Every little bit helps!!
Gutter my cats???
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,295
Likes: 14
From: Grand Sport #82
Gutter my cats???
Hi
Will this do me any good? I have a setup with some VERY simple mods.
-K&N
-Air foil
-Free Flow Exhaust
What gain will I get when guttering my cats?
Power?
Sound?
Will this do me any good? I have a setup with some VERY simple mods.
-K&N
-Air foil
-Free Flow Exhaust
What gain will I get when guttering my cats?
Power?
Sound?
Last edited by Lars87; Nov 29, 2004 at 04:22 PM.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
On my '85, gutting the cat made a huge difference, but my car, in addition to the 84's, still use the archaic C3 single monolith cat design...
I am not familiar with the setup on your '87...
I would guess about 15 chp gain in my car... but I have no proof to back this up... this is merely a SOTP feel
Also, I didn't notice much of a sound difference; slightly louder, but I still have the stock mufflers on- which leads me to believe that even the stock mufflers on my 85 are a big restriction
I am not familiar with the setup on your '87...
I would guess about 15 chp gain in my car... but I have no proof to back this up... this is merely a SOTP feel
Also, I didn't notice much of a sound difference; slightly louder, but I still have the stock mufflers on- which leads me to believe that even the stock mufflers on my 85 are a big restriction
Last edited by mikey whipreck; Nov 29, 2004 at 04:28 PM.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Rather than gut the two pre-cats install a 2 1/2" mandrel bent front Y; instead of just gutting the main cat cut off the ends and weld them to a straight pipe.
Yes you will get a nice power and sound gain from the above operations.
Yes you will get a nice power and sound gain from the above operations.
Race Director
Joined: May 2002
Posts: 10,306
Likes: 15
Originally Posted by 65Z01
Rather than gut the two pre-cats install a 2 1/2" mandrel bent front Y; instead of just gutting the main cat cut off the ends and weld them to a straight pipe.
Yes you will get a nice power and sound gain from the above operations.
Yes you will get a nice power and sound gain from the above operations.
Team Owner
Joined: Aug 2003
Posts: 24,987
Likes: 26
From: Kerrville, Texas USA Hook 'em Horns!
CentralTX Events Coordinator
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17
Originally Posted by xlr8nflorida
Get a random cat - don't pollute
Besides, if you gut your cats we may have to turn you into the SPCA.
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Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
I am a firm believer in updating the cats, and not gutting them.
Remove the precats... they are a pain in the ***.
then install a high flow center cat.
you will pick up 20hp. And won't be polluting the air!
Remove the precats... they are a pain in the ***.
then install a high flow center cat.
you will pick up 20hp. And won't be polluting the air!
Melting Slicks
Joined: Apr 2004
Posts: 3,287
Likes: 7
From: n/a SC
I had the cat taken off my z71 truck and a pipe welded in...Ih ad this done about 6 months ago when the truck had around 165k on it and it made a pretty big diifference I would say I gained about 15hp from this.
As far as doing it in my vette na....if I were you I would just have the old ones taken off and new original ones put on. You won't gain as much has not having them there at all but new compared to old WILL give you some lost HP back.
As far as doing it in my vette na....if I were you I would just have the old ones taken off and new original ones put on. You won't gain as much has not having them there at all but new compared to old WILL give you some lost HP back.
Burning Brakes
Joined: Oct 2004
Posts: 1,094
Likes: 0
From: West Palm Beach Florida
I was about to say "man I hope Bogus doesn't read this" but as I scrolled the posted here I see he has already been here. 
I have not found much noticable difference in removing or gutting the cats. I HAVE NOT tried this on my vette but I have gutted my share on other vehicles. I also have never documented anything on a dyno either... this is merely my own observation of before and after with no noticable difference.I say leave them alone unless you have built a major performance car, drag car or are having problems with them.
Safety Car
Joined: Aug 2002
Posts: 4,812
Likes: 1
From: New Albany IN
St. Jude Donor '03-'04-'06-'08-'09
I have not done it, but they add backpressure to the "total Picture" and it may feel like you have lost alittle low end....but since these other guys say they notice a difference..I say go for it!
Pro
Joined: Feb 2004
Posts: 723
Likes: 0
From: Nashville Tennessee
Originally Posted by Lars87
Hi
What gain will I get when guttering my cats?
What gain will I get when guttering my cats?
Drifting
Joined: Feb 2004
Posts: 1,277
Likes: 1
From: Santa Maria CA
well....testing shows by me and friend,gutting cat(only 1 cat on car)on a 86 non-turbo nissan 300zx 5spd showed a consistant 3 tenth drop in et and 2mph increase on the gtec.we all know how great 
cough cough! the gtec works!
cough cough! the gtec works!
Team Owner
Joined: Dec 2000
Posts: 21,094
Likes: 282
From: Phila., PA burbs
Originally Posted by PSO3120
Well, If it rains on them quite a bit, it will allow the water to be channeled down the sides of it and out a spout at the end. I would use "Gutter Guard" Gutters so you don't have to get up on a ladder and clean the leaves out of them every six months.
Drifting
Joined: Nov 2002
Posts: 1,593
Likes: 0
From: Mobile AL
St. Jude Donor '05
See Nathan's site:
http://www.wku.edu/~nathan.plemons/htmls/increase.html
before you make any changes to cats.
http://www.wku.edu/~nathan.plemons/htmls/increase.html
before you make any changes to cats.
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,295
Likes: 14
From: Grand Sport #82
Originally Posted by SilverBeast
See Nathan's site:
http://www.wku.edu/~nathan.plemons/htmls/increase.html
before you make any changes to cats.
http://www.wku.edu/~nathan.plemons/htmls/increase.html
before you make any changes to cats.
- but im not really seeking power, asmuch as sound!
I would love my vette to be more loud!!!
...som I dont really know what to do yet...
The law here in Denmark says that only cars newer than 1991 must have cats. Som im free to remove them on my 87´