D Max Question - Diesel Forum

DuramaxCowgirl · 10-19-2009, 03:49 PM

I can't figure out how to navigate this site, so sorry for jumping into the conversation randomly.

I have an 04 Duramax w/ an after market exhaust. 4inch tip. I want to straight pipe my truck, but I keep hearing different things about the legality of doing so. It seems like NO ONE knows what they are talking about.

Should I do it?
Is it legal? If it's NOT legal, is is really a big deal?
How much would it cost me?

thanks y'all,
DuramaxCowgirl

johnm · 10-19-2009, 04:25 PM

If It Came From The Factory With A Cat, Particulate Filter And Egr Then You Cant Remove It. Federal EPA Law.

SmokeyWren · 10-19-2009, 07:59 PM

Quote:

Originally Posted by DuramaxCowgirl

Is it legal?

Nobody can answer because you didn't tell us where you live, drive, and register the truck.

In some jurisdictions you don't dare touch the exhaust system. In other places just about any exhaust system mods are acceptable.

Out here in the sticks 25 miles from Midland, nobody cares. But if I drive in downtown Midland, the LEOs frown on straight pipes if you mash on the go pedal trying to make obnoxius racket. As long as you drive like an adult in town, there's usually no problem with straight pipes. But when High School Harry starts to show off with his "look at me!" straight pipes, the LEOs nab him toot sweet.

psd_va · 10-25-2009, 05:48 PM

like said above if it came with it then it has to have it. but it really depends on where you are if any one is going to say anything.

LMJD · 10-26-2009, 08:17 AM

It doesn't matter where you live, like JohnM posted, it's against federal law and the fine is high. Matter of fact it's probably still in the forum rules, posts were always deleted regarding cat removal just for that reason although a moderator above responded to this one and allowed it. Actually it's still there:

Quote:

Discussion of tampering with or the removal of the catalytic converter or EGR systems is strictly prohibited on The Diesel Stop forums. This prohibition applies regardless of the application, including so-called "off road use" or "testing". Such posts will be removed without notice.

Don't know about the south western states, but in the northwestern ones if you're hauling horses you have to stop at the Port of Entry with your brand, health and Coggins papers and it's not unheard of to have to get diverted to a random safety inspection. Big fine just to make more exhaust noise. Plus you'll probably be out over $1000 to legalize the entire exhaust again if you're caught.

Matt0987 · 11-07-2009, 02:26 PM

So, is it illegal even on an off-road machine? Or, as you are off-roading? I ask this second part in case, for some reason, someone wanted to fab up some sort of "removable' unit strictly for when off roading.

I am not asking what one can get away with. I am asking about what is illegal?

And, as long as we are on the subject, what about a low flow cat? Are they made? Legal?

chuckster57 · 11-07-2009, 02:30 PM

Quote:

Originally Posted by Matt0987

And, as long as we are on the subject, what about a low flow cat? Are they made? Legal?

Do you mean HIGH flow cat? If so then I posted a link somewhere here to a site that explained there is no such animal just the price for one.

Matt0987 · 11-07-2009, 02:35 PM

Ah.

Here is another question.

A person puts a 4" or 5" turbo exhaust system on. Can the stock cat be fitted to the newer size pipe?

Can you just use a hole saw and cut a larger hole int the cat ends, weld on a larger pipe to match the system and clamp it into place?

Do you think that would meet the law(s)?

Evel486 · 11-07-2009, 04:21 PM

SmokeWren is right. It depends totally on the jurisdiction you live in. Most areas do not have laws regarding mufflers, just noise decibels. A Duramax with a straight pipe is not very loud. 04's do not have a particulate filter. If it has a cat, laws regarding it's removal vary. EGR system is not affected by straight piping the exhaust.