JB4 is here!
that is really frustrating.
that is really frustrating.Yeah I hear you on the traction. Sunny and 75 here today and I can’t get grip until third gear, stock. And my tires are in good shape (also stock)
5 minutes to unplug the negative battery (2 min for me). 10 minutes to remove airboxes (5 min for me). 5 minutes to remove the 8 or so bolts to get slack in the front engine harness (2 min for me). And then the rest of the time is finagling with the plugs (only front two are difficult if you don’t know how to unclip them). Takes around 15-20 minutes depending on how difficult you find those two front plugs. Putting everything back together and buttoning up everything with zip-ties, mounting the Dinan module, is about 10-15 min.
The first time I really took my time going line by line with directions from multiple install guides, and it ended up taking me around 2.5 hrs.
Last edited by AlexZTuned; May 20, 2019 at 09:09 AM.
The Best of Mercedes & AMG
Took me over 6 hours, to install the JB4 and the BCM. I will say it was not easy, I have a lot of experience working on cars, and have previously installed a JB3 on my previous 335i. This was much harder as MBZ leaves not a mm of slack in ANY cable or loom. Most of your time is spent cutting ties, pulling clips to make more slack to get to the MAP sensors. The FPS are easy...cake! However all 4 MAPS are a *****, only 1 on my car was relatively easy compared to the rest. The BCM connection was also very hard, no room to get in there an get at the connector. I have slender and long finger and forearms and that hardly helped, if you have fat fingers and large forearms good luck with the BCM. I did spend a good amount of time maybe 45-60min on the button up, making sure everything was reconnected and put back in place and then zip tying and tiding everything the way I like it, nice and tight.
If I did it agin I would use a lift and air tools for the under car pans, mine are in storage

The app is easy to use and once I connected the neg batt terminal back up the car started right up and everything is working!
I have not driven it yet, will tomorrow. I put back in my stock paper filters so we can get a baseline dyno, then base + high flow filters, then start running the MAPS!
More to come next week
The good news is that the firewall penetration was one of the easiest of any car I have worked on so hooking up to the OBD2 port was super easy.
First, thanks for the update and thank you for scheduling dyno time to finally give us all concrete info on baseline, filters, and now the JB4 maps. Really looking forward to that!
Second, couple of questions.
Why did this involve removing anything from the bottom of the car? Was this only because you did the BCM? I scanned through the install instructions PDF and really don’t remember anything about getting at the car from underneath and removing shields.
How come you went with a BCM (rest of your car is stock except for high flow filters, it sounds like?). Is your plan to get pure Map 1 and Map 2 pump gas dynos before anything else involving the BCM and ethanol/meth/race gas, etc? Hoping that’s the case so we can see pure plug and play JB4 benefit to the S.
While you’re being so generous with your analysis, would you also mind documenting what you think about the boost reduction by gear? Maybe like trying with the baseline of 0 and seeing how it helps or doesn’t help to go up to the values BMS recommends on their N54 page? Do you have stock tires?
Thanks again for the info. Sorry to hear it is such a headache to do. Miss the days of 15 minutes for the JB3 on the 335i
Last edited by ezatnova; May 23, 2019 at 07:31 AM.
Yes planning to go with Ethanol and or Race Gas, then Water/Meth when that kit is available, maybe upgraded turbos in a year or so.
Yes, just need to learn and understand how to play with the BRBG feature, stock tires but the rears are bald at 8K miles so going stickier and wider (305) probably Nittos
Yes planning to go with Ethanol and or Race Gas, then Water/Meth when that kit is available, maybe upgraded turbos in a year or so.
Yes, just need to learn and understand how to play with the BRBG feature, stock tires but the rears are bald at 8K miles so going stickier and wider (305) probably Nittos
This meth kit took about 30 minutes to install
Will have some dyno numbers posted soon.
Shame that none of them have a little place to swap the AMG engine plaque on to. not sure how feasible it is to remove and place it anyway. Still, they could have the correct sized flat spot with a "BMS Tuning" plaque there that could be removed if people wanted to try and swap on the OEM plaque.






