There are numerous variables to consider when it comes to building a rotary engine. One of the first questions we come across is oftentimes the question of whether to build a 2mm apex seal motor, or a 3mm apex seal motor. For a street driven car with 300hp or less, a 2mm motor is more than adequate. In addition to requiring slightly less financial commitment compared to a 3mm motor, the 2mm motor is also has the added benefit of having a slightly less contact area and hence reduced friction. The 2mm motor is also slightly more efficient in sealing compared to its 3mm sibling.

If more than 300hp is desired, we highly recommend our 3mm prepared motor. The 3mm seals are inherently 75% stronger than its 2mm counterpart. With its increased strength, a 3mm motor has more tolerance to detonation. A further benefit with the 3mm motor is that it has no increase in its wear characteristics. Our 3mm motors go through a rigorous prep and machine process. The tolerances demanded by our 3mm motors are +/-0.0005" cut with a state-of-the-art CNC machine. In real world terms, 0.0005" is half as thick as a piece of paper.

Another factor to consider is whether porting is necessary; and if porting is performed, what type of porting is preferred. First off, let’s consider what the advantage of porting is. Basically, engine porting allows the engine to breathe easier. And for a vehicle that spends any amount of time driven on the streets, a street port is the only option. While there are numerous porting techniques, our proprietary street porting technique is the only one we consider mild enough for the car to be driven on the street in a civil manner without any loss in power.

Our basic porting procedures are to reshape and retime intake and exhaust ports, smooth out runners and flow volumes are matched from port to port. With a street port, more power can be made with less boost. Boost indicates resistance to flow and less restriction will allow more volume of air without impediment. Always keep in mind “balance in all things”. Over-porting will reduce power. So much overlap may occur that parasitic losses make the engine slower than stock.

We believe that we at Rotary Performance, builds the most reliable engines. The reasons are two-fold: with a combined 30 years of experience and 2 world drag racing championships. Every motor we build go through a rigorous inspection of parts before, during, and after it’s installed. After the final build of the motor, we test the fresh motor on an engine test stand where we can diagnose problems before the motor is installed. This final quality control process is unique to us and it helps ensure the best quality motors.

For answers to frequently asked questions about our engine program. Please click here.

Basic motor builds:
2mm non-ported motor: $2400
3mm street ported motor: $3400