Choosing a location
All catalytic converters need to reach a certain temperature before they begin working. They also have a maximum temperature which must not be exceeded. In order to enable the catalytic converter to operate within its optimum temperature range, it is recommended that the temperature of the exhaust gas at the inlet is as follows:
Minimum 250 Centigrade (480 Fahrenheit)
Maximum 500 Centigrade (930 Fahrenheit)
It is very important that the catalytic converter is installed in a location where the exhaust gas is usually in the right temperature range. The best method of measuring exhaust gas temperature is by drilling a small hole in the exhaust and then inserting a thermocouple connected to a suitable indicator. A less accurate but quicker way is to measure the temperature of the outside of the exhaust tube using either an infra-red temperature gun or temperature indicator strips. The temperature of the outside of the exhaust tube will normally be lower than that of the exhaust gas itself, so an allowance must be made for this.
Another reason that location is important is due to heat which will be generated by the catalytic converter itself. This might damage neighbouring components, especially electrical items. Thermal insulation can play an important role both in obtaining the temperature necessary for the converter to work and also in preventing excess heat from causing damage.
Insulation
In order to retain heat in the exhaust gases, it is common practice to insulate the catalytic converter and the exhaust tube between this and the engine. It may also be necessary to fit heatshields to items which must be protected from excess heat, for example electrical items.
Please click here for details of suitable insulation products which are available from Blackthorn.
Isolation from vibration
The durability of the catalytic converter will be improved if it is not subjected to excessive vibration. This is normally controlled by the installation of a flexible coupling between the engine and the converter. We can supply a variety of products for this purpose.
Supporting the weight of the catalytic converter
The catalytic converter will add weight to the exhaust system and this must be supported by suitable brackets. If a flexible coupling has been provided upstream of the catalytic converter then any subsequent brackets would normally be rigid. If there is no flexible coupling to isolate the converter from engine vibration then the brackets themselves should be flexible.
Connecting to the exhaust tubes
There is a variety of methods by which an in-line catalytic converter may be joined to the neighbouring exhaust tubes. Which option is most suitable will depend on a number of considerations, for example:
- how much space is available
- whether the tube run is straight or curved
- the necessity of being able to remove the converter later
- whether the joint will need to accommodate slight differences in alignment
The most widely used methods are as follows:
1. Welding
Advantages: low cost, compact, does not require a straight tube run
Disadvantages: permanent
Tube size range: all
2. Sleeve fitting and clamp
Advantages: low cost
Disadvantages: requires a straight tube run and sufficient clearance for installation
Tube size range: up to 3" (76mm) outside diameter
3. Bolted flanges with flared tube and olive
Advantages: can accommodate slight differences in alignment
Disadvantages: space requirements
Tube size range: all
4. Vee-band clamp with flare and olive
Advantages: compact and quick to assemble
Disadvantages: none
Tube size range: readily available for tube sizes up to 5" (127mm) outside diameter
5. Butted tubes with wide clamp
Advantages: low cost
Disadvantages: requires a sufficient run of straight tube
Tube size range: up to 6" (150mm) outside diameter
At Blackthorn we stock a wide variety of fittings such as flanges, clamps, olives etc- please us know what you require and do not hesitate to ask for our advice.
