2021 Toyota Sienna

Gecko

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@Gecko , if you remember I wrote about that exact same point, and how the 2 brands must live together, and how it was bad in the previous 2 decades to kill Toyota for Lexus

the solution was based on the TNGA

Which for which, and part from my humble solution is to make the GA-N profitable by turning the next generations NX & RX on it, and in the same time give the current NX & RX recipe to a brand new Toyota's

So then not only Toyota as a corp got 2 profitable architecture instead of 1, but also it will give the freedom to Toyota & Lexus as brands to up their games
I love that plan, but from what we know, 2NX and 5RX are both in development on TNGA-K and it probably makes more sense from a profit and powertrain perspective to keep them on that platform. As I wrote in another thread, I have a feeling GA-N and GA-L were pet projects that are not "key" for Toyota.
 

maiaramdan

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But GA-N and GA-L won't be profitable with only 4 models Century , LS , LC & Crown
 

Sulu

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Woah. The Sienna and the Venza are stunning.

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I see a new styling language for Toyota. The Highlander, Harrier/Venza, Sienna, and, to a less-visible extent on the RAV4 (i.e all new utility vehicles) have what Toyota described as a "shoulder", that obvious, muscular bulge in the rear fender. I wonder if the next-generation 4Runner, Prado/GX and Land Cruiser will have that styling also?
 

ssun30

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And as GM showed with the weird I-5 in the H3, if an engine doesn't have the torque to move the car, you're not actually saving fuel.
Actually this worry about the hybrid powertrain not having enough torque is unfounded. Since PSD complicates calculation of torque at the crank, the only thing we need to compare is the wheel torque (which is what really propels the car). It is very common to see people confusing engine torque with wheel torque. We actually have all the data we need to compare it to a 3.5L V6 Sienna:

The '350h' hybrid system has 34% more torque at the output axis than the '300h' system. They didn't define what 'output axis' is, but from these numbers it's not hard to tell these are wheel torque (i.e. after multiplication through PSD and final drive and accounting for all losses). So at its peak a FWD Sienna hybrid has 3235N.m (2386lb.ft) peak torque while the E-Four version has 4535N.m (3345lb.ft). However, I don't think the E-Four version could achieve the full peak torque due to battery power limitations (but from these numbers one can easily see how the '350h' can beome a '450h+' with a bigger battery).



We can calculate the wheel torque of a V6 Sienna using the numbers given by Toyota for the Highlander. The 2GR-FKS engine makes 356N.m (263lb.ft) at 4700 rpm. The first gear of the 8AT has a ratio of 5.52:1 and the final drive ratio is 3.00:1. Assuming 10% drivetrain losses this amounts to 5306N.m (3914lb.ft) at 4700rpm engine speed, 284rpm wheel speed, and 40km/h (25mph) vehicle speed. It sounds like the V6 has considerably more wheel torque, but remember, the first gear only goes up to 30mph! The first gears used on modern cars are only for hill starting and engine braking so it's not an entirely fair comparison here.

A better comparison would be at similar reduction ratios. We don't know the minimum ratio of the PSD but it's reasonable to assume it's ~10 given max motor rpm and top speed (we know the E-Four rear axle has a ratio of 10.8:1). This corresponds to the second gear on the 8AT with 3.18:1 ratio. Calculated that way the max wheel torque of the V6 Sienna is 3057N.m (2255lb.ft) which is 6% less than the Hybrid.

A better way to calculate wheel torque is just dividing power delivered to the wheels by wheel rpm, since this way we don't need to know the exact ratios (especially for CVT) and the only variable that matters is power. So with 181kW (243hp) against 220kW (295hp) it seems the hybrid system is at a disadvantage. It's actually not. Since it's effectively CVT, the hybrid will have 181kW delivered to the wheels for most of the speed range, while the V6 8AT will only have 220kW at exactly 6600 engine rpm. A quick calculations suggests that at 4700rpm the 2GR-FKS makes 175kW at the crank or ~158kW at the wheels. The engine will overtake the 181kW of the hybrid at around 5200rpm assuming the torque curve only drops a bit after peak.

So in conclusion? A V6 Sienna will *only* offer more wheel torque, and thus acceleration, in first gear or when engine speed is above 5200rpm. I don't think a lot of "soccer moms" will push their van above 5200rpm though... Still this means a V6 Sienna will win a 0-60 drag race because it's allowed to use the high rpm range. But for most daily driving, the 243hp '350h' system offers same level of performance as a real 3.5L V6.

