My Experience Installing MMP Stage 3 Turbos

suspenceful

700 HP Club (N54)
Aug 1, 2017
542
551
0
Ride
2015 M3, 2008 135i, 2009 335i
UPDATE: I ran the turbos hard at 28-30psi for about 500 miles and then my motor gave up. Dropped compression on cylinder #3. After removing the motor and turbos, I decided to switch my setup for various reasons. Watch this video I put together for the full scoop.


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On a constant quest for more power, I found myself looking to upgrade from my stock turbos. As you all know, there are a few different options available and even some single turbo conversion kits. After doing some research, I was set on a pair of MMP Stage 3 turbos. They offer 700whp capability with OEM fitment and come at a great price - everything I was looking for. While MMP has had some hiccups, I know Mauricio has great customer service so I didn't hesitate and pulled the trigger.

I opted for fully-optioned MMP Stage 3 turbos which included a 2 year turbo warranty with the bearing treatment. These turbos require larger inlets and outlets, so I opted for MMP's silicone outlets and aluminum relocation inlets since I already relocated things for aftermarket inlets on my stock turbos. I also ordered the turbo install kit because I wanted fresh o-rings, gaskets, etc.

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After reading some DIY N54 turbo install guides, I decided to tackle the job in my garage on jack stands. This would be one of the most involved projects I've ever attempted on my own, but I knew it was possible.

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If you don't want to read this whole article about my installation experience, you can scroll to the end to see a finished photo and a few videos. I have driven over 500 miles on these turbos already and they're great! I recently installed an upgraded fuel system and these turbos pull very hard at 28PSI without a problem. I would definitely recommend MMP Stage 3 turbos to anyone who wants more power out of their N54.
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Since I planned on dropping the front subframe, I wanted to replace some things while I was in there and had easy access. Here is a list of parts I bought for my 6-speed 2008 BMW 135i:
Since I am chasing 700whp, I decided to upgrade my clutch and fuel system at the same time (not required when just replacing turbos).
Preventative maintenance:
None of these are required except for the motor oil and coolant because they will be drained while removing the turbos. I simply replaced all of the above parts as preventative maintenance. My oil pan gasket and oil filter housing gaskets were slowly leaking and my passenger-side motor mount was torn.

NOTE: Some people also recommend replacing the 8 turbo oil feed/drain and water feed/return lines, but I reused my existing lines (with new gaskets/o-rings of course). Some people also replace the turbo manifold studs and nuts, but I left the studs in and reused the nuts.

Now that we've gathered all of our parts, let's get to business! I put the car in the air and took off the front bumper for easy access.

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Undertrays removed, time to get this subframe out!

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I don't have the most tools in the world, but I managed to get the subframe and steering rack out in about 4 hours. I used an engine support brace from Harbor Freight to hold up the engine before dropping the subframe.

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2 hours later I had the downpipes, intercooler, inlets, outlets, fan, engine mount, water pump, thermostat, and coolant pipe out of the car. Don't forget to drain the oil and coolant before getting too far.

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In the process I discovered what coolant tasted like and was covered in grime, but knew I was making good progress. Next, I disconnected the oil and coolant lines from the block, then removed the stock turbos. Unbolting the manifolds was the easy part. Removing the coolant and oil lines from the block was more difficult than I expected. It was a painful, tedious process because I needed to reuse the lines. Be careful with these lines if you plan on reusing them!

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Look at all of that room! Now that the stock turbos were out, I had to compare them to my new MMP Stage 3 turbos.

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Next, I removed the power steering pump so I could remove the oil pan to replace that gasket. Once the oil pan was out, I cleaned and reinstalled it with a new gasket, bolts, and oil level sensor o-ring. Be sure to follow the proper bolt torquing procedure if you're replacing the oil pan gasket.

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The subframe was filthy from the oil pan gasket leak, so I cleaned it.

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After this, I wanted to mockup the turbos with the MMP inlets and outlets attached to get a better idea of fitment.

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Then I began to swap all the oil and coolant lines over to the MMP turbos but ran into a bit of an issue.As Mauricio notes in the installation instructions, you must use the included small washers on the bolts when reattaching the oil feed and coolant lines to the turbos. If you don't, you will bottom out the bolt and pull the welds off that hold the mount on. Ask me how I know - whoops! This was my own fault.

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Luckily I had a friend who welded the stainless mount back to the cast cartridge housing.

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Make sure all of your oil and coolant lines are in good condition and free of debris. Clean them up and blow compressed air through them before reinstalling. I found it was easier to mount the two coolant return lines to the block first and then secure the rest of the lines to the turbos on the bench. Replace all of the o-rings and gaskets on these lines carefully. Remember, use small washers and do not over torque the bolts during reassembly.

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I got back underneath the car and cleaned up the mounting surfaces, then installed both turbos with new manifold gaskets. Rear turbo goes on first. It's easiest to reinstall the heat shields while the turbos are loose. Reconnect the coolant return lines to the turbos once they're mounted and then torque everything down.

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Next, I wrapped the inlets and outlets with heat-resistant tape just for added reassurance. Since I already relocated things for aftermarket inlets on my stock turbos, I didn't have to do anything special this time around. I did remove the bracket for the OEM rear inlet from the block at this time because I had the space.

I installed the outlets first. Make sure the couplers are properly seated and the clamps are tight. Then I installed the inlets, but had to remove the upper OEM heat shield and boost solenoids.

