Quad Turbo V12 From Two 1JZ Supra Engines


Photos courtesy Nicholas Tomsyck

This insane build isn’t complete yet, but it’s well underway, taking place in the home shop of Minneapolis-St. Paul-area builder Don Groff. The hot rod builder is well-known in the area for taking on all sorts of interesting projects, with the current V12 fabrication project front-and-center.

In order to create this masterpiece, Groff cut the bottoms from a pair of inline-six 1JZ Toyota engines with the intended result of creating a quad-turbo fabricated engine.

How, you ask? By machining, welding, stress-relieving, and align-boring a crankcase to end up with a 120-degree V-angle, upon which to set the machined castings from the original engines. The engine block was a Herculean undertaking with the original blocks needing modification to even bolt up to the crankcase.

Custom parts abound throughout the build – from the SCAT forged crankshaft that uses small-block Chevy main bearings, Honda connecting rod journals, and Honda H-beam connecting rods. The Toyota castings were modified to use the oil drainback holes to bolt the block castings to the central crankcase.

The former mechanical engineer has a garage full of the type of equipment needed to put all of the pieces together.

One of the cylinder heads has been reversed, with the exhaust ports located toward the center of the engine within the V area. With the common ports in the center of the engine, Groff will be able to run the “bundle of snakes” exhaust manifolds to improve fitment within the chassis, which at this point is undetermined. The choices so far are a custom tube frame chassis, or a 1955 Chevy pickup shell he’s been sitting on for a while.

The oil pan was fabricated from 3/4-inch aluminum plate and a dry sump oiling system has been fitted for oil control. In addition, a pair of cam drives and serpentine drive also had to be fabricated, and a pair of water pumps will also be used to help keep the engine cool.

Final displacement will be 5.0 liters, with a goal of 800 horsepower. We’re working to bring you another update on the engine as development progresses.

The question we always ask when we see projects like this is, quite simply, “why”? And the answer, in Don Groff’s case, is “because I can”.


About the author

Jason Reiss

Jason draws upon nearly 15 years of experience in the automotive publishing industry. Collaborating with many of the industry's movers and shakers assists him in the creation of compelling technical articles and high-quality race coverage.
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