Second Gen Posted December 27, 2012 Report Share Posted December 27, 2012 The RX7 has been running w/o a cat for years and I am tired of the wife complaining of the smell (They do run rich). Helped my daughters boyfriend install a high flow cat on an Evo X and was blown away as to how simple they look inside now (Assume very little loss). Now my issue - When most people remove all the emissions $hit they also remove the air / polution pump and change belt setup. I do not want to reintroduce the air / polution pump and hoped someone had a reasonable idea. Note I did see on one of the GN forums they were running an electric one, but unsure if this would work on the ReX. Quote Link to comment Share on other sites More sharing options...
Green Bastard Posted December 27, 2012 Report Share Posted December 27, 2012 I don't see why an aftermarket high flow cat wouldn't work for you. Iirc, the air/smog pump only helps the cat to light off faster. Quote Link to comment Share on other sites More sharing options...
Cordell Posted December 27, 2012 Report Share Posted December 27, 2012 The RX7 has been running w/o a cat for years and I am tired of the wife complaining of the smell (They do run rich). Helped my daughters boyfriend install a high flow cat on an Evo X and was blown away as to how simple they look inside now (Assume very little loss). Now my issue - When most people remove all the emissions $hit they also remove the air / polution pump and change belt setup. I do not want to reintroduce the air / polution pump and hoped someone had a reasonable idea. Note I did see on one of the GN forums they were running an electric one, but unsure if this would work on the ReX. Wow, not sure that would be a good enough reason for me. However installing a cat without the air pump and bits to keep it from clogging or going bad prematurely are important as it seems you know. Anything you do to reinstall a cat without doing everything else would be a risk at ruining the cat. Personally I'd leave it as is. If you want to try it, pull an electric AIR pump off any late model GM. Most cars have them and they move enough air. F-body ones should be pretty cheap and you can just plumb it in before the cat. I would think high flow cats would be less effected by the lack of and AIR system simply because they flow more and shouldn't clog very easily, but I have no experience with them. Quote Link to comment Share on other sites More sharing options...
Second Gen Posted December 27, 2012 Author Report Share Posted December 27, 2012 (edited) OK - Looked a little more and see Magnaflow makes a universal 3" high flow cat for about 75 bucks. As the Wankles / rotaries have realy high exhaust temps I wonder if I need one specifically designed for the motor or if a generic one would work? FYI - I am running an aftermarket turbo / manifold setup mated to a Racing Beat cat back. So pre- fabbed" is not an option. Also want to plumb the wastgate back into the exhaust (Too damn loud venting to the atmosphere) Wow - I am sounding old as hell in this post Edited December 27, 2012 by Second Gen .. Quote Link to comment Share on other sites More sharing options...
Rally Pat Posted December 27, 2012 Report Share Posted December 27, 2012 Rally cars move their cats as far back in the exhaust as possible because of the anti-lag system, most of which use a cat as a muffler. Maybe you can do the same sort of thing? Quote Link to comment Share on other sites More sharing options...
Smokey Posted December 27, 2012 Report Share Posted December 27, 2012 While people have successfully used the Bonez units on FDs without an air pump it's still generally suggested that you should use an air pump with any ceramic cat to keep it from clogging. You can use an electric pump if desired. You can also look into metallic substrate cats which can be run without an air pump without problems. The only downside to them is that they're expensive. Knights Sports and SMB make great options for the FD. http://www.smb.net.au/fullexhaustsystems-mazdarx7.htm Quote Link to comment Share on other sites More sharing options...
Furloaf Posted December 27, 2012 Report Share Posted December 27, 2012 What if you just punched a hole in the cat and attached a sufficiently strong one-way valve to let air in, but not let exhaust out? Quote Link to comment Share on other sites More sharing options...
gbracing81 Posted December 27, 2012 Report Share Posted December 27, 2012 I have an electric AIR pump from a 98 Trans Am. I would be happy to sell it too you PM me if you're interested. Quote Link to comment Share on other sites More sharing options...
