More Rumors on the Lexus Twin-Turbo 4.0L V8 Engine

[Rhambler]

The 3.5 liter isn't high revving comparatively speaking. Look at the redline in some photos that show it. The massively under square design is apparent, which are typically found in boats more so than cars. They're really not known for performance.

3.0l would have made way more sense and the only reason I think they chose 3.5l is because they think they don't need a 4.0l V8 and hence why the 4.0l rumors are all hogwash imo. This 3.5l is Toyota's answer to V8 and poor one at that. Thinking some slow, low revving, high torque charade of an engine will makeup for a V8 is laughable.

This thing will not perform like a TT V8.

 

[krew]

The reason to choose 3.5L and 4.0L is because of taxes. In Japan and China, Toyota's two major markets, cars are taxed based on engine displacement, in 500cc increments starting from 999cc. 3.5 and 4.0 are two "sweetspots" for two respective markets since going up (3.6/4.2, for example) in displacement will result in significantly more tax burden for buyers. That's why you don't see intermediate displacements like 1.8, 2.4, 3.2, or 4.4 in these markets because they just don't make any sense. All new engines designed after 2012 by major manufacturers are multiples of 0.5L to maximize power while staying in the lowest tax bracket possible.

Brilliant post, amazing insight. Thanks for sharing.

 

[krew]

3.0l would have made way more sense and the only reason I think they chose 3.5l is because they think they don't need a 4.0l V8 and hence why the 4.0l rumors are all hogwash imo. This 3.5l is Toyota's answer to V8 and poor one at that. Thinking some slow, low revving, high torque charade of an engine will makeup for a V8 is laughable.

This thing will not perform like a TT V8.

Your leaps of logic are something else -- despite multiple news sources reporting that the TT V8 is real, you think it's hogwash. You then criticize Lexus for your assumption that there's no TT 4.0 V8. Talk about a straw man argument.

 

[Rhambler]

Seeing is believing, so until it's formally announced, it's rumors.

I do think they need a V8tt, but on the other hand, I also believe this 3.5l V6tt is Toyota's stand in as this engine was supposedly seen testing and benchmarking against Audi A8 V8, or at least that's what the pictures showed.

3.5 and 4.0 makes no sense from an engineering perspective. Nothing can be shared or similarly designed.

However, a 3.0 and 4.0 from a V6 to a V8 can in regards to per cylinder displacement (e.g., valve sizes, fuel injection etc.).

That's why I said that and that's why most other manufacturers are going that route and that's why I believe a Toyota 4.0 V8 is a pipe dream.

 

[bogglo]

Seeing is believing, so until it's formally announced, it's rumors.

I do think they need a V8tt, but on the other hand, I also believe this 3.5l V6tt is Toyota's stand in as this engine was supposedly seen testing and benchmarking against Audi A8 V8, or at least that's what the pictures showed.

3.5 and 4.0 makes no sense from an engineering perspective. Nothing can be shared or similarly designed.

However, a 3.0 and 4.0 from a V6 to a V8 can in regards to per cylinder displacement (e.g., valve sizes, fuel injection etc.).

That's why I said that and that's why most other manufacturers are going that route and that's why I believe Toyota 4.0 V8 is a pipe dream.

You sir are something else. But everybody have a right to their opinion. With that been said, even if there are no rumors about a v8 engine from Toyota/Lexus anybody should be able to figure it out that at some point there is going to be a V8 for the LS and all other F cars. Why? because its common sense.
1.) One of the thing lexus is well respected for its their V8 engine, so am not surprised they are taking there time to perfect their next V8 engine.
2.) All the cars Lexus competes with all have a V8 engine. Merc, BMW, Audi, Porsche. So you really think Lexus is so stupid they wont offer a V8?
3.) Even lexus greatest threat as far has price economy Genesis has a V8 engine. So again do you really think Lexus is so stupid they wont offer a V8?

 

[Levi]

What if Lexus' "V8" will be a V6TT+Hybrid? Or a 5l NA V8 based on 2.5l DF + Hybrid?

 

[ssun30]

The 3.5 liter isn't high revving comparatively speaking. Look at the redline in some photos that show it. The massively under square design is apparent, which are typically found in boats more so than cars. They're really not known for performance.

It seems that you have mistaken the Dynamic Force engines for regular undersquare engines. But they aren't. Dynamic Force is a piece of engineering marvel since it combines so many favorable chracteristics into one package without the usual compromise.

