Review – Mazworx SR20DET S13 Intake Manifold

Mazworx Intake Manifold


To achieve higher power levels from an SR20DET, the engine has to be allowed to breathe. It is really an air pump, and allowing this pump to flow more easily will make more power. While the stock intake manifold is well designed, it is designed for lower end torque at limited power levels and simply cannot flow air effectively at higher power ranges. Upper 300 wheel horsepower may be the effective limit and the rapid fall off on the dyno plots over 6000 rpm tend to confirm the limitations.

The concern when upgrading to an aftermarket manifold is while one gains power at higher rpm, you sacrifice torque in the lower ranges. For our power goals we reached the point where the stock manifold was no longer adequate. A solid solution was needed.

We turned to Mazworx for an intake manifold. Mazworx has years of experience with and their products have been designed with that experience and knowhow in mind. Mazworx uses machined billet intake runners and this may be the secret sauce in the manifold’s performance.

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Check out this view of the inside of the plenum. You can see the billet runners are actually velocity stacks and they mate perfectly with the SR20DET ports.mazworx-13

Dyno results were impressive. With the help of RS-Enthalpy, before and after dyno tests were run to compare the stock and Mazworx intake manifolds.  

From Martin at RS-Enthalpy:

“Everyone knows that one thing you sacrifice when upgrading intake plenums is that you suffer from a 10-15% torque loss with a short runner Greddy or Greddy style manifold. For most setups trying to achieve over 375 rwhp it has been traditionally a toss up of better top end (with the Greddy) or better lower torque and response (with the stock manifold). We finally had a chance to test the new S13 Mazworx manifold back to back at the same boost level, on the same car within an hour’s worth of time to change out. Mazworx has absolutely nailed it with this piece. Take a look at the virtually zero change in spool up. Test car was a 2.2L Mazworx motor with Mazworx CNC head with a GTX 3071. Both runs were at 17 psi with no boost creep. Both runs were between 55-60 F and identical AFRs, identical timing values on 110 octane. So basically all the advantages of a larger plenum without the sacrifices of the traditional ones readily available.”

Dyno results:

manifold dyno comparison

The Mazworx manifold picked up about 40 whp when looking at peak to peak, but given the stock intake drops off badly after about 6300 rpm, the gains at higher rpm is more significant and as much as about 80whp. The area under the curve is significantly improved.

We strongly recommend the Mazworx Intake manifold.