Of course it's entirely possible the hybrid will run out of battery power after which wheel torque is severely reduced. But that requires a pretty long continuous gradient with no chance of recharging. Because the hybrid battery has an incredible 15C continuous charging rate, it only takes about 90 seconds to fully charge, so even a slight flat region may allow the car recoup a considerable amount of charge. In fact, the SOC management in modern Toyota hybrids is so good they rarely run out even when towing a load up majority of the gradient one can encounter. In the LM thread I mentioned the possibility of its failing to climb a gradient, but that's just because the ICE is so laughably weak for a 2.3 ton van.
 
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I see a new styling language for Toyota. The Highlander, Harrier/Venza, Sienna, and, to a less-visible extent on the RAV4 (i.e all new utility vehicles) have what Toyota described as a "shoulder", that obvious, muscular bulge in the rear fender. I wonder if the next-generation 4Runner, Prado/GX and Land Cruiser will have that styling also?
You're forgetting about the most important car that has that styling cue. Hell, this was the first Toyota production car to introduce the broad hips.
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Actually this worry about the hybrid powertrain not having enough torque is unfounded. Since PSD complicates calculation of torque at the crank, the only thing we need to compare is the wheel torque (which is what really propels the car). It is very common to see people confusing engine torque with wheel torque. We actually have all the data we need to compare it to a 3.5L V6 Sienna:

The '350h' hybrid system has 34% more torque at the output axis than the '300h' system. They didn't define what 'output axis' is, but from these numbers it's not hard to tell these are wheel torque (i.e. after multiplication through PSD and final drive and accounting for all losses). So at its peak a FWD Sienna hybrid has 3235N.m (2386lb.ft) peak torque while the E-Four version has 4535N.m (3345lb.ft). However, I don't think the E-Four version could achieve the full peak torque due to battery power limitations (but from these numbers one can easily see how the '350h' can beome a '450h+' with a bigger battery).



We can calculate the wheel torque of a V6 Sienna using the numbers given by Toyota for the Highlander. The 2GR-FKS engine makes 356N.m (263lb.ft) at 4700 rpm. The first gear of the 8AT has a ratio of 5.52:1 and the final drive ratio is 3.00:1. Assuming 10% drivetrain losses this amounts to 5306N.m (3914lb.ft) at 4700rpm engine speed, 284rpm wheel speed, and 40km/h (25mph) vehicle speed. It sounds like the V6 has considerably more wheel torque, but remember, the first gear only goes up to 30mph! The first gears used on modern cars are only for hill starting and engine braking so it's not an entirely fair comparison here.

A better comparison would be at similar reduction ratios. We don't know the minimum ratio of the PSD but it's reasonable to assume it's ~10 given max motor rpm and top speed (we know the E-Four rear axle has a ratio of 10.8:1). This corresponds to the second gear on the 8AT with 3.18:1 ratio. Calculated that way the max wheel torque of the V6 Sienna is 3057N.m (2255lb.ft) which is 6% less than the Hybrid.

A better way to calculate wheel torque is just dividing power delivered to the wheels by wheel rpm, since this way we don't need to know the exact ratios (especially for CVT) and the only variable that matters is power. So with 181kW (243hp) against 220kW (295hp) it seems the hybrid system is at a disadvantage. It's actually not. Since it's effectively CVT, the hybrid will have 181kW delivered to the wheels for most of the speed range, while the V6 8AT will only have 220kW at exactly 6600 engine rpm. A quick calculations suggests that at 4700rpm the 2GR-FKS makes 175kW at the crank or ~158kW at the wheels. The engine will overtake the 181kW of the hybrid at around 5200rpm assuming the torque curve only drops a bit after peak.

So in conclusion? A V6 Sienna will *only* offer more wheel torque, and thus acceleration, in first gear or when engine speed is above 5200rpm. I don't think a lot of "soccer moms" will push their van above 5200rpm though... Still this means a V6 Sienna will win a 0-60 drag race because it's allowed to use the high rpm range. But for most daily driving, the 243hp '350h' system offers same level of performance as a real 3.5L V6.