Usually an undersquare engine trades low end torque for high rpm, which means less specific power (hp/L) but better efficiency and driveability in normal driving conditions. That's why they are not known for performance. The GR and UR series were optimised for high specific power (first on the market to have more than 80hp/L), therefore they are both heavily oversquare to squeeze out as much rpm as possible. Do note here the discussion is about civilian engines without exotic internals: sports car engines can rev over 8000rpm because of forged components that are impractical to produce on a massive scale.

Dynamic Force does not have this compromise. The A25A-FKS has a bore of 87.5mm and a stroke of 103.4mm (for a bore/stroke ratio of 0.846). It almost looks like a truck engine, but it is nothing like a truck engine. The peak power is 205hp@6600rpm, and the peak torque is 250Nm@5000rpm. 82hp/L on such an undersquare design is very impressive, especially considering it does so while achieving more than 40% thermodynamic efficiency. Usually manufacturers set the red line at 200rpm above peak power, so this engine can rev up to 6800rpm. There simply aren't many truck engines that can rev this high. And you also have to consider with such a long stroke the mean piston velocity is 23.4 m/s, which is in the realm of most performance engines out there, yet the A25A does not use forged internals. 82hp/L, 40% thermal efficiency, 23.4m/s mean piston speed with regular internals, you cannot find ANY engine in the entire industry that can do all these things at once.

But you may ask, if it's so undersquare, why is torque so low? That's VVT-iW at work. At low rpm the engine operates in Atkinson mode so torque is very poor, but the undersquare design mitigates that to some extent. If you examine the full torque curve of the A25A you will also notice there is a significant torque dip during Atkinson-Otto cycle transition. This is where the complexity of this engine stops. The perfect solution here is to use continuous variable valve lift to smooth out that dip, and TMC does have that technology (Valvematic). But maybe it's not worth the added complexity and reliability concerns. Still the torque curve is way better than the previous 2AR-FE/FSE engines. The lack of low end torque can be easily rectified by turbocharging or hybridzation, so no concerns for performance cars.

 

[Rhambler]

I don't know. Is Toyota stupid? I agree they need one, but the bigger question is will there be one?

Rumors are just that: rumors.

The fact that Lexus had almost a decade to develop a V8 for the new LS and yet what do we see upon the introduction of the new LS? A 3.5l V6, that was caught testing against competitor's V8s.

Frankly those facts, real facts, gives more hints to their intentions then any rumors.

You sir are something else. But everybody have a right to their opinion. With that been said, even if there are no rumors about a v8 engine from Toyota/Lexus anybody should be able to figure it out that at some point there is going to be a V8 for the LS and all other F cars. Why? because its common sense.
1.) One of the thing lexus is well respected for its their V8 engine, so am not surprised they are taking there time to perfect their next V8 engine.
2.) All the cars Lexus competes with all have a V8 engine. Merc, BMW, Audi, Porsche. So you really think Lexus is so stupid they wont offer a V8?
3.) Even lexus greatest threat as far has price economy Genesis has a V8 engine. So again do you really think Lexus is so stupid they wont offer a V8?

 

[TsopranoMB]

Keeping fingers crossed!

 

[CIF]

It seems that you have mistaken the Dynamic Force engines for regular undersquare engines. But they aren't. Dynamic Force is a piece of engineering marvel since it combines so many favorable chracteristics into one package without the usual compromise.

Usually an undersquare engine trades low end torque for high rpm, which means less specific power (hp/L) but better efficiency and driveability in normal driving conditions. That's why they are not known for performance. The GR and UR series were optimised for high specific power (first on the market to have more than 80hp/L), therefore they are both heavily oversquare to squeeze out as much rpm as possible. Do note here the discussion is about civilian engines without exotic internals: sports car engines can rev over 8000rpm because of forged components that are impractical to produce on a massive scale.

Dynamic Force does not have this compromise. The A25A-FKS has a bore of 87.5mm and a stroke of 103.4mm (for a bore/stroke ratio of 0.846). It almost looks like a truck engine, but it is nothing like a truck engine. The peak power is 205hp@6600rpm, and the peak torque is 250Nm@5000rpm. 82hp/L on such an undersquare design is very impressive, especially considering it does so while achieving more than 40% thermodynamic efficiency. Usually manufacturers set the red line at 200rpm above peak power, so this engine can rev up to 6800rpm. There simply aren't many truck engines that can rev this high. And you also have to consider with such a long stroke the mean piston velocity is 23.4 m/s, which is in the realm of most performance engines out there, yet the A25A does not use forged internals. 82hp/L, 40% thermal efficiency, 23.4m/s mean piston speed with regular internals, you cannot find ANY engine in the entire industry that can do all these things at once.

