A few months ago we published our post about N54 upgraded twin turbo setups. Finally, after months of researching, we are happy to present our BMW N54 single turbo guide. These two guides can be used in conjunction to help N54 owners decide on the ultimate upgraded turbo(s) setup. We will also be writing a post in the near future that, in a way, combines the two upgraded turbo posts to discuss the benefits, downsides, and risks of each setup.
Check out our Precision Turbo 6266 135i Single Turbo Build!
N54 Single Turbo Spool & Low End Torque
We touched on this briefly in the N54 twin turbo post. To summarize, twin turbos are a bit tougher on the motor as they deliver so much instantaneous torque down low. Smaller twin turbo options offer an OEM-like feel with quick spool and lots of boost in the low RPM's. Larger, true TD-04 twin turbos, introduce a bit more lag and less boost down low.
Single turbos, especially large single turbo options, introduce even more lag. However, don't let this scare you away. Lag is not exactly the correct terminology. Let's clear this up quickly and discuss boost thresholds.
Turbo Boost Thresholds
This refers to the minimum engine speed required to produce enough exhaust gases to build boost. It is basically the RPM's at which the turbo has positive manifold pressure. At this point, the turbine is able to spin fast enough to begin building boost.
All else equal, larger turbos generally have higher boost thresholds on the N54. For example, a 70mm turbo simply isn't going to build much boost at 2,500 RPM's. That's not turbo lag, but rather the turbo is under its boost threshold.
Lag only applies once the engine/turbo is above the minimum boost threshold. It is the amount of time between the throttle opening and the turbo spooling to its boost target. When you go WOT, above the boost threshold, and it takes 2 seconds for the turbo to reach it's target - that's turbo lag.
Similar to above, larger turbos generally take longer to spool.
What Does This Mean?
The point we are making is this: often times when people cite turbo lag, they are really referring to boost thresholds. Yes, TD-04 twin turbos will have more turbo lag than stock turbos. Yes, massive single turbos will induce even more lag. However, it's often not as bad as you may believe.
The biggest catch is boost threshold. Downshifts on stock or small upgraded turbos are usually optional. Boost thresholds on stock N54 turbos are so low that they can build boost at 2,000 RPM's. Don't expect single turbos to accomplish this. The exact boost threshold depends on a lot of factors, but larger single turbos are generally going to need higher RPM's to spool. Get used to downshifting and keeping revs a bit higher.
N54 Ball Bearing vs Journal Bearing
Not to stray too far off topic, let's keep this quick. Ball bearing turbos are simply a better design than journal bearing turbos. Per Garrett, ball bearing turbos spool up to 15% faster when compared to traditional journal bearings. Additionally, they require less oil flow to provide adequate lubrication thereby reducing the chance of seal leakage. Ball bearings also allow for more precise control over shaft motion.
The downside? Ball bearing turbos are typically more expensive than their journal bearing counterparts. If the budget allows, ball bearings are definitely the way to go.
BMW N54 Single Turbo Companies
One notable difference between upgraded twin turbos and single turbos are manufacturers. Since most N54 single turbos are top-mount there are not as many space limitations as with the twin turbo setups. N54 twin turbo setups are designed by each turbo company specifically for the N54. On the contrary, most single turbos are made from reputable companies mass producing turbos, not only for the N54. Many have been around for decades with proven processes, quality control, and results. A few common turbo options include:
- Precision Turbo
- Forced Performance (FP)
This is not an exhaustive list, but they are among the most common, highly proven turbo options for the BMW N54. Precision Turbo has been making turbos since 1987. Garrett since the 1950's. Additionally, Garrett has powered engines to 18+ consecutive 24 hours of Le Mans wins. BorgWarner is the official turbo of NTT IndyCar Series. We could continue listing off plenty more facts, but let's cut straight to the point. RELIABILITY.
*To note - we do believe Pure and RB are producing high quality, proven twin turbos. It took some time for the N54 twin turbo options to get where they are today. We're twin turbo fans and will be opting for Pure or RB when the day comes.
