N54 JB4 vs Cobb vs MHD

BMW N54 Tune Comparison: JB4 vs. Cobb vs. MHD

About Zach Mayock - DieselIQ

Meet Zach

Zach is a BMW enthusiast with a passion for performance. With over 10 years of experience modifying and performing DIY work on BMWs, he’s developed a deep understanding of virtually every BMW engine. He’s also the proud owner of a 600whp N54 with upgraded twin turbos and an E30 325i drift car and has a particular affinity for the S58 engine. Zach is highly knowledgeable about all things BMW, but his expertise in tuning and performance mods sets him apart. His experience as an enthusiast, combined with his technical knowledge, makes him an essential resource for anyone looking to improve the performance of their BMW.

Tuning is without question the most important modification when it comes to extracting maximum performance from your N54 engine. Before purchasing a tune for your N54 it is important to consider the pros and cons of the available tunes on the market. This post will highlight the differences between the common N54 tunes and hopefully help identify which tune is right for your goals.

Piggyback vs. Flash Tunes

An important aspect of tuning your N54 is the difference between a piggyback tune and a flash tune. I will briefly explain the major, but not exhaustive, differences between the two types of tunes. A piggyback tune is a direct plug-and-play N54 tune; this allows you to install the tune directly to the stock ECU. A piggyback tune essentially controls boost by modifying or altering the signal sent to the computer; the ECU still believes the car is running stock boost levels (around 8-9psi). The computer is still running the factory timing and fueling tables. However, by altering the boost signal, various engine sensors and controls recognize the need to increase fuel flow and adjust timing on the fly to compensate for the higher boost and power.

On the contrary, a flash tune completely remaps or reprograms the stock ECU; this is installed by flashing the new software through the OBD port. A flash tune completely rewrites the stock boost, timing, and fueling tables. Flashing the computer allows for greater accuracy, but is more complicated than simply piggybacking the ECU. This, in turn, may negate or reduce the effectiveness of some of the safety features that are programmed into the stock ECU tune. However, the ability to completely reprogram the ECU does allow for more aggressive and consistent tunes.

In summary, both tunes are very safe and effective if done properly. Due to the ease of piggyback tunes, they are typically less costly than the alternative flash tunes. Piggyback tunes also allow you to switch maps in seconds while on the fly, while a flash tune takes several minutes to rewrite the ECU’s programming. Advancements in the N54 tuning community have allowed for the use of back-end flash maps coupled with piggyback tunes. This allows for the best of both worlds and will be discussed later in the post.

N54 Piggyback Tunes

Burger Tuning JB4 G5 – $479

Burger Motorsports JB4 G5 piggyback tune is without a question the most popular tune in the N54 community. Terry and the guys at Burger Tuning are highly involved in the N54 and BMW community and are constantly improving their products. Burger Tuning offers great product and tuning support and there is endless information regarding their products. One great feature of the JB4 is its Map 5 auto tune. This map is constantly making adjustments based on fueling (e85 mixtures vs. pump gas), temperature, and many other parameters.


  • Unparalleled product support and information
  • Great safety features
  • Exceptional boost control
  • In dash gauges
  • Auto-tuning variables


  • Cannot be used as a standalone tune for larger turbos
  • Limited by the stock ECU timing table and fueling

The cons of the JB4 may be irrelevant as back-end flash tunes coupled with the JB4 solve these issues. MHD offers some very cost effective back-end flash maps for the JB4. The back-end flash shifts the timing, VANOS, and fueling to the flash side while the JB4 retains its more accurate boost control, in-dash gauges, E85 autotuning, and various safety features.

Buy Here: BMW N54 JB4 Tuner

N54 Flash Tunes

MHD Flash Tunes – $148 to $364

If the piggyback JB4 option isn’t right for you, we highly recommend opting for the N54 MHD flash tuning app. We’ve written a few other posts regarding MHD. They offer great off the shelf (OTS) flash tunes. Four map packs are available, including: Stage 1, 1+, 2, and 2+. Each map pack comes with different tunes depending on octane or ethanol content. The N54 map packs must be purchased for $49 each (you only need one, unless you want more options).


