Nissan 200sx SR20DET Engine Tuning Guide

This document explains the engine various modifications, with a common path through them. However, these various modifications can be done in many different orders, and this is merely a guide.
The 2-litre SR20DET engine found in the UK-spec 200sx (s14 & s14a) provides 197 bhp and 195 ft/ lbs as standard. These figures can easily be increased, through a series of modifications, initially simple, and later more complicated. Reaching 280-300 bhp is relatively straight-forward; with more application and expense, figures of around 500 bhp and above can be achieved.
Engine breathing
The s14 200sx seems to have been designed and marketed not as an out-and-out sports car, but as a sporty car with suitability for the company-car market. With this in mind, the air intake and the exhaust are quite restrictive, making the car more refined. Removing these restrictions will unleash a good few horsepower just by allowing the engine to do its job unfettered, and as such, may even increase the fuel efficiency!
Air-box panel filter
The filter element from the standard air-box can be replaced with a less restrictive version, making it easier for the engine to suck through a bit more air. The power increase will be relatively small with this modification, as a large part of the restriction in the air intake comes not from the filter, but from the design of the air-box itself. One test of various filters (albeit not on a 200sx) found no performance gain whatsoever from a panel filter. This modification is useful as it isn’t obvious, and some people won’t worry about declaring its presence to their insurance company. The airbox can also be customised in several ways, to facilitate greater flow. The elbow between the airbox and its air-feed from the front of the car can be removed, holes can be drilled in the airbox (obviously in the pre-filter side!), and ducting can be directed to the airbox from a cold air feed.

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