N54 Single Turbo Sizes
Turbos are commonly measured in several ways. These include: compressor wheel, turbine wheel, and turbine housing sizes. Despite what you've been told your whole life - size does matter. Generally, larger single turbos push the N54's power band right and make more peak power, but sacrifice some low-end torque and spool. The compressor/turbine wheels and turbine housing all play a role in determining how "large" a turbo is.
Turbo Compressor Wheel Size
The compressor wheel is referred to as the "cold-side" of the turbocharger. As the name suggests, it compresses the fresh air entering the turbo. Compressor wheels are measured in mm at the inducer. Some will also reference the size of the exducer, separately. Both matter, but the size of the inducer is more important. This could be a lengthy topic, so we won't waste the time. Google inducer and exducer if you wish to learn more; it is explained much better than we could do.
Anyways, back on track. The compressor is measured in mm. Precision Turbos 6266 or 6466 are common N54 single turbos. The first two numbers represent the size of the compressor wheels, 62mm and 64mm respectively.
Turbo Turbine Wheel Size
Turbine wheels represent the hot-side of the turbo. Exhaust gases spin the turbine which is connected to the compressor wheel via a turbo shaft. Like the compressor, turbine wheels are measured in mm. However, opposite to the compressor, turbine wheels are usually measured at the exducer.
Using the same example from above, the 6266 and 6466 both use 66mm turbine wheels.
Turbine housings measurements are usually quoted as AR, or aspect ratio. The AR represents the ratio of the turbine inlet to the radius of the turbine wheel center. It sounds confusing and quite frankly we can't explain it clearly in few enough words. What's important is that higher aspect ratios result in additional lag but increase top-end performance. The opposite is true of lower AR's.
Turbo Size and Spool
Alright, well we've probably scared half the readers off with the boring, technical gibberish by now. An important take away is this - all else equal, a larger turbo flows more air on the top-end and results in more power. Though, it comes at the cost of reduced low-end torque and more turbo lag. The key phrase is all else equal. Tuning, fuel, turbo bearings (as discussed above) and many other factors also play a role in turbo spool.
Circling back to our 6266 and 6466 example, the 6266 turbo is going to spool slightly faster at the cost of less top-end power. As such, the N54 is going to be just about maxed at 700-725whp on a 6266. The larger 6466 turbo is capable of making closer to 800whp, but will likely take an extra ~200rpms to spool.
N54 Twin Scroll Single Turbos
We wrote a post about twin scroll turbos on our other blog. We recommend checking it out if you are unfamiliar with the design and benefits of a twin scroll turbo. In short, they are a better turbo design but come with some additional costs up-front. It is definitely something to consider when choosing the right turbo.
BMW N54 Single Turbo Options
Finally! We're moving on to the fun part. With dozens of different turbo options, and equally as many N54 turbo kits, how do you pick the right turbo setup? First, you must understand your goals. We'll lay out the remainder of this post in sections for the following goals:
- "Modest" 450-550whp
- "Full Send" 800+whp
As we recommend with any N54 upgraded turbo(s), you should opt for a setup that can handle a bit more power than your goals. Don't go too overkill, though. You likely don't want a 900whp capable turbo if your goal is 600whp. However, maybe you plan to daily drive on a 600whp tune with the ability to turn things to 700whp kill mode. You also don't want to be pushing the turbo wildly outside of its efficiency range to get there. As such, getting a turbo setup that allows a little headroom is never a bad idea.
We'll touch on this a bit more as we move through each power goal and respective turbo setups. Please don't ignore this information though. Proper supporting mods and understanding the risks of different power goals is extremely important. N54 upgraded turbos can be a serious financial commitment. As your power goals increase, so do costs.
A 500whp single turbo N54 won't be very demanding on supporting mods. You can likely get by with basic bolt-ons and a low pressure fuel pump. Once the N54 nears 550whp, port injection becomes a necessity. Push an N54 over 700whp and the possibility of a blown motor becomes significant. 800+whp stock N54's become a matter of when the engine lets go, not if. Then there are all the mods in between such as proper suspension, brakes, axles, clutches, LSD's - the list goes on and on.
Understand your goals. Then ask yourself if they are realistic. Keep supporting mods and risks in your mind as we move through this post. There are ways to accomplish big things on a budget, but don't cut too many corners.
