New to the forum as I got a 07 Classic 2500HD 6.0 earlier this year. Worked on some maintenance type items but am now into potentially modding it. I just picked up an AFE cold air just because it was on sale for only $50 more than the airaid Jr kit. Will likely tune it in the future but have also been thinking about full exhaust. I know LS pick up big with long tubes. I'm drawn to the speed engineering long tubes and true dual kit. I was hoping they would have a black friday sale but no go. I've been keeping an eye out for used kits as well but they seem few and far between for this truck. I have no goal to make this truck fast, it's mainly a tow pig for my fox mustang. But some added power, MPG, and sound would be nice. What's the best bang for the buck exhaust set up out there? Longtubes to ORY to stock 3" catback with muffler replace or delete?

Thoughts on the Speed Engineering kit? Most have good things to say but I've seen some horror stories too. By the time you replace their **** clamps, buy the extension tube needed for a CC6.5' bed, etc. I would likely have $1,200+ into their kit. Not Kooks or ARH territory but also not cheap. I'm then worried about fitment and will be pissed if I have to bash a pipe or the thing leaks like crazy, which is a real possibility. So wanted to get some other thoughts and ideas.

 

Oh well nvm. Looks like I've been on here since 2005 and have 29 posts. Man I guess it's been a while since I last visited LOL

 

Here's where I'm going to go against the grain again. For the long tubes, being a 2500HD, don't you have a factory true dual exhaust already? I KNOW I'M PROBABLY ALONE ON THIS, but personally, there is a LOT of regurgitated misinformation about the NBS floating around the internet. Some body said something 20 years ago, possibly didn't know what they were talking about, new products were made, new things were discovered, but somebody said it, other people read it, and wanted to help, or wanted to get up their post count, and kept it going until it grew out of control..... I think is one on the top 10, of incomplete information.

I still fully believe that the only reason long tubes work so much better on a 1500 is not because of the header, but because of the y-pipe / cats collector. The factory 4.8 and 5.3 exhaust goes from a 2.5" flange at the manifold, to a 2.5" pipe before then after the cat, and then goes into the collector as (2) 2.5" pipes and collects into A SINGLE 2.5" pipe before the intermediate pipe. The only way it wouldn't be restrictive is if it went from a dual 2.5" to a single 3.5". That is the choke point.

When you do long tubes, you get rid of that collector, and run a full exhaust back that doesn't reduce. If all you change is the manifold to shorties, you still have that main choke point restriction. I'm not saying long tubes don't help, they will. I just don't think they would be as much of a benefit on a 2500, compared to a 1500, if you already have a true factory dual exhaust. IN ALL FAIRNESS, I could be completely wrong. Searching around specifically for 6.0s in 2500's and finding out their experience would be best.

I would personally start with a tuner that you can learn on and improve along the way, and probably a better flowing and sounding muffler. IF YOU ARE already a true dual, I just don't think the bang for buck is going to be there, especially if you are talking about putting in the cheapest thing you can find.

 

No factory dual exhaust my good sir. Factory truck manifolds to catted y pipe to single 3” factory exhaust with one of the largest mufflers I’ve ever seen.

 

The GMT800 2500HD have a pretty large exhaust to the muffler. Dual all the way to the muffler inlet.
Mine already had the cats gone and some crappy muffler. So all i did was put a huge dynomax muffler on it and never looked back. Its pretty quiet in the cab and has some sound outside.
A tune helps these trucks a ton. I had part of a K&N intake laying around from a customers truck that didnt want it. And i put '05+ Efans on it so got rid of the factory tube. Replaced it with part of the K&N tube to the factory airbox with a 2002 Duramax air filter.
Had to touch up the MAF and VE table some to dial it in.

I would have a hard time paying ~$1200 for just exhaust. That is almost half way to a turbo setup.

 

Headers make more power than manifolds, every time, repeatable on a dyno, every day and twice on sunday. But to do good long tubes and then have an exhaust built by a shop or a kit is gonna cost you 2k or more, and thats if you do the work. I did mine, and love it, but not everybody wants to spend that much money to go a little faster and be a little louder.

 

I'm absolutely also weighing just the overall cost vs. benefit. I also know that odds are very strong I'm going to break a stud in the process. If that happens I will likely immediately say this wasn't worth it. I'm talking myself into just doing a good local dyno or street tune and calling it good. Maybe grab a nice used set up if I ever run across it.

 

Speaking of Efans, are they really worth it? Keep in mind I absolutely despise wiring.

 

My clutch fan was going out and i had fans already in the shop so i used them. I dont know if you want to call it worth it.. but it frees up some rotating mass.

 

I have mixed feelings on my E fans. If you tow in extremes they probably won't keep up. Mine have been alright so far, have towed heavy trailers a couple times and haven't had to pull over due to overheating but got close on one long grade where I was only going about 45mph at 3300RPM or so for a few miles, IAT was 100F. I did have to turn off the A/C, I don't remember if I needed to turn the heater on, coolant temp peaked at 232F and if it would have gone up a couple more degrees or started to run away i would have pulled over but it held there or slightly less for the pull.

For any typical driving they are great, A/C works great all the time. Throttle response is crazy snappy, especially since I am drive by cable anyway. When I'm commuting home in the summer (temps up to 113F occasionally, and this the sunny side of the hill which bakes), which is basically a 3 1/2 mile climb up a mountain, the truck keeps all of it's power which typically it would have lost some from the clutch fan locked solid.

It is noticeable in some ways, but MPG gains no... maybe on a half ton, but this 2500HD is just to heavy and the 6.0L to thirsty to care about a few hp gain.

If you get the OEM relay pack from an 05/06 truck/SUV the wiring is really simple and the fans just drop right in practically.