not that Im thinking about taking it off.are they as bad as the old gas car stuff.
thanks Richard

 

Well I have saw a lot of posts about the cat's restrictive nature. I have even posted pics looking through or rather into a cat. Most say yes, but I have not seen anyone do an actual before/after on same set up.

It looks like it would be or potentially could be restrictive if dirty, but I can't confirm that from experience. When mine was removed for cleaning and testing offroad there were other mods done at the same time. So I can not say one way or another. I don't really think for most trucks or even modded trucks it will make much difference for normal driving. Removing the cat will change the sound and smell of the exhaust, that I can confirm.

The stock muffler on the other hand is definitely restrictive and adding a high flow/straight through muffler will improve flow.

Just my .02.

 

i dyno'd over 500 on my stock catalytic converter.. the muffler is the most restrictive part

 

Loose the cat and replace the muffler with an aftermarket. Lower egts, faster spool, more mpg and sounds good

 

XXXX2222!!!!!

 

Nothing like a gasser...

Take it off and it'll soot things up more than if you left it on...

That's the only difference I can see...

But take it off for cryin' out loud!

 

and that good ole #2 smell is missing too with it in place....

 

Have no idea --- Someone Stole Mine!!!!

 

I have a brand new MBRP cat back stainlees steel system that I just purchased.I may forget a certain part that starts with a C.
Rich

 

I went from muffler delete to 5" w/muffler and no cat...BIG difference between the two...considerable drop in EGTs and noticible HP...

 

I left my cat on my mega, and put a MBRP straight thru in place of the OEM pipe.


so now, i have the cat, the MBRP, and the Mega over the Axle pipe.

it's not loud at all, but it's got a heckuva deep rumble to it.

you can't heard it beside it, but anytime you park outside a building, you can heard it inside. sounds like a UPS truck.

in the interest of future tree hugging, i left mine on.

 

Take it off and "try" to look through it. Very restrictive. Just took mine off and gained 1.5 mpg conservativley. Lower egts, better mileage, one off the cheapest performance mods you can make and doesn't hurt anything.

 

I welding in some tap ports on my exh system before I went straight 4" and found at cruise on the fwy at 60 mph I had about 2-2.5 psi of backpressure upstream of the CAT. After removing and goiing only straight thru design muffler it dropped to less the .5 psi.
Does that tell you something?

 

So it is a cat converter under the cab and it doesn't hurt to remove it.

 

Remove the Cat & replace the muffler...RIGHT? Any suggestions on which muffler to use?