BMW X1 35i E84 Project Sleeper – This is Going to be Fun :)

Here’s where you’ll find the status of our 2013 BMW X1 35i E84 Project Sleeper

BMW brought the E84 to the US in 2012 and offered the X1 35i using the awesome N55 power-plant. While still keeping a 3.0L displacement and a posted 300hp, the N55 is very different from the N54. The biggest difference being that the N55 has a single, twin-scroll turbo vs. the true twin turbo N54. BMW termed the N55 a “twin-power” turbo but in reality it’s a single turbo with a twin-scroll compressor wheel. This single turbo setup makes it tougher to produce N54 type hp gains without a turbo upgrade. The good news is there’s a number of great turbo upgrades out there. There’s also a ton of bolt-on upgrades as well. See our top 10 list below.

So where’s our BMW X1 35i E84 project Sleeper X1 today you ask?

Our current build status as of 4/30/2023:

-Red Start/Stop Button – Installed
-Sunglasses Holder – Installed
-Alpina B3 Transmission TCU Flash – Installed
-Burger Tuning JB4 Tune – Installed
-Fuel-It Stage 2 LPFP (low pressure fuel pump) – Installed
-20mm Rear wheel spacers – Installed and they fit perfectly – Removed w/F80 Rims
-15mm Front wheel spacers – Cancelled due to F80 M3 wheels
-12mm Front wheel spacers – F80 rims needed some clearance from struts
-Pure Turbo Stage 1 – Installed and running great with 50K miles on it!
-GoFastBits Metal Diverter Valve Upgrade – Installed
-VRSF Chargepipe – Installed
-Active Autowerks 6″ FMIC – Installed
-3.5 Bar TMAP Sensor – Installed
-Burger Tuning Intake – Installed
-Colder range spark plugs with reduced gap – Installed BMW OEM M2 plugs
-Black Kidney Grills – Installed
-Stainless Steel Pedals – Installed
-Burger Tuning WMI (water/meth injection) – We have the kit but this will be a future install
-Remote actuated cut-out before muffler – Future install
-H&R Sport Springs – Installed and they look awesome
-BMW F80 M3 19″ Rims – Installed and Sweeet! – 255/35 ZR19 upfront and 295/30 ZR19 in the rear
-Floating Center Caps – Installed
– Window tint 20% rear and 35% front – Installed
-Larger Sway-Bars – Future Install
-Strut tower brace – Future Install
– Back-End DME Flash – Future Install and requires a bench flash that we will perform in-house (Update 1/20/20: MHD BEF Installed and happy with smooth power delivery)

We’ll keep this list updated as we go along. Keep checking back on our BMW X1 35i e84 sleeper project 🙂

Here’s Our Top 10 List of N55 Mods For Your BMW X1 35i E84 Project Sleeper:

1. ALPINA B3 FLASH – The transmission in the X1 35i is sluggish. It’s robust and stands up to significant power but let’s be honest; it’s a dog with the stock software. The good news, it’s easy to fix with the Alpina B3 TCU Flash. Check out our article about flashing the trans on our project car HERE.
2. TUNE – There’s a variety of tune options on the market for your X1 35i. Stay with the name brands on this one, no eBay tunes allowed. We recommend and install the JB4 from Burger Tuning. The JB4 is very flexible and can be paired with a back-end flash for safer, smoother power delivery. The addition of the Burger Connect kit makes logging and tune changes a snap. You can buy one here on Amazon. For reference, your X1 35i requires the harness type B and has a pneumatic wastegate.
3. DOWNPIPE – The next step in building real power with your N55 is a downpipe. They come in a variety of sizes and both catted and catless options are available. Catless versions are designed for vehicles used in off-road racing applications only.
4. INTAKE – There are more options for intakes than we can list. Some of our favorites include Burgers N55 Intake, The carbon fiber Dinan intake and even the simple drop-in K&N filter. We’ve put down some real power with the K&N filter.
5. CHARGEPIPE – The stock chargepipe on your N55 is weak where it connects to the throttle body. The joint can separate and cause a massive boost leak. Bad news at the race track. We recommend the VRSF chargepipe upgrade with a meth bung. In the event that you decide to run a meth setup in the future, these pipes give you the option.
6. FMIC – The stock Front Mount InterCooler on your BMW X1 35i is too small to handle all the awesome power you’re producing now. The N55 is notorious for heat-soak under load and sees a significant power drop as IAT’s start to rise. Your turbos pressurize the air headed into your engine and the result is increased intake air temps. Even a stock N55 will see improvements after extended pulls on the street or at the track. You have a lot of great choices here ranging from 5-7″ upgrades. Good news is your BMW X1 35i E84 Project Sleeper uses the same FMIC as the 335i/xi. We’ve used VRSF Intercoolers and love them.
7. Turbo – The factory turbo on the N55 is a Borg Warner B03 twinscroll. This turbo can make more HP with the above mods but starts to show its weakness in the upper RPM’s. Significant drop-off in boost can been seen on the dyno in the upper RPM range. That’s where a larger turbo comes in handy. Pure Turbos makes one of the best options for upgrade with their Stage 1. They offer a Stage 2 turbo upgrade as well but cost and labor increase considerably. Stage 1 holds much higher boost levels in the upper RPM’s and has shown up to 70 more horsepower up top. Dinan also makes a big turbo upgrade as well as RB Turbos. Unless you’re building a race-car or you want to go BIG, the Pure Stage 1 turbo is our recommendation.
8. LPFP – If you’ve already done any of the above mods we recommend upgrading your Low Pressure Fuel Pump. As your power increases, so does your engines demand for fuel. An upgraded LPFP can also increase your ability to run a higher mixture of E85. Most N55’s do well running mixes of E20-E40 but higher mixtures require upgraded LPFP’s. Dinan and Fuel-It make excellent options for upgraded LPFP’s. Side note: your EKPS may overheat. We recommend adding some heat sinks to prevent fuel pump malfunction lights and being stranded on the side of the road. FYI, after cool down your baby will restart 🙂
9. METH – Water/Methanol injection WMI is a common upgrade today in turbocharged and supercharged applications. Water/Meth injection helps lower the Intake Air Temps. This makes for more power. The Burger Tuning Meth kit with FSB controller makes it an easy choice for those who run a JB4.
10. SPARK PLUGS – If you’ve decided to do most of the above mods we recommend changing your spark plugs to the one step colder NGK 95770’s. You need to manually gap these to a narrow 0.022”. We’ve seen improved power and reduced misfire issues as you start increasing the power in your BMW X1 35i E84 Project Sleeper N55.