Of course it's entirely possible the hybrid will run out of battery power after which wheel torque is severely reduced. But that requires a pretty long continuous gradient with no chance of recharging. Because the hybrid battery has an incredible 15C continuous charging rate, it only takes about 90 seconds to fully charge, so even a slight flat region may allow the car recoup a considerable amount of charge. In fact, the SOC management in modern Toyota hybrids is so good they rarely run out even when towing a load up majority of the gradient one can encounter. In the LM thread I mentioned the possibility of its failing to climb a gradient, but that's just because the ICE is so laughably weak for a 2.3 ton van.
And that's why it is in fact better to have a V6 engine over a hybrid 4-cylinder. It's good to have the high end torque and power for whenever you need to make a highway pull, and cars do reach close to redline more often than you think when you go for an overtake, merging onto or off a highway, or beating someone off the line at a stop-light. When you're not driving like a madman, and the engine runs at basically ~2k RPM at top gear when you're driving highway speeds or when you're driving around town in first or second gear, the engine has decent fuel economy as is. Toyota has a knack for underrating their performance and their EPA numbers, so the V6 should be fine for the masses. I'm not sure if the 4-cylinder hybrid could tow as well as the V6 Siennas, even in the livestream they sounded a little cagey about the towing capabilities of the new Sienna.

Also, the 4-cylinder engine is coarse and grainy as all hell. The 2.5L is an exact polar opposite of the sweet V6 engines that were in the Sienna (particularly the 3.3L and the 3.5L V6 engines) and can get genuinely annoying after some time. My personal experiences with a Sienna are great, I always crack a huge smile whenever I hear the V6 quickly change from being smooth in nature to being an absolute screamer with a drop of a gear or two and just hoon the car.

I don't know why, but I have a gut feeling if people start demanding for a V6, Toyota will just slap it in the Sienna with the 8-speed automatic. Unlike the mess that's in the Camry and even to a greater extent, the Avalon, the V6, 8-speed and AWD system worked in absolute harmony together. I hope they do it for the Venza as well.

That's honestly my main complaint with the Sienna. Or else, they've knocked the it out of the park with the new Sienna and Venza and the Sienna in particular has hands-down rightfully kept its spot as the best minivan in the entire automotive business.
 
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ssun30

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^^Own a 2.5L hybrid. Can confirm it's way smoother than the V6. It's far from grainy and coarse. You need to spend some time with a PSD-equipped car to understand how incredibly smooth the system operates. A lot of people have doubts about hybrids with ICE turning on and off all the time because they are so dreaded by the annoying start-stop systems. But in a PS hybrid, you don't feel the presence of the ICE at all. And that's what I think the 'moms' value a lot.

The 'highway pull' thing really confuses me. The moms are just not going to do that...are you mistaking the Sienna with some other car? I could understand that killing a V6 on the Camry is a bad move but not the Sienna. And BTW the V6 will lose against the hybrid in highway pulls as well since most overtake maneuvers happen at 3-4k rpm which heavily favors the hybrid and the hybrid reaches full 181kW instantly while the V6 needs to wait for the downshift and revs to catch up.
 
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^^Own a 2.5L hybrid. Can confirm it's way smoother than the V6.
It's very interesting to me since you're the only person ever that has said that the 2.5L I4 is smoother than the V6. I've universally heard otherwise. Even in its natural form a I4 is inferior to a V6 in terms of harmonics and even more inferior than an I6. If what you're claiming is true then Toyota must have pulled some real rocket-science sh*t with masking the coarseness of the engine and emphasized everything with the electric motors.

The 'highway pull' thing really confuses me. The moms are just not going to do that...are you mistaking the Sienna with some other car? I could understand that killing a V6 on the Camry is a bad move but not the Sienna. And BTW the V6 will lose against the hybrid in highway pulls as well since most overtake maneuvers happen at 3-4k rpm which heavily favors the hybrid and the hybrid reaches full 181kW instantly while the V6 needs to wait for the downshift and revs to catch up.
I don't blame you if it confuses you. I have been to many places around the world but North American roads are way different than other regions around the world. But it's not only the roadways that are different, but also add in the fact that people's driving behavior is markedly different in North America compared to the rest of the world. Now obviously driving is... just nothing more than driving to put into primitive terms, but when one starts to become a little more attentive, people in North America simply approach things differently and have different standards compared to other people around the world and these small differences really matter. With that being said, the fact is that people do pulls on a highway or on normal roads for a multitude of reasons and I'm betting my kidneys that the new Sienna won't be able to execute 0-100, 100-120, and 100-200 like a V6 Sienna.

