This is a brief guide on how to modify the air intake assembly on the M113K/55K AMG series engines found in the CLS55 (W219/C219) and E55 (W211) to name a couple. Reasons for doing this include better air flow, looks and induction noise.
You can buy some kits (Fabtech Performance (FTP) or NeedsWings) that achieve the same end result but they are quite expensive. Credit where it’s due, they have taken the time to get a complete intake system that just bolts into place with minimal effort – if that’s your thing, stop reading here and go and buy one of these:
Alternatively, do what I did and make something similar yourself
What You Need
- 2x Stainless Steel Tubing 3″ (76mm) OD: 90 degree bend.
I went for 600mm length but found that is quite long for this application…you can get away with a lot less and maybe a different angle.
- 4x Silicone Hose Coupler for 3″ (76mm) OD tubing
- 10x Silicone Hose Clamp for 3″ (76mm) ID Silicone Hose Couplers (79-87mm)
- 2x Spectre 9833 Inline Air Boxes (comes with Filter Elements)
1. Removing the OEM Air Filter Assembly
Remove the front engine cover (with the Mercedes Star) by pulling it off the rubber clips. Then remove two black air feed pipes from the front bumper that attach to the air filter boxes on either side of the engine. These just pull off at the air box end and then backwards out of the slot at each side of the bumper.
The air boxes can then be pulled upwards and off the two rubber stops that anchor them to the engine. Releasing the metal clips that attach the rear hoses to the air boxes should let you completely remove them.
Fortunately, the OEM Y-Pipe that connects the air intake routes to the supercharger snout are exactly the right size for 3″ diameter pipework so there is no need to change that.
2. Sizing Up Pipework
The next step is to measure up the stainless steel pipework as appropriate to get it to fit in the available space and leave enough room to accommodate the inline air filter boxes.
Using the 600mm long 90 degree bent examples I used, I cut perpenducular through 7″ from one end and approximately 9″ from the other end at an approximately 60 degree angle to end up with this sort of shape:
You can see now why 600mm length is a bit overkill! I advise lining everything up as best you can in the engine bay before making any cuts. You only get one shot at this!
Once cut, file down any rough edges and thoroughly clean the section of pipework that you intend to use – the last thing you want is metal shavings and filings getting sucked into the engine.
This fits snugly into the respective end of the Y-Pipe. Slide on the clips and tighten them up as you go.
Insert the inline filters with another hose coupler and pair of clamps, again tighten up as you go.
3. Reconnect the Intake Pipes
The black plastic intake pipes have a lip that is very slightly too wide to fit under the silicone couplers (and make them slightly too long anyway). I ended up cutting the lip away at the end of the pipe so it fitted snugly.
Again, tighten the couplers around the couplers.
Recheck all the clamps and make sure there are no gaps – everything should be sealed nicely. And you’re done – for a fraction of the cost and a little bit of time and effort.
If you don’t want to cut the OEM air duct pipes, they will slot over the end of the inline filter cases but don’t fit snugly without the clamps – the vacuum will pull in a small amount of hot air from the engine bay.
Alternatively, you can use some extended (flexible) 3″ pipework to reach the same ducts in the bumper – the OEM ducting is now the most restrictive part of the intake system as it is, so to get a more even and better flow, it would be worth doing but for now I am leaving these as they are.