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Discussion Starter · #1 · (Edited)
For those of you who have been paying close attention since Frankfurt last year this should come as no surprise, the NX200t engine is officially offical making use of an Atkinson cycle.

From Autoweek:

The NX 200t will feature Lexus’ first turbo engine, a 2.0-liter four with VVT-iW. Yes, that W is new. It signifies advance and retard of the intake cam. At low loads and rpm it can operate as an Atkinson cycle engine for greater efficiency and lower pumping losses. At higher engine speeds and greater loads it switches to the more standard Otto cycle…

The turbo is a twin-scroll for even more efficiency while the intercooler is an air-to-water-to-air unit. Output is said to be “over 200 hp.” It will be mated to a six-speed ECT automatic transmission which has been engineered for smooth transfer of power and seamless, linear acceleration, according to Lexus.
This is actually the second time this year we have seen lexus debut this dual cycle cam timing, we first saw the system on the RC-F's 5.0L V8.

Now consider:

Audi 2.0T 220 hp / 258 ft-lbs
BMW 2.0t 240 hp / 255 ft-lbs
Mercedes 2.0T 241 hp / 258 ft-lbs

So lexus saying over 200hp should be well over 200 hp. Lexus is also on record saying the 2.0T will match the 3.5 V6's torque figure, so expect 277 ft-lbs. 240/277, I wouldn't complain ;)
 

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Discussion Starter · #3 ·
Ok we now have officially official specs for the NX200t. We're looking at 235 hp/258 ft-lbs of torque. Which is basically right on par with the German three...
 

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Ok we now have officially official specs for the NX200t. We're looking at 235 hp/258 ft-lbs of torque. Which is basically right on par with the German three...
Not bad at all good power for a vehicle of this size, but im more interested in hearing what reviewers have to say about how it feels when driving
 

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Discussion Starter · #6 ·
Atkinson and Otto cycles are not vastly different. They both operate on a four stroke cycle (intake, compression, power, exhaust) The difference is the timing of compression vs power strokes. With a longer power stroke and shorter compression stroke it captures more thermal efficiency at the expense of power density (less combustion available). In the simplest terms an Atkinson leaves the intake valve open a fraction longer, allowing intake air to escape back into the manifold, this is effectively how the compression stroke/power density is reduced...
 

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and by reducing the air density inside the camber before compression/combustion.. what does that do? wouldn't it produce less power?
 

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Discussion Starter · #8 ·
and by reducing the air density inside the camber before compression/combustion.. what does that do? wouldn't it produce less power?
yes, thats the point. Less power means less fuel consumption. Thats why typically Atkinsons are only used with Hybrids, so that the loss in density can be augmented by the electrics...
 

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Discussion Starter · #9 ·
LExus released a video of the 8AR-FTS 2.0T. It uses a twin scroll turbo for low down kick, also has stop start... Power and Torque find their peaks at 4000 revs.

 
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