In our general MHD post we discussed some of the basics of the MHD tuning app and installation. This post will cover the various BMW N54 flash maps along with supporting mods and expected horsepower on each map. To note - this post is based on the V8.1 maps available for the N54.
N54 MHD Flash Tunes
You can skip to the next section if you're familiar with MHD flash tunes for the N54 and simply want to know the recommended supporting mods and horsepower. As a quick background, MHD offers OTS (off the shelf) flash tunes for the N54. Flash tunes essentially re-write the ECU/DME to target more aggressive boost. Flashing the DME also gives the tune full control over fueling, ignition timing, AFR's, etc. This is a major benefit of flash tunes as opposed to piggyback tunes, such as the JB4.
Piggyback tunes act as advanced boost controllers, but "trick" the DME. They do not have full control like flash tunes do. Piggyback tunes simply run higher than stock boost and allow the factory DME tune to make the necessary adjustments. Some people will knock piggyback tunes for this fact, which we do not intend to do. As such, it is important to note we run JB4 piggyback tunes on our N54's and highly recommend this setup to others. However, piggyback tunes have their limits. At some point, the factory tune with a piggyback simply cannot keep up with things like fuel flow.
Enter flash tunes, and MHD's OTS flash options. MHD offers four "stages" for the N54 along with different maps, dependent upon fuel quality, within each stage. Their flash tunes are highly proven and have been the go-to for many in the N54 community.
JB4 + MHD Back-end Flash (BEF)
We must diverge for another brief moment to discuss the setup we recommend above all else - stacking the JB4 piggyback tune with an MHD BEF. The JB4 is loaded with unique features that come with the tune at no extra cost. It allows for steering wheel controls to change maps on the fly within seconds. A great option for those who may want a modest DD tune with the ability to crank thinks into kill mode in a second. It allows for gauge hi-jacking to display boost, AFR's, ignition timing, etc on the fuel and/or oil temperature gauges. Additionally, the JB4 allows data-logging capabilities without the need to purchase the $69 MHD data-logging feature. You can limit boost by gear for 1st, 2nd, and 3rd gears. These are just a few features worth mentioning. We're not done yet.
Most importantly, the JB4 is loaded with excellent safety features. Set a boost safety limit; if boost exceeds target the JB4 instantly kicks back to stock boost. If AFR's go dangerously lean the JB4 may save your engine. Again, it kicks into the stock boost map. It does the same when fuel pressure or meth flow become dangerously low. These are safety features worth having that flash tunes simply do not have.
In summary, the JB4 when coupled with a back-end flash tune retains its advanced boost control, user-friendly features, and safety features. However, the MHD flash tune is given full control of AFR's, timing, fueling, etc. It really is the best of both worlds and the ultimate tuning setup for the N54. This is simply something to consider prior to opting for a standalone MHD flash tune. Anyways, the post is about MHD so let's get back on track.
N54 MHD Maps ("Stages")
As mentioned above, MHD offers four different stages for the N54. Each stage has different supporting mod recommendations. As the stages increase, so do boost and horsepower (assuming all else constant, such as fueling). The available stages include 1, 1+, 2, and 2+. Within each stage there are different options depending upon fueling. Throughout the remainder of the post we will discuss the different stages, requirements, and expected horsepower.
*We highly recommend replacing spark plugs and ignition coils prior to flashing any MHD tunes. Modded N54's are best suited to 1-step colder spark plugs, however OEM plugs should hold up under 400whp.
**ALL horsepower numbers are assuming the N54 is running the recommended mods for each stage. Additionally, power varies from car to car even with the same exact mods. This may come down to differences in dynos, temperature, altitude, engine health, etc. As such, the horsepower numbers we mention are simply rough estimates.
N54 MHD Stage 1 Horsepower & Mods
Mods Recommended: DCI
Target Boost: 14-16psi, tapering to ~10psi at redline
MHD's stage 1 flash tunes for the N54 are basic, entry level tunes. These maps do not require any supporting mods, unless opting for the E50 maps which requires an upgraded low-pressure fuel pump (LPFP). However, due to the increased airflow we recommend upgrading to dual cone intakes (DCI). If not for the slight bump in power, this $80 mod is worth it for the looks and sound alone.
91 Octane/95 RON: 310-320whp
93 Octane/98 RON: 320-330whp
95 Octane/102 RON: 330-340whp
Expected N54 wheel horsepower on the MHD stage 1 maps falls right in the ballpark of 310-350whp. Boost targets become more aggressive on better fuels. Expect 14psi peak on lower grade fuels and up to 16psi on E50. 91 octane is poor fuel and not recommended unless nothing better is available. As fuel quality increases, horsepower sees a bump as well. These stage 1 maps are not aggressive enough to the point E30 fuel has a huge benefit over 95+ octane fuels. However, E50 should give a pretty nice bump in power.
N54 MHD Stage 1+ Horsepower & Mods
Target Boost: 14-16.5psi, tapering to 10-12psi at redline
The stage 1+ tunes are slightly more aggressive, targeting boost a couple PSI higher than stage 1. Due to the additional boost, it is recommended to upgrade your FMIC. You can get by on the stock FMIC, but the tune will pull timing as IAT's get too high. An FMIC is a great mod to have, nonetheless. While peak horsepower on glory runs may not see a huge increase, upgraded FMIC's help with consistency.
