I found a LB7 down pipe at the local exhaust shop and installed. The job took a total of 45min. including the time to find and replace tools needed. I first removed the hanger bracket from the trans, then unbolted the pipe. The orginal pipe came out the front easily. I still have stock exhaust behind this new pipe.

I'm running the predator on 85h.p. setting and there is very little sound difference except a little more turbo wistle, although I've yet to hear it power up from the outside. The seat of the pants meter tells me there is more power. I would say about the same difference as going from the 65hp setting to the 85hp setting on the predator. I have no hard evidence, just the feeling.

If you want a power increase the swap is worth the effort. If you're looking for louder exhaust than you won't notice much if anything.

Of course the LB7 pipe was only used during offroad testing, and cat will go back in when street driven.

Rob

About 2 months ago I found an LB7 pipe and installed it. I noticed right away the turbo spools up quicker and more turbo whistle, and its quicker off the line. Just to be sure, I reinstalled the cat last week and drove about 300 miles with it. Needless to say, Its coming back off this week. It runs better all around without it. Best part....muffler shop just gave it to me for free.

did you receive any codes with just changing the downpipe and leaving the original muffler?

whats the difference between the lly and the lb7 downpipe? I put a whole new downpipe on my lly, its the same down pipe that magnaflow gives you when you order their 5" system (its a 4" downpipe). Only alteration I made was shortening the down pipe so that it went from 4" into 5" right after making a 90 degree turn toward the back of the vehicle. They way the down pipe came it was 4" all the way to where youre cat would be should you have one on your truck.

The lb7 49 state downpipe doesn't have a cat so switching gets rid of cat, bolt in change.

I have no lights on the DIC, but haven't checked with scanner. After some more driving the truck is differently quicker. On dry pavement with same conditions at the same spot as before pipe, my truck from a stop and just rolling on the throttle (no power brake), now will break the tires loose shifting into second. Didn't do that the day before the pipe was installed. Sweeeeeeet.

Rob

Gotcha...so I basically put an LB7 downpipe on my truck without even knowing it. But I even modified that):h and love it I might add:ro)

When I see a cat and muffler on a diesel I wanna -:t

I just did mine the other day. Using a buddies pipe from 03. Pretty simple. Like everyone is saying, more turbo whistle and spools faster. A little louder too. I tried running it with the cat pipe on and no muffler and it was quiet. That cat really kills the sound. It's louder with no cat and a muffler than with the cat and no muffler.
Some reason my stock exhaust is all rusted to crap already. The pipe I have from buddies 2003 isn't. What's the deal with that? I'll have to take some pics and post them. Never seen exhaust rust like that up here. We don't have salt on the roads. Heck it really hasn't been in that much water or snow. Odd.
Gonna get some 3.5" pipe when they restock at napa and take the tailpipe from my buddies 03 exhaust and straightpipe it. That way I have my entire stock exhaust to put back if I need to for warranty.

You guys never touched the down pipe. Down pipe is bolted directly to the turbo.

That's been pointed out multiple times, but everyone still calls it the down pipe anyway. Nobody makes a true replacement for the downpipe off the turbo... Fine... Calling it the intermediate pipe isn't catching on...

Yea, what nar said.

Rob

What is the gm part number for the lb7 downpipe ? I would like to do some testing of my own.

For a little more than new stock pipe, u could buy a new 4" exhaust.

I called the dealer and they wanted $180.00 for one. Venders sell 4" down pipes for around $100.00, I think. I just called around to my local performance exhaust shops and found a used one.

Good luck,
Rob

IdahoRob: How much was the used pipe?

The guy knows there is a demand. Sixty bucks, he has another one sitting out back if any one in Boise is looking for one. The trucks must have been driven from the dealer to the shop. Pipes look new.

I think that price is higher than what most have bought them for. At least there was no shipping involved. Beggers can't be choosers

Rob

The thing to do is find a buddy that installed a 4 inch of some sort and makea deal with him...

I just got my 4" cat delete pipe installed, to go with my cat back system. Much Much better sound IMO. Now to get busy and get the finger stick installed. :P

Will the intermediate pipe from an 01-03 a bolt in without any welding or modifications? I presume Chevy is the best place to get one if one cant be easily located.04 CC Dually

Will the intermediate pipe from an 01-03 a bolt in without any welding or modifications? I presume Chevy is the best place to get one if one cant be easily located.04 CC Dually
Sure it will bolt right in, it's really simple. Hard part is getting the cat to slide out past the mount that holds it up. You can remove it or just loosen it and shove it past. I would look around at exhaust shops or find a buddy that has one, it would be a lot cheaper. If you're gonna buy new you may as well spend the money on a 4 inch pipe. Cost less than from chevy.
:grd:

ya, thats what I did, is just buy the 4" pipe. 100 plus shipping from one of the vendors.

Is the lly down pipe, meaning the one directly off the turbo down to the intermediate pipe a crimped pipe or flat design? Is this thi benefit going to lb7 down pipe to have an actual pipe shaped pipe?