GT-Spec Exhaust Manifolds for Nissan 350Z
Installation / First Impressions
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Why upgrade the Nissan Z with GT-Spec Exhaust Manifolds?
     The idea behind an exhaust manifold is to eliminate the manifold's backpressure. A good way for an engine to lose power is during the exhaust stroke through back pressure. The exhaust valve opens at the beginning of the exhaust stroke, and then the piston pushes the exhaust gases out of the cylinder. If there is any amount of resistance that the piston has to push against to force the exhaust gases out, power is wasted. It turns out that the manifold can be an important source of back pressure because exhaust gases from one cylinder built up pressure in the manifold that affects the next cylinder that uses the manifold. On the Nissan 350Z three cylinders share one common exhaust manifold on each side; when upgraded with GT Spec manifold each cylinder receives an individual pipe. These pipes come together in a larger pipe called the collector. From there, the gases are passed through the rest of the exhaust system in a number of different ways.

Overall Quality
    GT SPEC's new racing header for Nissan 350Z does not disappoint. Featuring full 304 stainless steel runners with perfect mandrel bends, flawless machine TIG welds between all joints and flanges – designed for a perfect fitment into the Nissan 350Z. The highly polished tubing complements the overall finish of the headers. The 2mm thick runners offer a significantly larger inner-diameter, and are a substantial upgrade as compared to the restrictive stock exhaust manifold.

GT-Spec Header Fitment
     We found GT Spec header well-designed in terms of accessibility of the studs / nuts. Aftermarket Nissan Z headers are not usually designed to provide good accessibility to the bolts, for example – on certain brands of Z headers it is not entirely possible to tighten all nuts to proper torque specs. The runners are simply not positioned properly to allow any access to the nuts. In the case of GT Spec the runners are well placed and allowed plenty of clearance to replace the nuts and torque them to their respective spec. The GT-Spec manifolds fit as well as the stock and the flanges aligned perfectly with the factory cats or aftermarket cat-delete pipes.