DIY - Evolution Racewerks / N54Tuning S55 Downpipe Install Guide

[Mike@N54Tuning.com]

**EDIT**

I am happy to expand or add anything you guys want, so please let me know. If anybody thinks something is not clear we can work on fixing it.

**********

I have gotten a lot of requests for a comprehensive guide so I had the guys at ER send theirs over and I have edited it and added some more details where I saw fit. So this is a hybrid guide of the ER one that comes with their downpipes and some insight from when I was playing with the car.

Tools Needed:
Full set of metric sockets and wrenches.
Flat head screwdriver
External Torx E10
Metric Allen Wrench Set
Parts Needed:
Optional – Lubricant like WD-40 or better Silicon Grease
OEM Gasket (Gasket Part Number ; 18 30 7 851 168 (you will need two))
Install Time: 2-3 hours


First off here is the overview of what needs to be removed. The CF brace will need to come off as well as the airbox. CF brace is bolted down as indicated.

Once that is off

1. Remove the Plastic Engine Cover – The plastic engine cover is held on by rubber grommets. Grab the engine cover by the corners and carefully lift it up. The plastic engine cover will release from the rubber grommets. Remove the plastic engine cover from the engine.

2. Remove the MAF sensor plug – Disconnect the MAF sensor. Pull the MAF sensor wiring harness loose from it's mounting bracket.

- as indicated by white circle on overview picture

3. Remove the intake pipe – You will need to remove the right side (left side if facing engine) intake pipe. Use a flathead screwdriver or 6mm socket and unscrew the hose clamp on top of the intake. Once the hose clamp is loose, pull it out of the intake box. Shift the intake pipe towards the engine which will allow you room to reach the lower hose clamp on the intake pipe. Unscrew the lower hose clamp. See Figure #1. Once the hose clamp is loose, remove the intake pipe completely off the engine. COVER THE EXPOSED INTAKE PIPE. MAKE SURE YOU DO NOT DROP ANYTHING INTO THE EXPOSED INTAKE PIPE AS FOREIGN OBJECTS IN THE INTAKE WILL CAUSE ENGINE DAMAGE

[Mike@N54Tuning.com]

Next you will have to remove the charge pipes and the lower engine cover.

4. Remove the turbo to intercooler pipes – The turbo to intercooler pipes sit above the engine. There are two of them and they both need to be removed. Use a flathead screwdriver or 6mm socket and unscrew the left hose clamp (the hose clamp on the turbocharger side). There is a plastic vacuum line that is mounted to one of the turbo to intercooler pipes. Pull the vacuum line off the bracket and away from the turbo to intercooler pipe. Next, remove the external torx screws holding the turbo to intercooler pipe to the turbocharger. Remove the two E10 screws (one on each pipe) holding the pipe in place. See Figure #2 and #3. BE CAREFUL NOT TO DROP THE SCREW. IT MAY BE DIFFICULT TO FIND IF YOU DO. USE A MAGNET IF AVAILABLE WHEN REMOVING THE SCREW. The turbo to intercooler pipes can now be removed. Pull the pipes away from the intercooler first. Once the pipes are clear of the hose, lift up. There are rubber grommets holding the pipes so there will be slight resistance. Remove the pipes from the engine.

5. Remove the lower engine cover heatshield – Once the turbo to intercooler pipe has been removed, the lower engine cover heatshield can be removed. It is held on by rubber grommets. Lift the lower engine cover heatshield upwards. Once it is free from the engine, slide it forward towards the front of the car until it clears all the wiring harnesses. Remove the lower engine cover heatshield from the car.

There is a gasket in the charge pipe where it attaches to the turbo so make sure that is not damaged, and you will need to lubricate that with silicone grease upon re-installing to make it easier to slide on.

The last picture also shows the engine without the lower engine cover / heat shield. The wires exposed are the ones you tap for denoting (as an aside)

[Mike@N54Tuning.com]

The next step is unplugging the o2 (primary) so they can be removed with the downpipe from below the car.

