Review N55 JB4 w/ updated iso firmware

[370z-135i]

Hey guys,

2012 N55 135i JB4 stage 2 w/ iso firmware

This review is long overdo as I have been so grateful for the fantastic customer service of BMS. I'll stick with the short version as I could go on and on about all the bonus features that separate the JB4 from the rest. Getting a JB4 and updating the firmware is a must. I can't believe how much fun you can have from a relatively inexpensive mod.

My car is completely stock minus the BMS intake. I run 95 oct which doesn't hurt my case, but even on 93 the car is a beast. Obviously going from stock to JB4 is night and day, as everyone already knows, so I'll focus on the firmware upgrade. I was typically using map 5 prior to the firmware update and it was a blast to drive. The issues I had were the boost was inconsistent and varied constantly every time you drive. I know map 5 was made to be a self learner and constantly changed depending on many variables, but it definitely made me want a faster and more consistent map than 5 (1 just didn't do it for me).

I finally made the plunge and updated the firmware last week and let me tell you, it's a night and day difference. It feels as if I upgraded to a stage 3 if there was such a thing. The car is so much more responsive and pins me back in my seat every time I press my foot to the floor. The boost is way more consistent and I reach 14-16psi on every pull. Prior to the upgrade I would reach 12 and 14psi, but you never knew what you were going to get when hitting the gas. Sometimes only reaching 8-10psi under the same conditions from one pull to the next.

My comparison is based on using 95 oct before and after the iso update. Don't get me wrong, the JB4 is amazing right out of the box and plenty of fun, but with the iso mod, it's a beast. I can't even imagine what the car will feel like with a couple bolt ons. The update is a much simpler process than it seems and well worth the 10 min or so to do it. I can't imagine a better product on the market right now that can touch the JB4 with the iso update no matter what the cost (minus a dyno tune of course). These guys at BMS have something figured out and they really do care about the consumer. I haven't dealt with better customer service and faster responses in my entire life. No matter how stupid or annoying the question (there were many on my end), they answered gracefully and extremely prompt. When I say prompt, I mean minutes most of the time. They were even there for me on a Sunday when I desperately needed their help.

I assure you I am in no way affiliated with BMS or have anything to gain from this review. I feel that poor products and service are reviewed so frequently, that I like to give credit where credit is do. If you are on the fence, get the JB4, you won't regret it.

Thanks for reading

[Solo_M_Tech]

Been running the JB4 G5 ISO for a year now. Very happy with it. My feelings mirror your own. Wait till you get a better FMIC and Charge pipe. You will want them eventually. The Charge pipe as soon as possible since you will break the stock one sooner than later.

Also look into the Flex Fuel wire upgrade. Even if you don't use E85, the FF wire upgrade, allows the JB4 to monitor and change the fuel trims to keep the AFR happy. Even without E85, I consistently see 17 psi out of MAP5.

[370z-135i]

Originally Posted by ApexResistance

Been running the JB4 G5 ISO for a year now. Very happy with it. My feelings mirror your own. Wait till you get a better FMIC and Charge pipe. You will want them eventually. The Charge pipe as soon as possible since you will break the stock one sooner than later.

Also look into the Flex Fuel wire upgrade. Even if you don't use E85, the FF wire upgrade, allows the JB4 to monitor and change the fuel trims to keep the AFR happy. Even without E85, I consistently see 17 psi out of MAP5.

Thanks for posting, I had no idea the flex fuel upgrade has benefits w/out E85. I'll definitely look into that. I replaced the charge pipe at the same time I installed the JB4. I'm grateful there was so much info about it. I'm definitely going DP next. I hear it makes a big difference. I already had to put 100lbs in my trunk in order to get decent traction (winter in Chicago).

Thanks again for the heads up.

[TwinTurboXI]

Nice write up. What do you do for weight in the trunk? I have two 40lb bags of salt back there.

[Solo_M_Tech]

Originally Posted by 370z-135i

Thanks for posting, I had no idea the flex fuel upgrade has benefits w/out E85. I'll definitely look into that. I replaced the charge pipe at the same time I installed the JB4. I'm grateful there was so much info about it. I'm definitely going DP next. I hear it makes a big difference. I already had to put 100lbs in my trunk in order to get decent traction (winter in Chicago).

