Newb here in Milwaukee
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I'm up in the Fox Valley... Appleton/Oshkosh area. If you're ever up this way, let me know. I'd love to get a ride and I could do a nice photoshoot for you.
I'm looking at getting the latest JB4 with the 2-step cable and some downpipes... then I can run E85

Thoughts on JB4 vs. Cobb? I'm glad I have a K&N drop-in air filter... I was going to get the BMS DCI, but I've heard similar stories of a good drop-in filter being the best.
Definitely a possibility if there is ever a meet in that area this summer!
JB4 is more of a true tuner's solution. Cobb is more for Plug-n-Play when you just want a plain jane ezmode FBO setup to make great power. Until Cobb has Stage 3 maps out (or maybe they do and I've just been under a rock), then you're limited to the Stage 2+FMIC Aggressive which with great tires is good for 12 flat in the 1/4. Still very quick, but JB4 has meth control so if you want to step your game up and run e85 & meth with a custom tune for higher boost, that's where you start to see 11's.
Also Terry has a sterling reputation over at BMS and he is always available for support. You get more of a real service with JB4 because you're working with another enthusiast when you need support. Cobb is a big-box company supporting all kinds of different vehicles, and while there is a definite ease with installation and getting up and running, it does not come without tradeoffs.
So really it matters in regards to what you want to do. For me, I do a few track days a year, and I like having a 12 second car on the street. not many people can keep up if I want to pass, and on-ramps are absurdly fun. So Cobb is enough for me. That said, be careful with JB4 if you go meth/E85 - as soon as you go there, you will be pushing power numbers around 450, which is the limit for the stock clutch, as well as the standard differential.
You won't be putting that power down very well without also dropping a nice chunk of change to get a LSD. Basically, if you are enticed by higher boost, meth, and e85 then JB4 is for you, but be aware that above 400 whp is where you start to get into the very expensive part of modifying a 135i, and you will move closer to the "all-in" side of frankensteining a car

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Welcome!
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I'm looking at getting the latest JB4 with the 2-step cable and some downpipes... then I can run E85

Thoughts on JB4 vs. Cobb? I'm glad I have a K&N drop-in air filter... I was going to get the BMS DCI, but I've heard similar stories of a good drop-in filter being the best.
Currently my only mods are the jb4 and bms dci, and I run around 30% e85 with map 5 on the jb4. If I could just get rid of my fueling issues the car would be much more fun to drive...
For stock turbos a drop in filter will more than suffice, I went with the dci because I like to hear the spool and it looks nice when you pop the hood.

I consider the Cobb A/P a tuners tool, while the JB4 is more "out of the box tune" while running the generic maps. Map 5 is self learning, and there are some back end flashes which can be used via the combination of JB4 and A/P. I used an A/P on my last car (550 crank hp Subaru Legacy GT) and loved the device for switching between 91 octane and e85 maps. My tunes were pro tunes which were then stored on the A/P.
The downside of using the A/P, esp if you are under BMW warranty, is that it leaves a footprint in the DCM which says "I was flashed", whereas using the JB4 it's 100% stealth. The DCM only sees max stock boost (8 psi in my case) while the JB4 produces 16-17 psi.
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Delete me
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Definitely a possibility if there is ever a meet in that area this summer!
JB4 is more of a true tuner's solution. Cobb is more for Plug-n-Play when you just want a plain jane ezmode FBO setup to make great power. Until Cobb has Stage 3 maps out (or maybe they do and I've just been under a rock), then you're limited to the Stage 2+FMIC Aggressive which with great tires is good for 12 flat in the 1/4. Still very quick, but JB4 has meth control so if you want to step your game up and run e85 & meth with a custom tune for higher boost, that's where you start to see 11's.
Also Terry has a sterling reputation over at BMS and he is always available for support. You get more of a real service with JB4 because you're working with another enthusiast when you need support. Cobb is a big-box company supporting all kinds of different vehicles, and while there is a definite ease with installation and getting up and running, it does not come without tradeoffs.
So really it matters in regards to what you want to do. For me, I do a few track days a year, and I like having a 12 second car on the street. not many people can keep up if I want to pass, and on-ramps are absurdly fun. So Cobb is enough for me. That said, be careful with JB4 if you go meth/E85 - as soon as you go there, you will be pushing power numbers around 450, which is the limit for the stock clutch, as well as the standard differential.
You won't be putting that power down very well without also dropping a nice chunk of change to get a LSD. Basically, if you are enticed by higher boost, meth, and e85 then JB4 is for you, but be aware that above 400 whp is where you start to get into the very expensive part of modifying a 135i, and you will move closer to the "all-in" side of frankensteining a car

