BMW N55 Turbo Upgrade Options & Setup Guide

The BMW N55 engine represented a big step forward in terms of BMW’s turbocharged engine formula. The N54 inline-6 that preceded the N55 in 35i model BMWs became both an icon and a black sheep due to its power potential and subsequent unreliability. The N55 resolved most of the major issues with the N54, but it is often considered the less capable engine of the two.

A major limiting factor of the N55 is its factory twin-scroll turbocharger. While more efficient overall, it is impossible to squeeze anywhere near the amount of power out of the N55’s single twin-scroll as you can with the N54’s twin monoscroll turbos. That is where BMW N55 turbo upgrades enter the picture. 

N55 Engine Modification & Tuning Course

From tuning to bolt-on mods to turbo upgrades and everything in between. Learn how to build a 600whp+ N55.

Module 1: General: Power Limits, Maintenance, Setups by Goal
Module 2: Tuning & Bolt-On Mods
Module 3: Fueling Upgrades
Module 4: Turbocharger Upgrades
Module 5: Supporting Mods & Other Upgrades

Take Our Course Now

N55 Engine Modification & Tuning Course

From tuning to bolt-on mods to turbo upgrades and everything in between. Learn how to build a 600whp+ N55.

Module 1: General Information: Power Limits, Maintenance, Setups by Goal
Module 2: Tuning & Bolt-On Mods
Module 3: Fueling Upgrades
Module 4: Turbocharger Upgrades
Module 5: Supporting Mods & Other Upgrades

Take Our Course Now

Outside of the N55’s factory turbocharger, the N55 is an extremely solid engine that is capable of far more than its factory power and torque output. As a result, it is an engine ripe for upgraded turbo shenanigans. In this guide, we’ll cover everything that you need to know about BMW N55 turbo upgrade options including supporting modifications, various turbocharger stages, and turbo recommendations. 

If you are interested in learning more about how far you can push the N55 before needing a turbocharger upgrade, take a look at our BMW N55 Stock Turbo Max Boost article which covers that topic in detail.

N55 Turbo Upgrade Options: What Stage Should I Get?

Before jumping into the nitty gritty regarding supporting modifications and turbo recommendations, it is important to first understand that not all N55 turbo upgrades are created equal. In fact, the additional power that you can gain from an upgraded N55 turbo can range between 30 horsepower and 300 horsepower depending on the turbo that you opt to run. 

In general, N55 turbo upgrades are rated on a “Stage” scale. It is just a simple way of categorizing the potential of upgraded turbos into rough ballpark classes. Upgraded N55 turbos fall into a few different stages, with modest N55 turbo upgrades falling into the “Stage 1” class, more capable and in-depth N55 turbo upgrades falling into the “Stage 2” class, and extremely capable turbos failing under the “Stage 3” class. Outside of the main three stages, some manufacturers offer turbos that bridge the gap between stages i.e. Stage 2.5. Here is a rough breakdown of what you can expect from each N55 upgraded turbo stage: 

• Stage 1 Turbocharger Gains: 40-70 horsepower 
• Stage 2 Turbocharger Gains: 50-150 horsepower
• Stage 3 Turbocharger Gains: 150-250+ horsepower

I’m sure those stage 3 power gains are looking pretty enticing, but it is important to also know that the further you push the N55, the more supporting modifications are going to be required. While we’ll cover supporting modifications in detail in the following section, just know that stage 2 and stage 3 N55 turbo upgrades require quite a bit more support from additional modifications.

BMW N55 Turbo Upgrade Supporting Mods

It shouldn’t be a surprise that if you are planning on adding an excess of additional power to an engine via a turbo upgrade, you’re gonna need to beef up some surrounding components as well. As a general rule of thumb, full bolt-ons should all be done before an N55 turbo upgrade even enters the picture. That is especially true if you were already pushing your factory N55 turbo beyond its factory boost level. 