Now that you have your BMW X1 35i E84 Project Sleeper making some real power, let’s talk about cosmetic, brake and suspension upgrades. On the track, your car is only as fast as your brakes. Here’s a list of some of our favorite chassis upgrades.

Top 10 E84 X1 35i Chassis and Cosmetic Upgrades:

1. Stainless Steel Brake Lines – Whether you upgrade your brakes or stick with your factory setup, SS lines will improve pedal feel without costing you an arm and a leg. Your factory brake lines are made up of polymeric inner lining covered in thick rubber. As a result they expand under the extreme pressures found in your hydraulic brake system when under load. SS brake lines have a teflon inner lining covered in braided stainless steel. SS  Lines expand less and maintain a firmer pedal feel under heavy braking. You’ll notice more difference as you start pushing your awesome E84.
2. Performance Brake Pads and Rotors – Cross-drilled rotors help dissipate the heat during heavy braking and racing conditions. Once again, the great news here is that we have an abundance of options from multiple manufacturers to upgrade our brake pads & rotors. In most cases you can find excellent upgrade options for less than the BMW OEM ones. Stop-Tech makes some really nice pads and rotorsfor our X1 35i’s.
3. Swaybars – One of the most noticeable upgrades, with regards to improved turn-in that you can make to your cars suspension is a larger or stiffer set of swaybars. Depending on whether or not you have the Sport Package suspension, your E84 suspension may already be in a good place but you can always get improved turn-in with upgraded sway bars.
4. Lowering Springs – Springs can drop your vehicle along with its center of gravity. A lower center of gravity will improve your cars handling in the turns and make your vehicle  look more aggressive as well. We like the sport springs from H&R and Dinan but Dinan doesn’t list an application for the E84. The key to a good install is a proper alignment after installation.
5. Sport Shocks & Struts – There’s no doubt that upgraded struts and shocks will improve the handling of your BMW X1 35i E84 Project Sleeper. The biggest decision here is, which ones. You can choose from stock calibration all the way to race coil-overs. If your E84 struts and shocks are original, it’s time to have them checked and most likely upgraded anyway. Your decision here needs to be based on how you use your car and where you drive.
6. Strut Tower Brace – The chassis on the E84 is already pretty rigid and not known for a lot of chassis flex but a strut tower brace ties the two front strut towers together improving handling. Tons of options on the market for these. Prices range from as low as $150 to over $1,000 for pretty BMW M-Sport carbon fiber strut tower braces. Regardless of what you want to spend they all do the same job.
7. Rims – Where do we start? With so many manufacturers and styles this one comes down to budget and personal preference. Dinan makes some really beautiful options for your BMW X1 35i e84 project sleeper but we went with a set of F80 M3 19″ rims to really dress up our X1 35i.
8. Black Kidney Grills – This is a very simple mod but it can make a big statement when you black out your kidney grills. The look is considerably more aggressive and just adds a nice, sporty touch to you Bimmer.
9. Coilovers – We’ve decided to move over to coilovers from KW. The improved ride quality and height adjustability make coilovers the ultimate choice. We’re going with KW V1’s, check out the KW website for applications here.

These lists are just our opinion. Depending on your driving style, goals etc., we may recommend other upgrades. In some cases we may recommend a different order but overall these are our favorite BMW X1 35i E84 Project Sleeper upgrades.

Check out some of our other blog posts about our BMW X1 35i e84 project spleeper:
JB4 Install
20mm Wheel Spcaers

Thanks for visiting our BMW X1 35i e84 project sleeper blog by DIY Auto Galaxy

BMW X1 35i E84 Project Sleeper with F80 M3 Wheels