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Published 2007 Updated 2017

R16 Exhaust Manifold and Header

This dialog was pulled from the forum-Will, Nissanman, Conner and Sid were contributors.

Stock R16 exhaust manifold

The outlet flange can also be a circular ring instead of the 3 bolt seen in the first picture.

After market exhaust "header". And yes, I believe they do get close to the OE long starter motor. A good place for a heat insulating blanket perhaps :?:

In truth, the factory manifold is a very good design. The only problem with them is that they tend to crack. For the roadsters, there is no such thing as a factory set of headers. (Unlike the 510s and Z's where you can call up Nissan Motorsports and get a set of long tube 4 into 1 headers for either.) Honestly, I bet there isn't much of a performance gain unless you have a huge set of headers, and the head work to go with them. I'm going to try and verify this in the next month or so when I try and get my car back on the dyno. Last time it was on it ran a small exhaust, with common headers. I have since stepped up to a 2.25 stepping to a 2.5 inch pipe and went from the 1.50 headers to 1 5/8s headers. The place to gain a small amount of Hp and help keep things cool is by getting the manifold or headers Jet-Hot ceramic coated. The coating keeps the heat in and gives you better exhaust gas velocity.

Your exhaust diameter will be limited by the clearance where it passes through the X-member of the frame at the middle of the car. If you want to go much larger than stock you will need to modify that area where it passes through.

You should be able to get a full 2 inch pipe through the frame no problem. Whether you need that much flow is another issue. You would really need to do a lot of head work to make full use of the larger pipe. A R16 head doesn't flow all that much so having a super open exhaust can cause low end drive ability issues. You will need a serious cam, and carbs to go with it. Port work on the head (not just bigger valves, but reworking the ports themselves.) One thing you could do, and this will sound a little weird, is cut off the collector that is on your headers now. Replace it with a cone shaped one that tapers down toward the exhaust pipe end. Make sure its the same size as the pipe you are running. Look up Burns Stainless Steel Merge collectors to learn a little more about it. The simplified version that I have mentioned has worked really well for a friends race 510.

Before you get your torch and welder out to reinvent the header, have an honest conversation with yourself. Decide if you are going racing, or street driving. Do you NEED every last horsepower? The stock parts and available headers work just fine for 99 percent of the population...