hollowing out the cat on my 04.5

bill57 · #1 11-10-2005, 10:51 AM

i have an 04.5 and i have a cat bak magnaflow exhaust on it and i dotn want to void the warranty by taking the cat off so is there any good way i can clean out the cat or just ram a straight piece of pipe in it?
and what size diamiter is the stock down pipe?

twomorestrokes · #2 11-10-2005, 12:33 PM

Why would you want to do that?

Besides, you are affecting the warranty just as much by gutting as removing.

bill57 · #3 11-10-2005, 01:13 PM

if they see the cat they wont thinka nything of it when i take it in for soemthing but if they see an aftermarket downpipe thats a diff storry

BlenderWizard · #4 11-10-2005, 01:20 PM

the only thing that flows worse than a gutted cat is a clogged cat, and that is probably debatable

bill57 · #5 11-10-2005, 02:12 PM

what i wanan do is just punch a pipe thru the center then clean that part out and leave that pipe in there so it flows staright thru

twomorestrokes · #6 11-10-2005, 02:19 PM

I doubt that you will gain anything besides increased noise level and lawn mower smell. Newer convertors flow pretty good and the engine controls are calibrated to work with the backpressure that they do produce.

GMMerlin · #7 11-10-2005, 08:26 PM

A few thoughts here
First, the converters on these trucks have almost no backpressure. The maximum allowable backpressure is .5 psi. Most of the ones I have tested were in the .1 to .2 psi range
Secondly. since your vehicle is under warranty, any modifications that effect factory designed operation can void warranty coverage for that componant.
So if you destroy the catalytic converter and the SES light comes on for the post catalyst O2 sensor..you pay for the diagnosis.

TexasF355F1 · #8 11-10-2005, 08:31 PM

One they will notice, they may not see it, but they'll hear it. Two, it sounds like dog-piss. Three, you will not get any performance gains from it. You will more than likely lose power.

kenny-1907 · #9 11-10-2005, 09:50 PM

I am just curious as to what an 04.5 is. When ever you order something for it , do you ask for the 04.5 parts ?

mobil_12 · #10 11-10-2005, 10:14 PM

Hollowed out cat = gauranteed check engine light that wont go away.

If you are serious about getting more performance, check into a high flow cat from edelbrock or magnaflow. Thats way better than taking yours our or molesting it.

twomorestrokes · #11 11-11-2005, 07:14 AM

Quote:

Originally Posted by GMMerlin

A few thoughts here
First, the converters on these trucks have almost no backpressure. The maximum allowable backpressure is .5 psi. Most of the ones I have tested were in the .1 to .2 psi range
Secondly. since your vehicle is under warranty, any modifications that effect factory designed operation can void warranty coverage for that componant.
So if you destroy the catalytic converter and the SES light comes on for the post catalyst O2 sensor..you pay for the diagnosis.

Good post!

jeverett · #12 11-11-2005, 07:15 AM

Um. My cats are gone and I'm quite happy with the gain in performance and sound.

twomorestrokes · #13 11-11-2005, 07:49 AM

Quote:

Originally Posted by jeverett

Um. My cats are gone and I'm quite happy with the gain in performance and sound.

Hmmm. In the "exhaust cutout" thread I read that you hated your Flowmaster and hated the resonance from your altered cats, stating that your system was "loud as hell" and kills your head.

jeverett · #14 11-11-2005, 08:36 AM

Yeah. I like the increase in sound, I don't like the muffler though. If it didn't resonate inside the cab so bad it would be fine. I feel like if I had a magnaflow or something likewise, i'd have a bit larger increase in power and less interior resonance.

Sorry, I guess I was contradicting myself there.

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