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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 built-in bulge of the pipe was used to seal 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. The factory Datsun 1200 muffler was so quiet you couldn't hear the engine at idle.

1 Overview
2 Sizing for Performance
3 Options
4 Coupe vs Sedan vs Wagon
5 A12GX Exhaust
6 Part Numbers
7 Exhaust Pipe Gasket
8 Muffler
9 Extractors
10 System
11 Turbocharged

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Overview

Album 18142

Terminology

Exhaust Pipe, Muffler, Tail Pipe
Album 26085

Exhaust Manifold and Exhaust Pipe
Album 22644

Exhaust insulators: Rubber tailpipe hanger, Ring muffler hangers

Original mufflers came with integrated exhaust pipe - Bottom (old) is the factory piece
Album 11320

B210 is similar: 20100-H5000

#A12GX Exhaust from twin carb models used a quieter exhaust with a small resonator as well the regular muffler:

In addition the rubber hangers at the very end of the pipe and the muffler rubber hangers, B310 used a solid hanger at the end of the transmission:

Factory muffler: B110, B110A, PB110, PB110A, B110 GX, B110 GXA, B110 GX5
Album 22334

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Sizing for Performance

A large diameter exhaust pipe is needed for maximum high-rpm horsepower. However, a small diameter pipe is needed to boost low-rpm horsepower. So you can see that a properly sized pipe -- not too big or too small -- is advantageous.

Album 3092

Single Exhaust
* Stock 62 horsepower A10: 35mm (~1-3/8")
* Stock 68/69 horsepower A12: 1.5" (38mm)
* A12 GX 83 horsepower: 1.5"
* modded A-series engine: 1.75"
* Max fuel econdomy: 1.5"
* 108 hp engine: 1.75"
* 144 hp engine: 2"
* 185 hp engine: 2.25"
* 232 hp engine: 2.5"
* 339 hp engine: 3"

Of course you can vary this. For example:

The larger the engine relative to your car, you can get away with a larger pipe
For better street driveability, go a size smaller
For drag racing where it is flat-out full throttle, a larger size may work fine

2.5 inch works too, but results in less HP than 1.75 inch pipe
Album 13999

Although the larger pipe cuts down on low-rpm horsepower, if you have a big engine it's not so bad. Large exhaust increases high-rpm (peak) horsepower slightly while dropping low-RPM hp significantly.

Large pipes with "turbo" type mufflers sound great, but tend to have annoying resonances.
Album 9714

To solve the vibation & drone problems encounted with straight-through (turbo) mufflers:

Change to a chambered muffler which is baffled
or, adjust pipe diameter and length, possibly adding a resonator chamber in the middle of the exhaust system
OR, cancel out those specific pipe resonant frequencies. For example, if your exhaust drones loudly at 2,500 RPM, add a side branch pipe that is 28" long. It will cancel the drone and leave all other RPMs alone

3" exhaust system is possible under a 1200 sedan
Album 4985 Album 12687

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Options

Coupe vs Sedan vs Wagon

coupe muffler
Album 14826

The bends are slightly different.
The hanger near the end of the tailpipe (in the photo: where the price tag is) is a different place for sedan vs coupe

Sedan/Coupe/Wagon differ - left: exhaust pipe, right:muffler/tailpipe
Album 3771

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A12GX Exhaust

A12GX exhaust from A12GX Engine (twin carb) models used a quieter exhaust with a small resonator as well the regular muffler:
Album 12778

Notice the GX also used a cast header with dual outlets -- See Exhaust Manifold
Upload click to view Album 2585

downpipe portion of the exhaust pipe
Post 460546 Album 11830

GX used the stock muffler (coupe or sedan version) along with these special parts:

20010-H2301 ASS'Y-TUBE, exhaust front GX
20010-H3400 ASS'Y-TUBE, exhaust front GXA
20010-H7200 ASS'Y-TUBE, exhaust front 5 speed
20321-H2500ᴳ FINISHER-exhaust GL,GX < 20321-H2000

chrome tail pipe Finisher
Album 13931

For the B110 1200 there were three different GX tubes:

GX
GX Automatic
GX5

Only difference being the bend of the tube. Subtle difference

Exhaust Tube with resonator
Post 491959

Exhaust good for an engine with 20% more HP. Same tube diameter as regular
Post 491957
Post click for topic Post click for topic Post click for topic

Complete the GX exhaust with Sedan or Coupe muffler/tail pipe assemblies. Result is super-quiet yet more powerful.
Post 491957

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Part Numbers

Main: Exhaust Part Numbers

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Truck, Early

To 1978, a single muffler was used.

FRONT EXHAUST TUBE ASS'Y
20010-G0002 SB
20010-G1601 SB 7510-8503
20010-G1401 LB
20010-G1611 LB 7510-8503

MUFFLER WITH REAR TUBE
20100-G1003
20100-G1600 7510-7907
20100-G1660 7908-8503 > 20100-G1600

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Truck, Mid-model

From 1978 to 1989, a rear resonator was used.

FRONT EXHAUST TUBE ASS'Y
20010-G1900 SB 8504-8910
20010-G1910 LB 8504-8910

MUFFLER WITH REAR TUBE
20100-G1901 8504-8910

20673 CLAMP-EXHAUST TUBE

Nichira manufacture

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Truck, Late

From October 1989, a Catalytic Converter was used.

