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ZUKIWORLD Discussion Forum => Technical Discussion - Beginner / Repair => Topic started by: jow003 on July 20, 2010, 06:18:10 AM

Title: to cat or to cut the cat
Post by: jow003 on July 20, 2010, 06:18:10 AM
im debating on cutting out my cat and i was curious if there was a down side.  in Colorado its not a requirement, is anything gained or lossed?  when/if i do i will prolly upgrade and get a cherry bomb muffler or something.
Title: Re: to cat or to cut the cat
Post by: wildgoody on July 20, 2010, 06:51:15 AM
If it's still good keep it, better for the environment, but if it's
a goner then upgrade to a 2" exhaust and a new cat, it will
flow better and improve overall power. You need a little back
pressure anyway for best fuel mileage

Wild
Title: Re: to cat or to cut the cat
Post by: jow003 on July 20, 2010, 06:52:53 AM
whats stock size, 1.5"?
Title: Re: to cat or to cut the cat
Post by: wildgoody on July 20, 2010, 06:55:42 AM
1-3/8 at the tailpipe exit, a little bigger at the cat, 2" all
the way is a good increase in flow, that and a mild cam
will do wonders for the torque and HP, you will feel it

Wild
Title: Re: to cat or to cut the cat
Post by: jow003 on July 20, 2010, 07:34:19 AM
mild cam.... forgive me as i am just learning cars, cam shaft?
Title: Re: to cat or to cut the cat
Post by: wildgoody on July 20, 2010, 07:35:14 AM
Yes
Title: Re: to cat or to cut the cat
Post by: john1974 on July 20, 2010, 11:01:57 AM
im debating on cutting out my cat and i was curious if there was a down side.  in Colorado its not a requirement, is anything gained or lossed?  when/if i do i will prolly upgrade and get a cherry bomb muffler or something.

In my 2nd samurai, and in my lifted 94 tracker I had to remove the cats due to the stuff inside was moving around.  I wheeled, daily drove them this way for over a year or two and while its alittle louder its not bad.  Since we are taking about 1.3's and 1.6's the sound doesnt get to bad.  I even ran 2'' exhaust.
Title: Re: to cat or to cut the cat
Post by: jdcone on July 25, 2010, 10:27:01 PM
Don't toss the cat. They aren't cheap to replace. Save it in case the state start s requiring one later. I took mine off my 01 Cummins Diesel a few years ago. Guess what. Yeah. I had to use the one my son-in-law cut off his Ford last 4 years ago to get my truck through Calif's new diesel smog rules. It really sucked losig all that extra power.....for a day. I cut the cat out again and put the chip back in. Instant 100+HP!!!!!!!!!!!!!!!!!!!!
Title: Re: to cat or to cut the cat
Post by: Drone637 on July 26, 2010, 12:36:01 PM
I have to recommend putting a cat on for a vehicle that's run on the road on a regular basis.  It really is better for the environment.  If your worried about power loss you can pick up a high flow cat and put it in place.
Title: Re: to cat or to cut the cat
Post by: toofaroffroad on August 21, 2010, 05:22:38 PM
Yeah dude, these smaller 4-banger engines need the back pressure of a cat. you could actually loose power without a cat. Plus the newer highflow cats are great for flow. bump it up to a 2" all the way through and you notice a definite deeper sound plus a little bit more torque. Throw a header in there while your at it. A header with 2" cat and 2" muffler in a sammy could give you 10 to 12 horsepower.
Or you could just put the 1.6 16valve in and really get things interesting.
.
 
Title: Re: to cat or to cut the cat
Post by: Jluck on August 21, 2010, 05:46:42 PM
Curious to see proof about power loss after removing cat. I don't have a dyno or a PhD but I have removed or hollowed out allot of cats never to see a negative result, who really knows if they help the environment any way it's just what were told.
Cut it out or hollow it is my 2 cents
Title: Re: to cat or to cut the cat
Post by: Bigzook on August 21, 2010, 07:39:28 PM
I used to work at an exhaust shop and tried several different systems on my zuk. A good cat will not restrict your exhaust enough to make a difference. I would recommend not going bigger than 2" either way unless you do some radical engine mods. I found that anything bigger made the low end torque start going away.

16v's start sounding very raspy and ricerish compared to the 1.3l with the same exhaust. I actually run a glass pack as a resonator and a "flowmaster" style muffler on my sammy and think it is still a little annoying.

http://www.youtube.com/user/darnold87#p/u/46/W6EPyrEYp6E (http://www.youtube.com/user/darnold87#p/u/46/W6EPyrEYp6E)
Title: Re: to cat or to cut the cat
Post by: blaster716 on August 22, 2010, 05:33:01 PM
I removed the cat from mine and im running a flowmaster muffler , 1 3/4 pipe and it made a  big difference in power  and i believe i may have picked up an extra mpg or two.
The noise isnt any louder than my neighbors hopped up honda civic