Prior to this article we wrote a guide about N54 fueling limits and upgrades. However, we didn't dive fully into port injection (PI) since there's a lot that goes into these setups. Those familiar with the N54 platform likely have some idea about port injection. It's the ultimate fueling solution for those looking to make 500+whp on heavy E85 mixes. In this guide, we discuss some of the best N54 port injection kits, manifolds vs plates, PI controllers, setup, and more.
N54 Port Injection Basics
As many understand - N54 engines are very octane hungry. E85 is almost a necessity if you're shooting for big power goals. The stock N54 direct fuel injectors are very capable on their own. However, our HPFP simply cannot keep up with fueling demands at 500+whp on heavy E85 blends.
There are now some HPFP solutions on the market, but they come with concerns of their own. Ultimately, PI remains the most proven and capable method of delivering fuel on high power N54's. A proper port injection setup can deliver north of 900whp on 100% E85. It's an excellent setup for those looking to make 500+whp on full E85.
What's a Part of PI?
So what is this port injection? The concept is very simple, but there's a lot of info between. Anyways, port injection is essentially:
- Second fuel rail
- 6 port injectors
- Fuel lines
These are the basic parts of port injection. It's the addition of a second fuel rail, 6 injectors, fuel lines, and a method to control the setup. At the least you'll need the above parts. However, N54 PI kits have even more potential parts depending on goals. A few extras include:
- Return kit
- Ethanol sensor & analyzer
- Upgraded stock fuel lines
Return kits are for running an external fuel pressure regulator. You usually do not need a return kit or external regulators if your goals are less than 650whp. However, if you're targeting more power you should consider those upgrades. Then there are ethanol sensors and analyzers for those who want an easy means of reading ethanol content. E85 from pumps can actually vary between about E53 and E85. If you're pushing the limits it's important to know the exact ethanol blend.
N54 LPFP Upgrades for Port Injection
Port injection runs off the low-pressure fuel pump. Many N54's start with LPFP upgrades on stock turbos to support more power and higher E85 mixes. This often looks something like a single Walbro 450 or Walbro 525 LPFP. Single pumps usually support about 450-550whp on 100% E85 with port injection. It can vary a lot, though.
Bucketless fuel pumps can support more power, but come with their own cost. They're not good pumps for track-use, canyons, or low fuel conditions. We don't love the idea of these bucketless pumps even though they flow better. Regardless, a single LPFP isn't going to support much over 550whp on full E85. As such, most people running N54 port injection will require dual low-pressure pumps.
Dual setups are often referred to as stage 3 or stage 4 LPFP's. We touched on these N54 setups in our guide about fueling mods. These kits usually feature two Walbro 450 or 525 pumps. A second wiring harness is required to run the second pump. Hobbs switches are also a common method to trigger the secondary pump.
N54 135i, 335i, 535i Manifolds vs Plates
Before you decide on an N54 port injection kit it's important to understand some of the various options. Two major differences in PI kits are full port injection intake manifolds or simple plates. N54 PI manifolds replace the entire stock, plastic intake manifold. A port injection plate simply installs between the stock intake manifold.
Above is a picture of an N54 with a Phoenix Racing Port Injection Intake Manifold. We'll include an image in the next section showing the PI plates so you can see the very visible differences. Anyways, PI plates were the first development on the N54 and have been the go to for a long time. Manifolds are becoming more common for good reason, though. Let's run through some pros and cons of each.
PI Manifold Pros & Cons:
Benefits of a port injection intake manifold on the N54 engine include:
- Stronger than plastic OEM manifold
- Extra ports for BOV, hobb's switch, boost gauges, etc
- Less potential for boost leaks
Some also claim the intake manifolds offer better flow and power gains. However, we're not including that since we don't think results are proven or significant. Many use an aluminum design, which adds a lot of strength over the plastic manifold. It's not terribly common to see blown OEM manifolds. It does happen, though.
With an N54 PI manifold you no longer need to worry about tapping the stock manifold for larger 1/4" BOV lines. They're already integrated in most upgraded manifolds. Then there are the additional ports for a hobb's switch, boost gauges, and other accessories. Lastly, manifolds leave less room for potential leaks versus PI plates.