So, what does a full bolt-on BMW N55 engine look like? Here is everything that is a must-have for upgrading turbos (excluding anything that will come in the turbo kit):

• 1-step colder spark plugs: anyone running anything above stock boost should use these
• New N55 ignition coils
• Upgraded Intake: we recommend BMS
• Upgraded Intercooler: we recommend E-Series VRSF 7.5″ or F-Series VRSF 6.5″
• Catless downpipes: you can use hi-flow catted downpipes, but c’mon
• Tune: we recommend the JB4 or BM3
• Upgraded chargepipe: literally anything is better than stock

The most important BMW N55 modifications before even thinking about a turbocharger upgrade are unquestionably a quality downpipe and tune. When it comes to power mods outside of an upgraded N55 turbo, a downpipe/tune combo will not only yield the most power, but also set you up for a turbo upgrade. 

An N55 catless or high-flow downpipe ensures that the turbo faces as little backpressure as possible, leading to optimal performance. For such an inexpensive modification, an upgraded N55 downpipe is essential for an upgraded turbo build. The same goes for a quality tune. There are both piggyback and flash tuning options available for the N55 and the decision on which tune to run is entirely personal preference. We won’t cover the intricacies of N55 tuning here, but we have written dedicated N55 tuning guides about both BM3 and MHD N55 flash tune options if you want to learn more. 

Outside of those two modifications, other important N55 bolt-ons include an upgraded intake for increased airflow and lower IATs, an upgraded intercooler to prevent heat soak during hard driving, and an upgraded chargepipe as the factory N55 CP is known to crack under increased boost. Depending on how far you’re trying to go with your N55 turbo upgrade, you’ll likely need additional modifications as well. We’ll cover those in each “ Stage” section.

BMW N55 Stage 1 Turbo Upgrade

The N55 turbo stage 1 setup is essentially a slightly modified stock turbo. The turbo itself is the same size and uses the same housing as the stock turbo but the actual turbine/compressor wheel inside the turbo is made larger.

The larger wheel allows the engine to hold the boost until approx. 6500rpms, compared to the stock turbo which has pretty significant power drops after 5500pm.

Overall, a stage 1 upgrade is a great option if you blow your stock turbo and want a slight upgrade without any added headache (tuning, part upgrades, etc.). Since the turbo is a stock turbo, with the exception of the larger wheel, the dealership won’t be able to tell it is upgraded, so you can get away without voiding warranty.

If you are a more serious tuner and looking to break the 400whp mark by a good margin, stage 2 is likely the best option for you. Of course, that all depends on your power goals. If you are content with spending around $2,000-$2,500 for parts and installation for a 400-450whp end goal, a stage 1 turbo is a perfect option. 

Expected Horsepower: 400-425whp with reliability and consistency

Additional Mods Needed: None! (other than what comes with the install kit)

Price: $1,000 turbo + $200 install kit + install labor (approx. 4 hours of labor)

N55 Stage 1 Upgrade Options

Until we reach stage 3 territory, you’ll notice a pretty common theme in terms of our turbocharger recommendations. Generally speaking, there are two major manufacturer options that have dominated the stage 1 and stage 2 turbocharger space for quite a while. That goes for the N55 and a number of other modern turbocharged engines as well. 

Pure and Vargas are by far the most popular manufacturers of upgraded N55 stage 1 turbos and both of them have extensive support and praise from the community. While neither is a bad option, Pure typically takes the cake in terms of power potential, build quality, and customer support.

Pure500 Stage 1 N55 Turbo

Price: $1,095

Purchase Here: pureturbos.com

There’s no question that the Pure500 Stage 1 turbo is the most popular stage 1 N55 turbo upgrade option by a long shot. Pure has been in the upgraded BMW turbo game for quite a few years at this point and have unquestionably earned their stellar reputation. 

Like most other stage 1 options, the Pure500 uses a new factory N55 turbochager compressor housing, giving it a nearly identical appearance to the factory twin-scroll turbo. That is good news for those who are looking for additional power but don’t want to be prodded by the dealership. 

While the housing itself is the same as the OEM N55 twin-scroll, the internals of the turbo are notably larger and higher quality. While Pure doesn’t release their turbo specs, they do say that the Pure500 has a larger billet compressor wheel than both the stock turbo and their original N55 stage 1 turbo upgrade.

