Skunk2 Racing Ultra manifolds have set the standard for powerful yet affordable K series performance. The Ultra Series is the product of years of research and development, culminating in a multi-piece cast aluminum intake manifold that offers advantages only a modular design could allow. The much anticipated K series Street model is now available. Previously, the Ultra Race version, with short runners and a 3.5L plenum, was the only Ultra manifold available for the K series, but now the wait is over.
Skunk2 Racing has created a two-piece modular design that allows for easy disassembly, porting, and plenum volume changes through the use of a removable plenum and optional plenum spacers. This two piece design is also the key to this manifold being used in the Miata: the plenum can be unbolted, flipped over, and made to fit in a RWD vehicle.
In addition to CFD testing, the Ultra Street manifold has undergone extensive in-house dyno and on-car testing which has led to a design that is less restrictive, yielding higher horsepower and torque gains than many of its competitors.
Ultra Street manifolds are manufactured from 356 aluminum alloy for light weight and added strength over sheet metal manifolds. Each manifold is CNC-machined for a precise fit, and individually inspected for quality. The Ultra Street features a 71mm throttle body opening and is constructed with thick walls, minimizing concerns of breakthrough when port matching.
The 1.82L plenum distributes even airflow to all four cylinders under dynamic load conditions. Placement and design of the velocity stacks ensure maximum delivery of air to each cylinder through the 8.72” intake runners.
Don’t let the “Street” in the title fool you. The longer runners provide the mid-range power you want, with no compromise in power at 8000+ RPM. In fact, it makes the best mid-range power of any manifold we’ve dyno tested, and is perfect for road racing.
The manifold also includes a thermal intake manifold gasket (a $45 value).
In order to make this manifold a true plug-and-play solution for the K series Miata swap, we offer a custom throttle body adapter. Since an upside-down K series throttle body won’t fit, our adapter allows you to run a B series throttle body in its place, with the proper orientation. It tapers from 74mm to 71mm for a perfect fit. In addition, our adapter features:
- A Miata-specific throttle cable bracket (designed for the shorter NB cables)
- K series MAP sensor port
- B series throttle body bolt pattern so you can use the reliable B/D/H/F style TPS
If you combine this adapter with our MAP and TPS jumper harnesses, you can bolt up this manifold and throttle body solution without cutting your engine harness.
Also, we offer discounted pricing on the entire package - see options above.
Note: this manifold/throttle body/adapter combo is specifically designed for K24 fitment. It can be made to fit a shorter K20 block, but some modification to the alternator, PCV valve, and throttle body adapter are needed. Email us for details.