Thanks again for the heads up.

No problem. The DP will make a huge difference in performance. Best upgrade for the N55. Next would be the FMIC, but you have time for that. Get on N54tech.com and hit up Steve and Fuel-It tech and he can tell you all the benefits of running the FF wires. I wasn't going to until I talked to him. So glad I did.

[370z-135i]

Originally Posted by TwinTurboXI

Nice write up. What do you do for weight in the trunk? I have two 40lb bags of salt back there.

That's a great idea, dual purpose. I literally have 100lbs of weight plates and dumbbells (inside a tire so they don't move). I can't believe what a big difference it makes with traction. I'm glad I did that. I'll probably drop at least half of that weight for the summer.

[370z-135i]

Originally Posted by ApexResistance

Been running the JB4 G5 ISO for a year now. Very happy with it. My feelings mirror your own. Wait till you get a better FMIC and Charge pipe. You will want them eventually. The Charge pipe as soon as possible since you will break the stock one sooner than later.

Also look into the Flex Fuel wire upgrade. Even if you don't use E85, the FF wire upgrade, allows the JB4 to monitor and change the fuel trims to keep the AFR happy. Even without E85, I consistently see 17 psi out of MAP5.

How about giving me the short version of how it helps, hahaha. If you say it's worth it and you have spoken with Steve, I believe it.

Does this mean I already have it? Copy and pasted from their thread on N54

Are E85 fuels supported?

You can run up to 50% E85 on the factory fuel system with the factory N55 turbo. The only requirement is the E85 flex fuel connector with comes standard on new JB4 "typeB" harnesses and remains an add-on for JB4 "typeA" harnesses. The flex fuel connector and directions are on our N55 upgrades page.

[HyeWarrior]

Noob question but I just bought JB4 with flex fuel wires used off a forum member. How can I tell which software it's running and how would I go about updating it?

[Rob_BMW_PNW]

Was it easy to upgrade to the new firmware? Or did you buy it new with it upgraded?

Only reason why I am weary of buying used is I am not sure or able to 'upgrade'

[TheCaptain]

OP are you running winter tires or all seasons?

[Solo_M_Tech]

Originally Posted by 370z-135i

How about giving me the short version of how it helps, hahaha. If you say it's worth it and you have spoken with Steve, I believe it.

Does this mean I already have it? Copy and pasted from their thread on N54

Are E85 fuels supported?

You can run up to 50% E85 on the factory fuel system with the factory N55 turbo. The only requirement is the E85 flex fuel connector with comes standard on new JB4 "typeB" harnesses and remains an add-on for JB4 "typeA" harnesses. The flex fuel connector and directions are on our N55 upgrades page.

Some of the new JB4's come with the FF wires already installed. It's a black connector that's square on one side and round on the other; Should be the only ones in the harness with black wires.

[370z-135i]

Originally Posted by Rob_BMW_PNW

Was it easy to upgrade to the new firmware? Or did you buy it new with it upgraded?

Only reason why I am weary of buying used is I am not sure or able to 'upgrade'

It was a lot easier than it seemed when I read the instructions on N54-Tech. Just follow the directions and you will be good to go. I was apprehensive myself as I didn't want to screw something up, but it was nothing.

I bought it new, but you can always ask whomever you purchase from whether or not they did the update.

[370z-135i]

Originally Posted by TheCaptain

OP are you running winter tires or all seasons?

Continental extreme contact all season. Great tires year round, I had the same tires on my Z. The car is still terrible in the snow, but 100x better than the stock run flats.

[370z-135i]

Originally Posted by ApexResistance

Some of the new JB4's come with the FF wires already installed. It's a black connector that's square on one side and round on the other; Should be the only ones in the harness with black wires.

Considering there is a set of connectors unused, one would assume that would be the FF wires. I have no idea as I have not done any research as to what the FF does w/out E85 and what the wires even plug into. Guess I better do my homework. Thanks buddy, I'll look into it.

Noob question but I just bought JB4 with flex fuel wires used off a forum member. How can I tell which software it's running and how would I go about updating it?

When you hook the JB4 up to your laptop it will tell you what firmware you are running. The JB4 opens right up so you can check to see if the diode is cut. Either way you can always update yourself to the newest option.