Vargas Stage 1

Price: $1,109.99 – $1,329.99

Purchase Here: vargasturbo.com

When it comes to stage 1 N55 turbochargers, Vargas is the other primary option in addition to Pure. While Vargas isn’t quite as popular as the Pure500 kit, their stage 1 kit is equally as capable, if not slightly more capable, than the Pure500 kit.

As with the Pure500 kit, the Vargas N55 stage 1 kit utilizes the OEM compressor housing while swapping out the internals for higher-performance applications. The Vargas turbo contains a VTT custom reverse billet compressor wheel and brand new stock turbine that is capable of supporting between 40-75whp more than the factory turbocharger.

BMW N55 Stage 2 Turbo Upgrade

Stage 2 options are where the serious tuners should start. Stage 2 turbos include upgraded compressor and turbine wheels, as well as a machined/bored-out center section to allow for larger wheels. Like stage 1, stage 2 options are also direct bolt-on to the factory setup and therefore mostly undetectable by dealerships – although the rest of your mods probably won’t be!

Stage 2 systems will put you in the 450-550whp ballpark. Engine reliability obviously decreases as you push the upper range of the setup, but is also highly dependent on your tune and other factors. We will cover reliability in more depth a bit further down!

Stage 2 is the best option for N55 owners who are serious about tuning, want more than 425whp, and are willing to spend a pretty penny. If you are in between stage 2 and 3 as you read this, I will preface stage 3 by saying that it will likely require upgraded engine internals which means a pretty dramatic increase in cost.

Expected Horsepower: 450-550whp depending on tune and supporting mods

Additional Mods for Stage 2 Upgrade

While stage 2 N55 turbo upgrades can still be called plug-and-play options, especially when compared to stage 3  turbo upgrades, they do require an additional bit of work to run properly and safely. At the stage 2 point, fueling becomes a primary consideration if you want to get the most out of your upgraded turbocharger. There are a number of significant limitations when it comes to the factory N55 fuel system, especially when using alternate fueling like an ethanol blend.

Inlets and Outlets

These are required depending on the manufacturer and some kits may include them. While upgraded inlets and outlets are still beneficial to N55 owners retaining their stock turbocharger, they really shine when pushing big boost figures with an upgraded N55 turbo. The purpose of upgraded inlets and outlets is pretty simple; they are designed to make the turbo work more efficiently and with less effort due to increased intake and exhaust flow from the turbocharger itself. Upgraded inlets and outlets not only help increase the effective lifespan of a turbo but also improve throttle response and decrease turbo spool time.

Fuel Supply Upgrades

At a certain point – generally around the 400-450whp mark on 93 pump gas – a stage 2 turbo’s capabilities overcome the ability of the factory fuel system to supply adequate fuel to compensate. As a result, you’ll need to find a way to introduce additional fuel to the engine. Ultimately, you have a few options when it comes to fueling modifications for the N55. The three main ones include a methanol injection kit, port injection, or an upgraded high-pressure and low-pressure fuel pump combo.

I won’t go into too much detail about the various forms of N55 fueling upgrades here, as we have a dedicated article about the subject.

Fuel Upgrades

In addition to needing some fuel supply upgrades, you will also need some actual fuel upgrades. Running high levels of boost and generating high power levels requires higher octane fuel to operate safely. The easiest option here is to run an E85 blend – it’s cheaper and more accessible than 100+ octane pump gas.

The stock LPFP can handle an approximate 40% E85/pump blend. This will have your LPFP running at 100% and will likely be a performance limiter. Best bet is upgrading to a Stage 2 (or 3) LPFP. Stage 2 will run you about $450 and stage 3 $850 and should be a relatively easy DIY.

Without fuel and fuel delivery upgrades, on 93 octane pump gas, you can expect to run around the 450whp range.

N55 Stage 2 Turbo Upgrade Options

Stage 1 N55 turbocharger upgrades tend to run out of steam around the 425-450whp mark, at which point you’ll need to start looking into a stage 2 turbocharger upgrade. Generally speaking, stage 2 is where most N55 owners start in terms of a turbo upgrade, as there is far more power potential with a stage 2 turbo than a stage 1 setup.

