LBZ: Magnaflow Downpipe

ChadS

New member
Nov 27, 2012
70
0
0
west bend wisconsin
I installed mine yesterday.
Stocker was a real PITA Mf'er...no better way to describe it than that:mad:
Heres what i learned yesterday which should help you...
-remove fender liner on passenger side
-Remove the 2 13mm bolts that hold the trans dipstick to the bell housing, pull the dipstick up almost out of the trans. I did not lose any fluid
-remove the turbo heatshield or atleast unbolt it and get it out of the way, I cut mine off and left it off.
-remove all of the 10mm bolts holding the heat shield on the stock downpipe. Get all that you can now and then you may have to go and get a few once youve removed the band clamps holding the downpipe to the turbo and the exhaust so that you can move the downpipe around to get access.
-remove band clamp on back of turbo and on exhaust, Also remove the 13mm bolt holding the downpipe to the exhaust bracket off of the manifold. My bracket was broken off and had cracks all over it.
-Youll have to wiggle the downpipe around to get the heatshield out, Mine came out from the top of the motor.
-Once the heatshield was gone i was able to get the downpipe out, It was still kinda a PITA and took some real mean words being said to it but eventaully it came out through the fender well.
-New pipe slides right in with no problems at all. It amazed me how hard the stocker was to get in compared to how easy the bigger pipe was to install.

It sounds like a real pain in the a$$ to do...Im going to be changing out my exhaust and was thinking of aftermarket downpipe. By the way it sounds i better start it on friday night so i can be to work on monday.
 

SoCalMike

Member
Dec 12, 2010
760
18
18
SoCal
its not that bad. about half a day for your first time. ( 4hrs)
this is how i did it.

First i started at the top. I took the turbo heat shield bolts out (3 bolts on top)and rolled it to the back. there was no way to get the the band clamp so i removed the glow plug controller. once that was moved out of the way i got my flex head ratchet and a 11mm deep socket and removed the band clamp. While i was up there i also removed one of the down pipe heat shield bolts. the one by the trans dipstick. (10mm)

Next i removed the passenger wheel well liner. Now you can see what your working with. I removed the other down pipe heat shield bolt and the band clamp holding the down pipe and the front pipe together. I moved to the back of the front pipe and loosened the clamp holding the exhaust and front pipe together. I did not remove the front pipe. i just twisted it out of the way when needed.

Now you can loosen the trans dip stick bolts. there are 2. do not remove them just loosen the nuts till you can pull the trans dipstick up. i did not remove the dipstick. i just pulled it up so you can move it from side to side.

I removed the 14mm bolt holding the down pipe to the up pipe. now you can wiggle the down pipe out and down a little. There is one more down pipe heat shield bolt. Its on the drivers side and very hard to get to.the trick is to lay on the passanger side under the truck and look in between the trans and the floor board. from there you can see the top of the trans. I moved the down pipe around till i could see the last down pipe heat shield bolt. I used a 2 foot extention and a universal joint with a 10mm on the end of it and removed the last heat shield bolt.

With all the heat shield bolts removed push the down pipe back in the stock location. Now push the heat shield up as much as u can. you will see it get caught at the bottom corner of the heat shield. bend it and push it us some more. now move to the top and lay on the engine. start pulling the down pipe heat shield up and out. you will have to move it around and massage it out. I tried to muscle it out through the bottom at first but i was by my self and did not have a 2nd person to bend the top of the heat shield while i pulled from the bottom. taking the heat shield out the top was pretty easy and it came out without getting all bent up.

Move to the bottom and pull the down pipe out. make sure you pull the trans dip stick up so it gives you more room when pulling the down pipe out.

Now you can install your new down pipe! What i did is install the new dp from the bottom. move to the top and slide the down pipe in the turbo. install the band clamp loosely but enough to hold the the down pipe in the turbo. attach the trans dip stick back to the trans. you might have to masage the dip stick a little.

Install the 14mm bolt that holds the down pip to the up pipe. Install the band clamp that holds the up pipe to the the front pipe. Tighten the clamp that holds the front pipe to the rest of the exhaust.

Now move back up to the engine and tighten the band clamp for the turbo/down pipe. Reinstall the turbo heat shield and bolts and finally reinstall you glow plug controller and your done!
:woott:
 

dmax_ty

Member
Aug 18, 2011
435
8
18
Utah
Doesn't lower exhaust temps even 1* I bought one years ago mainly for sound.

They are one of those mods where you will never gain anything back from the truck, but "know" that it helps.

You will for sure know it is there when you go WOT, the lack of god awful screeching sound will make you happy

What these fellers said :thumb:

I was all sorts of giddy when I romped on it for the first time and there was no God forsaken screech. I forgot all about the no EGT drop because the change in sound was worth every penny. :woott:
 

DMAXXD

New member
Aug 4, 2010
1
0
0
Michigan
I have two Dmax powered trucks, 04 LLY and a 07 LBZ, that my son and I replaced the downpipes with new ones from Magnaflow. It took about 2hrs to get crappy old GM pipes out and about 30min. to install new ones. The heat shields were our biggest pain to move out of the way! Reduced EGTs by about 75 to 100deg, Little faster spool up, little deeper sound out of Magnaflow 4" on LBZ, 4" Diamond on LLY, Will have to wait for Spring-Summer to learn more! Got em from Alligator for $112.00ea. Good place to shop!!!