I tried MMP Stage 3 twin turbos, but never felt the “wow” factor I was hoping for. After worrying about wastegate rattle and smoking turbos for too long, I decided it was finally time to go big or go home. Meet the Doc Race 135i/335i N54 single turbo kit!
Once I decided to convert my N54 from twin turbos to a single turbo, I spent countless hours researching what kit I should go with, which parts needed to be replaced, what upgrades needed to be done, etc.
To save you that same hassle, I will share all the information you need to know below. With this complete list, I was able to safely make 749whp on the stock motor in my BMW 135i. Even if you’re not after a ton of horsepower, this is a great kit to go with when getting rid of the stock turbos.
If you want to read about my journey converting my N54 to single turbo, check out my previous post. Otherwise, all of the information and products are linked below.
DOC RACE N54 SINGLE TURBO KIT
In my opinion, this is the best single turbo kit on my market. I would suggest opting for the ball-bearing turbo like I did. However, if budget is a concern, you can save $1000 by going with the journal bearing 6266 turbo kit. If you have AWD, you will need the X-Drive specific kit instead.
The fitment is perfect. This kit includes much more than others. The parts are top-notch quality. The serviceable areas (O2 sensors, wastegates, etc.) are easy to access. Their customer service is amazing. I could go on…
You can click each item below for a direct link to the product.
ABSOLUTELY NECESSARY ADDITIONAL PARTS:
- Coolant Pipe Gasket
- Mac Solenoid
- Exhaust Heat Wrap – wrap downpipe AND manifold!
- Heat-Reflective Tape – use on valve cover & A/C line!
- Heat Sheath – use on oil feed line and vacuum lines
- BMW Coolant
- Motul X-cess 5W-40 Oil – 5L
- Motul X-cess 5W-40 Oil – 1L (2)
- Mann Oil Filter
- JB4 Tuner
- Download the free single turbo firmware
- MHD Flashing Cable
- OTG USB Adapter
MY UPGRADES FOR HIGH HORSEPOWER:
- XClutch 9″ Ceramic Twin Disc Clutch (for 700+whp)
- SPEC Stage 3+ Clutch and Single-Mass Flywheel (for 500-650whp)
- BMW 335is Clutch Kit (for 400-500whp)
- VRSF 7.5″ Race Intercooler
- BMS Charge Pipe & TiAL BOV
- Precision Raceworks Ignition Kit
- NGK spark plugs gapped @ 0.020″
- Precision Raceworks Stage 3 LPFP
- Black Market Parts Port Injection Kit
- JB4 Port Injection Controller
- BMS Oil Catch Can
- BMS Upgraded PCV
- 3.5 Bar TMAP Sensor
- 3.5 Bar TMAP Sensor adapter harness
- Poly Transmission Mounts
- BMR 3.5″ Exhaust (if you have 135i)
- Corsa 3.5″ Exhaust (if you have 335i)
- Doc Race Intake Manifold
- MFactory 3.08 LSD
- DSS 1000HP axles
- Burger Motorsports differential brace
PARTS TO REPLACE WHILE YOU’RE IN THERE:
- NGK Spark Plugs (6) – if yours are older than 15k miles
- Ignition Coils (6) – if yours are older than 30k miles
- Front O2 Sensor (cyl 1-3)
- Front O2 Sensor (cyl 4-6)
- Rear O2 Sensors (2)
- Index 12 Injector Kit
- Valve Cover Kit
- Water Pump Kit
- Oil Pan Gasket
- Oil Pan Bolts
- Oil Filter Housing Gasket
- Oil Cooler Gasket
- Pair of Motor Mounts
- Flywheel Bolts (8)
- Transmission Bellhousing Bolt Kit
- Serpentine Belt
- Tensioner/Idler Pulley
- Vacuum Lines
- Magnetic Drain Plug
TOOLS THAT MAKE THE JOB EASIER:
- Engine Brace
- O2 Sensor Removal Socket
- Magnetic BMW Spark Plug Socket
- BMW Jack Pad Adapter
- Spark Plug Feeler Gauge
- QuickJack System
- Torque Wrench
- Magnetic Work Light
- Cordless Screwdriver
- Pair of Jack Stands
- Low Profile Jack
After putting a couple thousand miles on the exact setup above, I couldn’t be happier with my decision. The car makes great power and has been very reliable for me because of a diligent installation with proper parts. Cheers to another couple thousand miles!
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