  • Cost effective
  • Excellent OTS tunes
  • Unique features
  • Highly proven


  • Cannot be used to control meth or port injection
  • Unable to change maps/tunes on the fly
  • Less safety features compared to JB4

All things considered, the MHD is an excellent tuning option for the N54. Ultimately, as referenced above, we recommend opting for the JB4 and coupling it with the MHD back-end flash maps. The back-end flash maps are free with the purchase of the MHD flasher module for $99. Additionally, JB4 + MHD back-end flash allow for aggressive tunes. Map 7 on the E85 back-end flash may target in excess of 20psi.

COBB Accessport V3 – $650

COBB’s Accessport V3 is one of the most common flash tunes for the N54. The device comes with many built-in flash maps and can be flashed simply by plugging the Accessport into the OBD-II port. Additionally, COBB and other tuning companies offer customized flash tunes specifically for your car (although this comes with an extra cost for each tune). These customized tunes are able to deliver great accuracy and consistency by developing maps designed specifically for your mods and goals.


  • Store up to 100 flash maps
  • Customized tunes
  • Greater accuracy and consistency than standalone piggyback tunes
  • Great support and product information
  • Supports all different mods, including larger turbo(s)


  • More costly than JB4
  • Additional costs for customized tunes
  • Less safety features than piggyback tunes
  • Less boost control

COBB offers an all around great product and is an excellent option for those looking for a flash tune. Customized flash maps deliver excellent accuracy, however, they come with an extra cost. Flash tunes alone also do not allow for gauge hijacking and the stock ECU safety features offered from piggyback tunes.

Link: https://www.cobbtuning.com/products/accessport/bmw-n54-accessport-v3-ap3-bmw-001

Other Flash Tunes:

Dinan and Wedge, among many other tuning companies, offer standalone flash tunes for the N54. Many of them have similar pros and cons to the COBB, as such, I decided to skip mentioning them. Most importantly, I wanted to cover the benefits of running these flash tunes coupled with a piggyback tune.

Back-End Flash for N54 Piggyback Tunes

As mentioned throughout the post, running a back-end flash coupled with a piggyback tune allows for the best of both worlds. Piggyback tunes have unmatched safety features, boost control, ethanol auto tuning, and many other features that flash tunes cannot offer. However, piggyback tunes are limited by the ECU’s factory flash. They simply modify the boost signal sent to the ECU and allow the ECU to adjust timing and fueling on the fly based on the increased boost levels. This allows for less accuracy as the ECU can only adjust these parameters so much.

A back-end flash reprograms the ECU and allows the flash tune to control timing, fueling, VANOS, and other functions. The piggyback tune allows for superior safety features and boost control, while maintaining on the fly map changes, gauge hijacking, shift lights, etc. Combining the benefits of piggyback and flash tunes gives the best of both worlds; the flash tune ensures accuracy while the piggyback tune maintains many safety and control features that flash tunes do not offer as standalone tunes.

BMW N54 Tuning Options Summary

This post was intended to highlight the differences between piggyback and flash tunes while addressing the benefits of combining the two. Due to the JB4’s superior product support, development, and information related to the product, we believe this is truly the best standalone tune for the N54. The JB4 has many excellent safety features that a flash tune cannot offer; it also allows for ultimate boost control. The JB4 offers many options to add a back-end flash for more accurate and customizable tuning.

Burger Tuning’s excellent involvement and support in the N54 community means the JB4 is always evolving and improving. Regardless of your tuning goals, the JB4 has something to offer for everyone. Couple the JB4 and MHD back-end flash tunes for the most powerful, aggressive off the shelf tunes.

What tune do you run on your N54?

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    1. Hi Mario – great question. You are indeed able to run the JB4 stacked with a COBB back-end flash. The COBB flash tune would control most of the tuning parameters while the JB4 would act as an advanced boost controller. Additionally, the JB4 would still provide all of it’s features including the gauge hijacking (should you choose) and advanced safety functions. In our opinion, running a JB4 with a back-end flash offers the best of both worlds.

