JB2 installed in the 335….

I purchased a Stage 2 Juice Box (JB2) from Burger Motorsports and installed it in my 335 last weekend.  I must say that I’ve been beyond pleased with this tuner’s performance so far.  The price was right, installation was not difficult, and best of all there are no fault codes or check engine lights.  Most importantly, the JB2 delivers a genuine and substantial seat-of-the-pants increase in power.

I’m using only the JB2, so I’ve not added an H-Pill or X upgrade.  For those of you who don’t know, Burger sells tuners in the following iterations: Stage 1 (JB1), Stage 2 (JB2), and now the beta form of Stage 3 (JB3).   With the JB2, you can add Hot Pills (JB2H or JB2HH) that take advantage of 93/94 octane gas to offer up even more power.  The X upgrade goes even further by allowing up to 16 psi of boost with race gas.  With just the JB2, you can get around 11 psi of boost plus remapping of the air/fuel ratios for gains of around 40+ hp and 50+ lb ft of torque.  Hot Pills will raise the gains to 50 hp and 60 lb ft, respectively.  Burger just recently released the new JB3, which shows gains of 80+ hp and torque and is compatible with BMW latest ECU and software. 

Installation of the JB2 is not difficult if you follow the instructions (downloadable with pics) to the letter and pay attention to detail.  You will have to remove various underhood components to get to the ECU.  Once you open up the ECU, you have to install the JB2 by connecting its wires to certain pins within the ECU’s harnesses.  Always double-check your pins.  Then, you will have to bypass the left boost solenoid. The installation procedure took me quite some time because I was constantly double-checking my work, but it was well worth the extra effort. 

Once I installed the JB2 and checked to make sure no check engine light (or “half-engine” limp-home modes) showed up, I put the rest of the engine bay back together.  Then I went for a drive.  The car seemed to have some more power all over its already vast powerband.  After a few days of driving, it seemed to get even more powerful, as if the ECU was somehow “learning” the JB2.  At this point, I am experiencing a substantial seat-of-the-pants difference that really seems to confirm Burger’s claim that the JB2 adds 40+ horsepower. 

Power is as smooth as the factory, with the same powerband.  There is no peakiness, spikes, or jerkiness. In fact, the car is markedly less jerky in first gear, which used to require a lot of concentration to prevent the car from bucking especially when cold.  I ended up with the factory powerband, but it is much much fatter than it was before.  For example, the 335 now takes off with real alacrity in 6th gear on the highway; it will put you back in your seat whereas before it merely moved away with reasonable dispatch.

While driving, I did notice what appeared to be some additional “throttle delay” or even lag when aggressively transitioning from off-throttle to judicious application of throttle.  Burger has a boost solenoid kit that may alleviate this effect, and I just ordered it. 

The JB2 has some slightly different instructions if your car was built March 2008 or later, or it otherwise has the 29.2/v81ECU.  So you need to pay attention to your build date, or confirm that your dealer did not download the 29.2 software into your ECU.  Links:

Burger Motorsports:


N54 Tech:



6 Responses to “JB2 installed in the 335….”

  1. Sounds great and it’s nice that it’s still just as street driveable. I didn’t realise these ECU enhancements were do-it-yourself.

    Does this in any way void BMW warranties, especially since it was user installed?

  2. I could see it voiding the BMW warranty if you nuke your engine due to excess boost. However there’s very little chance of that happening, in my opinion.

  3. I doubt the JB would cause any problems or major failures such as nuking your engine, but a quick Google search seems to indicate that if a dealer detects it as being installed the BMW powertrain warranty will probably be voided.

    The consensus seems to be to pull the JB mod out prior to any major service work. Hope it was easy to remove and re-install. 😉

  4. True, it appears BMW has tried to void warranties based on modifications. But at the end of the day, they cannot deny a warranty claim and have it stick unless they prove the modification caused the problem the customer is complaining about. On the other hand, if you modify your engine in any way and blow it up, the manufacturer should not be responsible for replacing it. I also seruoisly doubt the JB2 will cause any harm to the engine. That’s whay I got it……

  5. @lee76: Hummm…That raises an interesting point. If there was a problem, would BMW need to prove the installed mod caused the problem or would they only need to prove that the owner willfully violated the terms of the warranty by installing an unapproved modification thus making the warrenty null-and-void?

    I would think the second case would be far easier to prove. Perhaps that’s the consensus on the Internet was to remove it prior to major service by a dealer.

    Have a good one.

  6. Eventually, in court, BMW would have to make the first case to make the denial stick. The second case is still used for denials at the dealer level. The gamble is whether or not the customer will fight the denial. I do agree with the consensus–remove the modification prior to major service.

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