Some cons of the manifold setup include:
- ~3 pounds heavier
- Heat soak
- Can be more expensive
The aluminum design is pretty light-weight, but you'll still pick up about 3 to 5 pounds of extra weight. Manifolds are also going to soak a bit more heat from the head. However, we don't believe this is a major point. With the velocity of air it shouldn't pick up much of the heat (plus the air is on its way into a much hotter combustion chamber). Otherwise, N54 intake manifolds can be more expensive options.
N54 Port Injection Plate Pros & Cons
Running port injection plates doesn't have quite as many benefits as manifolds, but there are a couple:
- Cheaper setup
- Highly proven
A simple N54 port injection plate is likely to be cheaper than an entire intake manifold. Of course, it depends on brand and exactly which options you look at. It's still generally cheaper. Plates were also the original development on the N54. Many owners run PI plates with great success meaning these are highly proven setups.
A few downsides to N54 PI plates include:
- More areas for boost leaks
- Less compatibility
Adding a plate between the head and manifold simply adds greater potential for boost leaks. A good setup shouldn't run into any issues, though. Otherwise, the N54 port injection plates just don't add as much simplicity or compatibility as manifolds. You don't get any extra ports or features that a full intake manifold upgrade offers.
Best BMW N54 PI Kits
With some of the basics out of the way it's time to decide on the N54 port injection kit that best meets your needs and budget. There are tons of options around, so this is by no means an exhaustive list. Instead, these are a few setups we believe are best for the N54.
1) N54 Phoenix Racing Port Injection Manifold
This is the setup we personally run on our 2007 335i with RB Twos Plus turbos on 100% E85. It's a cheap manifold option that isn't going to win any awards for looks or welds. However, the N54 Phoenix manifold gets the job done for those not looking to break the bank. It uses a strong and light aluminum design to add strength over the plastic OEM intake manifold.
Phoenix manifolds also have the extra ports for a BOV and Hobb's switch. You can buy the N54 intake manifold alone with no extra hardware for $599. Otherwise, add in calibrated 750cc injectors and fuel lines for $999. It's a price that's tough to beat for a complete N54 port injection intake manifold. We really like the simple setup, basic design, and price.
With a proper dual LPFP the 750cc injectors should flow plenty of fuel for 700+whp on 100% E85. You can also upgrade injectors down the road if you ever need more fuel flow. 750cc injectors will typically support about 750whp. You'll want 950cc injectors if you want to go further.
Price: $599 manifold only or $999 with 750cc injectors and fuel lines
Buy Here: BMW N54 Phoenix PI Intake Manifold
2) Fuel-It Basic N54 PI Kit
Here we're looking at the basic Fuel-It port injection kit for the BMW N54 engine. Fuel-It has been building these kits for ages with many of them in use. They're a little more expensive than some other options. It's for good reason, though. Many trust the Fuel-It brand and their products are highly proven on the N54 and many other BMW's.
Anyways, this kit comes with the PI plate, installation hardware, gasket set, and fuel line adapter. This part of the kit will set you back $399. Fuel injectors are sold separately and we'll provide all the necessary links below. 550cc injectors run $269 while 750cc fuel injectors are $369. They support roughly 650whp and 750whp, respectively. If you need more fuel then the 950cc injectors are $469 and will support 800+whp.
Fuel-It makes some great products for a fair price given the fact they're proven. Had we not gone with the N54 Phoenix port injection manifold then this would have been our next choice.
Price: $399 kit + $269-469 for calibrated injectors ($668-888 total)
Buy Here: N54 Fuel-It Port Injection Kit (plate, hardware, gaskets, fuel line adapter)
3) N54 PFS Port Injection Kit
Last up is one of the cheapest N54 port injection solutions we could find. Performance Fueling Solutions (PFS) PI kits start at $249 for the very basics. This kit doesn't have any fuel lines or injectors. Add in fuel lines and you're at $299 while flow matched 550cc injectors bring the price to $549.
These 550cc injectors will flow about 650whp as is standard for that size injector. PFS only offers these 550cc injectors as far as we can tell. As such, if you need more flow you'll want to stick with the $299 kit with lines and source your own injectors. Anyways, we don't know much about Performance Fueling Solutions on the N54 engine.
It's one of the best looking budget options we could find, though. We would personally spend the extra $119 to run with the similar N54 550cc port injection kit from Fuel-It. However, if you're on a tight budget those savings can go a long way.
