W205C43AMGCoupe

I'm in process of installing the Weistec downpipes and became frustrated with the lack of installation instructions on these, so decided to DIY and write down the steps I followed. Note: I did this by myself in the garage on jack stands. Ideally you'd have a lift and a partner to help, but it can be done alone. Its not terrible install once you know what needs to be done. I hope this helps someone interested in installing these themselves.

All Below steps are from working inside the engine bay

Step 1: Remove engine cover by lifting up in all four corners to release clips, then remove front of engine cover from front inlet tube.

Step 2: Remove left and right air intake tubes from front cowl inlet. They just pop off when you pull.

Step 3: Pull up on left and right intake tubes to release the clips that hold the tubes onto motor and then pull the tubes out of the airboxes left and right (they just pop in).

Step 4: Remove the lower intake pipe left and right which attach to manifold. There is one bolt which needs to be removed 5/16 I believe and once loose you can lift the entire piece out. Now that the front(manifold side is loose) you can look to the rear where the pipe attached to airbox. You will see two screws holding the pipe onto airbox. It helps if after the first screw you rotate the entire tube/box to get to the second. Make sure to put rags in manifold holes so nothing falls into them!

Step5: Remove actual airbox left and right: First unclip MAP sensor on corner of each airbox and then just lift up on airbox to release similar style clips as on the intake tubes. The airboxes will lift out.

Step 6: Unclip O2 sensors harness engine side. To the left and to the right of the motor located above silver heat shields you will see two 02 sensors harnesses which are held into metal brackets with simple clips. These need to be removed so we can remove the bottom portion of senor with removal of the cats. First, unclip the sensors harness and slide them off-they will hang freely. Next you will see the female portion of sensors held In place by metalbracket. These sensors will just slide out of the metal bracket with help of small flathead screwdriver. Once the o2 sensors are removed from metal brackets follow each wire down to the downpipe. You will see a blue one and silver one. Both those wires if you follow them are run through little c clips which hold them into place and away from touching the exhaust. They need to be removed by lifting up on the clip (expanding it) and then pulling the wire free. There are two or three different clips the wire are run through. Now both 02 sensor wires should be freely hanging. We will be removing the 02 sensors at the cat side once the cats are removed.

Step 7: Remove passenger side small heat shield. The Vband clamp that holds the upper part of the cat onto the manifold is hidden beneath the heatshield. To remove heat shield is simple. Remove one bolt and then a clip and the shield will slide off revealing the clamp.

Step 8: Remove v band clamp by lossening and fully removing the bolt on the clamp. Once removed the v band camp will most likely be stuck in place, it helps with a large flat head screwdriver to pry the band clamp off with some force and then it can be removed. We are now done with passenger side in engine bay.

Step 9: Drivers side engine bay-repeat steps above removing the 02 sensor harness and sensors for metal brackets. The only difference on this side is that the heat shield is larger and more cumbersome. I only removed the one bolt from the rear of the heat shield and the one clip and while still attached pushed it out of the way. There is another bolt upfront that is hard to reach, but the vband clamp can be reached with it pushed out of the way.
Step 10: Loosten vband clamp on drivers side and fully remove. We are now done on the inside of the engine and are moving beneath the vehicle.

All below steps are done beneath the vehicle:

Step 1: remove the black belly pan. There are several bolts which hold this in place. Not difficult to figure out. Remove and set aside.

Step 2: Remove the exhaust hangers for the left and right midpipes. This helps give you more play in the exhaust to remove the downpipes. There are two bolts that attach the exhaust to the bracket with the red circular dampener.

Step 3: Now move up to the downpipes and look towards the front of the downpipes. There are metal brackets which are attached to the downpipes and attach them to the car with two bolts. Remove the two bolts and the downpipes can now be free’d. To remove the downpipe from exhaust I used a rubber mallet and a lot of wiggling and they will come loose. Once loose the downpipes can be removed from bottom and the 02 sensors can be removed from the Downpipes

Install new downpipes in reverse order.

AMG__POWER

amazing write up

MatthewJ

Thanks for the write up! This forum needs more of this.
Do you have a full tune or piggyback? Did you do catless? O2 sim? If so which one?
Would like to heard your thoughts on power gains from this after the car learns the trims in a few days of driving. Seems to be mixed results on if downpipes are worth the install or not. Whats the pipe size of the stock downpipes?

Csandoval1988

Thanks for taking the time to write this up! Just to tack on to MatthewJs questions, did you swap out your exhaust as well or did you just install the downpipes and left everything as is? How was the "rasp" after install?

Dieseldan9

iTrader: (1)

This should be a sticky

marshdub

Has anyone completed this and (audio) recorded the results?

Fresh_Mass

I followed this to install my RSE DPs this morning. All went well until trying to reinstall the driver side turbine/ engine side clamp. What a pain in the ***... I have no advise other then you will eventually get it on there.

b6tbfmp

That V clamp was a chore.

c0d3917

Attempting this install right now with a set of Brondex DP's. My AMG is a 17 GLC43 coupe. I'm to the point of removing the heatshields now, but need some assistance. If anyone can lend some advice from experience that would be greatly appreciated! Thank you.

Matthew Cohen

Not sure but somebody will need to know what specifically is giving you trouble.

c0d3917

I'm currently removing the heatshields. I have multiple clips and bolts as it seems my heatshields are in 3 pieces. Looking for additional details as to which bolts/clips need to be removed to facilitate access to the clamps on the DP's.

MatthewJ

on the passenger side i only removed the farthest rear heat shield. there are just a couple 10mm nuts holding it on if memory serves me.
For the driver side i removed a few of the nuts and loosened the front one so i could swing it out of the way. the DP to turbo outlet v band clamps are pretty far back there. no need to mess with most of the shields up by the BBV.

c0d3917

Thanks MatthewJ! I'm going to be working on the heatshields tomorrow. Interestingly, my GLC43 uses e10 torx, both external and internal for all fasteners. If I get stuck I might just grab a few pics and post them.

c0d3917

Had a chance to tackle the install a little more today. Good news as I was able to complete everything inside the engine bay from the top side. Found the correct torx bolts, removed the heatshields, the v clamps and O2 sensors. Tomorrow it's onto the underside. 🤞

Fluffy Nuggets

Hey anyone have any tips for connecting the downpipe to the turbo with the v-Band? Installed some new downpipes yesterday and was having a hard time getting the downpipe seated into the clamp. I see some have said its a hassle so I knew going into it I was gonna struggle but not this bad lol. Any type of tips would help.

MatthewJ

I had to have a neighbor come by and help hold up the downpipe while i clamped it. tried for too long by myself before asking for help.

Fluffy Nuggets

Okay thanks for the info I will try with a friend this week. I tried using a jack to hold it up while I clamped it from up top but didn't work out too well. I have one more question. Did you connect the downpipe first to the turbo and then connect it to the mid pipe/bracket or vice versa?

MatthewJ

Its been a few years since i installed it but i believe i did turbo side first, then flex pipe section.

Fluffy Nuggets

Appreciate the info/tips, I was able to get them installed properly yesterday with the help of a friend. Definitely helps to have a second pair of hands for anyone trying to do this D.I.Y