Great info! I don't plan on running meth anytime soon, but do plan on mixing in a little E85 once I get the JB4. And for another $100, I can get the Walbro fuel pump and add up to 80% E85.
I don't plan on the clutch lasting forever, especially with 84k miles now. I'll swap in an ACT clutch once this one fails. It's currently holding real strong without any issue. I was unaware that the differential could have issues around 450whp. Either way, an LSD has been on my list once money permits. I'm on the hunt to break 11's with the 6MT... which is tough.
Currently my only mods are the jb4 and bms dci, and I run around 30% e85 with map 5 on the jb4. If I could just get rid of my fueling issues the car would be much more fun to drive...
For stock turbos a drop in filter will more than suffice, I went with the dci because I like to hear the spool and it looks nice when you pop the hood.

I consider the Cobb A/P a tuners tool, while the JB4 is more "out of the box tune" while running the generic maps. Map 5 is self learning, and there are some back end flashes which can be used via the combination of JB4 and A/P. I used an A/P on my last car (550 crank hp Subaru Legacy GT) and loved the device for switching between 91 octane and e85 maps. My tunes were pro tunes which were then stored on the A/P.
The downside of using the A/P, esp if you are under BMW warranty, is that it leaves a footprint in the DCM which says "I was flashed", whereas using the JB4 it's 100% stealth. The DCM only sees max stock boost (8 psi in my case) while the JB4 produces 16-17 psi.
What fueling issues are you referring to? What kind of power are you seeing with those mods and 30% E85?
Also, how does one go about getting the "BMS backend flash" that I hear about on the forums? Do I have to purchase the COBB tuner then?
I'm long out of warranty, so that doesn't bother me

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Currently my only mods are the jb4 and bms dci, and I run around 30% e85 with map 5 on the jb4. If I could just get rid of my fueling issues the car would be much more fun to drive...
For stock turbos a drop in filter will more than suffice, I went with the dci because I like to hear the spool and it looks nice when you pop the hood.

I consider the Cobb A/P a tuners tool, while the JB4 is more "out of the box tune" while running the generic maps. Map 5 is self learning, and there are some back end flashes which can be used via the combination of JB4 and A/P. I used an A/P on my last car (550 crank hp Subaru Legacy GT) and loved the device for switching between 91 octane and e85 maps. My tunes were pro tunes which were then stored on the A/P.
The downside of using the A/P, esp if you are under BMW warranty, is that it leaves a footprint in the DCM which says "I was flashed", whereas using the JB4 it's 100% stealth. The DCM only sees max stock boost (8 psi in my case) while the JB4 produces 16-17 psi.
I still feel JB4 is more a tuner's tool given it has direct support for meth control, and it is produced by an active BMW tuner who has dedicated most of his focus to the N54/N55 platform. Terry is just an awesome resource. Cobb has so many maps nowadays, but yeah BMW warranty snoopers will get ya
Great info! I don't plan on running meth anytime soon, but do plan on mixing in a little E85 once I get the JB4. And for another $100, I can get the Walbro fuel pump and add up to 80% E85.
I don't plan on the clutch lasting forever, especially with 84k miles now. I'll swap in an ACT clutch once this one fails. It's currently holding real strong without any issue. I was unaware that the differential could have issues around 450whp. Either way, an LSD has been on my list once money permits. I'm on the hunt to break 11's with the 6MT... which is tough.
What fueling issues are you referring to? What kind of power are you seeing with those mods and 30% E85?
Also, how does one go about getting the "BMS backend flash" that I hear about on the forums? Do I have to purchase the COBB tuner then?
I'm long out of warranty, so that doesn't bother me

