danalex

I know the info is probably posted somewhere, but not sure how to search for exactly what I'm asking.

05; 2500; 4x4; Laramie.

Question: Will I create any mechanical/engine problems by removing the Cat & Muffler? and going with a straight pipe?

I believe Texas emission laws / inspections are different than California, so shouldn't be a "legal" problem....and no intention to ever cross California borders...

Question: If I do remove the Cat/muffler, will I see any positive performance changes? (MPG? power?)

thanks!

Danderson

The cat has next to no flow restriction. It is a violation of federal law to remove it. Just a better flowing muffler with the cat will yield a throaty sound and will assure you will have some hearing left in years to come.

torquefan

I agree. Went down the same road at one time, and gained absolutely nothing by removing a perfectly good cat. Made a noticeable difference though by swapping the factory muffler for a better flowing one.

danalex

Thanks! Ref the muffler, which one did you go with, and ref "noticeable difference"--was "difference" in performance or simply sound?

Tks D

torquefan

I went with the BD muffler and tailpipe. Noticed a faster spoolup right away. Not a huge difference of course, but I was impressed (and surprised) that I could actually feel a change.

https://www.dieselperformance.com/page/homepage

sojoe

My 04 did not come with a cat, so I can`t comment on the difference. BUT I can`t / won`t buy the" not restrictive" CRAP. Just cut the cat apart and you can`t help but notice that it has gotta be restrictive.
One of the main reason I shall keep my 04

By some posts I could gain mpg with a cat-----I don`t think so Tim.
Removing the cat is not legal-BUT any "greaser" knows how much better the engine will breathe.
I don`t wish to step on toes but we still have(for now) the 1st amendment.
Hell, why don`t we just drive a prius..............................
Better be careful as I know "big brother " and all his "greenies " may be monitoring!
Just my.02

torquefan

I have measured back pressure with a gauge, on many engines (gasoline) that I suspected of having a plugged cat. If the cat is working normally, I couldn't say there was any measurable restriction, more than what a factory exhaust would provide. Granted, I wasn't able to measure while the engine was under a heavy load, but on most engines at OEM power levels, I don't think it makes a difference. Add 50 or 100 HP to that engine and that cat probably becomes restrictive; as does the muffler.

Danderson

At least two guys on the TDR did dyno tests before/after cat removal. Removal of the cat yielded 4-6 rwhp per 400 rwhp made.
I wish mine didn't have one but the cat's not the restriction. The stock muffler is.

CRF450R RIDER

A number a guys have seen a slight fuel millage drop when removing their cat. 1-slightly over 1 MPG.

sojoe

Golly-I think I will put a cat anf factory exh on-Happy daze and at least 1.5 MPG more.....................

Danderson

Keep us informed.

CRF450R RIDER

maybe you should do some research about these trucks and the cat. Then you'll understand there stud.

sojoe

Thank you for the upgrade to "stud" status...................[duhhh
So I will remove the free wheeling hubs also + the grid heater delete + the smarty + the magnaflow exh AND keep the ehx brake engaged to increase back pressure and be good to go.......................................
Da**, I wasted all that money when all I had to do was put a cat on.
Thanks for the input

Danderson

There 'ya go.
I have a Shuttleworth diesel truck muffler out of Canada. The last one yielded 11 yrs. They're expensive but a quality unit.

CRF450R RIDER

grid heater delete and the magnaflow was a waste of money, you are correct there stud. But that still has nothing to do with the cat.