Ironically I believe that the notion of losing the V6 in the Sienna is worse than losing the V6 in the Camry.

Also your point about the V6 losing highway pulls is if the stretch of road was like 50 metres. The sheer immediacy of Toyota's V6 engines would help the car on the bottom-end, and like I mentioned previously, once it drops a gear or two it just hauls serious a** in the top end, so the V6 is barely losing anything out compared to the hybrid 4-cylinder with the exception of the hybrid's healthier mid-range torque. In a vehicle like the Sienna which carved its own niche fanbase (heck it's called the swagger wagon for a reason) and critical acclaim, the V6 is the engine that will deliver on all necessary fronts even for a soccer mom.

If they're an experienced Sienna owner, soccer moms will notice that after the initial split-second jump off the line, the 4-cylinder will be way more sluggish than a V6. Also as an aside, the reason why the RAV-4 Hybrid gets so much love is because the normal 4-cylinder is absolute garbage and there is no V6 RAV-4 for consumers to compare the RAV-4 Hybrid to.

I respect that fuel efficiency and going to the pump less often is more valuable to Sienna customers more then just focusing on gas prices per Toyota's words. But what's important for North American buyers is the luxury of choice, and customers from Canadian and the US market value a manufacturer that gives the customer options for them to pick from, all in the while that more customers can also be attracted to their showrooms as their products can appeal to different people, their lifestyle and their driving style, and hence more sales for Toyota too.
 
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maiaramdan

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@F1 Silver Arrows

Keep in mind it's not a normal comparison between i4 & V6, it's a comparison between Atkinson cycle engine with low torque mated to 2 or 3 electric motors Vs normal Auto cycle engine.
 
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@F1 Silver Arrows

Keep in mind it's not a normal comparison between i4 & V6, it's a comparison between Atkinson cycle engine with low torque mated to 2 or 3 electric motors Vs normal Auto cycle engine.
I'm definitely aware, now some of you guys may think that this is nothing more than a discussion about "there is no replacement for displacement" for the Sienna, but the point I'm trying to bring home is that the V6 Sienna has nailed everything for buyers and what they've wanted since the late 90's and to an even greater extent from 2004-2020 with the introduction of the second generation Sienna, I just don't see the point of completely getting rid of this powerplant at all.
 

Ian Schmidt

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Now... y'all can tell me if this is more than bordering crazy, but does anyone else see a spindle grill that got Mirai'd / Toyotafied?

This definitely underpins a Lexus at some point, no?
Pretty much all of the TNGA Toyotas have more or less wholesale adopted Lexus-esque front and back ends. They mostly look like you could bolt on a spindle grille and call it a day. At least on the Honda/Acura stuff it's often not as obvious, even though in many cases you really can just swap the parts.

I can't imagine a business justification for a Lexus Sienna, but they're clearly hedging their bets on most of these cars.
 

suxeL

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Pretty much all of the TNGA Toyotas have more or less wholesale adopted Lexus-esque front and back ends. They mostly look like you could bolt on a spindle grille and call it a day. At least on the Honda/Acura stuff it's often not as obvious, even though in many cases you really can just swap the parts.

I can't imagine a business justification for a Lexus Sienna, but they're clearly hedging their bets on most of these cars.
Haha time to capture those former upscale Chrysler Town and Country buyers, while the former Caravan and Voyager customers go to toyota (i kid of course)
 

Sulu

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@F1 Silver Arrows

Keep in mind it's not a normal comparison between i4 & V6, it's a comparison between Atkinson cycle engine with low torque mated to 2 or 3 electric motors Vs normal Auto cycle engine.
That is it exactly. It is not a comparison of a 3.5-litre V6 with a 2.5-litre I4; it is a comparison of a V6 with an I4 in a Toyota hybrid.

I drive a 2015 ES 300h. I find it exceptionally smooth but did not really appreciate it until the first time I drove a non-hybrid V6-powered ES 350 loaner. I found the ES 350 rather rough and coarse especially when idling. My ESh idles smoothly, accelerates smoothly and quickly, and unless I am expecting it, it can be difficult to know when the engine switches on or off while the car is travelling. I don't know if the automatic stop-start system starts with an obvious starter rumble (as all those Mercedes-Benz and BMW models with idle-stop systems start with a rumble at a green light) but I don't notice it from inside the car.

The Hybrid has spoiled me. I will not own another non-electrified car.
 
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