91 Octane/95 RON: 320-330whp
93 Octane/98 RON: 330-340whp
95 Octane/102 RON: 340-350whp
Compared to N54 stage 1, the 1+ maps pick up a bit of extra horsepower due to the increased boost and addition of an upgraded intercooler. Expect your N54 MHD stage 1+ tune to put you in the ballpark of 320-370whp. As with any of the N54 stages, 91 octane will result in lower boost targets and horsepower. Higher octane fuels will provide a nice bump in power while E85 mixtures show the best results.
N54 MHD Stage 2 Horsepower & Mods
Target Boost: 15.5-17psi, tapering to ~12psi at redline
Stage 2 maps are not too much more aggressive than stage 1+ maps. Boost targets will likely increase slightly, but catless downpipes will provide the biggest difference. The butt-dyno will definitely approve as DP's will reduce turbo spool time. Excellent N54 mod that we recommend irregardless of the map you choose. Additionally, as with the above stage 1+ tune, a FMIC is not absolutely required but recommended. IAT's and heat soak, on the N54, become more concerning as we increase boost.
91 Octane/95 RON: 330-340whp
93 Octane/98 RON: 340-350whp
95 Octane/102 RON: 350-360whp
Expected horsepower for the N54 on stage 2 maps is in the ballpark of 330-390whp. This is about where E85 mixtures are going to begin providing the big benefits. We're starting to generate enough heat and boost to the point E85's cooling and knock resistance becomes important. Expect boost targets around 15.5-16psi on pump fuels and up to 17psi on E50 mixes.
N54 MHD Stage 2+ Horsepower & Mods
Target Boost: 16-18psi, tapering to about 13-14psi at redline
As with stage 2, we recommend going full bolt-on. These stage 2+ tunes are beginning to push towards the upper "safe" limits of stock N54 turbos. You may even consider upgrading turbo inlets and outlets to help with turbo longevity. They flow more air and assist in reducing WGDC, especially towards redline. You will likely need a custom MHD flash tune to reap the full benefits of upgraded inlets and outlets. Nonetheless, they will make the stock turbos job a bit easier thereby assisting in reliability and longevity.
91 Octane/95 RON: 350-360whp
93 Octane/98 RON: 360-370whp
95 Octane/102 RON: 370-380whp
Stage 2+ maps are the most aggressive OTS maps from MHD. Horsepower is going to max out in the 350-430whp range, depending greatly upon fueling. Stage 2+ with E50 fuel should push peak boost to 18psi. This is also about the max boost we recommend running through the N54 stock turbos with stock inlets and outlets. Pushing the N54 any further on stock turbos is going to require higher E85 mixtures and custom flash maps.
N54 MHD Custom Flash Maps
Recommended Mods: FBO + LPFP + Inlets & Outlets + Meth Injection
Target Boost: 18+psi
Custom flash maps will vary significantly depending upon the tuner you choose to work with. We assume most people considering custom flash options are looking to push beyond 18psi. In this case, you will definitely want to be running FBO with an upgraded LPFP to run E50+ mixtures. Inlets and outlets will also give massive benefits with large torque increases. Power will also see some benefits, but the torque gains will be most impressive.
93+ Octane: 380-410whp / 420-450wtq
E50: 420-460whp / 450-480 wtq
100% E85: 460-500whp / 500+ wtq
It's tough to put any exact numbers on custom tunes. These numbers are pretty aggressive and assume your N54 is about maxed out on stock turbos. There are a few N54's running ~420whp on 93 octane, but that's best case on aggressive timing and absolutely maxing stock turbos. The same can be said for the E50 and full E85 numbers. Again, we are assuming aggressive tunes running FBO + Inlets/outlets + Meth. While these numbers may look tempting, we do not advise pushing the stock turbos this far unless you have plans to upgrade in the near future. If you're not in a position to upgrade your turbos, stick to OTS maps or a modest custom flash.
BMW N54 MHD Flash Tunes Summary
MHD offers an excellent selection of OTS flash tunes for BMW N54 engines. Expected horsepower ranges from 310whp, on stage 1 maps with poor fueling, up to 430whp on the stage 2+ E50 map. It is important to ensure you are running proper supporting mods, especially as you opt for more and more aggressive tunes. For anyone new to the N54 platform, or tuning/modding in general, we recommend starting on a less aggressive tune. Those looking to push their N54's stock turbos to the upper limits should opt for a custom flash tune. However, pushing much past 18-20psi becomes a risky endeavor. As such, these setups should be reserved for those willing or looking to upgrade their turbos in the near future.
As a final note, our favorite setup is the JB4 + MHD back-end flash maps. You must purchase the MHD flasher module for $99, which unlocks free BEF maps. The JB4 allows more aggressive boost targets without the need for a custom flash. With the MHD E85 back-end flash and the JB4 switched to map 7, you can target boost in excess of 20psi.