B48 Tuning Guide – 300whp for $1500

The B48 is one of BMW’s newer modular engines, that are fitted in a host of entry-level models in their lineup including the 230i, 330i, 430i, and 530i.  You will find this 4-cylinder turbo to be responsive and fuel-efficient. However, once you get used to the power, the B48 may feel a bit flat and could use performance and tuning upgrades. To unleash easy horsepower gains, we will be going over 5 modding options in this guide that are available for your BMW or MINI with the B48 engine. Given the BMW B48 is a relatively new engine, you may consider the fact that you could be voiding your warranty with certain B48 performance mods.

For more information about the BMW B48 engine including specs, performance mods, and reliability information, take a look at our Ultimate BMW B48 Engine Guide.

If you would rather consume this content via a video, check out our How to Build a 300WHP B48 video below:

1) B48 Tuning – Flash & Piggyback Tunes

Tunes are one of the easiest modifications to unleash an additional 30-50hp and similar torque on the B48 engine. There are two common tunes you will come across: flash and piggyback tunes. Although both types of tune increase power, there are some major differences between how they go about it. A flash tune essentially re-writes the factory ECU whereas a piggyback tune controls boost and allows the factory ECU to make the necessary adjustments.

B48 Tuning – Piggyback Tunes

In other words, a piggyback tune uses stock timing, load, fuel tables, etc; it simply tricks the ECU into thinking that boost is under the factory level. For example, assuming stock B48 boost target is 10psi, the piggyback tune would trick the ECU into thinking it is only running at say 5psi. The ECU would then increase boost another 5psi to reach its 10psi target when in reality the B48 is now actually making 15psi. Various sensors then make the necessary adjustments to compensate for the additional load, AFR, fueling, etc. required for the increase in boost.

*Since piggyback tunes “trick” the ECU they are hard or impossible for dealerships to recognize. As long as you uninstall the tune, there should not be any evidence your B48 was ever tuned.

B48 Tuning – Best B48 Piggyback Tune Options

While piggyback tunes might not be the go-to tuning solution for most people in the BMW community anymore, they are still a great option for those who want a no-hassle tuning solution that is as easy as plugging it in and pushing a button.

JB4s are one of the most common tunes in the BMW turbo era – and for good reason. The JB4 is an excellent piggyback tune with advanced safety features, simple data logging, and tons of product support. You can’t go wrong with the simple plug-and-play installation, on-the-fly map changes in seconds, and impressive power gains. Additionally, the steering wheel controls and gauge hijacking are unique, convenient features that complement an already excellent product for the B48 engine.

If you aren’t sold on the JB4, Dinan offers two piggyback tunes for the B48 as well: a simple boost controller (Sport Performance Tuner), and a more advanced piggyback (Elite V2). The sport performance tuner is a solid budget option that simply controls and raises boost. It is about as basic as a piggyback tune can get and does not come with the same features or flexibility as compared to the JB4.

Dinan’s Elite V2 for the BMW B48 has a large price increase compared with the sport performance tuner but offers more advanced control. The Elite V2 actually adjusts more parameters than simply boost. Dinan claims this delivers the smoothest performance. Take it as you will – we don’t fully buy into that claim. Nonetheless, it offers additional power over the Dinan boost controller.

JB4 B48 HP Gains: 30-40whp

JB4 B48 TQ Gains: 30-40wtq

Buy Here: B48 JB4 Tune

Dinan Sport Performance Tuner HP Gains: 20-25whp

Dinan Sport Performance Tuner TQ Gains: 25-30wtq

Buy Here: Dinan.com

Elite V2 HP Gains: 30-35whp

Elite V2 TQ Gains: 30-40wtq

Buy Here: Dinancars.com

*All tune horsepower and torque numbers assume the car is otherwise stock running 91/93 octane pump gas

B48 Tuning – Flash Tunes 

At this point in time, flash tunes have unquestionably become the most common tuning option for most modern turbocharged BMW engines, including the B48. Since flash tunes offer a more comprehensive method compared to piggyback tuning, they tend to be far more customizable and extensive in their scope.

