megamacx

Hi Guys,

I do have a E60 LCI 535xi Manual Transmission (N54), and I came with the term "JB", which after digging into what was it, made me keep doing more and more research.

WHAT I KNOW:

- JB (JB+ and all its variations, JB3, JB4) is a performance tuning mod that I can install in my car to make the engine deliver more horsepower on N54 turbocharged engines.

- Is an electronic piece that for some models (JB2, JB3, JB4) gets installed in the ECU connections, and in the one I could be interested in (JB+), it goes attached to the TMAP
sensor in the intake manifold area. All models are relatively easy to install (<30 mins).

- I know that JB+ can be adjusted to deliver more power (based on a dial the component has that can be adjusted).

WHAT I DON'T KNOW (And where I need help clarifying):

- Other than interfering between the ECU and the engine (which is a really high level description), how does JB really work? What exactly makes it generate more power that stock programmed vehicles don't deliver? (Does it change the air/fuel mixture parameters, what is the actual mechanism that makes this deliver more power?)

- Since JB+ allows a dial to be adjusted, is there something that should be preventing me from just adjust it to the MAX setting? I have read that sometimes at 100%, the ECU can throw error codes, but other than this, any other implication of having it to the MAX?

- Once it is installed, what triggers the power boost? I read somewhere that was kind of having the gas pedal past 50% pressed, Is this accurate?

- Are there any mechanical implications of using this? Like risk of drivetrain (transmission, transfer case, differentials, turbochargers) failure? In other words, other than the speed and acceleration you can reach (which you would need to know where to use it) is there a "word of caution" as far as mechanical components?

- If I ever get the ECU throw error codes, can these be cleared out using INPA (I have been using INPA for long time and wanted to check if that would help me clear out the ECU errors), or I need another software?

- Is this legal? My car is out of warranty, so I am not concerned about voiding it. I am more concerned about being "street legal".

- If I just invest in JB+ (and nothing else), would I be safe enough to have a little of fun with my 5-series once in a while (I by no means intend to run this in a racetrack or anything of that sort)? Or I need to also to replace some other components (like intake pipes, etc.) to prevent any failure of stock components?

- Are there any long term risks of using this (other than having more fun ?. It is my understanding that since this is controlled by the pedal, you can adjust your driving to know exacty when to activate it.

I think it is enough for now. Thanks for any help? I am close to buying one (By the way, if anyone has one used that wants to sell (a JB+), I could be interested in saving some bucks).

Any guide or links pointing to answer these questions will also help!

Thanks!

darkrider

The JB+ relies mainly on more boost to get the power gains, and is capable of about 75-80% of what a JB4 can net when dialed all of the way up. It's one of the best "bang for your buck" mods you can do for the N54. If you shop around on n54tech.com or 3post, you can snag one used for about $125 shipped. The only down side is that you will cause more prematurely wear on your stock turbos, but the gains are worth it, especially with the reasonable price of RB rebuilt aftermarket turbos, which use the stock body. If you get a BMS CAN Tool at the same time, you will be able to reset any tuner codes as well. The JB4 can do this stock, and has the ability to run totally custom maps.

megamacx

Thanks for the reply darkrider!

Ok, I kept reading about this subject, and now understand that JB makes the turbos run faster and apply more pressure than what the stock is programmed to do. That results in the increased horsepower. Now, when you say "will case premature wear on your storck turbos", do you have a way to measure that? How much wear? If I'd drove the car in a way that JB kicks in about 10%-20% of the time, how much should I expect my turbos to withstand? My car has +69k miles on it now. I am trying to understand if this gain in boost is really worth the damage you will do to the turbos over time. Also, how much could it be in labor+parts to repair the turbos once they go bad? If the turbos go bad, does it mean the car is not drive-able?

Booyaazaa

Any tune adds more stress to the engine since you are exceeding the factory settings. So it takes a little more maintenance with the added boost and timing. Spark plugs every 20/25k instead of 45k, oil changes at 7500 mile intervals vs factory 15k miles. The good thing is your turbos are covered for 8yrs/82k miles due to wastegate issues and your hpfp is covered for 10yrs/120k miles. Just make sure you turn off the jb4 or remove it when taking it in for those services at the dealer.

megamacx

what is exactly what would trigger the boost? If I get this installed, I would only use it from time to time. Is there a way for me to drive and be confident I am not just wearing out all these components unnecessarily but only when I mean get the extra boost?

darkrider

Boost is triggered by how hard you are accelerating. If you don't want the premature wear and tear, easy solution is to not accelerate so hard during everyday driving. The good news is that it's always there when you need it! The JB4 and CAN tool have a guage hijacking feature which will allow you to see how much boost pressure your turbos are running in real time, which is a handy feature! It's also easy to dial boost back on the JB+ (requires removal/reinstall), or very easy to change maps on the fly for the JB4.