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This article will show you how to remove the Catalytic Converter (Catcon) from your R15.
Note: This Tread is only for R15 and may not be applicable for any other bike, do not compare any info in this article with other bikes please.
Catalytic Converter (Catcon) is a element in exhaust pipe to treat the exhaust gas and convert them into harmless gas, in-order to comply with emission norms.
Why Removal?
This is the 1st question for almost everyone who see this article. Let me brief my story. I have a modified 180CC setup for my R15 with modified ECU, High Flow Air Filter all supplied by Joel (Except for the Piston), as you know most modified/Joel'd R15s have Free Flow Exhaust as a part of the package. I personally do not like the screaming sound and my perception is like "I own a 1+ Lakh bike and it must be gentle"
. Moreover I work for a corporate and folks here give their worst attention towards loud free flow exhausts.
So I decided to have no compromises anywhere in my setup like retaining the Stock engine smoothness, exhaust note, but still gain 17HP at the rear wheel. (Approx 19-20Hp at Crank).
In order to accomplish the above task, I had to stick with the stock exhaust. So just to tweak the stock exhaust to give more exhaust flow, I removed Catcon,
But the true story is,
The mesh type single catcon in R15 is very accurately designed/placed in such a way that it would hardly block any air flow, But the Catcon tends to get Red hot under normal operation which in turn dissolves the unburnt gases before hitting the muffler assembly. So this process tends to slow down the air flow and increase the exhaust temperature/back pressure.
Also while the Catcon turns red hot, actually the engine gains more back pressure, but there is no direct relation between catcon and back pressure, its achieved through resonators present in the muffler assembly. Its just the Airflow process is delayed in microsecs causing this virtual gain in back pressure.
Let me keep the article as simple as possible, and before getting into the DIY steps, lets see the Positive and negative aspects. Theoretically removing catcon has various drawbacks and also illegal in terms of emission norms, but practically in my 20,000Km experience I have nothing to bother upon.
+ves
1) Better cooling
2) Increased Air intake
3) Mileage 45+Kpl For stock R15 (Before cat removal it was >40Kpl)
4) Vibe free, revs smoothly
5) No change in Exhaust note
6) better topend
7) Practical Emission test passed for BS3
8) Must for bigger bore modifications
9) Also remember a Free Flow Exhaust will not have a Catcon, We can assume that this is an FFE in-terms of emission
-ves
1) For custom ECUs, you need accurate Fuel supply, else exhaust backfire. (No an issue with stock R15)
2) Risk of local Welding.
3) Theoretically Engine life factor gets affected (But I have done 20K)
4) If its custom bore/comp ratio then loss of engine backpressure (No an issue with stock R15)
5) Looks - The welding mess creates a bad impression.
6) Theoretically should fail emission norms. (But Practically its passes with stock values)
Prerequisites:
Find a good welder near your place, I have done normal gas welding, while the industrial TIG welding will be much better and accurate.
Cost involved:
97Rs Apache 150's Exhaust side cover
250Rs Welding and cover fitting Charges
Steps:
Step 1:
Remove the exhaust cover and also make sure the Brake hose to rear disc caliper is secured and instruct the welder that the hose and other wires are to be considered while welding.
Note: Step 2 is the most important step, if you get this right then the job should complete in 15mins, else it will become a big mess and you may end-up spoiling your exhaust.
Step 2:
Start opening the exhaust pipe at the exact spot indicated by the arrow by welding cut process, Which is just 0.5CM next to the factory welding.
Note: Observe the factory welding ring, it is the last one that connects the muffler assembly.
Step 3:
After opening the exhaust can, you can find the Cat con as shown below,
Step 4:
Make the welder do the same welding cut process at the spot indicated by the arrow and remove the catcon by cutting down the entire catcon all round.
Step 5:
The remaining 10% of catcon will stick in the exhaust itself, use a hook or bend a screw driver like a hook and pull out the remaining Catcon.
Step 6:
Without the muffler assembly, start your bike and immediately twist the throttle upto 5K RPM, so that the left over particles in exhaust pipe will be thrown out.
Note: Remember without muffler assembly your bike will sound really loud, so turn off the bike in 30-40 Secs.
Step 7:
Place the exhaust muffler back and screw it and then start the Join welding process and complete it.
Note: Make sure you screw the Muffler assembly back and then weld, else the angle of muffler assembly may change.
Note: Ensure that the weld job is 100% sealed. You can check this by keeping your hand closer to the welding area and idle the bike. If in case there are any tiny openings, you will get to feel the exhaust gas through that opening.
Step 8:
The welding job will look like a mess, so find the image below to see how the Apache 150's exhaust side cover is placed, the same welder will be able to complete this task for you.
Thats is it, you are ready to roll, you will find a good increase in pickup, topend and mileage!!!!!
Step 9: (Only for 165CC Big bore users, Not applicable for Stock R15)
In case if you find any issues with loss in back pressure and throttle getting flat, find the below image and add a small extension pipe at the end (A normal PVC wiring pipe will do the job)
My setup is 180CC and opening the catcon resulted in making throttle response flat, like it will go on to 7K RPM and stay there in all gears. Absolutely no torque felt, somewhat similar to a huge compression loss. At first I added this extension pipe for 1CM and with trial and error ended up at 0.5CM for accurate back-pressure gain.
Last Word: Honestly you will forget that you removed Catcon in a few days, because gives no trouble further.
My Bike after the Cat con removal.
Hope the article was useful to you, also sorry for not including many pics, coz I had no intention to post a DIY while removing the Catcon and these were the only pics clicked.
Please provide your valuable suggestions and Questions below.
