Mazda 6 Forums banner

1 - 20 of 56 Posts

·
Registered
Joined
·
69 Posts
Discussion Starter #1
so i was under my car since 5am pulling the trans for a clutch/flywheel swap and had a thought.. what if i gut my cats, well i noticed the front pre cat has and o2 sensor before and after it. would anyone like to enlinghten me a bit on the cons of gutting that?? will it throw a CEL if i do, because if not, im gonna do it before i put the trans back in the car... also should i do a 2.5in cat back or a 3in cat back??? mufflers? or no mufflers.. if i go with mufflers do you think the DTM style mufflers(remus) would look nice or maybe some old HKS Dragger mufflers or the Apexi N1 mufflers
 

·
Registered
Joined
·
232 Posts
Definately do not go with 3". Maybe if you had a turbo on your car but obviously you dont. With the gutting of the cats. That would be like if you took them off totally so yes you will get a Check Engine Light. But the car will still run fine. If you want a few more HP just install high flow cats so you dont get the cel.
 

·
Registered
Joined
·
69 Posts
Discussion Starter #4
if you gut your cats you will get cels. there are 2 sensors that measure both cats efficiency ... only way is to fool them with an aftermarket resistor hack or cel eliminator.
[/b]
you think i could use the CEL eliminator mod that we used on our vettes and f bodies with long tube?? it might not be direct plug in, but i should be able to wire it
 

·
Registered
Joined
·
1,687 Posts
you think i could use the CEL eliminator mod that we used on our vettes and f bodies with long tube?? it might not be direct plug in, but i should be able to wire it
[/b]
Mike so did you get the tranny out? you never called me back so i assume that you did........
 

·
Registered
Joined
·
69 Posts
Discussion Starter #7
on a different topic charles yes new clutch is done car drives fine.. i think i busted my front motor mount (passenger side) in the process though.... and id love to experiment with my cats.. i jus dont have any spares in case i screw up.. anyone have any donations?? i do think that if they were gutted a CEL eliminator would geterdone.. the pre cats are gay, and then all the other million cats behind them are jus as gay.. i say we chop them all off.... well ill let everyone know how the gutting of the precats goes when i start on them
 

·
Registered
Joined
·
826 Posts
I ran w/ gutted precats for quite a while (~15k miles) and never had any CELs, but I suppose YMMV. There was no real increase in power and a small increase in exhaust noise (w/ Magnaflow catback)...
 

·
Registered
Joined
·
167 Posts
This is something I have been looking into also, gutting the precats. One issue I see as a potential issue is the erv and the potentual for increase back flow pressure up to the exhaust ports. One question I have fore anyone that has the non-catted CPE headers - have you had any cells with no cats? I believe if you gut the pre cats you may have to gut the post cats also as to eliminate any ERV and back pressure issues.
 

·
Registered
Joined
·
1,078 Posts
I ran w/ gutted precats for quite a while (~15k miles) and never had any CELs, but I suppose YMMV. There was no real increase in power and a small increase in exhaust noise (w/ Magnaflow catback)...
how did you gut yours? i wish they were detachable from the manifold like the Accord V6's! i've read about people jabbing at it with a crowbar, but i'd rather find a better solution like a strong azz liquid to pour in like some kind of acid to melt the material inside without eating away the metal on the exh.
 

·
Registered
Joined
·
826 Posts
I gutted em with various pointy metal objects... mainly a prybar and a long screwdriver. I also ended up bending a piece of steel rod into an "L" shape, chucked the long leg into a drill, and let the short leg whiz around in there @ a few hundred rpm. One manifold is pretty straight through and isn't all that hard... the "crooked" one took a little time.
 

·
Registered
Joined
·
57 Posts
I'm at about 1k miles on gutted precats. Not getting a CEL but when I connect my scanner the catalyst test is incomplete. That would be a problem for those with an OBDII emission check.

The front manifold I gutted with it removed from the car. I used a long screwdriver through the O2 sensor bung. The rear manifold I gutted while still on the car using a long screwdriver up through the bottom.
 

·
Registered
Joined
·
1,078 Posts
lol, i gotcha. im saving for the msds but in the mean time ill prob try it for the hell of it. where did you buy yours, mazda? steel material gaskets?
 

·
Registered
Joined
·
596 Posts
Thanks for the replies on the gutted pre-cats. ;)
I've been pondering this for quite some time (especially since hearing of all the issues v6 owners have been having).
This seems like a simple mod to do... that is until I get my MSDS'.:cool:
 
1 - 20 of 56 Posts
About this Discussion
55 Replies
20 Participants
e4w
Mazda 6 Forums
Mazda6club.com is a forum dedicated to the Mazda6 / Atenza. Come and discuss reliability, performance, modifications, and more!
Full Forum Listing
Top