cats or no cats...debate

Just wanna throw in my .02 on this. While this is true on many vehicles (especially NBS/NNBS trucks), it all depends on the cat design.

My 05 5.3 Silvy gained nothing by removing the cats, actually lost a little low end. My '11 Mustang gained quite a bit of power all through the power band by deleting the cats. Others have dyno documented as much as like 20-30hp. So it really depends on the design/material used in the cats, and every manufacturer is different.



Sent from TapaTwat

just a question, is that by just removing cats, or are they changing exhaust/header/tune at the same time.
 
I like the way mine sounds without the cats. There was a thread over on pt.net about a guy getting before and after 1/4 mile time with and without cats, ill try and find it. If I remember correctly he picked up a couple tenths without them.


Sent from my iPhone 4s
 
Stock cats are high flow cats. The GM cats outflow many high end performance cars. The way I see it, if it ain't broke....

I have always kept cats on my vehicles, even when my Tahoe was pushing 11psi with headers and a cam. Customized the exhaust to work with the LTs and the catback.
 
just a question, is that by just removing cats, or are they changing exhaust/header/tune at the same time.

That's along with a tune, usually see ~20hp from not changing anything other than turning off the CEL and making sure A/Fs are ok. Then the ~30hp or more comes when the tune is "optimized" or really tweaked and set up the way it will stay. And this is all using stock manifolds, ORX/ORH, and mufflers.
 
Well all of the Ford passenger car cats I've seen are bent at funny angles, none of them are really round like the GM truck cats are.
 
damn ford cats must be shitty as hell.

i assume if you had the coin and wanted cats and put high flows on it would have similar HP to no cats.

They look like it. Can't really go by looks, but I just can't see how the cats wouldn't restrict. I'm assuming the same thing, haven't really seen guys running LTs do dyno runs before/after adding high flows, but I do know there are a few guys running 600+hp with cats

Well all of the Ford passenger car cats I've seen are bent at funny angles, none of them are really round like the GM truck cats are.

The cats on these Mustangs are pretty straight, just an oblong case, but there's a ~100* bend immediately after them for the exhaust to go underneath the car.
 
if I didnt have to fabricate to make the stock cats work with longtubes I would have them. I dont like the smell of an uncatted vehicle as a daily driver, especially if you have your windows down or idle in traffic alot.
 
I think it's like others said...if it is tuned right...mine I can tell it is a bit richer, but I never notice it driving really. Or not on normal streets.
 
^This. My parents bitch if I'm in the garage or parked around back up against the house. My car's so loud it rattles the windows/doors/cabinets/plates in the cabinets lmao
 
Just read through this thread. Some good info. Do y'all think my 6.2 would benefit from having no cats? Like yall said, every application is different.. I've been thinking of running lt's, x pipe and either true dual magnaflows with 2.5" pipping or just a single magnaflow race muffler with 3" piping.


Sent from my fuckin iPad
 
You won't benefit anything as far as performance goes by running cats. Really boils down to inspections. Do you have to get them? Visual?
 
Nah. No smog or emissions test or anything like that down here. I think I would like the sound a lot better also.

2 things: 1) shoud I do x-pipe with no cats and either 3" single or 2.5" dual magnaflows before I do Lt's or should I just wait and do it after I put Lt's? 2) true dual vs single, what's gunna have more gain/better sound?


Sent from my fuckin iPad
 
With lt's and no cats and single 3" that bitch will be loud. Just ask anybody that's heard my truck running.


Sent from my iPad using Tapatalk HD
 
Last edited:
I would do a single 3" if I were you... I have dual 2.5" and I love the sound but it was almost double the cost.


Sent from my Samsung Galaxy SIII using Tapatalk 2
 
With lt's and no cats and single 3" that bitch will be loud. Just ask anybody that's heard my truck running.


Sent from my iPad using Tapatalk HD

You have any vids on YouTube? I have a single straight right now so its pretty loud already lol. I really miss the sound of my 2 nbs 5.3's I had. My 01 had a single y pipe straight with duals out the back and my 06 had true duals with 2-1/4" pipping from the cats back 45'd. Popped and crackled like a mother!!! I seriously wish my 6.2 sounded nasty like that. Call me what u want but I love that sound. That's also my reason for askin about the lt's and no cats. Muffler will probly just be a magnaflow race muffler.

Think it would sound good with stock manifolds, no cats/x-pipe, and a single race muffler?

I would do a single 3" if I were you... I have dual 2.5" and I love the sound but it was almost double the cost.


Sent from my Samsung Galaxy SIII using Tapatalk 2


Cost really isn't a bother.. If the sound will have a little more tone vs like a race car being just loud and echoey (kinda how it is now :( I have a little pop but not as much as I like) I wouldn't mind paying the extra. Which is better for performance?


Sent from my fuckin iPad