This is my 1st diesel (2001 GMC Sierra 2500HD LB7 motor) and i want to put stacks on it, but for now i've heard to optimize sound, some performance i can cut the muffler out and clamp on a extension and have the exhaust come out right in front of rear tire... are there any negative things i should watch for?? i've also heard even with stacks the LB7 motor is hard to get to produce smoke so is a stack even worth going for? looking for some good advice please??

if you dump it in front of the rear wheel, wash the truck a lot, as that wheel will turn black, even on a stock truck.... cuttin out the muffler not only sounds good but takes a lot of restriction off the motor. i noticed an improved responsiveness from a dead stop.

lb7 will produce smoke, and lots of it providing you have the right tune. mines stock save for a straight pipe so i couldnt tell you which one which tuner/tune to use. if you do go stacks, they will be even louder since they will dump right behind the cab. much louder than out the side....
however these trucks sound good with no muffler soooooooo.... :D

luck with the truck an welcome to DP

Thank ya much. glad to have a place like this to give some good advice on issues. I love to Duramax almost went with a Powerstroke till i read more about the Duramax, the only problem i encountered was my fuel injectors but thank god GMC stands by their product and upped the warranty to 200,000 miles on the injector systems because of this flaw with Bosch, otherwise i'd be out $3,000 and couldnt do a thing to my new love, :-D

The only downside if you want to call it is waking up the neighbors and making people roll up their windows when you drive next to or by them. I liked mine when I had it straight piped and I am probably getting a muffler delete pipe for my 4" system too. Going under an overpass with your windows down lets you kinda see how loud it really is. I didn't think my truck was really loud, but other people told me differently. You will love your truck straight piped.

Well, I picked my truck up last night, and I am kind of disappointed. I opted to keep my cats becuase they will be "sniffing" here in 09. Also, did not want to make it horribly loud. I went with the shorter muffler, 24" I think, hoping to achieve some sound and performance without removing the cats. At low RPM, you can hear a little rumble, but when I get on it, the turbo and motor sounds drown the exhaust out. Also, I can't really feel any improvement in performance. Should I have just removed the muffler completely? I don't want highway resonance, but I would like to be heard driving around town, you know. Also, maybe 1 MPG and a little wake-up on power. How loud, or "droney" will it be, if I take it back and just replace the muffler with a 4" spool piece?

Well, I picked my truck up last night, and I am kind of disappointed. I opted to keep my cats becuase they will be "sniffing" here in 09. Also, did not want to make it horribly loud. I went with the shorter muffler, 24" I think, hoping to achieve some sound and performance without removing the cats. At low RPM, you can hear a little rumble, but when I get on it, the turbo and motor sounds drown the exhaust out. Also, I can't really feel any improvement in performance. Should I have just removed the muffler completely? I don't want highway resonance, but I would like to be heard driving around town, you know. Also, maybe 1 MPG and a little wake-up on power. How loud, or "droney" will it be, if I take it back and just replace the muffler with a 4" spool piece?


just whacking out the muffler altogether makes it sound good but not the "v8 gasser" loud you're thinkin of. the turbo helps eat up a lot of the noise as well as the diesel being louder to cover up pthe exhaust sound.... mines stock with no muffler an its perfect. it definitly turns heads when you open it up :D

This is my 1st diesel (2001 GMC Sierra 2500HD LB7 motor) and i want to put stacks on it, but for now i've heard to optimize sound, some performance i can cut the muffler out and clamp on a extension and have the exhaust come out right in front of rear tire... are there any negative things i should watch for?? i've also heard even with stacks the LB7 motor is hard to get to produce smoke so is a stack even worth going for? looking for some good advice please??

hey welcome to the dp. stacks are great:D but the lb7 will chug aout some smoke. so be careful if you dump out the side. not so much stock but it will do it. the stacks are mild noise just putzing around town, and then when you get into it hard it gets pretty noisy.

hey welcome to the dp. stacks are great:D but the lb7 will chug aout some smoke. so be careful if you dump out the side. not so much stock but it will do it. the stacks are mild noise just putzing around town, and then when you get into it hard it gets pretty noisy.


what kind of tuner would you recommend for me since i plan on going with stacks?

hey i just put a 4" cat back muffler delete mbrp exhaust on my 2007.5 lmm . i was not impressed because it did not sound much different than the stock system. does anyone no how i can get some more noise and still pass emmissions tests?????

hey i just put a 4" cat back muffler delete mbrp exhaust on my 2007.5 lmm . i was not impressed because it did not sound much different than the stock system. does anyone no how i can get some more noise and still pass emmissions tests?????

what kind of tuner would you recommend for me since i plan on going with stacks?

i hear PPE makes a killer smoke pakage with plenty of power check that out

hey i just put a 4" cat back muffler delete mbrp exhaust on my 2007.5 lmm . i was not impressed because it did not sound much different than the stock system. does anyone no how i can get some more noise and still pass emmissions tests?????


the dpf an cat probably suck up a lot of the sound... getting rid of those might get you some more rumble... as long as you're in a non-emissions checked state....

footer, any one of them will make smoke. but also remember just about all of them will kill your trans if you beat on it. my edge smoked like a train in level 3. and it is for sale. pm if you want it.

footer, any one of them will make smoke. but also remember just about all of them will kill your trans if you beat on it. my edge smoked like a train in level 3. and it is for sale. pm if you want it.

i'm actually going with superchips i think thank you though. but also dont i need an edge for the LB7 since my engine is that. im new to the diesel thing (finally got $$ for one)