6. Disconnect the primary O2 sensor plugs – With everything removed, you can now reach the o2 sensor plugs. There are two primary o2 sensors, one on each downpipe. The o2 sensors are located on brackets attached to the right side of the engine (left side if facing the engine), next to the coil packs Disconnect the o2 sensor plugs and release the wiring harness from the mounts. MAKE SURE THE O2 SENSOR WIRING IS COMPLETELY FREE FROM THE ENGINE. THE O2 SENSORS WILL BE ATTACHED TO THE DOWNPIPES WHEN YOU REMOVE THEM. The rear o2 sensor plug goes to the rear downpipe. The front o2 sensor goes to the front downpipe. The primary o2 sensors both have black wiring sleeves.

On the second pic you will see where the sensors clip in which is the release tab (Inner red circle)

Also its important to not mixup the o2's but if you do luckily they each have a part number on them, and I have attached the schematic diagram so you can ID where they go (don't ask why I have this info)

[Mike@N54Tuning.com]

7. Raise the car up on a lift or on jack stands. (Lift is preferred)

8. Remove the factory Metal Skid Plate – the factory metal skid plate is held to the chassis by twelve 8mm screws and eight 16mm bolts. Remove from the car.

9. Remove the lower chassis brace – The lower chassis brace beneath the mid-pipes is held in place by six 6mm allen socket screws. Remove them. The lower chassis brace can now slide off the car. DO NOT REMOVE THE SIDE MOUNTS (which are attached to the rear subframe) THE LOWER CHASSIS BRACE IS ATTACHED TO.

10. Lower the exhaust system. Leave it attached at the mufflers but jack it up. ER says to completely remove the exhaust but I find this unnecessary.

There is two external torx E10 screws holding the mid-pipe hanger. Remove these screws. There is one 8mm screw (right side hanger) and two 13mm nuts (one on each side) holding both the rear mid-pipe hanger. Remove these screws and nuts. Remove the mid-pipes from the factory downpipes. The mid-pipes are held to the downpipe by two Torx T30 bolts and four 11mm nuts. See Figure #5. ONCE THE MID-PIPES ARE DISCONNECTED FROM THE DOWNPIPE, THE WEIGHT OF THE EXHAUST SYSTEM WILL NOT BE SUPPORTED ANYMORE. HOLD AND SUPPORT THE EXHAUST SYSTEM

[Mike@N54Tuning.com]

11. Remove the donut gaskets from the factory downpipes – There are donut gaskets at the end of the factory downpipe. Remove them and inspect. If they are not in good condition, they will need to be replaced. Once the donut gasket has been removed, remove the gasket spacer. DO NOT LOSE THE GASKET SPACER. IT WILL BE REUSED.

I recommend installing new gaskets!!!

12. Disconnect the downpipe bracket from it's mount – the front (left side) downpipe has a bracket that is held on by two 10mm nuts. You only need to remove the lower 10mm nut. Keep the upper 10mm nut in place. Once the nut is removed, slide the pin out of the mount. There are two washers on each side of the bracket that will now be loose. DO NOT LOSE THEM. THEY WILL BE REUSED. The downpipe bracket should now be free of the mount.

[Mike@N54Tuning.com]

13. Disconnect the secondary o2 sensor plugs – The secondary o2 sensor plugs have a gray wiring sleeve. Disconnect the o2 sensor plugs and release the wiring harness from the mounts.

14. Remove the downpipes – The downpipes are now free to be removed. Each downpipe is held onto the turbocharger by a v-band clamp. Locate the 13mm bolt on the clamp and remove it. Force open the clamp (may require some effort) which will release the downpipe from the turbocharger. Remove the downpipes.

[Mike@N54Tuning.com]

15. Remove the o2 sensors from the factory downpipes – THE O2 SENSORS ARE NOT INTERCHANGEABLE IN LOCATION. DO NOT MIX UP THE O2 SENSORS. TAKE ONE O2 SENSOR OUT AT A TIME AND INSTALL IT IN THE CORRESPONDING LOCATION ON THE NEW DOWNPIPE. The o2 sensors require a 22mm or 7/8” wrench of o2 sensor socket.

If you mix them up refer to diagram above and cross reference part numbers.

[Mike@N54Tuning.com]

1. Install the o2 sensors into the new downpipe – The primary o2 sensors have a black wiring harness sleeve. The secondary o2 sensors have a gray wiring sleeve. The secondary o2 sensors are color coordinated at the sensor plug (blue and yellow). Make sure you connect each secondary o2 sensor to the corresponding colored plug.

