I installed the Doc Race single turbo kit and wanted to document the process as reference.
The doc race box came in and I could wait to open it up! The kit showed up pretty quickly about one (1) week after ordering it. It came in 2 separate orders, a box from Precision (Turbo) and a large box from Docrace (everything else).
There were smaller boxes within the larger box.
The turbo kit was packaged well and looked very high quality.
The hot parts of the kit came ceramic coated from Docrace and includes almost everything (Hardware, o-rings, and Manifold install studs) to convert to single turbo!
Everything fit perfectly (almost), there was a few modifications needed such as turbo studs, placing washers on the engine mount to help with turbo clearance, etc..
Wrap Hot Parts!
Remove Turbos and Water Pump
Remove the lines attached to the engine block
Worked on the project over several weekends with Keith Morrill and Jamie Hepp so I didn’t document everything but I will attempt to highlight the most important parts. There is also and video summarizing the install at the bottom of this page.
- Wrap the downpipe AND manifold in exhaust heat wrap!
- Use heat sheath on the oil feed line and vacuum lines and anything that can be exposed to heat under the hood.
- Clock the turbo so that the oil feed line is at the top center of the cartridge.
- Wastegate springs… install them accordingly. I installed the single black spring (8.7psi) in each and I’m getting 11.6 psi at wastegate pressure. Apparently this kit is known to overboost by ~2psi and TiAL underrates their springs.
- Make sure the vacuum lines are not binding, rubbing or pinched. Check them twice, I even heat wrapped them for protection.
- Install the Mac Solenoid into the OEM boost solenoid plug. Install the one of the old OEM boost solenoid and leave it plugged in for good measure.
- Load the JB4 with the correct firmware and Backend flash at N54tech.com.
Wrap Manifold with heat shielding
Install studs then install the Manifold on to the head with the nuts
Look at the beautiful Turbo in amazement
Install O2 Sensors with heat shielding
Install Turbo and make sure you clock it towards the intercooler piping!
This was the first time I tried to turn over this used motor and see if the single turbo kit worked…
REJOICE! The long nights paid off.
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 TunerDownload the free single turbo firmware
- MHD Flashing CableDownload MHD mobile app (requires Android and iOS)Use the free JB4/MHD Backend Flashes
- OTG USB Adapter
- BMW 335is Clutch Kit (for 400-500whp)
- CSF 5″ Step Race Intercooler
- Charge Pipe & HKS BOV
- Stock Ignition Coils Kit
- NGK spark plugs gapped @ 0.020″
- Custom Stage 2 LPFP ( Walbro 450 in stock bucket)
- 3.5 Bar TMAP Sensor
- 3.5 Bar TMAP Sensor adapter harness
- Vibrant 1197 EGT Sensor Bung
- Adapter Fitting Tee 3 Way 1/8″ NPT to 4AN w/Plug Block Oil Feed Pressure Sensor
- Custom Exhaust 2.5″ (Magnaflow Mufflers) – MagnaFlow 11236 Exhaust Muffler
- Magnaflow 10791 Tru – X Pipe Exhaust Stainless Steel 2.5″
PARTS TO REPLACE WHILE YOU’RE IN THERE:
- Front O2 Sensor (cyl 1-3)
- Front O2 Sensor (cyl 4-6)
- Valve Cover Kit
- Water Pump Kit
- Oil Filter Housing Gasket
- Serpentine Belt
TOOLS THAT MAKE THE JOB EASIER:
- Engine Support Brace
- O2 Sensor Removal Socket
- BMW Spark Plug Socket
- BMW Jack Pad Adapter
- Spark Plug Feeler Gauge
- QuickJack System
- Torque Wrench
- Work Light
- Cordless Screwdriver
- Cordless Electric Ratchet Wrench, 3/8″ 40 Ft-lbs
- Jack Stands
- Aluminum Floor Jack
- Low Profile Jack
ACCESSORIES FOR THE CAR:
- BMW Sunshade for E90/E91 3 Series
The car is a blast to drive and sounds amazing.
I’m frequently changing my oil (every 2-3k miles) for peace of mind. Always keep an eye on things. Check everything for melting or damage. I love this car and glad I completed this build!
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