FRONT EXHAUST TUBE ASS'Y
20010-95W00 8910-9401
20010-95W02 9402-

MUFFLER WITH REAR TUBE
20100-95W01 SB 8910-
20100-95W11 LB 8910-

20711 GASKET-EXHAUST
  20691-G5100 8910-9401
  20691-51E01 9401-
20711M GASKET-EXHAUST
  20692-02E00 8910-9208
  20692-1E810 9208-
20520 INSULATOR-HEAT, EXHAUST TUBE CENTER LOWER
  20532-95W10 LB
20522 INSULATOR-HEAT, EXHAUST TUBE CENTER LOWER
  20530-95W00 SB
  20530-95W10 LB
20540 INSULATOR-HEAT, EXHAUST MUFFLER
  20540-95W01 SB + LB
20731 BRACKET-EXHAUST MOUNTING
  20720-95W00 SB + LB
20802-G5126 THREE WAY CATALYST 8910- <> 20802-81A26

20624 INSULATOR ASSY-EXHAUST MOUNTING
20630-G1001 ALL (2)
Album click to view
* fixes muffler to chassis

9401- Front Exhaust Tube (uses 51E donut type gasket)

EXHAUST GASKET manifold-to-pipe
20691-G5100 flat type 8910-9401
20691-51E01 ring type 9401-

EXHAUST GASKET pipe-to-converter
20692-02E00 8910-9208
20692-1E810 9208-

20691-51E01
BECK/ARNLEY 0396441 $3 rockauto.com
FEL-PRO 60905
VICTOR REINZ F31814
* A32B 0601- VQ30DE
* A33B 0499- VQ30DE
* B13 0890- SR20DE
* B15U 0100- SR20DE/QG18DE
* D22U 0898- KA24DE
* L30 0697- KA24DE
* U13U 0893- KA24DE
* WD22 0599- KA24DE

20691-51E01 Steel ring gasket
Post 481133

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Converter

To meet 1988 'R' emission standards, a 3-way catalytic converter was fitted. Due to the converter beneath the floor, a special passenger seat is used.

CATALYTIC CONVERTER GASKET
Nissan 20692-M3060
BECK/ARNLEY 0396035
* 720 L20B, Z20/Z22/Z24
* 910 L24E
* B11 E15X/E16S
* N10 A14/A15/E15S
* N12 E16S
* S110 Z20E/Z22E
* S12 CA18ET/CA20E
* S130 L28E/L28ET
* T11 CA20S/CA20E

Album 27039
20802-G5126 THREE WAY CATALYST < 20852-81A26 コンバーター、カタリスト ウイズ　シェルター
20802A　01121-00751 BOLT 4
20853-53A00 LOWER SHELTER シェルター、コンバーター ロア
22740-95W00 [EXH TEMP] SENSOR ASSY-CATALYST センサー アッセンブリー、カタリスト

Album 27040 Album 27041 Album 24462

Racing Pipe for replacing the converter.
Album 24463

Budget racing pipe
Post 481196

Slimline catalyst
Album 14935

B211 catalyst piping
Post 481198

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Exhaust Pipe Gasket

See Main Article: Exhaust Manifold#Gasket

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Muffler

Main: Muffler

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Extractors

See Main Article: Headers

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System

David Vizard says exhaust pipe diameter makes a significant difference.

In practice though it is better, especially for a street-driven machine, to have pipes a little too small rather than a little too big. If the pipes are too large a fair chunk of torque can be lost without actually gaining much in the way of top-end power.

More interesting is about the tuned-header and collector lengths:

on a well-tuned race engine ... the exhaust system draws on the intake port as much as 500 percent harder than the piston going down the bore...the exhaust is the principal means of induction, not the piston moving down the bore.

Vizard recommends a sized extractor and a resonator box placed at the correct length. Then after the resonator it doesn't matter how long the exhaust pipe is or what muffler type is used (open chamber or glass pack). Without a resonator the type of muffler makes a huge difference on horsepower.

For racing, don't worry about equal length extractors, it's a waste of time.
For a downdraft induction system, don't mess with the length of the extractor primaries
The collector length is where you should concentrate your efforts
At the end of the collector length fit a large expansion chamber (pressure wave termination box)
The chamber should be 8 to 15 times the volume of one cylinder (larger is better). For an A12 this works out to about 3 liters.

Collector Length:
Pick an appropriate length from the collector. This makes a huge difference on high overlap camshafts and not just a "dyno difference". There is no "correct length" for all A12 engines. It depends on how you build the engine. What cam do you have? Where do you want the max HP to occur? Via the length you can shift the power band somewhat.

Having a proper length (long) collector can provide a lot more HP while in the power band. Up to 22% more. So it's definitely worth doing.

Discussion by jmac: Extractor selection

Long collector
Album 14857

Stock collector
Upload click to view

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Turbocharged

2.5" off turbo for about 2" then 3" all the way all mandrell bent a straight through offset centre muffler and a resonator at the rear with a 3.5" tip
Album 19170 Album 19171 Album 19172 Album 19173