Where did the 3.5l Atkinson originate from?

I'm quite happy with the power and getup and go of my Tacoma. But then again. It's paired with a Manual Tranny.

 

The specific engine (2GR-FKS) in the Tacoma is used in the Lexus GS350, RX350 and the Toyota Tacoma, Sienna and Highlander. There are 3 major variations on the tune, namely 278hp for the Tacoma, 295hp for the Sienna, Highlander and RX350 and 311hp for the GS350.

There are other similar engines from Toyota, the most similar being the 8GR-FXS, followed by the 2GR-FSE and then the 2GR-FE, then probably the 1GR-FE Dual VVT-i and the 1GR-FE Single VVT-i that was used in the 2005-2015 Tacoma. All are GR-series engines, however the methodology used for certain components varies. I excluded other similar, but less relevant engines such as the 3GR/4GR-FSE, etc.

All are GR-series engines, which means they share a core design, though the 1GR is notably larger in certain aspects (crank pin size, larger flywheel/flexplate to crank bolt pattern), though it does share the same cylinder spacing among other similarities. The 1GR-FE and 2GR-FE are port injected only while the 2GR-FSE, 8GR-FXS and the 2GR-FKS use the D-4S direct/port injection system. The 1GR-FE had single VVT-i while all others have some form of dual VVT-i. The 2GR-FKS and 8GR-FXS both use the newer form of VVT-iW/VVT-iE, which uses a front-mounted controller and Atkinson-cycle capability due to the wider adjustment angle the system provides. The 8GR-FXS and 2GR-FKS both have integrated exhaust manifolds in the head, while the 2GR-FSE, 2GR-FE and 1GR-FE all have external collectors outside the heads. The 8GR-FXS and 2GR-FKS both use resin valve covers, while the others used alloy valve covers.

In conclusion, the GR series share many commonalities, the variations between them aren't huge. The single VVT-i 1GR-FE was the most outdated design, mainly on the top-end, using a cylinder head design more similar to 90's Toyota designs. All other members of the GR engine family use the more modern design, with the 2GR-FKS in the Tacoma getting the latest updates to the head design (both as far as valvetrain and flow goes).

I find the arguments of a "truck" vs. a "car" vs. a "minivan" engine a bit comical, I mean there are certain aspects of an engine's design that do lend themselves more to one application than the other, but the similarities between the engines are much greater than their differences. The biggest thing I would say that a truck engine would want over other uses would be a longer stroke and an appropriate tune to provide good torque for hauling purposes. Gearing to match the engine's performance curve and what it's being used for is also important.

Some people seem to have a fundamental stance against an engine revving a bit though.

Jeff

 

Thanks for that post. Very informative.