2. Install the new downpipes – Inspect the v-band flange gasket on the turbocharger. If it looks worn, they will need to be replaced. Install the left downpipe (longer pipe) first. Slide the downpipe into the turbocharger and attach the v-band clamp. Make sure the v-band clamp is securely over both flanges. If you have anti-seize, apply it to the v-band bolt. Close the clamp and screw the v-band bolt in until a few threads have engaged. DO NOT TIGHTEN THE CLAMP YET AS YOU STILL NEED TO ADJUST THE DOWNPIPE. Attach the downpipe bracket to the mount using the factory hardware. Make sure the washers are on both side before you slide the pin back into the mount. Screw in the 10mm nut but DO NOT TIGHTEN CLAMP. Install the right downpipe (short pipe). Repeat the process of installation. AGAIN, DO NOT TIGHTEN THE V-BAND BOLT ON THE DOWNPIPE YET. You will now notice that the longer downpipe does not have a studded flange. You will reuse the factory one. Slide the factory studded flange onto the longer downpipe. Mount the gasket spacer that was removed in REMOVAL #11 and then reinstall the donut gaskets. The gasket spacer will align the downpipes to the proper location. Now tighten the 13mm v-band clamp bolt and then the 10mm nut on the bracket.

3. Connect the secondary o2 sensor plugs and wiring harness – The secondary o2 sensor plugs are color coordinated. Make sure you connect the matching colors.

[Mike@N54Tuning.com]

Finally re-install everything in the engine bay and you are good to go. Great opportunity to install drop-in filters as the CF brace will be out and the airbox will be more accessible.

Mike

[///M.Tonee]

What is it that you are doing differently that requires the engine bay cover and the intake pipes to come off? I've seen alot of shops that does the DP install and they only work from under the car. Nothing is touched in the engine bay from the top.

Thanks for the write up.

[Mandi90TT]

Good writeup

[Hobbination]

O2 sensors I think is all that need to be unplugged. Feels like you don't need to though huh?

[Mike@N54Tuning.com]

Originally Posted by zero_z4

What is it that you are doing differently that requires the engine bay cover and the intake pipes to come off? I've seen alot of shops that does the DP install and they only work from under the car. Nothing is touched in the engine bay from the top.

Thanks for the write up.

Yes disconnecting the primary o2 sensors. Only way to get at them is through the top.

If you don't unclip them then you will be forced to unscrew them on the downpipes, which will torque and twist the cord. Not something thats recommended. By undoing them from the top you remove the downpipes completely from the car and then undo the o2 sensors on the bench.

You don't want to damage them as they are pricey

Mike

[M3Fanatics]

Can you please PM installation cost, Im local in the GTA.

[Mike@N54Tuning.com]

Originally Posted by M3Fanatics

Can you please PM installation cost, Im local in the GTA.

Cool nice to see another local M. Sent you a PM. We can get you up for sure.

Mike

[MKParris]

nm, I found my answer two threads down.

[DanielBimmer]

Is all this engine bay work necessary? I remember my f30 was done completely from the bottom of the car

[M-terkait]

Originally Posted by DanielBimmer

Is all this engine bay work necessary? I remember my f30 was done completely from the bottom of the car

the benefits of being Single turbo, easier to work on.

[DAJAN_M3]

Thanks

[fackamato]

Sorry for bumping.

This is a guide to install catless downpipes, correct? So the cats will be removed from the car?

I suppose coding is required after this as well?

Thanks

[psedog]

So, I pulled everything apart. I didn?t remove the exhaust. I just slid it back about an inch or so. I removed the gasket. I opened up the v band on the dump pipes. I pulled and pulled and pulled. No luck. One side of each V band didn?t move, but the other side moved completely off. Does the other side have to come as well? I couldn?t figure out if or how. It?s such a tight space.
I ended up giving up after around 4 hours. At least I was able to hook up my wastegate connections

[zhan28]

Currently changing my catless DP back to stock DP. I'm at the point where I'm taking off mid pipe from DP.

Unfortunately, broke off the head of the T30 bolt holding the MP and DP together. Anyone know what the part number is or what the dimension of that bolt is?