*Heavy E85 mixes are required for optimal power and performance. For example, a turbo setup capable of 650whp is not going to make 650whp on 93 pump gas. You'll likely need to opt for one of the larger turbos in the 700-800+whp sections to reach anywhere near 650whp on pump gas.
**Many turbos we list are capable of a bit of extra power than we quote in the titles (roughly 5-15%) when pushed to their absolute limits/maxed out. We try to quote numbers a bit lower than a turbos absolute maximum.
450-550WHP N54 Single Turbo Options
These are the entry level single turbo kits. As we mentioned briefly above, 450-550whp N54 turbo setups will get by with minimal supporting mods. They're generally smaller turbos that remain responsive and quick on the lower-end. However, don't expect them to be as twitchy and spool happy as the N54 stock turbos. This is a great option for those on a budget. They're also good setups to consider if your OEM turbos are tired or blown, and no longer want to deal with the hassle of the stock twins. Recommended supporting mods include:
- FBO (with 7-7.5" FMIC)
- LPFP (stage 2 or 3, ideal)
That's really it for supporting mods on these modest N54 single turbo options. One thing to consider - if you're planning to push upwards of 550whp, especially on full E85, you may need port injection. It may not be required, but be sure to keep an eye on trims and AFR's. Here are a few N54 single turbo options for your modest goals.
Precision 5558 CEA JB (450-525whp)
55mm compressor, 58mm turbine
Kit Offered By: SpeedTech (*Bottom Mount Single Turbo*)
Complete Kit: starts at $3,900
SpeedTech's kit with the 5558 CEA JB turbo from Precision is about as small a single turbo you will find for the N54. This kit will peak around 540whp, but it's likely best kept in the low 500's for daily driving. Expect a PT 5558 to retain solid spool on the N54. You can also upgrade to the 5558 CEA GEN2 turbo capable of making nearly 600whp. The complete kit starts at $4,350 and is a great option for N54's that may be pushed harder down the road.
The catch? Unfortunately, this is a bottom mount kit. Forget the eye candy when you pop the hood. It also makes the install tougher should you decide to upgrade to a larger turbo down the road.
On 3 Performance GT30/GT35 (450-550whp)
55mm GT30 or 61mm GT35 turbo available
Complete Kit: starts at $2,995 (or $2,621 if you already have FMIC and chargepipe)
With the price of the On 3 N54 single turbo kit, it's a great option for those on a tight budget. Some people love this kit, however the quality definitely isn't up to par with more expensive N54 upgraded turbos. You get what you pay for. Although, it has shown to be a fairly reliable kit if your goals are modest and you don't plan on pushing these turbos to the limit. Another benefit? If you blow the turbo you can buy a new one from On 3 for $339.
The GT30 is likely best kept under 500whp and we recommend the $300 ball bearing upgrade. On 3's larger 61mm offering will help boost the N54 upwards of 600whp. An N54 top-mount single turbo is hard to beat for this price.
Final Thoughts on 450-550whp Single Turbos
There are a few other solid options out there for 450-550whp goals. With modest power goals, the N54 can get by with minimal supporting mods. Additionally, the N54 is hardly breaking a sweat at 550whp. Although, if your power goals are under 550whp then we strongly suggest considering a twin turbo setup. Another option, if budget isn't a huge concern and you want room to push more power in the future, consider going for the larger turbos in the following sections.
550-700WHP N54 Single Turbo Options
This is a broad range of horsepower. We decided to use this range for a few reasons. 550whp is the ballpark where port injection becomes a must. Meaning, these setups are starting to get pretty expensive on top of the turbo kits. Scaling up to the higher 650-700whp range is right around the limit that SHOULD be "safe" on a healthy N54 with proper tuning and fueling.
Things can still go wrong at these power levels. It's impossible to put an exact safe limit on an engine. It will never be as simple as, "Oh yeah, the N54 is going to grenade itself at 710whp, but hold up for 10 years at 690whp". If only things were that simple. Anyways, let's dig into a few supporting mods at these power levels:
- FBO + LPFP
- Port Injection
- Meth and/or E50+ fueling
- Especially on 650+whp setups
If you plan to frequently launch hard from a dig then you may even consider upgraded axles. Suspension will help handle all of that power. And, of course, upgraded brakes will help stop the newfound power. Without further ado, let's dive into some options to accomplish your 550-700whp goals.