There are 3 (reputable) companies that offer stage 2 setups: Pure, Vargas, and Steam Turbochargers. Pure and Vargas are the more widely used setups, but Steam has a good offering which has about 25whp of additional upside vs. the other two. Here is some info on the setups in no particular order:

1. Pure Stage 2 Turbo Upgrade

The Pure Stage 2 turbos is probably the most widely used turbo upgrade for both E-Series and F-Series N55’s. With the supporting fuel mods that we discussed above, this setup is good for about 525whp.

Similar to their stage 1 offering, the turbo uses all OEM housings and appears stock from the outside. The center of the housing is machined out to allow for larger wheels.

Ultimately, there isn’t a whole lot to say about the Pure Stage 2 N55 turbo kit that we haven’t already said about the Pure500 kit. The primary difference between the two kits is a larger turbine wheel and the inclusion of a custom turbofold with the Pure Stage 2 kit. While that might not seem like that substantial of an upgrade, both of those included elements help the turbo flow much more than the stage 1 option, making the stage 2 offering far more capable from a power production standpoint.

It is also important to mention that the Pure Stage 2 kit is only priced at $2,500 if you ship your factory turbo as a core back to Pure. Without sending them a core unit, the price of the kit is bumped to $2,800.

Horsepower: up to ~525whp

Price:
+$2,500 or $2,800 w/o Core: turbo kit
+$220: install kit
+$250: inlets and outlets (not required but stupid to not upgrade)
$2,970: barebones parts cost with no supporting mods
+$405: stage 2 fuel pump
+$1,200: direct port or meth injection (-$900 if you want to use the chargepipe method)
$4,575: parts cost to do it the right way

And then you’ve got labor on top of that. And to note, these are just the major parts costs and assume you are already FBO with an upgraded chargepipe, etc. There will likely be other hoses and small things that will need to replaced as well. Don’t forget the 2-step colder spark plugs and ignition coils!

2. Vargas (VTT) GC/GC+ Stage 2/Stage2.5 Turbo Upgrade

The Vargas setup is almost identical to the Pure setup with the slight exception of the wheels – this setup also uses an OEM-styled turbo with a bored-out center and larger wheels. Unlike the Pure option, and despite being less expensive, there is no need to deal with sending a core back to Vargas. The Vargas GC kit is an interesting one, as it is offered in two different tiers. While the standard GC kit is unquestionably a stage 2 turbo, which Vargas claims is good for 600whp, the GC+ turbo, which is also offered from the same webpage, falls more in line with a stage 2.5 turbo. Vargas claims that their GC turbo is good for 700whp.

Like the Pure offering, both the Vargas GC and GC+ turbo kits come with a custom turbofold which improves overall flow over the factory turbo manifold. The GC+ turbo features a larger compressor than the standard GC, allowing it to flow more. Vargas claims that the larger compressor slows spool time by 200-400 rpm, trading boost lag for more power potential. Despite being a more capable turbo, the GC+ is the same price as the GC.

Horsepower: GC up to 600whp, GC+ up to 700whp

Cost: 
+$2,200: turbo kit
+$185: install kit
+$130: shipping
$2,515: barebones cost for parts (plus $206 if your car is 2014+)
$4,120: cost with direct injection and stage 2 LPFP

3. SteamSpeed Turbochargers Stage 2.5 N55 Upgrade

In addition to the big two (Pure and Vargas), there is one more primary player in the N55 stage 2  turbo game, and that is SteamSpeed. While the SteamSpeed name doesn’t carry the same name recognition as the prior two companies, they produce quality products with proven results.

As with the Pure and Vargas turbos, the SteamSpeed turbo was specifically designed to look and function in a similar way to the factory turbo, albeit with a much higher power ceiling. The SteamSpeed turbo comes equipped with a dual ceramic ball bearing cartridge and custom GTX3076R-sized compressor and turbine wheels. The SteamSpeed turbo also comes with a custom cast manifold for better turbo performance, a better torque curve, and quicker spool times.

