[Info@mad-us.com]

Originally Posted by evidence

Just wrapping my install up. Have you guys been swapping the gasket between the turbo mani and DP for a new one, part 18307553601? The one between the DP and mid is a lot beefier and makes solid contact, but the one on the turbo is looking pretty crushed. Curious if anyone has had any leaks.

Also just a note for anyone using the bigdaddies mini cats, an extra spacer between the mini cat and the stock o2 sensor is needed to make sure you don't crush the cat. Wondering if some people are seeing codes because they are squishing the cat and getting the inefficient code, or clogging it and getting the slow to heat code. These worked perfectly for $10 (just the crush washer):

https://www.autozone.com/ignition-tu...009/730544_0_0

If they look damaged replace them, it's easier now than later.

If your downpipe is catted those extenders in the link may work.

[evidence]

Originally Posted by Info@mad-us.com

If they look damaged replace them, it's easier now than later.

If your downpipe is catted those extenders in the link may work.

Yeah just didn't want to have my car down an extra few days while I waited for the turbo gaskets to come in. Dealer wanted $49 each Ended up ordering them, figured I'd swap next time I took off the splash guard.

I was getting the delayed rich/lean CEL that some get w the minicats. Just swapped out the minicats for the spacers on my 200 cell DP to avoid that CEL, dropped the new gaskets in while in there. So as others have said, go bare spacer w a highflow cat, minicats for catless.

[OM4R]

Thanks to all who have contributed. This post is truly, the most helpful comprehensive resource available for downpipe installs on our platform.

After having completed the install myself I’d like to further add to this thread, to help others noobies like myself who who would like to DIY the install.

My install - I installed MAD Catless DPs on my 2021 G82 11k miles, using a lowprofile Jack and flat topped Jack stands. I did the install alone; Install took several days. My mechanical knowledge is novice to intermediate.

Helpful tips:

• Label everything, especially fasteners (nuts, bolts, etc.) there are a lot that you will remove and you will forget where they go.
• Use a fastener lube (rust pen, WD-40, etc.) on all the exhaust bolts above the mid pipes including: connecting pipe, downpipes, and O2 sensors (obviously don’t get anything on the sensors themselves).
• As another contributor mentioned about using a flathead screw driver to remove the part connecting the downpipe to the Turbo Assembly….. to clarify, this is the V-Clamp - the gold colored clamp. You must completely remove each clamp to break the downpipe free. An extra long flathead or prybar will help and you may have to use a rubber mallet on the butt of said flathead/prybar. Note that even when you completely remove the bolt, the clamp remains attached very tightly to the downpipe until you pry it off, thus freeing the downpipe.
• As this same aforementioned contributor mentioned, don’t forget to pull off the metallic colored, rubber flanges off of the OEM downpipes from the side that connects them to the mid pipe, as you will reuse these on your new DPs to connect them back to the mid pipe/connecting pipe.
• When you are in the engine bay, it is helpful to disconnect the two connections running to the positive battery relay, in order to access the O2 sensor that is right there and to also fish the connections back and forth. As was mentioned in this thread make sure you disconnect your battery, which is located in the trunk under the flat carpeted liner, before you even start the install.
• If installing mini cats (big daddy’s garage spacers), they go in the O2 sensors closest to the rear of the car in the long and short DP, respectively.

[OGOverkill]

I don't see torque specs for the turbo to downpipe clamp, does anyone have these?

I see O2 sensors are 29 foot pounds and downpipe to mid pipes are 16 foot pounds.

Also, is there gaskets on the turbo side that should be replaced? I see the downpipe to midpipe is part #18308053348

[evidence]

Originally Posted by OGOverkill

I don't see torque specs for the turbo to downpipe clamp, does anyone have these?

I see O2 sensors are 29 foot pounds and downpipe to mid pipes are 16 foot pounds.

Also, is there gaskets on the turbo side that should be replaced? I see the downpipe to midpipe is part #18308053348

Turbo to DP is 18307553601. I replaced mine, but ultimately don't think I needed to. Can find them online for $10 if you want the peace of mind tho.

downpipe to midpipe ones seemed fine, reused those.

[StephenWyker]

Originally Posted by OGOverkill

I don't see torque specs for the turbo to downpipe clamp, does anyone have these?

I see O2 sensors are 29 foot pounds and downpipe to mid pipes are 16 foot pounds.

Also, is there gaskets on the turbo side that should be replaced? I see the downpipe to midpipe is part #18308053348

Cat to turbo is 14nm per the service manual.

[OGOverkill]

Originally Posted by StephenWyker

Cat to turbo is 14nm per the service manual.

That seem very light! Guess it doesn't need to hold much.