Precision 5862 GEN2 CEA (550-600whp)
58mm compressor, 62mm turbine
Kit Offered By: Doc Race, SpeedTech
Complete Kit: $5,095
First off, Doc Race makes some absolutely beautiful top mount turbo kits for the N54. These kits are highly proven and we'll be mentioning them a few more times throughout this post. They offer a good selection of turbo options from both Garrett and Precision. For this one, we're focusing on the Precision 5862 GEN2 CEA option.
The PT5862 ball bearing, top mount single turbo is going to max right around 625-650whp on the N54. As you likely noticed, this kit comes at a pretty steep cost up-front. If you want a bit more room, opt for the 6062 GEN2 CEA turbo for the same price. This larger turbo is capable of making closer to 700whp. Quality turbos and a quality kit, overall.
Garrett GTW 3684R (650-700whp)
62mm compressor, 62mm turbine
Kit Offered By: Doc Race, SpeedTech
Complete Kit: $4,300 - $5,095
The Garrett GTW 3684R is not a common turbo choice on the N54, but is a great option for those looking to stick under 700whp. Garrett makes excellent turbos, but most N54's are running Precision turbos. Although, we'll mention Garrett a few more times throughout. They deserve more recognition than they get on the N54.
Doc Race and SpeedTech both offer this turbo option. Doc Race is a top mount kit, while SpeedTech only offers bottom mount kits. As such, we recommend the Doc Race option for most. A GTW 3684R equipped N54 will peak around 700whp
Final Thoughts on 550-700whp Single Turbos
As discussed above, taking an N54 to 550+whp can become relatively expensive; port injection adds some considerable costs. We decided to only mention a few turbos here. The Precision 5862 is a good option for 550-600whp goals. Those wanting 650+whp are likely best choosing a turbo in the next section. You will not be sacrificing much spool for these more capable single turbos. Also, opting for a larger turbo that can make more power with less boost will only help with longevity.
700-800WHP N54 Single Turbo Options
Now we're getting into some pretty serious stuff. A lot of the turbos in this section, especially the Precision 6266, are great options for N54's wanting 650+whp. Though you may sacrifice a small amount of spool, these turbos can just about max out an unopened N54. 700+whp will put some pretty serious stress on the N54. You want to have a really good tune and err on the side of caution, or build your N54, unless you don't care about your engine.
For people looking to push 700+whp through an un-opened N54, you may even opt for the biggest, baddest 800+whp turbos. In general, larger turbos will need less boost to make the same power. Less boost is typically easier on the engine. Again, 700+whp is asking a lot out of the N54. Though this isn't all required, we recommend getting a bit wild on supporting mods.
- FBO + LPFP + Port Injection + Meth AND E85
- LSD + Axles
- Larger Brakes
- Upgraded oil cooler(s), transmission cooler, etc
- Built Motor (if you want to be extra cautious)
Not cheap. This stuff can add up quickly. Sure, you don't NEED most of these mods. However, a 700+whp N54 is pushing the boundaries and we recommend doing it right. Good luck putting the power down without a LSD or stopping from extremely high speeds. It's also a good idea to keep temperatures in check with some cooling mods. We haven't really mentioned this part yet, either. Automatic transmission N54's are really going to struggle with this power. The ZF 6HP is a stout transmission, especially with the flash options out there now, but this is still too much power for the A/T in the long run.
Precision 6266 CEA GEN2 (700-750whp)
62mm compressor, 66mm turbine
Kit Offered By: Doc Race, SpeedTech, AD Engineering, VM
Complete Kit: $4,400-$6,500
Precision's 6266 is probably the most common turbo on the N54. Countless dynos show the PT6266 making well over 700whp. A modest 25psi can push the PT6266 to 700whp. Heck, some have even maxed the turbo near 800whp though we recommend upgrading to the 6466 if you want to push these boundaries. Anyways, not much else to say about the 6266 from Precision. This is likely the most proven turbo on the N54 and is an excellent option for almost anyone looking to push 600-750whp.
