[Bluesun]

I know there are a ton of these, but I decided it may be worthwhile to throw in my $0.02. I know before buying mine (and while waiting to install), I wanted to read any/all posts about it that I could. So, for what it's worth, here's my experience.

I had been playing with the idea of buying a tuner module for a long time -- ever since I bought my car. But, while I was still under warranty (CPO), and given that I was in and out of the shop with my car so many times (VANOS issues, turbo issues, vacuum issues, I could go on forever...), I decided it would be prudent to wait awhile. It's been a little over a year without any major failures (last being a water pump), and I'm out of the free maintenance and "new car" warranty, so I was ok with the idea. I didn't pull the trigger, however, until an old friend of mine visited from TX with his '08 135i with JB4 and DCI. He offered to take me for a ride, and suffice it to say I was blown away.

Two days later, I had ordered a JB4 and DCI. Two days after that, it arrived on my doorstep. Two days after THAT (last night), I installed it.

The Install
I have to say, it was a bigger pain in the ass than I was expecting. The clips for the ECU are a nightmare to get off. Part of it may have been it was ~95 degrees outside, and I was crouched over a hot ass engine in my hot ass garage, dripping sweat after coming back from the gym (I did eat first, though). Thankfully (by the grace of Odin), I got everything plugged in right the first go around. I was somewhat nervous about mating wrong connectors with each other, but it all seemed to go together easily enough.

First Drive
I was pretty nervous the first time starting it, but I received no error lights (aside from the damned rear tail light error that comes up all the time) and the motor honestly felt like it ran a little smoother. I checked the settings that mattered for a first drive (map 1, and gauge calibration for my 335), and my buddy jumped in for the maiden voyage.

Call me crazy, but I swear that it seems to run smoother in general. Even out of boost, just shifting at low revs (think parking lot speeds), it seems to run really smooth. I was a little surprised at this. Once it warmed up, however, and I stepped on the gas the first time...I giggled like a school girl.

Bear in mind, I have been riding crotch rockets for about 11 years now. I currently have a liter bike, so I am not new to fast stuff. But being in a car, sitting in that seat and being mashed into it, there's nothing quite like it. Even after having ridden in my buddy's 135 with a JB4, I felt surprised at how responsive my car was, and how hard it pulled. I drove around for a little while, slowing down, doing WOT pulls. I switched to map 5 (where I currently am), and it felt a little quicker/more responsive. I run 93 in my car, so I figured it may be worthwhile, but it may just be in my head.

Conclusion
Honestly, I could not be happier with the JB4 so far. The little stuff like the gauge sweep and the CANflap option are nice (so I can plug the relay back in...my flap is broken and rattles, which is embarrassing), and the ability to change tune on the fly is pretty incredible. Suffice it to say, I am in love with my car all over again, and I fully intend on more mods.

Next in line is likely downpipes and FMIC, then meth (and whether I want to or not after that, a clutch, hah!).

Lastly, thank you so much to everyone on these forums for contributing to this community, and for helping amass such a wealth of knowledge about our wonderful machines. I have been reading this place incessantly over the past couple weeks, and there are so many knowledgeable/helpful people on here. I feel very fortunate. Thank you everyone!

[Mike@N54Tuning.com]

Glad you're enjoying the JB4 and thanks for the review. The JB4 has put a smile on a lot of faces

Mike

[skarl]

Thanks for the awesome review! I was just about to buy a JB4 kit. =)

[Titan54]

Thanks a lot, mine is sitting in my back seat right now waiting for the install next week.

Can't wait.

[plague]

wait until you have downpipes and meth. car will be MUCH faster than it is already.

[Cypress]

Nice write up and review. I couldn't agree more, the juice box rocks.

[no1jetdoc]

Love the JB4 too!!!

[e92oholic]

Dude your in Ohio find some e85 ethanol. Put 7 gallons in your tank and top off the rest with 93. Switch to map five and prepare to fall in love all over again... Will make map 1 seem like stock..

[e1001usa]

Nice review

[bceagle1991]

Great review, I agreed 100% about the smoothness you mentioned, I noticed the same thing.

[BigRedAEM]

Just checked my tracking information and it should be here tomorrow afternoon and I'm also planning on installing tomorrow. Can't wait get it in and unleash the power it should have had from the factory.