Due to the increasing demand for quality flash tunes for the B48, the market is full of some great flash tuning options provided by a number of quality vendors. The two most common B48 flash tune providers include both MHD and BM3. 

Before we jump into specifics about the specific flash tunes available for the B48, let’s talk a bit about what B48 flash tunes are. Overall, flash tunes are the more in-depth and comprehensive method of tuning, as they essentially rewrite the original DME programming. This grants the tune complete control over critical engine tuning parameters, including boost, fueling, timing, and load, thereby enabling precise customization. Typically, they are uploaded to the DME rather than being physically plugged into anything. 

Most flash tuning software comes with supplied off-the-shelf maps that are designed with specific modifications in mind. For example, MHD and bm3 both offer stage 1 flash tunes that work with no additional modifications. However, their stage 2 flash tune was made to be used in combination with a downpipe upgrade and an intake. 

Flash tuning software is also how most custom tuners develop custom tunes for B48 BMWs and most other makes and models as well. If you intend on getting a custom tune, it is important to ask your preferred tuner what software they are most familiar with before pulling the trigger on any of the available B48 flash tunes.

*Since flash tunes re-write the ECU dealership can identify that the B48 is or has been tuned/modified in the past.

Best B48 Flash Tuning Options

Ultimately, deciding on which flash tune to tun on your B48 pretty much boils down to personal preference. At this point, the B48 flash tuning space is dominated by two B48 tuning companies including Bootmod3 and MG Flasher. Both options are quality, with both tune options being highly touted in the B48 community.

With that being said, the Bootmod3 B48 flash tune is unquestionably the most popular option, as bm3 has been around for a long time and has built quite a good reputation for themselves in a number of BMW engine communities. Bootmod3’s B48 package comes with a number of ready-to-go canned tunes that are capable of boosting horsepower and torque by over 50% on some 20i B48 models. Additionally, the bm3 tune offers a number of other perks and features, including anti-lag, ethanol, and flex-fuel support, datalogging, and plenty of other features.

MG Flasher is a newer offering in the B48 flash tuning space, but those who have installed it have nothing but good things to say about it. Performance gains are very impressive, with MG Flasher claiming that 310 horsepower is attainable with their stage 2 OTS tune. MG Flasher offers their flash tunes for both gen 1 and gen 2 B48 engines, with the latter version yielding more impressive results. At just $299.00, the MG Flasher B48 tuning software is significantly cheaper than bm3’s tune. However, it does lack some notable features that bm3 offers, including datalogging.

bm3 B48 HP Gains: up to 54% whp gain

bm3 B48 TQ Gains: up to 50% wtq gain

Bootmod 3 (bm3) Flash Tune B48 – protuningfreaks.com

MG Flasher B48 HP Gains: up to 100 whp gain

bm3 B48 TQ Gains: up to 70 wtq gain

MG Flasher B48 Flash Tune – mgflasher.com

2) Catless/High Flow Downpipe

A catless downpipe for the B48 is the second-best bolt-on B48 modification, only behind a tune. The restrictive OEM downpipe, which contains a catalytic converter, results in increased back pressure, decreasing the efficiency of the turbocharger. While a high-flow B48 downpipe retains a catalytic converter, they are far less restrictive than the factory cat, freeing up some power and decreasing turbo spool time. A catless B48 downpipe removes the catalytic converter altogether, allowing for the biggest gains. By upgrading to either a high-flow or catless downpipe, you eliminate the biggest restriction in the factory exhaust system.

By upgrading your B48 downpipe, you will immediately notice a surge in low-end torque that hits almost instantly. With that being said, it is also important to note that a catless B48 downpipe will have an impact on emissions. If you choose to install a B48 catless downpipe, it will cause you to fail an emissions test.

B48 Catless Downpipe Sound

Some people are concerned about making their B48 too loud with the installation of a catless downpipe. While it will make the car louder it is nothing absurd. Cold-start will make a bit more noise and WOT pulls will sound slightly louder and deeper. However, if you accelerate normally or cruise at highway speed, the B48 sounds nearly stock. Therefore, in our opinion, it is really the best of both worlds. Great sounds when you want them at WOT, and stock sounds cruising around town. We’ll include a sound clip of what a catless B48 sounds like below.