As this turbo is so common, many different companies offer N54 single turbo kits featuring the PT6266. There are too many to list. SpeedTech and AD Engineering both offer bottom mount kits. Again, Doc Race offers the top mount kit. There are other top mount options out there, but Doc Race is tough to beat for the quality and price.
Garrett GTW3884R / GTW6465R (700-775whp) or GTW6765R (800-850whp)
64mm compressor, 65mm turbine OR 67mm, 65mm
Kit Offered By: Doc Race (both options) OR SpeedTech for larger GTW3884R
Complete Kit: $4,300-$5,095
Garrett's GTW3884R turbo comes in a few different sizes. Options for the N54 include the 6465R and 6765R. The 6465R will make around 775whp peak with room for a bit more when pushed to its limit. On the other hand, the 6765R will make upwards of 850whp but comes at the cost of added lag. However, they are both solid options for 700+whp N54's.
Doc Race offers the 6465R and 6765R Garrett Turbos. These are both ball bearing turbos, but Doc Race also offers journal bearing options. It saves you about $500, but is an inferior option to the ball bearing turbos. SpeedTech offers the largest 6765 ball bearing GTW3884R for only $4,300 but it is a bottom mount kit.
Final Thoughts on 700-800WHP Single Turbos
There are other good turbo offerings from both Precision and Garrett that will put your N54 in this power range. Although, there isn't much else worth mentioning as the PT6266 is so good. Many N54's run this option with excellent results. Garrett's GTW3884R offers great competition with the option to upgrade to the larger 6765R turbo. Look no further than these two options to push the N54 to its breaking point.
Speaking of, we must re-iterate, 700+whp is serious power. You're pushing past the generally accepted safe limit of the N54. Be cautious as it is easy to push the N54 to its ragged edge with the above turbo options. Moving on to the next section, we're not talking about pushing to the ragged edge. We're going WAY past it.
800+WHP Single Turbo N54
Finally, the section we've all been waiting for. These are the setups we all drool over, and most of us can only dream about. Previously, we talked about serious power. 800+whp is stupid power. Actually, it's so stupid these setups rarely outperform the "modest" 700whp N54's. Yes, they outperform them on a dyno. In the real world, though? As far as we know, 800+whp N54's hold nothing more than dyno records.
It's so hard, darn near impossible to be precise, to actually put this power to the ground. Also, turbos large enough to support 800+whp are best suited to fully built motors ready to handle extra revs. Top-end power is the name of the game when it comes to turbos this large. 7,000 RPM's simply isn't enough to reap the full benefit of these turbos. Lastly, push 800+whp through a stock N54 and it becomes a matter of when you blow the engine. Not if. Supporting mods are endless. What was important at 700whp becomes almost required at 800+whp.
- FBO + LPFP + Port Injection + 100% E85 and Meth
- LSD + Axles
- Suspension, Brakes, etc
- Oil cooler(s), trans cooler(s)
- Syvecs ECU
- BUILT MOTOR
I'm sure we're missing a few things, too. Anyways, it's not much different from the recommended 700whp mods. It simply becomes more important to ensure you have the correct supporting mods. Also, building the N54 should be at the forefront of discussion to achieve 800+whp. A Syvecs ECU is a great mod even for lower power cars. However, it's important if you truly want to push the limits of the N54 platform.
Precision 6466 CEA GEN2 (750-850whp)
64mm compressor, 66mm turbine
Kit Offered By: Doc Race, SpeedTech, AD Engineering, VM
Complete Kit: $4,300-$6,500
This is the one "modest" turbo we are going to mention here. Like the Precision 6266, this turbo is among the most popular and proven on the N54. It is not only a great option for anyone looking to push 700+whp, but also anyone looking to push the 6466 towards its 850whp limits. This turbo retains respectable spool for its size but definitely isn't for everyone. Consider sticking to the 6266 unless you really want the added headroom.
Again, like the 6266, a lot of companies offer 6466 kits for the N54. VM and Doc Race offer solid top mount options. SpeedTech and AD Engineering options are also great for anyone wanting a bottom mount kit.