Mr. Jones Posted December 27, 2012 Report Share Posted December 27, 2012 I wouldn't bother with the AIR pump honestly. Their primary function is to get the cat up to operating temperature quickly. This is done more for emissions reasons, than actual cat longevity. Almost no new cars have AIR pumps, they just have a cold start enrichment cycled. For about 30 seconds, it runs an elevated idle and dumps tons of fuel to help kick start the cat. If your FD runs as rich as most do, you shouldn't have too much of a problem after a stab of the throttle or two. Oh, and definitively this: You can also look into metallic substrate cats which can be run without an air pump without problems. The only downside to them is that they're expensive. Knights Sports and SMB make great options for the FD. http://www.smb.net.au/fullexhaustsystems-mazdarx7.htm The MS cats are the only cats used on most high end builds.. Option C, and my personal favorite: Tell wife to live with it! Quote Link to comment Share on other sites More sharing options...
Fubar231 Posted December 27, 2012 Report Share Posted December 27, 2012 Option C, and my personal favorite: Tell wife to live with it! Seems like it would be the easiest and cheapest way. How bad does it smell? My camaro runs no cats and a dump under the pass. seat and i never smell anything. Quote Link to comment Share on other sites More sharing options...
Second Gen Posted December 27, 2012 Author Report Share Posted December 27, 2012 (edited) Magnaflow makes a MS cat with a 3" in/outlet that should work for 113. Assume this would be a good fit for the car if I can get a shop to weld it in for me. Assume since I am going back on with a cat I can get most exhaust shops to fab this in place? If you have a suggestion as to go let me know (Understand this would be the Cat and replumbing the wastegate tube back into the exhaust). I have previously dealt with Mad Hatter over on the West side (Sullivant) According to my wife is smells like isonitriles (Some funky chemical) - I have smelled exhausts from piston and rotaries (W/O Cats) and hands down the rotaries are the worst. Edited December 27, 2012 by Second Gen Can't type into words what I tried to say Quote Link to comment Share on other sites More sharing options...
Mr. Jones Posted December 27, 2012 Report Share Posted December 27, 2012 Magnaflow makes a MS cat with a 3" in/outlet that should work for 113. Assume this would be a good fit for the car if I can get a shop to weld it in for me. Assume since I am going back on with a cat I can get most exhaust shops to fab this in place? If you have a suggestion as to go let me know (Understand this would be the Cat and replumbing the wastegate tube back into the exhaust). I have previously dealt with Mad Hatter over on the West side (Sullivant) According to my wife is smells like isonitriles (Some funky chemical) - I have smelled exhausts from piston and rotaries (W/O Cats) and hands down the rotaries are the worst. Especially as you re talking about having the wastegate re-plumbed, I'd take it to a nice shop, IE: IPS who does custom fabrication stuff regularly. Too nice of a car, and a delicate of a task to leave to the hatter, IMO. Quote Link to comment Share on other sites More sharing options...
Smokey Posted December 27, 2012 Report Share Posted December 27, 2012 As someone that lives with the horrible smell of a rotary without a cat I can certainly understand where she's coming from. After I drive my car I smell like I was riding a sport bike for 100 miles. These days mine isn't driven on the street much and when it is I'm the only person in it so I don't care. As Jones mentioned I'd just have any reputable shop weld it in. Quote Link to comment Share on other sites More sharing options...
Second Gen Posted December 27, 2012 Author Report Share Posted December 27, 2012 (edited) Guess I should schedule some time up at IPS to get this installed / plumbed. I purchased my current Precision turbo from them this year and was happy with the communication / service. Thx guys! Chris / Smokey - Your RX7 looks a lot like mine https://picasaweb.google.com/103422430281488540719/RX7#5793678765302495426 Edited December 27, 2012 by Second Gen .... Quote Link to comment Share on other sites More sharing options...
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