09/24/2026
The factory Nissan SR20 is a two-liter four-cylinder with an 86 mm bore and an 86 mm stroke. Mazworx Racing Engines in Sanford, Florida, turns it into something that supports around 1,200 horsepower at the wheels on ethanol, and still gets driven on the street.
The block is billet, machined in-house from solid aluminum. Billet is strong, but a solid block can struggle to cool, and several of these engines end up in drift cars where heat is a constant problem. So Mazworx worked with Darton on custom sleeves that keep proper coolant flow around the cylinders instead of trading cooling for strength.
Displacement depends on the job. A street engine gets a 90 mm bore and a 91 mm stroke for about 2.35 liters, because the longer stroke gives more usable torque. Maximum-power engines go back to the factory 86 mm stroke at about 2.2 liters, which allows higher RPM and room for a thicker connecting rod. New engines start at 89 mm bore so there is material left for future rebuilds.
The cylinder head is not the usual turbocharged SR20DET head. That head uses floating rockers that can pop loose when the valves float at high RPM or during launch control, and then the camshaft breaks them. Turbo four-cylinders with big turbos often use aggressive anti-lag to get off the line, which makes the problem worse.
Mazworx uses the VVL head from a front-wheel-drive SR20 of the early 2000s instead, because it has shaft-mounted rockers that stay put. Adapting it to a rear-drive engine takes custom conversion parts, and the variable lift system is eliminated entirely, running only the larger cam lobes with Kelford camshafts.
Then the details that only show up at four-digit power.
The factory engine read its position from the exhaust camshaft. That is far from the crankshaft, and timing can drift at high load. At 1,000 horsepower, a couple of degrees of drift can destroy an engine. Mazworx moved the main trigger to a reworked damper with a steel shell and a 60-2 trigger pattern right on the crank.
The factory flywheel used 10 mm bolts. At these power levels, the vibration a four-cylinder produces was letting the flywheel move against the crankshaft until the two surfaces started welding together. The billet cranks now take half-inch ARP fasteners with far more clamping force.
Inside are custom CP pistons, custom Carrillo rods, and a billet crankshaft. A dry-sump pump sits where the alternator used to be, keeping it away from exhaust heat, while the alternator moves to the hot side. Compression is 10:1, and the head gasket is a copper fire ring design.
It is still recognizably an SR20. It has simply been re-engineered wherever the original design stops working at five or six times its factory output.