Precision 6870 CEA GEN2 (800-1000whp)
68mm compressor, 70mm turbine
Kit Offered By: Doc Race, SpeedTech, VM, AD Engineering
Complete Kit: $4,950-$5,795
Here you go. The Precision 6870 is a massive turbo capable of 1000whp. Yet no one has quite accomplished that on the 6870. Not because it isn't capable. Rather due to the extensive time, tuning, mods, barriers, etc required to accomplish such a feat. This post gives you an idea of what it takes to push well beyond 800whp:
I believe this N54 ended up making about 940whp on 35psi. They were also running NOS to assist in turbo spool since it takes so much to get this 6870 going. If you're bold enough, quite a few companies offer kits featuring the Precision 6870.
MOTIV Single Turbo Kit (800-950whp)
Xona Rotor Turbo. 72mm compressor, 68mm turbine
Kit Offered By: MOTIV
Complete Kit: $7,999
MOTIV's single turbo kit is one of the top of the line options for the N54. The price may also scare many away. Their kit features a massive Xona Rotor ball bearing turbo. MOTIV held the single turbo record of 978whp for quite some time. (It did dyno over 1000whp with corrections and smoothing set to 0.) Only recently was that record taken by the next N54 upgraded turbo on this list.
The MOTIV turbo kit does retain respectable spool for it's size, though it's definitely too large for many. It's hard to argue with 978whp, though. Great option for those looking to take the N54 platform to the next level.
Precision 7275 CEA GEN2
72mm compressor, 75mm turbine
Kit Offered By: Unknown
Complete Kit: Unknown
Precision's 7275 turbo is the largest, most capable turbo we will discuss. As far as we know, no one even offers a kit with this turbo. You will likely need to buy a turbo kit without a turbo and get this turbo separately. Although, if you're looking to smash N54 records, this may be the route for you.
Expect this turbo to suffer from considerable lag on the N54, but deliver bone crushing power on the top-end. We're really only mentioning this turbo because, as of writing, this is the N54 world record holder. The below video shows the PT 7275 breaking the 1000whp barrier.
Final Thoughts on 800+WHP Single Turbos
Pushing 800+whp through an N54 is impressive stuff. It takes a big budget, patience, and knowledge just to name a few things. These are the setups pushing the N54 platform further and further. We think it's exciting to see the N54 continuing to break records, and applaud those with the courage to send it. However, the N54 platform still has a long way to go. As we mentioned, a lot of these 800+whp setups hold nothing more than dyno records.
We suspect people will continue pushing the N54 until proven solutions exist. For now, the N54 is simply struggling to make a truly usable 800+whp. It seems, regardless of power, the N54 is simply stuck in the 10.xx @ 13x mph range. Sure, some have done better but they are very few and far between. Also, the 1/4 mile isn't everything. However, even 1/2 mile and 60-130mph don't match what these N54's are doing on the dyno.
Our Upgraded Single Turbo Choice
We're going to be boring here as it would be our true decision, and the option we believe it right for most readers. We'll take the Precision 6266 or 6466. They're highly proven turbos and can push the N54 right around its limit in stock form. We couldn't justify the budget to truly push an N54 further than 750whp. As such, the 6266 and 6466 are a perfect medium.
On a stock N54 pushing upwards 750whp, we would opt for the 6466 to make that power on less boost. For 650-700whp, we'll take the quicker spooling 6266 option that can make the power on a "modest" 24-26psi. Much under 650whp and we'll take the upgraded twin turbo options.
BMW N54 Upgraded Single Turbo Conclusion
In general, the larger the turbo you opt for the more lag you introduce while simultaneously increasing the boost threshold. Additionally, ball bearing turbos are more reliable, quicker spooling options. This, of course, assumes all else constant. There are many other factors that affect turbo spool such as tuning, fueling, etc. Before opting for the upgraded single turbo that is right for you, strongly consider your goals and budget. Keep in mind the more demanding N54 supporting mods as you push for more and more power.
Ultimately, there are dozens of different single turbo options for the N54. You can find excellent setups for power goals as low as 500whp up to 1000+whp, and everything in between. We honestly believe most N54 owners are best off with a twin turbo setup unless your goals are 600+whp. The Precision 6266 and 6466 are likely great options for most looking to push 650-850whp. Larger, more capable offerings are best left to anyone hoping to push the envelop and move the N54 platform forward.