thermal reactor
11-28-03, 07:45 PM
#1
thermal reactor
what exactly is inside of the thermal reactor that helps heat it to break down exhaust gas? anyone have a pic??? do they have a tendancy to go bad or crack? also, did earlier engines like the 10a or 10b or even earlier 13b's have the thermal reactor??
11-28-03, 07:56 PM
#2
84SE-EGI helpy-helperton
Thermal reactors are actually remarkably simple in design, as there is really nothing inside of it apart from the two inserts that help to direct exhaust gases against the outside wall and helps to direct the gases (somewhat) into the direction of the outlet leading to the 'downpipe'.
The thermal reactor's purpose is to get the exhaust gases to mix with fresh air that's being pumped in by the airpump, as well as remixing the exhaust gases from the reactor with the incoming exhaust gases to help to quiet the exhaust noise. The two inserts are simple 2" pipes that are cut off and the front insert has about a 45 degree cut in the end to help point the exhaust toward the rear of the car.
As the engine runs, the thermal reactor takes unburned fuel and combusts it within the reactor with the fresh air, thereby reducing emissions. It essentially gives the engine exhaust a bit more time to burn before it's released to the downpipe and there is an additional fresh air pipe that runs from the bottom of the thermal reactor to the expansion chamber just behind and below it. This secondary pipe is only open to fresh air under power (IIRC), and again, helps to burn any unburned hydrocarbons.
The thermal reactors were not very efficient at what they do, particularly when cold. My 80LS never had a problem passing inspection, however, as long as the engine was warmed up, the thermal reactor was hot, and the plugs were clean.
In 81, Mazda went with the more expensive, but much more effective platinum catalyst design commonly called a catalytic converter. All later designs had staged 'cats', both with and without fresh air being pumped into them to aid in the catalytic reaction. HTH,
The thermal reactor's purpose is to get the exhaust gases to mix with fresh air that's being pumped in by the airpump, as well as remixing the exhaust gases from the reactor with the incoming exhaust gases to help to quiet the exhaust noise. The two inserts are simple 2" pipes that are cut off and the front insert has about a 45 degree cut in the end to help point the exhaust toward the rear of the car.
As the engine runs, the thermal reactor takes unburned fuel and combusts it within the reactor with the fresh air, thereby reducing emissions. It essentially gives the engine exhaust a bit more time to burn before it's released to the downpipe and there is an additional fresh air pipe that runs from the bottom of the thermal reactor to the expansion chamber just behind and below it. This secondary pipe is only open to fresh air under power (IIRC), and again, helps to burn any unburned hydrocarbons.
The thermal reactors were not very efficient at what they do, particularly when cold. My 80LS never had a problem passing inspection, however, as long as the engine was warmed up, the thermal reactor was hot, and the plugs were clean.
In 81, Mazda went with the more expensive, but much more effective platinum catalyst design commonly called a catalytic converter. All later designs had staged 'cats', both with and without fresh air being pumped into them to aid in the catalytic reaction. HTH,
11-28-03, 10:24 PM
#4
My wife bought me 2 RX-7s
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As for your question about what earlier cars had the TR, according to Felix Miata's FAQ, all rotary engined cars from '70 onward were equipped with a TR, so that would include the 10A, 12A and 4-port 13B motors.
11-29-03, 10:57 AM
#7
holley guy
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There are no negative effects to replacing the TR w/ performance exhaust. My car stopped backfiring, increased gas milage and performance, and ran more smoothly after replacing the TR w/ an RB header.
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11-29-03, 11:41 AM
#8
My wife bought me 2 RX-7s
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My car responded beautifully to a RB header/presilencer system. As soon as I scrape together the cash for a new midpipe and muffler, I'll get some more gains. 
'79 motors have larger exhaust ports than the later models, so I would imagine that they may benefit slightly more from an exhaust system.
'79 motors have larger exhaust ports than the later models, so I would imagine that they may benefit slightly more from an exhaust system.
11-29-03, 12:31 PM
#9
Originally posted by LongDuck
Thermal reactors are actually remarkably simple in design, as there is really nothing inside of it apart from the two inserts that help to direct exhaust gases against the outside wall and helps to direct the gases (somewhat) into the direction of the outlet leading to the 'downpipe'.
Thermal reactors are actually remarkably simple in design, as there is really nothing inside of it apart from the two inserts that help to direct exhaust gases against the outside wall and helps to direct the gases (somewhat) into the direction of the outlet leading to the 'downpipe'.
12-02-03, 09:06 PM
#16
Well, the little exhaust sleeves get burnt up or loose, and the inner cores disintegrate when they get overheated. Make sure your air pump is working properly is about the only advice I can think of to make them last longer.
I gave away a couple of 12A thermal reactors some time back, I absolutely loathe the things. Once you finally get the damned things off, you just want to hurl them as far as you can.
I gave away a couple of 12A thermal reactors some time back, I absolutely loathe the things. Once you finally get the damned things off, you just want to hurl them as far as you can.
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