Here are some specs on their setup:

-Bearing System: custom ceramic BB
-Custom Compressor wheel In:59 / Ex:78 (the size is between GTX3076 and GT3582)
-Custom Turbine wheel In:60 / Ex:57 (The size slightly bigger than GT3076 – In:60 / Ex:55).
-Flow capacity: 70 lbs/min (est.)

Horsepower: up to 600whp

Price: $2,999 for the turbo kit

BMW N55 Stage 3 Turbo Upgrade

Alright…stage 3…this is where Vargas and Pure bow out and let the big kids play.

The stage 1’s and 2’s we looked at above all had a bit of the sleeper thing going for them…stock sized turbos that are machined for larger compressor and turbine wheels. Now we are talking turbos that can engulf a child.

A stage 3 turbo upgrade is the best bet for any N55 owner looking to break past the 550whp mark or push more than 500whp on a day to day basis. With stock-sized turbos, you can only machine out so much of the turbo internals to make it bigger. Eventually, you have to go with a turbo that is itself bigger. You lose the sleeper/undetectable turbo upgrade once you go stage 3 since the turbo is now bigger and sometimes relocated to different spots inside the engine bay.

Since these turbos don’t bolt directly up to the stock setup, a stage 3 kit will come with a custom manifold, and you will most likely have to make the decision around which turbo you want to use. The biggest decision is around the size of the turbo – obviously, the bigger the size, the more horsepower the setup is capable of.

Expected Horsepower: 550whp+

We are big believers in not running your setup at 100% for 100% of the time. With that being said, if you want to run 500-550whp on a daily basis – not just on track days or dyno runs – then going stage 3 is a good bet for you. Stretching a stage 2 setup to run 525whp on a daily basis will put a lot of stress on your engine and turbo setup which will result in a pretty significant decrease in reliability.

Additional Mods for Stage 3 Upgrade

Everything we listed above on stage 2
No more cutting corners with chargepipe injection, you will need port injection here. It’s also worth the extra $400 to go stage 3 on your LPFP.

Upgraded Engine Internals (rods, pistons, etc.) – recommended for 650whp+
While BMW built a great engine with the N55, the internals are unfortunately slightly inferior to the N55’s predecessor, the N54. The N55 has been known the bend and crack rods above 600whp, so we recommend anyone who is seriously looking to push the envelope here go with some upgraded engine internals. However, I will note that bending rods is a lot of times caused by improper tuning. Which brings us to our next upgrade: a custom tune.

A proper, custom tune
With stage 3 turbos, you are likely going to be heavily modded: FBO, port/meth injection, fuel pump upgrades, custom piping, etc. The JB4 is a great plug and play mod for people looking for easy and inexpensive horsepower, but the auto-tune map is no longer going to suffice. It’s time to get a proper custom tune.

N55 Stage 3 Turbo Upgrade Options

1. BigBoost N55 Stage 3 Turbo Upgrade

Please note we linked to the F-Series kit and there is an separate kit for E-Series BMW’s.

While BigBoost used to provide multiple turbo options for their stage 3 N55 kit, it appears that the kit has been standardized to include one of two Master Power Racing (MPR) turbochargers with different compressor sizes. The dropdown menu on the kit’s listing allows for the selection of either a stage 3.3 or stage 3.4 turbocharger, both of which are supplied by MPR. The stage 3.4 turbo features an MPR 6564 turbo. With that being said, the stage 3.3 kit is rated for around 600-650+ wheel horsepower while you can expect around 650-800+whp from the stage 3.4 kit. 

In addition to their MPR kits, BigBoost also offers an N55 stage 3 kit with the option of two Garrett turbochargers as well. Obviously, due to Garrett’s undeniable quality and reputation, the BigBoost Garrett kit is notably more expensive than any of the MPR options, with a starting price of $4,650. With that being said, both of the Garrett options are capable of over 1,000whp.

