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The Datsun 1200 used a 1-1/2 inch exhaust system. The cast iron exhaust manifold has a flat two-bolt flange. A donut-type asbestos seal was used to connects to the exhaust pipe, which extended past the rear axle. Finally a very, very quiet muffler with a short tail pipe was suspended by two rubber rings.
muffler with integrated pipe
Bottom (old) is the factory piece
A12 GX engine (twin carb) models used a quieter exhaust with a small resonator as well the regular muffler:
Notice is also used a cast header with dual outlets.
Sizing for Performance
A large diameter exhaust pipe is needed for maximum high-rpm horsepower. However, a small diameter pipe is needed for low-rpm horsepower. So you can see that a properly sized pipe -- not too big or too small -- is advantageous.
Single Exhaust
- Stock 68/69 horsepower A12: 1-1/2"
- lightly modded A-series engine: 1-3/4"
- 100 hp engine: 2"
- 150 hp engine: 2-1/4"
- 200 hp engine: 2-1/2"
Of course you can vary this. For example:
- The larger the engine relative to your car, you can get away with a larger pipe. Although the larger pipe cuts down on low-rpm horsepower you have a big engine so it's not so bad. This increases high-rpm (peak) horsepower
- For better street driveability, go a size smaller
- For drag racing where it is flat-out full throttle, a larger size may work fine
Options
- Muffler system with resonator
- Chrome tailpipe extension (bell-shaped)
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