Price: $299 kit w/ lines or $549 with 550cc injectors
Buy Here: PFS N54 Basic PI Kit
4) Summary & Other PI Options
Again, the above is far from an exhaustive list. There are other great PI manifolds around, such as Doc Race. The list could go on and on. We really like the Phoenix option for its excellent price and simplicity. Some other manifolds use non-OEM designs that require new charge pipes and other stuff. They're also more expensive up-front.
When it comes to N54 port injection plates we like Fuel-It and would pay a small premium for the brands proven product. There are budget options around like the PFS kit we discussed. You could also probably use a bit of ingenuity and piece things together, source your own injectors, etc for a lower price. It would take some time and effort to save maybe $100, though.
Anyways, when it comes to port injection kits with lines, adapters, hardware, gaskets etc $550-850 is a standard price. On the lower end are budget kits with 550cc injectors. N54 kits with higher flowing 750cc or 950cc injectors will cost a bit more, but deliver fuel flow for 700+whp on full E85. The $999 complete Phoenix kit is about as cheap as things get for port injection manifolds. Note - you could downgrade to 550cc injectors and get the price down to $899.
N54 Port Injection Controllers
Now that you now what kit best meets your needs and budget it's time for the next step. You need a way to actually control the flow of port injection. The two common methods are the JB4 PI controller or the Split Second AIC6 controller for flash tunes only. If you're running a JB4 tune already then the decision is an easy one - the N54 JB4 Port Injection Controller. You could also run an AIC6 with JB4 integration, but we don't like that option.
Those running flash tunes only will likely opt for the Split Second AIC6 PI controller at $399. Note - you might find it cheaper if you buy it with an N54 PI kit. Otherwise, you're going to need to purchase a JB4 piggyback tuner which will set you back $479. Then add in another $349 for the PI controller. It makes control a lot more expensive if you don't already have the JB4 tune. As such, if you're flash only the AIC6 is by far the cheaper option.
The JB4 PI controller does feature better integration than a Split Second AIC6 controller. We really like the JB4 setup. However, we understand those with flash only will find it tough to swallow another $479 for the tune.
JB4 PI Controller - Older JB4's*
*Applies to any JB4 shipped before 11/2015.
We're adding this section for those running older JB4's. We bought the JB4 for our 2007 335i back in 2014. It was after the G5 ISO boards, but the JB4 went through some updates since then. One notable update is the N54 JB4 Anti-Lag & Port Injection Driver. It's the 24K22 chip and JB4's shipped before November 2015 do NOT have this updated chip.
As such, you'll need to update to the 24K22 Anti-Lag and Port Injection chip. The link for JB4 upgrades can be found here. Don't overlook this step as the JB4 will not be able to control the port injection without this chip.
Total Cost of BMW N54 PI Kits
We were hoping to have a bit more time and space to cover setup and install. However, we'll skip over this info as there are tons of great guides, DIY posts, videos, etc. regarding install. You can find info pretty easily whether it be for simple setups or full blown PI kits with return kits and ethanol sensors.
Instead, we'll devote some time to give a breakdown of all in costs for N54 port injection setups. Please note - this info is full of rough estimates. Actual costs by power goals can vary. A lot of it simply depends on the health of things like the stock HPFP and injectors. After all, even with port injection the stock DI system is still responsible for a lot of the fueling demands.
*Power ranges in the titles are assuming 100% E85. We'll try to add some clarification, but more power may be possible on lower blends like E40, E50 and E60.
N54 500-550whp PI Setups
To make up to about 500 to 550whp on 100% E85 you'll be looking at pretty basic PI upgrades. These setups may support up to about 575-625whp on lower blends like E40 or E50. The higher end of the ranges will be for the bucketless LPFP solutions. Again, these have the downsides of fuel starvation on less than 1/2 a tank of gas. They're especially prone to starvation on the track or canyon runs.
- Fuel-It Kit w/ 550cc injectors = $668
- OR PFS Kit w/ 550cc = $549
- Walbro 450 or 525 LPFP = $200-500 (also DIY options for less than $150)
- PI controller = $300-400
Total Price = ~$1,050 to $1,600
Fuel-It also has simple packages you can purchase for 500-600whp goals for about $1,480 to $1,600. Again, the higher end of the power range is with bucketless LPFP's on less than 100% E85. Most of these kits will start running low on fueling around 550whp with 100% E85. We recommend building in some headroom with fueling mods, so if you're pushing the limits you'll want to consider dual LPFP upgrades.