  1. Hey, I just picked up a used 2011 335is manual. Since it already has a factory tune from BMW would a JB4 or Cobb be as effective? In other words i don’t want to spend $1000 if the boost would only be minimal. So mainly do you think it is still worth the tune since it is an IS. if so, both flash and piggyback?

  2. Drew – Congrats on the new car, that thing will be a lot of fun. Always loved the 335is, but didn’t want to pony up on the $ to get one. Anyways, I’m not overly sure what factory tune you have from the dealership, but my guess is it provides very minimal power gains. From their perspective, they aren’t going to increase your boost pressure (psi) in order to generate more power, knowing that it likely might cause more repairs needed for your car under warranty.

    I would recommend picking up a JB4, installing it and driving it around for a bit and then go from there depending on how happy you are with the power. You can click our link above to buy it on Amazon! (it helps us pay for the costs of running this website, which isn’t cheap!)

  3. How is MHD compared to these tunes? Also can you tell me if it would be okay to switch out the JB4 with an MHD tune, I got this from your post about building a 500HP N54. Sorry, I’m new to the car scene but I’m growing on to it! Thanks

    1. MHD is a backend flash that you can couple with the JB4 or other tuners. For example, Zach runs the JB4 and couples it with MHD’s flash to run 50% E85. The two are complements rather than separate tuners. You can run MHD without a JB4, but I wouldn’t recommend it. Terry has a good write-up and FAQ about using the JB4 and back-end flashes such as MHD.

      You can read it here: http://www.n54tech.com/forums/showthread.php?t=29236

  4. Hi, idk if anyone is paying attention to this article 2 years later but here goes nothing. Like Drew I also picked up a 2011 335is. I’m actually interested in tuning for fuel economy (very unusual, I know). I was inspired by an “Ecovette” video on YT. The guy got 40 mpg on the highway without sacrificing power. Does such a thing exist for the N54 without a custom tune? Ideally something like a JB4 that I can change between ‘eco’ and ‘sport’ on the fly.

  5. Hi I have MHD and do not have jb4 software. Can I use the Jb4 backened flash app and maps through MHD. Thank you

  6. So I have a jb4 and want to run an aggressive tune with bolt ons and upgraded fuel pump. Will ruing an mhd flash with the jb4 limit my hp or is there a way to actually get the stage 2+ performance with a jb4 ?

    1. Hi David,

      Good question. A JB4 and MHD back-end flash is actually the most aggressive OTS tuning option for the N54, as far as we’re aware. MHD stage 2+ generally runs under 20psi at its absolute peak boost. The JB4 on Map 7 with the E85 MHD back-end flash map can and will target boost in excess of 20psi in suitable conditions with proper fueling and supporting mods. E40 or greater mixtures are recommended for this tuning setup. You’ll want to consider an N20 TMAP sensor if you plan to run that map as the N54 OEM TMAP can only read boost up to about 20.5psi.

      Best Regards,

      1. Thank you Zach Is there a way you can give me a link or point me in the right direction for the best map setting for my setup. Thanks

        1. Hi David,

          Shoot. I am trying to remember where to locate the information on boost by map. It may be buried in the thread found here. I know map 1 targets about 17psi peak, map 2 about 18.5psi, map 3 remains for WMI, map 4 is stock boost, map 5 is “auto-tuning” and I believe will target about 16-18.5psi, map 6 is user adjustable, and map 7 can target 20+ psi.

          The pump gas BEF can be used for pump gas or up to E30 fueling. E85 BEF maps are designed for those running E40+ fueling. I’ve mostly stuck with running the pump flash on E30 fueling and map 2 and I generally see boost targets around 18-18.5psi. I tried my hand with the E85 BEF on Map 7 and managed to blow my bank 2 turbo on ~19.5-20psi peak boost. Long story and there were other factors at play that likely caused the blown turbo. I’m also at ~5,300 feet elevation so that adds another factor where the turbos are working much harder than they would be at sea level.

          Happy to discuss more in-depth on the phone and/or via text. You can reach me at 832-443-1506. Please leave a voicemail or shoot me a text if I don’t answer so I know to get back to you.