If you are still concerned with the noise factor and don’t want to be quite so ostentatious, a high-flow downpipe might be your best bet. While you will sacrifice a bit of performance when compared to a catless downpipe, a high-flow B48 downpipe will still provide a good bump in power while drawing less attention.

B48 Catless Downpipe HP Gains: 10-15whp

B48 Catless Downpipe TQ Gains: 15-20wtq

Buy Here: B48 VRSF Catless Downpipe

3) Upgraded Air Intake (“Cold Air Intake”) B48

B48 cold air intakes are an excellent mod not only for the slight power gains, but also for the intoxicating sound. Additionally, an upgraded intake for the B48 is an excellent stepping-stone modification that will help bring the most out of other mods later down the line. Unlike some older turbo BMW engines, such as the N54, the stock B48 air intake is not quite as restrictive. In fact, many B48 owners opt to stick with the factory airbox and simply upgrade to a larger and higher-flowing filter instead of upgrading the entire intake assembly.

Despite the factory B48 airbox not being that restrictive, there are still a few additional benefits to upgrading to an aftermarket intake. Most of the aftermarket B48 intakes on the market are open-air intakes, meaning that the air filter isn’t encased in an enclosure. In general, open-air intakes aren’t as good as closed-air intakes in terms of intake air temperatures. However, it isn’t as big of a factor with intercooled engines like the B48. The real benefit of open air intakes is their ability to funnel the maximum amount of air into the engine as possible, increasing combustion, helping turbo efficiency, improving throttle response, and making awesome induction sounds.

B48 Intake HP Gains: ~5whp

B48 Intake TQ Gains: ~5wtq

Buy Here: BMS B46/B48 Intake

4) E85 Mixtures

With the right tune, we recommend running a 20-30% E85 mixture on the B48 engine, if available. Really, we recommend E85 on any tuned, turbo BMW engine. E85 is like a godsend in the tuning and performance world. It burns cooler and is higher octane as compared to pump gas. This leads to significant benefits such as reducing the chance of knocks and pre-detonation events. As such, higher boost and more aggressive timing can be run on E85. In layman’s terms – power, safety, and more power are all attainable when using an ethanol blend.

The JB4 can handle roughly 20-30% E85 mixtures. Certain flash tunes can handle similar E85 mixtures, and possibly more with the right supporting mods. More E85 equals more power.

B48 E85 Gains: 10-30+whp

B48 E85 Gains: 10-30+ wtq

*20% E85 mixtures will be on the lower end while 100% E85 will be on the higher end of power gains. Exact power gains also highly dependent upon tune.

5) Charge Pipe B48

Although a charge pipe will not increase power, it is a highly recommended supporting mod for the BMW B48. Like many of the other turbo BMW engines, the B48 chargepipe is susceptible to bursting or cracking even on stock boost. Upgrade the B48 chargepipe sooner than later and avoid being left stranded on the roadside.

Buy Here: Masata B48 Aluminum Chargepipe

BMW B48 Tuning Guide Summary

At the time of writing, the B48 is still a relatively new tuning platform. Not many are out of factory warranty so few people are really pushing the limits of the B48 platform. However, the above mods can be had for roughly $1,500 or less in total. The B48 is already proven as underrated from the factory making 220+whp and 240+wtq stock. With some B48 tuning, it is possible to push over 260 wheel horsepower and 290 wheel torque with no additional mods. Throw a few bolt-ons and some E85 in the mix and you’ve got an engine capable of pushing upwards of 300whp.

300whp may not seem overly impressive in today’s world of big horsepower cars. Though, the B48 is a newer platform that has a long way to go in the aftermarket world. We suspect the B48 will be an affordable, high-performance engine once its full potential is tapped. With instant low-end torque and a broad power band it is hard to go wrong with B48 tuning.

Looking for more mods and power? Check out our B48 turbo upgrade guide and intercooler/heat exchanger upgrade article. We’ve also written a comprehensive B48 Engine Guide, which covers all aspects of the B48 in detail.