N54 550-750whp Port Injection
If your goal is a reliable 550+whp on full E85 then it's time to upgrade to dual low-pressure pumps. These stage 3 and stage 4 LPFP's can add quite a bit of cost, especially if you stick with bucketed fuel pumps. We really prefer buckets and believe it's the best choice for most. Otherwise, you really don't want to push the car hard with less than 30-50% fuel in the tank.
- Fuel-It Kit w/ 750cc injectors = $768
- OR Phoenix Manifold w/ 750cc injectors = $999
- Dual Walbro LPFP
- Fuel-It stage 3 & 4 bucketed pumps = $850-1,300+
- BMP stage 3 bucketless = $500-650
- DIY bucket options = $400-600
- Hobb's switch to trigger secondary pump = $45
- N54 port injection controller = $300-400
- OPTIONAL under 700whp - Return kit & external fuel regulator = $300-400+
- OPTIONAL - Flex fuel kits (ethanol sensor & analyzer) = $200-350+
Total Price = ~$1,550 to $3,000+
For the savvy crew willing to spend time researching, DIY'ing, and piecing stuff together you can save some decent money. 550+whp setups can start around $1,300 if you're willing to go to great lengths. Off-the-shelf options with the Fuel-It kit and BMP bucketless pumps will start around $1,650. If you want to stick with the bucket then your costs are going to come in around $2,000.
Above 650whp it's a good idea to consider a return kit with an external fuel pressure regulator. This can drive N54 port injection costs into the $2,500 ballpark. Then there are flex fuel kits and other possible add-ons that can drive the price to $3,000+. It can be cheaper depending on how and where you source everything, but 650+whp on full E85 is still a pricey setup.
750+whp N54 PI Setups
First of all - 750+whp is above the long-term limits of the N54 engine. Even on 100% E85. As such, these setups are mostly for built motors and people really pushing the limits of the platform. This is where you enter no expense spared territory. Don't cheap out on stuff if your goals are 750+whp. You're going to need a good port injection kit with all of the add-ons.
The price can be pretty similar to above except you'll be spending about $100-200 extra on injectors. It's time to make the move to 950cc or even more capable injectors. It's just that the return kit becomes a necessity at this power. We'll avoid breaking down all of the costs again and just give a quick overview instead.
Yes, setups can be had for less than $2,000 if you're savvy. Piece things together, bucketless DIY fuel pumps, etc can help drive costs down. However, if you're looking for an off-the-shelf option then $2,500-3,000+ is about the starting price.
Total Price: $2,000 - $4,000+
Fuel-It offers a complete kit with all lines, stage 4 bucket LPFP's, return kit, and options for fuel injectors. There is a $400 coupon code on their website for this package. Even with that discount the kit starts at $3,000 with only 550cc injectors. Start adding in all of the upgrades and this kit can push about $3,650 after the discount.
BMW N54 Port Injection Summary
Well, there you have it. Sorry for the lengthy 3,000+ word article, and the fact we still didn't cover some of the specifics. There is just so much that goes into N54 port injection. Fortunately, we're talking about an older platform with tons of info and knowledge out there. DIY guides and videos exist for all the various installs and setup. Plenty of tuners are very familiar with PI, too. Point is - the extra resources are floating around.
Back to the summary. N54 PI is the proven method to make 500-900+whp on this platform. Down to the basics it's essentially just a second port fuel rail, 6 more injectors, fuel lines, and a controller to handle the fuel flow. Of course, there is so much info and other details in between. There are also endless N54 port injection kits from many different vendors and manufacturers.
PI manifolds and simple plates both have their pros and cons. We like the manifolds for there simplicity, but the entry price is generally about $300 higher. Fuel-It makes some awesome kits, but there are cheaper options for those on a really tight budget. Regardless, starting prices for complete N54 port injection setups is about $1,100 for the savvy crew. OTS options where you click to buy a complete setup are going to start around $1,400.
If you're looking to make 550+whp on full E85 then PI kits start to get a bit more expensive. You'll want dual LPFP's with more capable injectors. Want more than 650whp? Now you're looking at return kits and external regulators, so the price can quickly add up to $2,500 to $3,500+.
What's your experience with N54 PI? What setup are you running or considering?
Drop a comment and let us know!