Advise needed

crewleader22 · October 15, 2004

Hello to all! I have been reading around on this site and joined a little while back. This site is GREAT!! It seems everyone has their own opinion, but that is what is so interesting.

The questions I have are about performance.

I have a 2001 2500HD 6.0 crewcab 4x4. The mods I have done on this so far are

-K&N FIPK 2

-HyperTech Programmer

Question 1: I want to put a set of mufflers on my truck. I have a small child, so I don't want the resonance in the cab like was in my '91 Suburban. I do want one that is deep but not as loud as the Flows on my Sub. What do you guys recommnd for a muffler?

Question 2: Can a tuner be added with the HyperTech (Westers, Nolan, etc.)?

Question 3: Thoughts/availability of underdrive pulleys?

Thanks in advance.

Frank S · October 15, 2004

First off, welcome to the board. That seems to be a nice start to the HD, now let me try and answer some of the questions you have posed.

1) If you don't want a lot of in cab noise, stay away from the dual in/dual out 50 series Flowmaster. I have this muffler on my truck and love the sound but there is in cab noise. You may want to try a MagnaFlow system as others on the site have given it good marks.

2) I do not believe you can "stack" a PCM with a Hypertech nor is there really any reason to. If you want the PCM, they will custom write the program for you so it will override any gains you may see from the Hypertech.

3) I'd personally stay away from underdrive pulleys. I've known too many people who've had them and ended up with so many issues (charging, slinging belts) that they ditched them in favor of the stockers.

MountaineerTom · October 15, 2004

Welcome.

I know mines no the same configuration as your truck, but I had a single in/dual out 40 series flowmaster on my 5.3 a few years back. It sounded great, but really got to be annoying at 70-75 mph on our 5 1/2-6 hour trips back home. It was pretty loud in the cab. The longer I had it, and the more the muffler rusted out (I guess), the louder it got. I think may have rusted out due to me mostly driving short trips at the time and not really building up enough heat in the muffler to dry out any condensation. I now have a single in/dual out 70 series flowmaster. It sounds better than stock, but not nearly as loud as the 40 series, or 50 series for that matter.

I've been happy with it.

LikeaRock14 · October 15, 2004

Welcome to the site!

As far as programmers, I think Frank's dead on. A custom tune might be the better route for what you want.

As far as muffler, BEWARE! The 6 liter IS a loud motor! A member over at CTW said going from his 02 Tahoe w/ a 40 series to an 03 Denali w/ a 70 was almost as loud as the Tahoe, amazingly.

Many are switching and/or currently running a Magnaflow 5x11x22" case muffler. The 5x11" case utilizes dual internal pass tubes and extra packing for more sound and heat absorbtion (heat is one cause of resonance). Going from a 70 to a Magnaflow, or other mufflers that people w/ the 6.0 have ran, they favor the Magnaflow the best. Keep in mind, you WILL get a certain amount of "resonance" w/ any aftermarket free-flowing muffler. Resonance doesn't have to be drone however. It can be just a slight rumble at cruise speeds w/ out drone, that's basically not heard over the radio. The 70 in our 00 used to make my nephew fal right asleep (before he turned into a monster lol). Just a slight rumble at cruise speeds, yet no drone