15 miles of mixed city and freeway driving in snowy, icy conditions with the salesman on board so I wasn't able to get more than an initial impression. I could try to rent one in a few months and try a better test. I could drive up Teton pass to Jackson. That would be worth the money.
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  15. RedylC94

    RedylC94 Well-Known Member

    My previous generation Toyota hybrid may be only semi-relevant, but I'll comment anyway ...
    I don't make that emergency "hard braking from Regen to mechanical" transition often enough to feel able to comment on it. It must be ok, or I would've noticed. The transition from regeneration to mechanical that normally occurs in gentle-to-moderate braking at about 7 mph is impressively smooth. However, at even lower speeds, the transition from light mechanical braking to zero braking (and vice versa) is annoyingly abrupt. In other words, very light braking is impossible, so stopping completely smoothly is also impossible, as is backing up very slowly (as opposed to as a series of short lurches).
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  16. Jay

    Jay Well-Known Member

    Couple questions for those knowledgeable about this drivetrain: 1) How is ABS done with regenerative braking? ABS is pretty important on snow and ice in this area.
    2) How is cabin heat handled on cold starts? On my sister's hybrid Sonata, the engine has to run just to support cabin heat and gas mileage really suffers in the winter if you want that heat.
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  17. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    Good questions! I can't say I know the true answer to the first one. The second one is almost certainly engine operation required to obtain cabin heat. Only EVs and plug-ins have any chance of resistive heat or heat-pump operation to warm up the cabin.

    Regarding ABS and regenerative braking, I suspect they can work separately. The ABS just has to apply the physical brakes when the contralateral tires spin at sufficiently different rates. I also suspect traction control also operates through the physical brakes, beyond what it does to ease engine output.

    I saw an interesting (to me) video showing a Tesla Model Y being tested with slip rollers applied to 1/2/3 wheels and still being able to gain sufficient traction with the remaining wheels to make forward progress. It only failed on one scenario, where a non-dominant (front) wheel was available for traction. It was impressive to see the traction control (as mentioned above likely having nothing to do with regenerative braking) getting the Model Y "unstuck." https://tflcar.com/2020/12/tesla-model-y-slip-test/
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  18. RedylC94

    RedylC94 Well-Known Member

    Bill is generally correct, as far as I know.
    On bumpy surfaces, the transition from regenerative to ABS can be awkward, at least with Toyota hybrids the vintage of mine.
    I usually forgo interior heat the first few miles of cool but sunny starts, to minimize needless engine run time. Whether the partially warmed engine stops or runs during coasting periods is strangely unpredictable, anyway.

    Once I got the right front wheel stuck in mud. I expected traction control to brake that wheel sufficently to allow the left wheel to get me out (or spin, whichever came first). It didn't; I don't know whether it braked the right wheel at all.
    Last edited: Dec 20, 2020
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  19. Jay

    Jay Well-Known Member

    Been looking through the 600pg+ (!) owner's manual. Some observations:

    1. The Orwellian Toyota. Toyota tells you right off the bat that they store all kinds of data about where you drive and how you drive. The cameras store pictures of anything Toyota wants to record, including people, and they upload this stuff to Toyota without your permission, and they'll turn over this data to any govt. agency that asks for it. So now the first thing you've got to figure out is how to defeat this spy-car crap.

    2. The high voltage drive system is 650V (!). Get across that and there will be no need for an ambulance or a funeral. They'll just sweep your ashes off the floor if they can find them.

    3. Toyota's hybrid system uses geolocation data to optimize charge/discharge cycles. This was an idea that Hyundai/Kia promoted for their Ioniq and Niro way back when, but I don't think they ever implemented it in NA.

    4. Run your Sienna out of gas and you'll need at least 3 gallons to get going again. Enjoy your walk to the station and back to your thirsty Sienna carrying a 5-gallon container of fuel.
    Last edited: Dec 21, 2020
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  20. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Jay:

    You can opt out of data to Toyota in the Toyota app. At least with the Prime you can? None of us own the last 30-seconds of data recorded before an accident. A court order whether to Toyota or any other OEM and they will release it if it was transmitted OTA. If not, the Court can order the data pulled from the box in your car directly if they want.

    The 650V from 280ish volts though Transverter via Inverter to create AC, a step up transformer to bring the output to 650V, and a Rectifier to change the high voltage/low current waveform back to DC as needed. This has been a std. Toyota Hybrid voltage design since the 2004 Prius was introduced back in 2003.

    Do not count on Geolocation charge/discharge algorithms to work worth a damn.

    What is the deal about 3-gallons?


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