UZ Swap Decision Matrix
See the PDF version with beautiful pictures HERE
- Output is based on Wikipedia, real power is application dependent
- Weight is based on block material: cast iron or cast aluminum
- Complexity is based on the easiest swap (2UZ) as a baseline
- Cost may vary. 2UZ VVTi is came in later generation, thus higher cost
2UZ swap is documented very well on YouTube. The 2UZ VVTi swap I am sure has been done before and should be very similar to the standard 2UZ swap, aside from things like the drive by wire.
1UZ non-VVTi is a very popular swap as well due to simplicity and cost. A mid-90’s SC400 or LS400 can be fetched for a couple grand. They also have an A340 bolted to them so it’s easy to have the stock ECU run the factory 4Runner transmission.
1UZ VVTi is not a popular swap for various reasons. The 5 speed automatic transmission (A650e) that came with it does not easily convert to 4WD. The 3UZ had the same transmission up to about 2006 when it started coming with a 6 Speed automatic (A761E) which does allow you to convert it to 4WD using a 2UZ VVTi Transmission tailshaft.
Late model 3UZ VVTi can be used if using the later model 6 speed (A761e) and swapping the tailshaft from a A750f. You can use the stock A340 transfer case adapter by modifying it slightly for an oil passage. This is the baller swap.
This swap will document the process of swapping an 1UZ VVTi into a 3rd Gen 4runner. The hardest option aside from a possibly a DBW 3UZ. The decision was made due to finding a 98 SC400 for $800 on Facebook Marketplace, drastically reducing the initial investment. The SC400 has a wiring harness that will fit closely to what the stock 4runner harness is because it routes the harness into the cab. LS400 and GS400 1UZ VVTi’s have ECU’s in the engine bay next to the battery, so the harness needs a lot of work to get it to work. Consider this if buying a JDM engine. One possible option is using a harness from a 2UZ VVTi since all the external components are the same, although this is unverified. ECU pinouts maybe different. All this info will apply to early 5 speed 3UZ’s as well, the main difference is the 3UZ being drive by wire instead of a cable throttle. 3UZ harness info is unknown and different from 1UZ/2UZ VVTi.
The Transmission
Plan A: Design and make an adapter for A650e to VF3AM Transfer Case
1.A650e has a 26 spline output shaft
2.A340f has a 23 spline output shaft
3.There is a coupler that mates the transfer case to the transmission and a custom one that adapts a 26 spline to a 23 spline would need to be made.
4.It is rumored that a input shaft from a manual transmission (W series) 3RZ Transfer case is a 26 spline. This may work, depending on the actual diameter of the spline, which is unconfirmed.
5.On top of making the custom coupler, a very complex transfer case adapter will need to be made.
Plan B: Manual 5 Speed R150f with Stock Transfer Case
1.Same method as converting a 1UZ to manual transmission
2. Either a custom bellhousing or adapter to adapt the R150f to the UZ bellhousing
Plan C: Use A750f from a 2UZ and run a standalone
1.Stock 1UZ VVTi ECU will not run a A750f
2.Stock 2UZ VVTi ECU may run a 1UZ VVTi, although it is not recommended
3.One option is to run a standalone ECU on the 1UZ and use the stock 2UZ ECU to run the transmission
4.Another option is to run standalone’s for both the engine and transmission (separately) or a high end Haltech that can run both ($3k+)