BMW N55 Turbo Upgrade Options & Setup Guide

Turbos are great. Especially BMW’s N55 twin-scroll turbocharged engine. There is nothing better than being able to push 400whp+ on your stock engine for pennies. Well, maybe there is something better…UPGRADED TURBO!

This N55 turbo upgrade guide will dig into the intricacies of upgrading your N55 turbo and help you decide whether stage 1, 2 or 3 is right for you and your power goals.

N55 turbo upgrade options: what stage should I get?

Before we get into specific turbo manufacturers, the first question you need to answer before you upgrade your N55 turbos is: what “stage” upgrade should I get?

Turbo upgrades for the N55 fall into three stages, with stage 3 generating the most horsepower gains, which of course also comes with a bigger price tag.

1. N55 Stage 1 Turbo Upgrade: ~400-425whp
2. N55 Stage 2 Turbo Upgrade: 450-550whp
3. N55 Stage 3 Turbo Upgrade: 600-650whp and beyond (for the brave)

Supporting Mods before Upgrading your Turbo

We’re upgrading our turbo for more power right? You might as well maximize your stock turbo power before you go chasing for more. This list below will get you to FBO (full bolt-on) and should get you in the 350whp range.

Read: How to Build a 400whp N55 for Under $1500

As you start making more power, you need parts that can handle and deliver that power. 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
• Upgraded chargepipe: literally anything is better than stock

You can add E85 to this list if you want to be sitting around 400whp on your stock setup. I’ll do my best to add any additional supporting mods that will be needed for the different setups we list below. As you get more aggressive with your N55 horsepower goals, you will need to start thinking about things such as fuel pumps, meth kits, port injection, etc.

Before I get chopped, I will say that you do not need to upgrade your intercooler or exhaust for any of these turbos upgrades. Other than downpipes, forget the exhaust, we agree with that but upgrade your intercooler – it’s $400 and your about to drop $4k on upgrading your turbos.

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/compressir 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 its 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. The install cost of upgrading turbos warrants doing it right the first time!

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

I won’t go into too much depth here since these two options are virtually the same and will both add anywhere from 40-70whp depending on your tune and supporting mods.

Pure Stage 1: https://www.pureturbos.com/

Vargas Stage 1: https://vargasturbo.com/product/n55-stage-1-jb-upgrade-kit-new/

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 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 interals which means we are talking pretty serious dough $$!

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

Additional Mods for Stage 2 Upgrade

Inlets and Outlets
Upgraded inlets and outlets: these are required depending on manufacturer and some kits may include them.

Fuel Supply Upgrades
To reach the full power potential of a stage 2 turbo you will need additional fueling. Your two options here are a meth kit or port injection. These things will run you about $1,200 for parts + install for direct injection setups. N55 Fuel Injection Kits from Fuel-It.

We recommend direct injection setups, but for those ballin’ on a budget, you can use a chargepipe injection kit for $300 + DIY: Fuel-It Chargepipe Injection Kit.

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 will require….higher octane fuel. 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

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

WARNING: This setup will walk on supercars!

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.

Horsepower: up to ~525whp

Price:
+$2,500: 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) Stage 2 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.

The setup is good for 500whp,with proper tuning and fuel upgrades, on a stock chargepipe (if you want it to blowup) and 525whp with an upgraded chargepipe, per Vargas.

Horsepower: up to 525whp

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. Steam Turbochargers Stage 2.5 N55 Upgrade

Steam is a new(ish) company to the N55 tuning market and recently released their stage 2 setup, after a stage 1 setup which delivered 400whp with pump gas and meth.

The extra 0.5 of a stage (this is new to us too) is good for an additional 25whp upside on Vargas and Pure, although I haven’t been able to find any dyno charts to substantiate the claims.

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 550whp

Price: $2,500 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.

Pin

Unfortunately that ^ is a Honda. Does anyone here have a BMW 2002 that we could try this on??

Anyways, back to the N55’s turbo….

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 itself is bigger. You lose the sleeper/undetectable turbo upgrade once you go stage 3 since the turbo is now bigger and sometimes relocated to difference spots inside the engine bay.

Since these turbo’s 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 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.

BigBoost offers 4 separate stages within their stage 3 turbo kit, these stages all refer to the size of the turbo:

• 3.1: 5459 turbo – capable of 470whp (per BigBoost)
• 3.2: 5959 turbo – capable of 520whp (per BigBoost)
• 3.3: 6159 turbo – capable of 620whp (per BigBoost)
• 3.4: 6564 turbo – capable of 800whp (you guessed it, per BigBoost – we haven’t seen an N55 hit 800whp yet)

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 – lets 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

These guys at DOC Race built a badass top-mount single turbo for the N54 that can put down 900whp+.

More info on DOC Race is coming! Along with more info on reliability!