But you may ask, if it's so undersquare, why is torque so low? That's VVT-iW at work. At low rpm the engine operates in Atkinson mode so torque is very poor, but the undersquare design mitigates that to some extent. If you examine the full torque curve of the A25A you will also notice there is a significant torque dip during Atkinson-Otto cycle transition. This is where the complexity of this engine stops. The perfect solution here is to use continuous variable valve lift to smooth out that dip, and TMC does have that technology (Valvematic). But maybe it's not worth the added complexity and reliability concerns. Still the torque curve is way better than the previous 2AR-FE/FSE engines. The lack of low end torque can be easily rectified by turbocharging or hybridzation, so no concerns for performance cars.

Excellent post. Would just like to add, as far as I know, there are no reliability concerns with Valvematic, as it was designed to be a very reliable electrically-controlled system. Also for the A25A, the Atkinson-Otto transition results in not so much a torque dip, but more of a torque lull. Low-end torque up to about 2400 rpm is much better than the previous AR generation. The Atkinson-Otto lull occurs between 2400 or so to about 3200 rpm, and then torque continues to increase. Even so, torque remains higher than the AR predecessor, and does not drop, but only stagnates. Proper transmission gearing and spacing can also help somewhat with this torque lull.

 

[mediumhot]

There are good reasons for choosing 3.5L and 4.0L. But not what you are thinking of. The Dynamic Force engines are highly undersquare (~0.8 bore/stroke ratio) while the GR/UR series are oversquare. In that sense the block needs to be completely redesigned. Also the internals need much better metallurgy to cope with the extra stress caused by a long stroke. Dynamic Force engines do not trade rpm for stroke, instead they are both high revving and long stroke. The combustion chamber are also completely redesigned to promote turbulent flow. They are also the first family of engines to combine the entire technology package Toyota has developed in the past decade, sans Valvematic. They left that alone since many Dynamic Force engines are designed with turbocharging in mind, which doesn't benefit from variable valve lift as much as NA.

The reason to choose 3.5L and 4.0L is because of taxes. In Japan and China, Toyota's two major markets, cars are taxed based on engine displacement, in 500cc increments starting from 999cc. 3.5 and 4.0 are two "sweetspots" for two respective markets since going up (3.6/4.2, for example) in displacement will result in significantly more tax burden for buyers. That's why you don't see intermediate displacements like 1.8, 2.4, 3.2, or 4.4 in these markets because they just don't make any sense. All new engines designed after 2012 by major manufacturers are multiples of 0.5L to maximize power while staying in the lowest tax bracket possible.

I've missed out that 3.5 is Skyactive/Dynamic Force engine. I was aware of new 2.5 in Camry to be the one but they ever said anything about 3.5 V6. If it is indeed true than it has to be a complete new engine block and Skyactive like technology is really good for turbocharging or supercharging as it can boost performance and especially torque to diesel like levels compared to displacement. Let's wait for V8 to see how that turns out.

 

[Ian Schmidt]

The fact that Lexus had almost a decade to develop a V8 for the new LS and yet what do we see upon the introduction of the new LS? A 3.5l V6, that was caught testing against competitor's V8s.

*Caught* testing it against competitor's V8s?

1) All of the cars in the segment are going to a turbo six as the base engine
2) All of the manufacturers know these sixes will be compared fiercely against the segment's existing base V8s
3) QED, Lexus is testing the TTV6 against the segment's existing V8s. I would be shocked if the Germans weren't doing the same thing with their sixes.

 

[Rhambler]

Are you saying that because the V6 was tested against the V8s that Lexus will introduce a V8? That makes no sense.

Listen to Jeff Bracken at the NAIAS unveiling. The first thing out of his mouth when it came to the engine was "V8 level power...". Yeah, V8 level power from a decade ago, lol.

To me, that statement is another indication Lexus has no intention of introducing a V8.

If Lexus had foresight, they would have introduced a V8 at launch. They missed it.

