Over the last five years, REC has been performing two types of the apex machining developed specifically for the RX-8 rotor. After learning how the fragile Renesis apex seals tend to easily fail under aspirated as well as boosted applications, we decided to create a method to increase the durability of this component. For the last 5 years, REC has been using our branded "2 mm full depth" and "3 mm custom depth" apex seal and rotor configurations.
The first method allows for the builder to use the conventional early style 2 mm RX7 type apex seal. Since Mazda's upgrade from the original three-piece seal, which was found in 86 and up model 13B engines, to the 2 mm two piece, and the majority of aftermarket 2 mm seals including our own seals, which are also two piece, this seal design has proven to be one of the more favorable seals to use*. REC uses our EDM process only. Using this EDM process we accurately extend the short slot found in these rotors to a full depth slot similar to those found in the RX7 rotor's. The EDM process uses a very thin wire electrostatically errodes away the material within the slot. Providing one of the most impressive and accurate finishes and clearance tolerances EDM is optimal for any high-performance or racing application. Providing tolerances accurate to one ten thousands of an inch. Once this is completed, the slots can be fitted with a standard RX7 2 piece apex seal along with custom modified corner seals. This now completes the first of two choices to utilize a much stronger apex seal configuration for this type of rotor.
Cost: $75.00 per slot
The second method, similar to the first method above, allows for the same advantage of seal options to obtain the maximum life and strength of the engine. Although as described in the 3 mm RX-7 rotor machining category listed above, the 3 mm machining process here is not designed to allow the slot to accept a full depth 3 mm seal. This is simply due to the fact that REC has learned that there is much less available material between the top of the spring seat and the sump of the rotor. Consequently, we compromise the total depth that we allow the EDM to go. And then subsequently we provide a variety of 3 mm apex seals which are actually short for in-depth. A special corner seals which we also offer is it available to work with this setup. This modification is usually recommended either for turbo applications or where the customer is looking for maximum available strength. This is actually the application where we recommend using a custom designed ceramic two piece apex seal specifically designed for boosted engines.
Cost: $80 per slot