• 3.3: 6159 turbo – capable of 620whp (per BigBoost)
• 3.4: 6564 turbo – capable of 800whp (you guessed it, per BigBoost)
• Garrett GTX3582R Gen2 (GTX800) – capable of 1,000whp
• GTX3584RS (GTX1000) – capable of 1,000whp

These kits use Master Power turbochargers and require port-injection and a stage 2 or 3 LPFP after their stage 3.2 turbo option. We have seen dyno verification of 630whp at 27psi and 604whp at 24.5psi with the 6159 turbo which is awesome. The setup that hit these was the full 3.3 kit which comes in at $3,300.

Cost:
+$3,300: turbo kit (give or take depending on turbo)
+$1,200: port injection
+$850: stage 3 LPFP
+$500: custom tune (depending on tuner, prices could range from $200-700)
+$1,100: Carillo forged piston set (OPTIONAL – recommended for 650whp+)
+$1,500: Carillo forged rods (OPTIONAL – recommended for 650whp+)
$8,450: parts cost including optional internal upgrades before installation. Note: installation will be expensive for all this.

2. Speedtech N55 Stage 3 Turbo Upgrade

Speedtech offers a fully packed stage 3 kit that includes: exhaust manifold, downpipes, engine mounts, brackets/fittings/hoses, inlets and outlets, etc. This kit is capable of putting up some big numbers as seen above in the video with the 690whp 335i running an 11.3 at 130mph.

This setup uses Borg Warner EFR turbos and offers selection of either a 7064, 7670, or 8374 EFR turbo.

The car in the video was running the 8374 setup with port injection, Bootmod3, JB4, and E40 fuel. Additionally, boost was set at 15psi for 1st gear, 20psi for 2nd/3rd gear, and 25psi for 4th and 5th gear.

We will note that this setup is safe to run with a stock intake, intercooler, and exhaust. (But why?). Here are the power outputs you can expect from the Speedtech setup.

• 7064 Borg Warner Turbo: 500whp daily driver
• 7670 Borg Warner Turbo: up to 625whp
• 8374 Borg Warner Turbo: up to 750whp (per Speedtech – let’s see someone hit this!)

Cost:
+$4,500: turbo kit itself – this also includes a custom tune. It is $200 less if you don’t want a custom tune with it.
+$1,200: port injection
+$850: stage 3 LPFP
+$1,100: Carillo forged piston set (OPTIONAL – recommended for 650whp+)
+$1,500: Carillo forged rods (OPTIONAL – recommended for 650whp+)
$9,150: parts cost including Carillo upgrades, and not including installation.

3. DOC Race N55 Top Mount Single Turbo Kit

Now that the DocRace N55 stage 3 turbo kit has been on the market for a while now, it is clear that it is a very popular and well-liked option when gunning for ridiculous power figures as well. As with the previous two stage 3 turbo kits that we have covered, the DocRace kit comes with everything that you need to get your turbo swap rolling, including the choice between a number of Precision turbo options. 

The DocRace kit can be ordered with one of six different Precision turbochargers ranging from a Gen 1 5962 to a Gen 2 6466. Obviously, turbo choice is entirely subjective and truly depends on what you want your boost characteristics to be. Larger turbos allow for more power potential at the expense of spool time and the opposite goes for smaller turbos. The 6266 is a fantastic option for those who want something in the middle, as it is small enough to have a reasonable spool time, but is still capable of 925whp.

Despite being one of the newest players on the N55 stage 3 scene, the DocRace kit has received nothing but glowing reviews since its release. Here’s what you can expect from the DocRace kit:

• Gen 1 PTE5862 Precision Turbo: 640whp
• Gen 2 PTE5862 Precision Turbo: 700whp
• Gen 2 PTE6062 Precision Turbo: 750whp
• Gen 1 PTE6266 Precision Turbo: 735whp
• Gen 2 PTE6266 Precision Turbo: 800whp
• Gen 2 PTE6466 Precision Turbo: 900whp

Cost:
+$4,500: turbo kit itself – this also includes a custom tune. It is $200 less if you don’t want a custom tune with it.
+$1,200: port injection
+$850: stage 3 LPFP
+$1,100: Carillo forged piston set (OPTIONAL – recommended for 650whp+)
+$1,500: Carillo forged rods (OPTIONAL – recommended for 650whp+)
$9,150: parts cost including Carillo upgrades, and not including installation.