Author Topic: High Flow Catalytic Converters  (Read 4604 times)

Offline bladerunner

  • Registered Users
  • *
  • Posts: 241
High Flow Catalytic Converters
« on: August 09, 2011, 07:34:31 PM »
So I am looking at installing cats this week and I am in the process of choosing what I want. I have dual Flowmasters and I like the current sound; deep and throaty with a little rasp.  Maine has no restrictions on high flow cats so I will definitely go that route.  Anybody have any recommendations that won't restrict performance or sound? Will any high flow cat work or should I look at particular brands?
85 K10 Shortbed
94 Impala SS

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7543
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: High Flow Catalytic Converters
« Reply #1 on: August 09, 2011, 08:19:19 PM »
Any cats will soften the sound somewhat just by the nature of them.
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline bladerunner

  • Registered Users
  • *
  • Posts: 241
Re: High Flow Catalytic Converters
« Reply #2 on: August 09, 2011, 08:48:55 PM »
I suppose that is what I am really asking. Some guys say the sound reduction is more drastic and others say it is only slight.  My experience is that it is a slight change, maybe a little less raspy. I am just curious what others think. Thanks!
85 K10 Shortbed
94 Impala SS

Offline Da67goatman

  • Site Supporters
  • Junior Member
  • ******
  • Posts: 757
  • Burban
Re: High Flow Catalytic Converters
« Reply #3 on: August 09, 2011, 09:01:48 PM »
Compared to a stock cat, a high flow is louder and more crisp, but compared to no cat, its softer and more blended.  Now we're only talking a couple decibels but it is a difference.
<Pitcrew>
1989 R2500 Suburban mild 350 TBI 700r4 10.5" 14bolt 4.10 w/ 33s
1992 fullsize Blazer 4x4  35s no lift, 4.10s, Hella driving lights, TJ Flares, Huge bumpers, Snorkel, custom interior

Offline 1979C20

  • Senior Member
  • ****
  • Posts: 1659
  • Kyle Taulton.
Re: High Flow Catalytic Converters
« Reply #4 on: August 10, 2011, 01:57:51 AM »
Why not hollow a cat converter out and run a tube through the middle so a "cat" is installed, but not hindering the sound? I know a bunch of people around town that do it.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Irish_Alley

  • Tim
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13319
  • Family is not an important thing. It's everything.
Re: High Flow Catalytic Converters
« Reply #5 on: August 10, 2011, 02:14:08 AM »
i would just punch one out. i dont see the point in a tube inside of it maybe for mother air flow but its not needed i have heard of a company that sells the shell you can weld that onto a strait pipe so it looks like a cat

If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline ToddN

  • Newbie
  • Posts: 93
Re: High Flow Catalytic Converters
« Reply #6 on: August 10, 2011, 11:39:40 AM »
I use stainless clamps to run true duel to two cats to two turbo mufflers...after inspection I take off the cats and run two 8" glasspacks right from the headers and they dump out just behind the cab. The whole setup takes less than an hour to switch out.
A government big enough to give you everything you need, is a government big enough to take everything you have.

Offline ToddN

  • Newbie
  • Posts: 93
Re: High Flow Catalytic Converters
« Reply #7 on: August 10, 2011, 11:40:06 AM »
Oh....and I am also from Maine.
A government big enough to give you everything you need, is a government big enough to take everything you have.

Offline Psycho71

  • Registered Users
  • *
  • Posts: 239
Re: High Flow Catalytic Converters
« Reply #8 on: August 11, 2011, 01:29:08 AM »
http://www.frozenboost.com/index.php?cPath=210&osCsid=87b8b8d4882f7395e304a9f3530288b7

I put these on my burb, they passed the visual inspection no problem.
There are two tools needed, duct tape and WD40. If it moves and shouldn't, use the duct tape. If it doesn't move and should, use the WD 40.

Offline bladerunner

  • Registered Users
  • *
  • Posts: 241
Re: High Flow Catalytic Converters
« Reply #9 on: August 13, 2011, 02:42:44 PM »
In Maine, a visual inspection is all they do.
85 K10 Shortbed
94 Impala SS