Advise On Gutting The Catalytic Converter
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From: colombo
Advise On Gutting The Catalytic Converter
Hi Guys,
I have 1992 JDM FD RX7 with 69,000km on the clock.
The HEAT signal near my meter gauges come on after like 5 mins from starting the car and it stays coming on and going. I can hear the air pump coming on and going off too.
Is it because my CAT is clogged and getting heated up ?
If yes is it ok for me to gut the cat (break the elements inside and make it hollow) ?
I did a search here there are both positive and negative comments. Hence I am confused.
My car has the stock ECU, Stock sequential twin turbos and front mount intercooler.
Please advice me on what can be done.
Thanks in advance.
I have 1992 JDM FD RX7 with 69,000km on the clock.
The HEAT signal near my meter gauges come on after like 5 mins from starting the car and it stays coming on and going. I can hear the air pump coming on and going off too.
Is it because my CAT is clogged and getting heated up ?
If yes is it ok for me to gut the cat (break the elements inside and make it hollow) ?
I did a search here there are both positive and negative comments. Hence I am confused.
My car has the stock ECU, Stock sequential twin turbos and front mount intercooler.
Please advice me on what can be done.
Thanks in advance.
If you're still running a basically stock car, with the exception of a FMIC, then I would not recommend removing the exhaust restriction provided by the main Cat. I would definitely verify if your cat is clogged, if so I'd replace it.
Removing the exhaust restriction provided by your main cat would probably result in negative (overboosting) consequences with your current setup.
Removing the exhaust restriction provided by your main cat would probably result in negative (overboosting) consequences with your current setup.
Gutting the main cat is certain to cause boost creep and possible engine damage on a stock car. It will also be significantly louder. If the car is otherwise stock, install a high flow catalytic converter such as the Bonez or RX7 Store and a 2.5" restrictor plate to keep the boost in check,.
If your cat is clogged, you may be able to unclog it. Remove it, and shake it. You will likely hear loose particles in it. They can be removed by shaking the cat until the debris comes out of both ends. Take your time with this, because it wont empty out quickly.
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Sounds like a problem with the exhaust overheat signal, not the cat. That's about 42k miles on a stock car, I highly doubt the cat failed on a stock car with that low of mileage. It could be a bad ground or something. The air pump is cycling probably in failsafe due to the overheat signal.
Joined: Nov 2011
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From: okinawa to tampa
you can test to see if its a faulty sensor before go messing with the cat. in this particular issue, it should be step 1 with troubleshooting. the plug for the sensor is under the driver seat. if you are able to remove the sensor from the cat without destroying the hardware then you can test it. also, im i agree with everyone else. DO NOT gut your cat with a stock set up like yours.
OP,
Don't be so quick to gut out the cat. If you must do it right and buy a MP, resonated MP, ect. Just make sure that you have the right mods and have taken the proper precautions.
FYI- Besides a few years back, due to the precious metals these cats were worth a few hundred dollars at recycling places (I remember some people claiming $400 usd). I'm not sure what the ongoing prices are but it should be something that you should be aware of before you gut one out lol.
Don't be so quick to gut out the cat. If you must do it right and buy a MP, resonated MP, ect. Just make sure that you have the right mods and have taken the proper precautions.
FYI- Besides a few years back, due to the precious metals these cats were worth a few hundred dollars at recycling places (I remember some people claiming $400 usd). I'm not sure what the ongoing prices are but it should be something that you should be aware of before you gut one out lol.
^No.
Boost controllers are for boost SPIKE, a result of opening the intake side of the engine. But those do nothing for boost CREEP. That is a result of too little back-pressure in the exhaust side of the engine. The only way to avoid CREEP is to port the wastegate on the twins (requires removal), or keep some restriction in the system. It really doesn't take much. Usually even a hi-flow cat is enough.
Boost controllers are for boost SPIKE, a result of opening the intake side of the engine. But those do nothing for boost CREEP. That is a result of too little back-pressure in the exhaust side of the engine. The only way to avoid CREEP is to port the wastegate on the twins (requires removal), or keep some restriction in the system. It really doesn't take much. Usually even a hi-flow cat is enough.
Sgtblue, thank you for your reply. The problem is how do you know when you have passed the borderline of an adequate restriction in the exhaust system (assuming a stock car, no afr or egt gauges)? Is there a rule of thumb for what size catalytic converter, 100, 200?
^Just personal experience of other owners I’ve known and information available here. The wastegate on the stock twins is relatively small. Some years back I knew someone who added a midpipe (though it was an aftermarket cat-back brand I don’t remember) and he had creep issues as reflected on a commander. The only other "mod" I recall was a k & n drop-in and no emissions. It was also an auto.
I guess if you believe the STOCK cat-back is restrictive enough you can go with the mid-pipe. But it’s a potential overboost situation that jeopardizes your engine. Plus the car will stink.
As for what size hi-flow cat, I recommend one with a proven track record with our cars...I’ve got a Bonez but there are others as well as resonated pipes that reportedly work. A search will have more info.
I guess if you believe the STOCK cat-back is restrictive enough you can go with the mid-pipe. But it’s a potential overboost situation that jeopardizes your engine. Plus the car will stink.
As for what size hi-flow cat, I recommend one with a proven track record with our cars...I’ve got a Bonez but there are others as well as resonated pipes that reportedly work. A search will have more info.
Last edited by Sgtblue; Aug 17, 2018 at 03:00 PM.
