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Catalytic converter stolen - what parts do I need to fix?
I am working on a 1993 JDM RX-7 FD3S that had the catalytic converter (and muffler?) stolen. See pictures below.
It is loud! I want to quiet the car as inexpensively as possible, without doing any potential harm to the rotary engine.
I am guessing a straight pipe won’t cut it — that there has to be a muffler added, right?
What do I need? Since I am not experienced with working on cars and this would be installed by a non-RX7 shop, can you provide links or specific part names/numbers? I just want to order the right thing(s) and bring it to the welding shop.
One other thing. The car is registered in Florida. I believe a catalytic converter is required, but is this true even for such an old car?
so is the downpipe (connects from the turbo outlet to the main cat) intact? from the looks of it, just the cat and o2 sensor harness are cut and the downpipe is ok? I'm not sure which USDM aftermarket cats fit the factory JDM downpipe, as the JDM downpipe is shaped differently due to the steering system being on the other side of the car vs left hand drive. I do know the factory USDM cat connects to a JDM downpipe on a left hand drive car, because that's a setup I have had. I'm assuming it would bolt up to a right hand drive car.
You can try calling these guys up and see what they recommend as far as aftermarket options. Anything that changes the restriction level of the exhaust significantly (like a straight pipe replacing a factory cat) will cause overboost problems, making the engine go into a failsafe mode without doing other mods. It gets to be a slippery slope of increasing risk or requiring more and more mods to make everything work.
Otherwise, source a USDM factory catalytic converter used here on the forums, and someone else here can chime in if it will fit a RHD car with factory downpipe. There are probably low mileage ones around. The o2 sensor is hard to say from the pictures. Is the harness plug still there on both sides? If so a universal sensor could be wired in.
You may not need any welding done at all, but you are dealing with old rusted parts so anything is possible.
Looks like the sensor wire is for the over temp system that is on JDM cars. Unless you can find a JDM OEM cat you will need to plug the hole in the underbody. I believe that a US OEM catalyst will bolt right up, my FD has a JDM downpipe and JDM rear muffler section with a US OEM catalyst in between and it fits perfectly. The US OEM catalyst is no longer available from Mazda afik. You could possibly order a JDM OEM catalyst and new sensor through amayama, still shows as available (N3F120600C) but very expensive and seems to not include the heat shielding. A used US-spec catalyst is likely the best option if you can locate one in good condition.
@jza80 is correct. You can source a used USDM or JDM cat or order a Bonez high flow catalytic converter from one of the vendors like RX7.Com.
The wire dangling is, in-fact the temp sensor that is for cat overheat. The JDM car doesn't have the red light on the center console like USDM cars. Instead your check engine light would activate. I believe the part is still available. If you can't source the sensor, you can simply remove your driver seat, pull up the carpet and find the grommet that runs the wire down underneath the car. The sensor is a simple two wire resistance type deal and can be wired together without causing any faults. A lot of aftermarket cats won't have the bung to accept this sensor and that is something you must do anyways if you get something like a Bonez.
I personally run a Bonez hi-flow cat on my car. I'm running a PowerFC so not sure what ECU you are running.
As for Florida, we don't have emissions testing here. So a catalytic converter technically isn't required. A rotary without one is miserable and a big polluter. I'd get a Bonez to fix your problem. Also in Florida, once the car hits 30 years old you can actually get "Antique" plates for it.
thats a very clean cut for a thief.... the car would have had to been fully raised to do this. thats simply not possible on the ground
anyway..... florida doesnt have an emissions requirements. you dont NEED a cat to please the state. looks like the cat back was cut. youll need an all new exhaust from the downpipe back.
thats a very clean cut for a thief.... the car would have had to been fully raised to do this. thats simply not possible on the ground...
I was thinking the same thing. Around here, scumweasel cat thieves sometimes jack up the side of the car to get access to the exhaust. that, with a new blade, will get the part. Prius' are a big target in CA, they are common and the cats have a high precious metal loading. They are also close to the ground so the side jacking method becomes well-honed. The thief here probably saw the large catalyst body and thought he/she hit the jackpot. In reality, the JDM cats have relatively low precious metal loading as the emissions standards in Japan were much less stringent than in the US in the 1990's and 2000's. Now, not so much different IIRC.
@pmurf5, you are lucky that there was no collateral damage. There have been cases in my area where catalyst thieves' chop saw cut indiscriminately into other parts in addition to the exhaust pipe. They care not for the damage they do. Good luck with the repair, on the bright side this is a good opportunity to pick up a nice aftermarket cat back system. Maybe your insurance will cover the cost.
Thank you to everyone for your help. I have some good leads. And I know not to do a straight pipe between the two cuts!
As an aside, the car had a parking space in the bottom level of an underground parking garage for an apartment/office complex. This was specifically to keep it off the street and out of view. Not successful, obviously...
The thieves must have jacked up one side. I can barely get my iPhone underneath to get a photo of the cuts.
Any additional info is helpful; for example, who in Central Florida might be good to take it to for the install.
Full Detail Automotive in Tampa is the go to FD shop in the area. Not sure how "central" Florida you are but they're worth the trip if you're able. If not, kilo is pretty good but from what I hear he has quite the wait list
Most shops fall apart when it comes to rx7s for some reason. There isn't anything unique about installing an exhaust on fd but for some reason people see the car and panic. Its dumb but it actually is a risk to take an fd to a normal shop. Its crazy 😒😒
Just curious. Why the need for a specialty shop when it seems like something most muffler shops can handle?
A shop familiar with the rotary should know that exhaust temps (EGT) tend to run ALOT hotter and a lot of aftermarket cats don’t last. When that happens it can damage an engine. A muffler shop will throw on anything that will fit.
I second (or third) those that suggested the Bonez cat. It’s an all-stainless proven hi-flow design for the FD. Mines still going strong after over 20 years.
And you definitely want a cat even w/o emissions. In addition to avoiding overboost (boost creep) it’ll be louder and stink to bejesus.
Thank you all, this is good info, especially for someone like me who is not a petrolhead!
Mazdatrix said they didn't have a part for a JDM (RHD) FD3S. They suggested Pettit. I contacted them and will let you all know how it goes ... especially to help someone else in the future if they have the same problem.
08-08-22, 09:56 AM
