Focus Fanatics Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
3,368 Posts
Discussion Starter · #1 ·
OK. So I am chatting today with some 'car enthusiasts' at work. One guy wanted to know why I did not have a turbo on my 07. I said because it would not pass inspection. He looked at me a little odd, and I said that I had to have a cat. And he said, "so run a cat after the turbo", and I sorta just sat there thinking 'why would that not work'. So why would that not work? (small note here. I have been told that I could run a header if it is followed by a cat. No real point doing that, but a turbo is a different critter).
Thanks! [wiggle]
 

·
br/o/stang
Joined
·
5,563 Posts
depends on what emissions laws are like where you are. I just passed with no cat but have it tuned to turn off the extra o2 sensor(s). In my state they just plug it into the OBD2 port and do a ready check.

i think in some places even moving the cat is a no no
 

·
Aurelius Pardus
Joined
·
26,535 Posts
^^ they can be strict and look for every incorrect component or they can just plug it in and see if it reads ready.

only reason why the cat theoretically should not be moved further back is that it becomes less efficient and on more sensitive systems could give you a p0420 code for catalyst efficiency being below threshold.

so yes it would work... you could also make an 02 cheater, in other words move the secondary sensor out of the direct exhaust stream and it will read "cleaner"

then just ask around to find a shop that is more lenient on their testing. I would recommend having a cat to stay "legal" (yes I'm catless but there is also no emissions here) but the 02 cheater method may be needed if the cat doesn't keep the light off. thankfully the Mazda only has one 02 in the downpipe so decatting was no problem.
 

·
Shot me 3 deer!!!
Joined
·
9,247 Posts
there is no reason though you can't run a turbo w/ a cat. the roush kit ran a turbo on the zetec, i'm not sure what options there are for an 07
 

·
FF Affiliate
Joined
·
31,169 Posts
Well there actually is a reason , when running boost you run more fuel through the engine which means more work for the CAT to do a lot more and in most cases the added fuel stops up the cat , back psi on a turbo engine is very very bad

You do not want to run a CAT with boost the cars that come with boost use a diff type cat and its more a high flow

Then there is the higher EGT of boost again not good on the CAT and makes them come apart , stop up etc

Tom
 

·
Aurelius Pardus
Joined
·
26,535 Posts
Tom aren't all cats high flow now anyway?

but yeah I didn't mean factory cat..... which would be incredibly stupid to try and fit later down the line.
 

·
Registered
Joined
·
249 Posts
How about just running a cat with a cut-out? That way you can bypass it whenever you want without getting under the car. You could even feed it into the exhaust after the cat so its a little more street friendly.
 

·
Aurelius Pardus
Joined
·
26,535 Posts
I'm not sure if its the same there but cutouts are illegal for use as far as safety an I/M go.

good point Tom... you're right I have noticed the difference.
 

·
Registered
Joined
·
3,368 Posts
Discussion Starter · #12 ·
Not all are HFC some are still the honey comb type vs the wire type which works great on turbo cars and almost unable to stop up

Tom
So! I would want to have the wire type, NOT the honeycomb type. I got that right? FYI: I did look at a cat (I have two. one barely used and the other not used). They look like wires (fine mesh actually). I don't think that's what you mean. So do you know of a brand that would work?
Thanks
 

·
w/ my magic bag
Joined
·
29,472 Posts
Tri-Point engineering!

OK. So I am chatting today with some 'car enthusiasts' at work. One guy wanted to know why I did not have a turbo on my 07. I said because it would not pass inspection. He looked at me a little odd, and I said that I had to have a cat. And he said, "so run a cat after the turbo", and I sorta just sat there thinking 'why would that not work'. So why would that not work? (small note here. I have been told that I could run a header if it is followed by a cat. No real point doing that, but a turbo is a different critter).
Thanks! [wiggle]
Tri-Point Engineering's Turbo kit for Mazda 3's come's w/ a intergrated catalyst in the down pipe, & their kit come's w/ a GT2871R turbo.
 

·
Registered
Joined
·
3,368 Posts
Discussion Starter · #15 ·
Post a picture

Tom

Here is a combined pic. Both were taken from the same approx distance, but I had to zoom in to get detail. One on the left is the OEM secondary cat, one on right is as labeled. There not honeycomb, but there not wires either I don't think as, if you look at the mesh very closely (no pic, sorry), there are some details to suggest that these are punched.

 

·
Registered
Joined
·
3,368 Posts
Discussion Starter · #16 ·
I did some research. I now understand what Tom means by "stone honey comb", which the magnaflow appears to be. There is another type marketed as and claiming to be a high flow metalic (google "High Flow Metallic Catalytic Converter" for various links). But I cannot find any specifics on them (I.E. many claims, no hard data). I really don't have any background in this to know if there shining.
 
1 - 16 of 16 Posts
Top