This article will show you how to remove the Catalytic Converter (Catcon) from your R15.
Note: This Tread is only for R15 and may not be applicable for any other bike, do not compare any info in this article with other bikes please.
Catalytic Converter (Catcon) is a element in exhaust pipe to treat the exhaust gas and convert them into harmless gas, in-order to comply with emission norms.
Why Removal?
This is the 1st question for almost everyone who see this article. Let me brief my story. I have a modified 180CC setup for my R15 with modified ECU, High Flow Air Filter all supplied by Joel (Except for the Piston), as you know most modified/Joel'd R15s have Free Flow Exhaust as a part of the package. I personally do not like the screaming sound and my perception is like "I own a 1+ Lakh bike and it must be gentle"
. Moreover I work for a corporate and folks here give their worst attention towards loud free flow exhausts.So I decided to have no compromises anywhere in my setup like retaining the Stock engine smoothness, exhaust note, but still gain 17HP at the rear wheel. (Approx 19-20Hp at Crank).
In order to accomplish the above task, I had to stick with the stock exhaust. So just to tweak the stock exhaust to give more exhaust flow, I removed Catcon,
But the true story is,
The mesh type single catcon in R15 is very accurately designed/placed in such a way that it would hardly block any air flow, But the Catcon tends to get Red hot under normal operation which in turn dissolves the unburnt gases before hitting the muffler assembly. So this process tends to slow down the air flow and increase the exhaust temperature/back pressure.
Also while the Catcon turns red hot, actually the engine gains more back pressure, but there is no direct relation between catcon and back pressure, its achieved through resonators present in the muffler assembly. Its just the Airflow process is delayed in microsecs causing this virtual gain in back pressure.
Let me keep the article as simple as possible, and before getting into the DIY steps, lets see the Positive and negative aspects. Theoretically removing catcon has various drawbacks and also illegal in terms of emission norms, but practically in my 20,000Km experience I have nothing to bother upon.
+ves
1) Better cooling
2) Increased Air intake
3) Mileage 45+Kpl For stock R15 (Before cat removal it was >40Kpl)
4) Vibe free, revs smoothly
5) No change in Exhaust note
6) better topend
7) Practical Emission test passed for BS3
8) Must for bigger bore modifications
9) Also remember a Free Flow Exhaust will not have a Catcon, We can assume that this is an FFE in-terms of emission
-ves
1) For custom ECUs, you need accurate Fuel supply, else exhaust backfire. (No an issue with stock R15)
2) Risk of local Welding.
3) Theoretically Engine life factor gets affected (But I have done 20K)
4) If its custom bore/comp ratio then loss of engine backpressure (No an issue with stock R15)
5) Looks - The welding mess creates a bad impression.
6) Theoretically should fail emission norms. (But Practically its passes with stock values)
Prerequisites:
Find a good welder near your place, I have done normal gas welding, while the industrial TIG welding will be much better and accurate.
Cost involved:
97Rs Apache 150's Exhaust side cover
250Rs Welding and cover fitting Charges
Steps:
Step 1:
Remove the exhaust cover and also make sure the Brake hose to rear disc caliper is secured and instruct the welder that the hose and other wires are to be considered while welding.
Note: Step 2 is the most important step, if you get this right then the job should complete in 15mins, else it will become a big mess and you may end-up spoiling your exhaust.
Step 2:
Start opening the exhaust pipe at the exact spot indicated by the arrow by welding cut process, Which is just 0.5CM next to the factory welding.
Note: Observe the factory welding ring, it is the last one that connects the muffler assembly.
Step 3:
After opening the exhaust can, you can find the Cat con as shown below,
Step 4:
Make the welder do the same welding cut process at the spot indicated by the arrow and remove the catcon by cutting down the entire catcon all round.
Step 5:
The remaining 10% of catcon will stick in the exhaust itself, use a hook or bend a screw driver like a hook and pull out the remaining Catcon.
Step 6:
Without the muffler assembly, start your bike and immediately twist the throttle upto 5K RPM, so that the left over particles in exhaust pipe will be thrown out.
Note: Remember without muffler assembly your bike will sound really loud, so turn off the bike in 30-40 Secs.
Step 7:
Place the exhaust muffler back and screw it and then start the Join welding process and complete it.
Note: Make sure you screw the Muffler assembly back and then weld, else the angle of muffler assembly may change.
Note: Ensure that the weld job is 100% sealed. You can check this by keeping your hand closer to the welding area and idle the bike. If in case there are any tiny openings, you will get to feel the exhaust gas through that opening.
Step 8:
The welding job will look like a mess, so find the image below to see how the Apache 150's exhaust side cover is placed, the same welder will be able to complete this task for you.
Thats is it, you are ready to roll, you will find a good increase in pickup, topend and mileage!!!!!
Step 9: (Only for 165CC Big bore users, Not applicable for Stock R15)
In case if you find any issues with loss in back pressure and throttle getting flat, find the below image and add a small extension pipe at the end (A normal PVC wiring pipe will do the job)
My setup is 180CC and opening the catcon resulted in making throttle response flat, like it will go on to 7K RPM and stay there in all gears. Absolutely no torque felt, somewhat similar to a huge compression loss. At first I added this extension pipe for 1CM and with trial and error ended up at 0.5CM for accurate back-pressure gain.
Last Word: Honestly you will forget that you removed Catcon in a few days, because gives no trouble further.
My Bike after the Cat con removal.
Hope the article was useful to you, also sorry for not including many pics, coz I had no intention to post a DIY while removing the Catcon and these were the only pics clicked.
Please provide your valuable suggestions and Questions below.
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