I think you've got it right, then. And again I'm not saying the diff will blow up at 450, what I'm saying is you just won't put power to the ground well - you are honestly at a pretty high risk of losing control due to the very high amount of power that could be getting sent to 1 wheel instead of evenly distributed. At a certain power level, you just need an LSD in order to be safe.
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I've had fueling issues since I bought the CPO car last year. Romp on the car, CE light, DCM stored codes, BMW service checked things out and deemed all to be OK initially. Next trip in they swapped all 6 injectors, 3 weeks later they swapped 2 more, and I've got another appointment in early May and I'm pushing hard for a swap of the high pressure fuel pump. In my mind that's the root cause/underlying culprit. My DCM is currently storing 29F2, 29E2, 2D2E and 2E9F.
I've not strapped the car to a dyno yet, but suffice to say the car woke up nicely. Just going from 8 psi stock to 13 psi with JB4 map 1 put a grin on my face. On map 5 after the DCM/JB4 learned about the octane level (3 freeway on ramp pulls from 2k rpm to redline) my AWD car was breaking wheels loose during hard acceleration & throwing traction control warning lights.

The BMS back end flash is a bin from Burger which can be loaded via Cobb A/P or by using the bimmerboost free flash utility and a BT cable. More info can be found here. N54tech.com is more or less a JB4 specific N54 site, lots of good information there if you've not found it yet. And to echo what i_love_cars said, Terry Burger is an awesome resource.
The JB4 has a ton of capability, my current use is very basic. Once the fueling issues are ironed out, I install the parts waiting in my garage plus do an upgrade of the low pressure fuel pump, the car will be making some decent power. I'm also considering meth injection sometime down the road.
As an aside my KW variant 1 suspension parts arrived yesterday. That will most likely get installed in early May, today my car is at a body shop for some paint work as my drivers side rear quarter panel got scuffed over the winter.
What fueling issues are you referring to? What kind of power are you seeing with those mods and 30% E85?
Also, how does one go about getting the "BMS backend flash" that I hear about on the forums? Do I have to purchase the COBB tuner then?
I'm long out of warranty, so that doesn't bother me

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I've had fueling issues since I bought the CPO car last year. Romp on the car, CE light, DCM stored codes, BMW service checked things out and deemed all to be OK initially. Next trip in they swapped all 6 injectors, 3 weeks later they swapped 2 more, and I've got another appointment in early May and I'm pushing hard for a swap of the high pressure fuel pump. In my mind that's the root cause/underlying culprit. My DCM is currently storing 29F2, 29E2, 2D2E and 2E9F.
I've not strapped the car to a dyno yet, but suffice to say the car woke up nicely. Just going from 8 psi stock to 13 psi with JB4 map 1 put a grin on my face. On map 5 after the DCM/JB4 learned about the octane level (3 freeway on ramp pulls from 2k rpm to redline) my AWD car was breaking wheels loose during hard acceleration & throwing traction control warning lights.

The BMS back end flash is a bin from Burger which can be loaded via Cobb A/P or by using the bimmerboost free flash utility and a BT cable. More info can be found here. N54tech.com is more or less a JB4 specific N54 site, lots of good information there if you've not found it yet. And to echo what i_love_cars said, Terry Burger is an awesome resource.
The JB4 has a ton of capability, my current use is very basic. Once the fueling issues are ironed out, I install the parts waiting in my garage plus do an upgrade of the low pressure fuel pump, the car will be making some decent power. I'm also considering meth injection sometime down the road.
As an aside my KW variant 1 suspension parts arrived yesterday. That will most likely get installed in early May, today my car is at a body shop for some paint work as my drivers side rear quarter panel got scuffed over the winter.
Great to hear! I think I know of a guy who can do the BMS back end flash for me. Not really sure what the flash entails, but I'm interested in finding out.
Do you have a build thread? Hopefully you get those fuel issues sorted... HPFP is definitely something to look into.
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It fills my heart with joy that my first thread has inspired more talk of people spending money in the best way possible: further modifications to their N54's

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Welcome, but I would stay away from MM, they couldn't figure out how to S/C my M3.
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Welcome, but I would stay away from MM, they couldn't figure out how to S/C my M3.
Interesting. I've been using them for some basic maintenance stuff as well as the DPs and FMIC install on my car. Haven't had any issues yet. But that's basic stuff.
As soon as I move in a month and actually have a garage again that I can work in it will be a non-issue because I'll be able to get back to working on my own vehicles

What couldn't they figure out with the S/C ?
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