Seriously, some of the arguments now are borderline funny.

 

[Ian Schmidt]

Are you saying that because the V6 was tested against the V8s that Lexus will introduce a V8? That makes no sense.

You were trying to claim it was some great calamity that the all-new Lexus TTV6 was being benchmarked against the current German base V8s. I'm saying that it's entirely sensible for them to do so, because the entire segment is moving down to 6 cylinders as the base engine, and all of the base sixes in the category are going to be judged on if they're better than the V8s they're replacing. If final measured power on the Lexus TTV6 is even ballpark it's going to beat all the German sixes and pretty much all of the current base V8s as well, and probably have the best fuel economy to boot.

Meanwhile people will notice Mercedes has been rebadging Nissans, the rumors will come true about Audi/VAG merging with FiatChrysler, and BMW will re-hire Chris Bangle ;-)

 

[Yuan]

Are you saying that because the V6 was tested against the V8s that Lexus will introduce a V8? That makes no sense.

Listen to Jeff Bracken at the NAIAS unveiling. The first thing out of his mouth when it came to the engine was "V8 level power...". Yeah, V8 level power from a decade ago, lol.

To me, that statement is another indication Lexus has no intention of introducing a V8.

If Lexus had foresight, they would have introduced a V8 at launch. They missed it.

Seriously, some of the arguments now are borderline funny.

S500 TTV8 4.0L 421HP, LS500 TTV6 3.5L 415HP

 

[Rhambler]

Well, I guess you missed the point: I said that in rebuke to a Lexus V8.

I'm claiming these rumors are wishful thinking. I'm INFERRING that by them testing the V6 against competitor's V8, Lexus probably felt the V6 will stand in for a V8, which lends credence to the wishful thinking part.

I also think their omission of a V8, in this class of car, is a gigantic mistake.

So I'm not sure where you're going with "it's natural to test a V6 against a V8" as that has nothing to do with what I was trying to imply.

 

[Yuan]

Well, I guess you missed the point: I said that in rebuke to a Lexus V8.

I'm claiming these rumors are wishful thinking. I'm INFERRING that by them testing the V6 against competitor's V8, Lexus probably felt the V6 will stand in for a V8, which lends credence to the wishful thinking part.

I also think their omission of a V8, in this class of car, is a gigantic mistake.

So I'm not sure where you're going with "it's natural to test a V6 against a V8" as that has nothing to do with what I was trying to imply.

Just wait and get slapped in the face when Lexus release the TTV8. We shall see.

 

[bogglo]

Well, I guess you missed the point: I said that in rebuke to a Lexus V8.

I'm claiming these rumors are wishful thinking. I'm INFERRING that by them testing the V6 against competitor's V8, Lexus probably felt the V6 will stand in for a V8, which lends credence to the wishful thinking part.

I also think their omission of a V8, in this class of car, is a gigantic mistake.

So I'm not sure where you're going with "it's natural to test a V6 against a V8" as that has nothing to do with what I was trying to imply.

if this don't tell you anything then only Lexus can put your argument to rest.

Its obvious every car maker do their research on their competitors. Lexus made a move by offering a powerful engine with V8 power don't mean the V8 engine is GONE. what do you have to say about this

https://www.autoblog.com/2017/08/09/new-mercedes-amg-53-430-horsepower-turbo-inline-six/

Does that mean Mercedes Benz is getting rid of there V8 engine?

LS500 = new Mercedes s class inline 6 tt engine
Porsche Panamera 2.9L turbo engine. Audi and BMW is going to do the same
And am glad Lexus chose the 3.5L engine it only shows there dedication to build an engine that wont be stressed and would be reliable (what Lexus is known for)

So Lexus making a V6TT as powerful as a V8 was done because of critics like you. I understand we are all humans and we can never be satisfied.

 

[Rhambler]

There's nothing I have to say because Mercedes just put in a brand new V8 in the new S560 making northward of 460 HP. Even Porsche, known for their six cylinders, offers a V8 of all things in their panamera, today, and I'm sure tomorrow as well, that pushes 550 HP. So the point of your argument is what? You brought up those cars because of why?

If anything it goes to show you how Cadillac or Lincoln Lexus has become in regards to engine choices, especially for its top offering. In fact Lexus offers even less.

 

[Levi]

I doubt Lexus would put a TTV8 with 600 PS in a RWD car. Even the new M5 goes AWD.