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I could see the light at the end of the tunnel and was determined to get the car back on the ground. I set the camera down and did the following:
  • Reattached power steering pump to oil pan
  • Reinstalled coolant pipe, water pump, thermostat with new hoses
  • Reinstalled intercooler
  • Reinstalled downpipes with new v-band clamps
  • Connected the O2 sensors
  • Attached new motor mounts
  • Finally reinstalled the subframe!
  • Reinstalled power steering rack and refilled power steering fluid
  • Mounted boost solenoids (required heat shield modification)
  • Connected all vacuum lines
  • Replaced the oil filter housing gaskets
  • Double checked that everything was connected and tightened
  • Added oil, oil filter, and coolant, then bled the coolant system
  • Unplugged the injectors and cranked the car to prime the turbos
  • Started the car!

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I was able to put on about 200 miles over weekend without a single issue! It was a great feeling being able to start the car and drive it without any problems.

These things are loud (in a good way)! I didn't reattach the exhaust to the car yet, so it's just dumping from the downpipes.


After putting a couple hundred miles on the turbos, I decided to see what they felt like targeting 20PSI to redline.


After this pull, I ordered a Stage 3+ LPFP and port injection from Precision Raceworks so I can raise the boost (read my post about installing those parts here). Stay tuned for updates!

Overall, I'm very impressed with the quality, fit, and performance of these turbos for the price! I would definitely recommend them if you're looking to upgrade your N54 turbos. Quick spool, OEM fitment, higher boost ceiling, and no wastegate rattle!

UPDATE: Check out my post where I installed the upgraded fuel system and turned up the boost!
 
Last edited:

tholte1

New Member
Aug 1, 2017
4
2
0
Ride
335i
my stock twins have been rattling like crazy. Considering going this route. Installation it only thing scaring me
 

Hokie_335i

Specialist
Jul 29, 2017
51
24
0
North Carolina
Ride
2009 E90 335i 6MT
Very detailed write up! I'm also looking to jump into the 650-700whp category and am debating between MMP vs. Motiv. Interested to see how these do for you when you crank it up.
 

suspenceful

700 HP Club (N54)
Aug 1, 2017
542
551
0
Ride
2015 M3, 2008 135i, 2009 335i
This is an awesome write up

my stock twins have been rattling like crazy. Considering going this route. Installation it only thing scaring me

Very detailed write up! I'm also looking to jump into the 650-700whp category and am debating between MMP vs. Motiv. Interested to see how these do for you when you crank it up.

Thanks guys!

Installation was fairly straight forward, just time consuming. Definitely not for the faint of heart, but do-able.

So far the MMPs are pulling strong at 28psi with 600 miles on them. I'll update this thread and my website (www.my1series.com) with any changes. If anyone is on the fence about them, PM me. I have a promo code that can save you a little $$$.
 

Twinnin

New Member
Aug 1, 2017
5
0
0
Upstate NY
Ride
09 335i
EPIC man, I plan to install mine this winter along with inlets, outlets etc. I've done all the maintenance and prepped her. She is mainly ready :)
 

suspenceful

700 HP Club (N54)
Aug 1, 2017
542
551
0
Ride
2015 M3, 2008 135i, 2009 335i
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devildog0905

Specialist
Jan 21, 2018
78
29
0
Ride
2007 BMW 335i E92
Thanks guys!

Installation was fairly straight forward, just time consuming. Definitely not for the faint of heart, but do-able.

So far the MMPs are pulling strong at 28psi with 600 miles on them. I'll update this thread and my website (www.my1series.com) with any changes. If anyone is on the fence about them, PM me. I have a promo code that can save you a little $$$.

Hey. awesome write up. I really appreciate it. I am looking to do upgraded twins soon and this made me excited. how long did this take you? you said time consuming, but i want to get an idea of how long my car will be down. Did you need a second person for anything? Any specialty tools needed? again, thanks for the pictures and info! also, did you get a custom tune yet? who did it?
 

suspenceful

700 HP Club (N54)
Aug 1, 2017
542
551
0
Ride
2015 M3, 2008 135i, 2009 335i
Hey man great post. Any updates? Mileage on the turbos? Thanks for any info. I’m installing mine this weekend.

You're probably not going to like this, but watch this vlog I made last night.

TDLR; ran the turbos hard at 28-30psi for about 500 miles and then my motor gave up. Dropped compression on cylinder #3. After removing the motor and turbos, I decided to switch my setup for various reasons.


Hey. awesome write up. I really appreciate it. I am looking to do upgraded twins soon and this made me excited. how long did this take you? you said time consuming, but i want to get an idea of how long my car will be down. Did you need a second person for anything? Any specialty tools needed? again, thanks for the pictures and info! also, did you get a custom tune yet? who did it?

It took me about a full 40hr work week, maybe more. I wasn't particularly keeping track and wasn't moving very fast because I was doing this all in my spare time for fun. I have a stock 335i that I drive every day.

I had a friend or two help me with a few things throughout the process. I had pretty much all the tools I needed, you should have a good idea of what to expect based on the info and pictures I posted. I went with a BMS Hybrid E85 PI backend flash, but will get a custom tune with the new setup.

very nice and great that you got pictures along the way.

Thanks!
 

luchocamp

Corporal
Dec 9, 2017
147
80
25
Ride
f30 335ix / e90 335xi
great .... I will try to do the same next April with my 2010 BMW 335xi