Give Your N54 BMW 135i or 335i 500HP For Under $1,500

n54 tuning upgrades 335i downpipes intercooler

ARM 5" FMIC $297
ARM 7" FMIC $387
ARM N54 Downpipes: $237
ARM N54 AWD Downpipes $267
N54 Charge Pipe: ARM $107
N54 Intake: ARM DCI $67
BOV: TiAL $279
N54 Tune: JB4 $479

NOTE: To get the multi-item discount prices listed above for ARM Downpipes, Charge Pipe, and Intake, please select these additional items from the drop down menu on the FMIC Product Page.

To see how we built a 500hp 11-second 335xi using this exact guide CLICK HERE!

The BMW N54 is bursting with opportunity and changing the tuning scene due to its easy horsepower and now inexpensive price tag. Starting back in 2007, the N54 engine first hit the scene in the BMW 335i. It then made its way to the 135i in 2008 and a slew of other models all the way through 2010.

Out of the box, the 335i comes with a 300hp engine which produces an equal 300ft/lbs of torque. But we’re here for REAL power! So how do we get it?


It all begins with a tune. A tune will absolutely transform your N54 and increase power by almost 100hp! Not a bad start, right? There are many tuning options out there for the N54 platform, but there are a few that stand head and shoulders above the rest.

The N54 tune that deserves prime recognition is Burger Motorsports’ JB4. This piggyback tune flipped the N54 tuning game on its head. Before it came about, only expensive flash tunes were available. There are many features that make this a great tuning option, among which is the unique ability to change tuning maps on the fly with your steering wheel controls!

BMW 335 N54 JB4

COBB Tuning also released a flash tuner, the AccessPort. It comes with a well-designed programmer that hooks up to your OBD port. With this unit, you can change the tuning program on your N54 to one of their off-the-shelf maps or a custom map.

COBB BMW N54 Accessport

Another tuning option that has been becoming increasingly popular is the MHD Flasher tune. This is available as a download on Google Play. The MHD Flasher allows you to buy tunes for your N54 right off the mobile app and upload it to your ECU via OBD connection. An excellent option if you don’t want the hassle of rearranging your DME wires under the hood.

BMW N54 MHD Flasher
Most importantly, regardless of which tuning platform you go with, you will want to make sure you have access to a map that allows you to run E85. It may come as a surprise to some, but an N54 can pick up anywhere from 30-50hp from adding this eco-friendly alternative to the tank. Of course, you can use any of these Stage 1 tunes as is on a stock car, but if you want to go Stage 2 and beyond you'll need to get…


Downpipes for your N54 are the next biggest bang for your buck. Why? It’s simple: if it weren’t for the restrictive OEM N54 downpipes, you would be able to increase boost on a Stage 2 tune and make more power. But the OEM downpipes are so restrictive that they prevent this simple increase in boost from being a safe option.

BMW N54 135 335 DownpipesBy replacing your OEM N54 downpipes with catless or high-flow catted downpipes, you allow more flow through your exhaust system, and now you can increase the boost! Expect gains of approximately 50HP when upgrading the downpipes and flicking the switch to Stage 2 tuning.
The difference in power gains from a catless downpipe compared to a high flow catted downpipe are only a few horsepower. If you want the absolute maximum power available, go with catless.

In addition to prepping your BMW for increased boost, upgrading your downpipes will also improve your turbo spool times. Being able to move more air, the turbos on your N54 can now hit target boost sooner.

Don’t forget about the sound! Yes, it will get louder. While many think that you need to change the catback section on your car to change the sound, upgrading your downpipes will also make a big change in the acoustics. Be prepared for awesome noises! But if you want more awesome noises, get an…


There are many intake options out there, all with different designs, but by far the most popular and effective is the DCI (dual cone intake). Why?

Power. Its simple design allows for maximum horsepower gains. Expect around 20HP.BMW N54 DCI 335 Intake

Installation is a breeze. Installing a DCI system only takes a conservative 45 minutes.

Cost. The N54 DCI system is by far the least expensive, as it only includes 2 cone filters, 2 aluminum pipes, and clamps.

Fitment. The N54 DCI seems to be most compatible with the many different charge pipes available for the N54 platform. Some other intake designs are not compatible with certain charge pipe designs.

Other intake styles occupy different parts of the engine bay and can interfere with other upgrades by different companies. With a DCI system, you can be sure you have the most compatible design for a harmonious relationship with the other upgrades in your engine bay.

When turning up the boost on your N54, you’re going to want an intercooler. More boost equals more heat. You want to keep your IAT’s (intake air temperature) as low as possible. In general, the cooler the air entering your engine, the more power you will make.

BMW 135 335 FMICA larger intercooler allows for more cooling, hence more power. We won’t go into all the details about the physics behind it here, but just know that bigger isn’t always better when it comes to cooling. The best is a balance between being large enough to effectively cool the charged air, but not so large that there is a significant pressure loss.

We have selected the size of our intercooler cores to match the needs of the N54 depending on what your needs are. We’ve broken it down into 2 categories, A and B.

Category A: Everything from a stock 135 or 335 to a full bolt on car with stock turbos.
Category B: Full bolt on car running E85 blend/race fuel all the way to single turbo kits.

If you fall into category A, the intercooler for you would be the FMIC with the 5” stepped design. It provides a significant reduction in IAT's without the pressure loss of a larger intercooler. If Category B sounds more like you, then check out the 7” FMIC, which is equipped with the cooling efficiency to handle the most demanding setups.

No matter which design you choose, expect installation to be fast and easy. The entire installation takes only about 30 min. Not bad for gains of 25HP! With all this extra power, you’ll need a…

As always, when you crank up the power on a car things start to break. One of the most common things to break on tuned N54’s is the OEM charge pipe. It’s plastic, it’s old, it’s not BMW N54 Charge Pipedesigned for 20psi! Upgrading your charge pipe not only prevents a random halt to your fun, but ours has 2 NPT bungs allowing the use of methanol injection and/or nitrous.

In addition, it uses an upgraded BOV (sold separately). This is a critical factor many overlook because spending the extra money to upgrade your BOV doesn’t sound too attractive. However, the N54’s OEM diverter valves were never designed to hold the boost levels of stage 2 tuning and will let all the extra power you've worked hard for escape.

Investing in an N54 charge pipe with an upgraded BOV is not only recommended, it is the only way to ensure you are locking in all of the additional boost you have programmed the turbos to produce.

Equip your 135 or 335 with these upgrades and you can expect to be clipping the quarter mile in the low 12 to high 11 second range depending on your other upgrades and driving skills. Not too shabby for an investment of around $1,500! And all in the lap of German luxury.

To see how we built a 500hp 11-second 335xi using this exact guide CLICK HERE!

For additional information about upgrading your N54 car, email us at