          Best Regards,

  7. Hi Zach,
    I have an interesting situation, that I’ve not seen mentioned on any of your posts so far. I have recently bought and upgrade a 2009 335i E92. It’s LOADED!!! VRSF catless downpipes, M Performance exhaust, 7.5″ FMIC, upgraded Hexon RR600 turbo’s, VRSF custom inlets/outlets and charge pipe, FORGED aluminum diverter valves with upgraded yellow springs, engine ported and polished w welded custom pcv by Motiv, I also run a Walbro 450 LPFP, BMS cowl delete, DCI’s and hi/low Oil Catch Cans and a Spec Stage 3+ clutch with SMFW, M3 suspension and KW coilovers. It also has a custom MHD tune by Jake at Motiv.
    What I am interested in doing is putting a JB4 on it, and using a MDH backend flash, for the safety and control just as you guys recommend. However, my car already makes well over 20psi of boost. Sometimes hitting upwards of 26-28psi. But more regularly, 21-22psi. So I’m a bit confused how to proceed, after reading this information. In end I definitely want to go with the JB4 w/ a MHD backend flash. But I’m full of questions now that I’m reading the really low boost pressures from doing this. Can you give me some advice?

    1. Hi Stevae,

      I’d stick with your current custom tune unless you’re having any issues for whatever reason. A JB4 + MHD is great for off-the-shelf tuning options (the boost referenced is for OTS tunes) and can be great for custom tunes too. However, you’d need a new custom flash tune if you added the JB4 (or you can run a hybrid turbo OTS map). Either way, custom tuning is definitely a superior option to off-the-shelf tunes in the longer run.

      The overall control and flexibility with the JB4 is nice to have in some situations. From what we know there’s nothing but great things over at MOTIV. Since you’re already running a custom tune from them I think you’ll be best sticking to it.

      We probably should specify more in the post, but we really like the JB4 + MHD BEF for OTS tunes. Once you move onto custom tuning it’s mostly personal preference. Some like the JB4 for meth and/or port injection control among a few other features. However, plenty others run standalone flash tunes with great success too.

      Best Regards,

  8. …Also would like to know can you put a JB4 on a car that ALREADY has a custom MHD flash on it, or do you have to get rid of the custom flash before adding the JB4? Thanks.

  9. So just to be clear, you don’t think the safety features of the JB4 is worth putting on my car, and then getting a custom BEF??? I understand that normally, the BEF’s are OTS flashes, but can’t you put a custom BEF with a JB4? And to further be clear, one of the biggest reasons I want to add a JB4 is two fold, first I want to be able to change performance on the fly, and second the safety built into the JB4 is better than the MHD flash alone. Or am I missing something?

  10. Even though I haven’t gotten an answer from you on my last few questions, I’m still going to share another bit of information I got from BMS. They told me that I can install a JB4 right on top of a custom MHD flash, and then just set it to BEF, without actually flashing a BEF. So that’s also very interesting, as IF this works, and I can get all the benefits of my current custom flash, and the safety and versatility of the JB4, then I will definitely have the best of both worlds. Cheers!

    1. Hi Stevae,

      Sorry we didn’t get back to you on the last few. Got caught up with travelling and some family in town during the holidays. Interesting – I didn’t think it would work that way, but I suppose that makes sense as long as all the JB4 settings are correct.

      As you mention, the versatility of the JB4 is nice to have. It adds a bit more flexibility with boost control without the need to continually re-flash the DME every time. Definitely one of our favorite features. It’s nice to daily drive on a modest, lower boost map and be able to turn things into kill mode in seconds.

      Best Regards,

  11. Ando
    stevae wei

    Tue, Dec 29, 2020 at 10:17 AM

    Yeah, that was the first time I had heard this as well. I’ve copy/pasted their message to me below:

    Hi Stevae,
    That is actually pretty common to do. You can stack JB4 on top of any flash tune.
    Ideally you want to load our own back end flash, but you can also use JB4 on top of any regular flash.
    You just need to enable back end flash mode on the JB4

    Burger Motorsports Support

  12. I have a 2008 335xi with an n54, I just added 3.5″ vrsf silicone inlets and catless downpipes. It runs great when it first starts bit as soon as the cycle changes it starts misfiring and cutting the power, what tune would be best for me?

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