I have a 2006 Chevrolet Colorado Crew Z71 I was trying to order a high flow catalytic converter for it and I wanted it to match up were I couldhave clap on installation. Does anyone know what size exhaust pipe these colorado's have on them? And should I go like 1/4in bigger so I could slide it over the existing pipe? Thanks for looking at this question and all the help!

 

Hey man, I amnew here but I think I can help you out or point you in the right direction. My buddy has one just like yours only I believe it is a year older.The3.5 5 cyl.enginein your truck is just likemy blazers 4.3 in the department of what it likes for exhaust. Now as far as size of the stock pipe I believe its 2.25" butI am not a 100% sure.I stronglybelievethat you go nobigger than 2.5 inch as the torque will drop off. I know this because I did this. I had a 98 Silverado for a in high school for awhile and big plans for it and I got in a hurry (because I wanted it louder, I grew up in a small town that it was who had the loudest truck in high school) before I did any thing else and I put a 3" y-pipe and 3" exhaust with a high flow cat and mufflerpipe after the muffler was 3.5"(on a stock truck)and lost torque. Believe me you can feel the difference. 2.5" for your size of motor is more than enough.
A high flow cat is an excellent idea its a good way to free up some power and be emissions legal. (I am not a tree hugger, just an outdoorsman that treads lightly when ever possible). Also it not worth not passing you emissions testing and no cat doesn't necessarly give you anymore power. Here is a link to a truck just like yours but only 2wd which won't make any difference. I believe it has a Magnaflow muffler and I don't think its got a high flow cat but I would think do to the size of the motor and the fact that it is a 5 cylinder that the cats gonna make a lot of difference in sound just power. Another good idea if you don't already have one a CAI (cold air intake w/ high flow filter) this some more power.
Heres the link:
http://www.youtube.com/watch?v=4hqr145UtRc

I also puta few otherlinks here for ya it have a lot of parts for your truck.
http://www.rockymountainsusp.com/
on this site once you click on the suspension lifts (highlighted in blue on the center of the screen above the brand names click on the section titled phot gallery then selectChevy GMC then find your truck. They have some cool picts of what your truck would look like lifted.
The next one is 4wheelparts.com search for your vehicle I think they can even help you with the exhaust.
I posted the last to link for you to just check. If your like me this isjust the beginning for you and your truck.

Hope this help out, let me know if you have more question. I would be more than happy to help. Zach

I forgot a couple of things. 1 if you just doing this for the sound and don't plan on any further performance mods except maybe a CAI you may want to stick with the stock pipe size because if you go to a muffler shop there pipe is extreme crappy ( at least around here, they typically use the standard cheap pipe which might last 2 year before going through it all over again. This also depends on where you live if its in the south (no snow) great but if you live in a place like I do where they believe they have to put down 100 lbs of salt and brine for every block.lol), yourexhaust system won't last. The one thats on your truckI believe isstainless and will last a heck of a lot longer.2. If you plan on more mods and you want to go bigger fine but at least spend a little more and get stainless. 3. If you stick with just replacing the cat with a high flow unit and swapping out the muffler you need to coat the welds of the cat ( not the cat though) and coat the muffler itself and the welds. Doing this is a great help in keeping the damn rust off the muffler and protecting the welds against rust which can damage them causing you to potentially loose the muffler down the road. 3. Be sure to check the laws conserning the cat because alot of state prohibit replace unless there is a problem i.e clog or other, and will cause you to fail inspection if you have to have it inspected.

 

Just for some quick info I went ahead and went with a high flow cat and a magnaflow muffler. It is the one that comes with the kits you buy but I just got the muffler. It sounds terrible! I guess I am use to my old 98 Silverado with Flowmasters but this was not what I was expecting at all ! It sounds like onoe of those little fast and furious cars just not to mainly at all haha. Just to let all other Colorado owners with the 3.5L go with the 40 series flowmaster i have heard it and it sounds way better on the colorado than the magnaflow XL just my opionion. I did not hear the Flowmaster on the colorado until after i had already put my magnaflow on but now im broke and cant afford to change it OH WELL!

 

Bummer, I put the link with the truck just for an example of a modified Coloradoit just happened to havethe magnaflow muffler. That stinks that it sounds like that. I think the I5 has a big effect on sound.Magnaflowssound goodon 4.3s though. I have a flowmaster 40 on my truck for the time being, sounds good but I think it could be better.

 

firefighter, i have the same truck as you and want an aftermarket exhaust. i was looking at a magnaflow exhaust, duel they have on their website for colorados, but you said that it sounded terrible. what exactly did it sound like? and do you have a link for the flowmaster so that i could hear it?

 

He's no longer an active member of the forum, so I doubt he will answer.... I've heard that glasspacks sound really good on the 5-cyl engines... I'm not sure about Magnaflow or Flowmaster, I've never heard a Colorado with it.

 

i have an 07 z71 and i have from the cats back a 2.5 in to a 1 inlet 2 outlet flowmaster 40 seris and it sounds good. granite my motor is the 3.7 but it doesnt have the riceburner tone i hate at all. it sounds really crisp for a smaller motor and ive been really happy with the setup. the only downfall is the loss of the spare tire underneath.