I've owned my BMW 335i for a few months now so I've treated myself to a JB4. A JB4 is similar to a tuning box with a few addition features. This is a very popular mod for the N54 engine as used in the 335i.

JB4 features

Since fitting the JB4, the power delivery has gone from being very linear to now having an aggressive kick on boost.

I currently using the JB4 at its factory default settings so I still need to tweak the settings as there seems to be a lot of lag. There's a lagfix option which can be adjusted but I havent had chance to alter or play about with this yet. First impressions are great when on boost but way to laggy at the moment. I hope with some fine tuning the lag will be reduced. The JB4 has an auto learning feature and need's time to work correctly with the ECU so I'm going to leave everything at their default settings for now so the lag may sort itself out.

Heres a couple of short video's.

30mph-70mph sprint

Decided to remove the other video for obvious reasons

Very nippy!!

So it basically up the power by just over 100 bhp on your car??
Nice gain for not a lot of dough!
There prob wouldn't be much in it, in a straight drag race with a M3!!
Money well spent!
Don't really understand why it makes it more laggy though as it the same turbo (turbo's), boost has more than likely just been hiked up!!
No doubt someone will be along to explain why in a minute!!

Nick

Please say you're not filming that yourself while driving.

Yes, you get really good gains for cheap from tuning the BMW N54 engine bolt on mods are pretty expensive.

People say that BMW purposely released the 335i with a lot less power than it was capable of. Apparently, this was so people would still spend the extra £15k on the M3. If the 335i came with almost 400bhp standard then BMW would of sold a lot less M3's! Even the claimed 0-60 times are underestimated. I think the claimed 0-60 is about 0.5 slower than the average figures owners are achieving.

A standard 335i with JB4 doe's 0-60 in 4.5 seconds when timed with GPS equipment. There are loads of video's on YouTube to back this up. The 335i is a very capable car but the latest generation M3 is a purpose built machine. The M3 is the better car, but in a drag race there wouldn't be much in it I would think. But, that's tuned vs standard so not a fair comparison really as a tuned E92 M3 would be faster still

The standard boost is 8 psi but depending on which map you choose, it up's it to between 13-16 psi on an otherwise standard car. I still need to fine tune the anti lag settings so the lag should reduce significantly. I just need to get a VANOS solenoid replaced first.

A cahp I work with has a 335i and has been telling me about this tuning box. He's on the E92 forum (?) and has been following your thread on there. Sounds like a bargain for what it can do!

speak to good old Mr Vanos
www.mrvanos.com

I don't have a thread on an E92 forum? I have briefly commented on a thread on bimmerpost regarding the turbo lag but that's it really?

My car is booked in at my local speciallist on Tuesday to get the VANOS solenoid sorted. He says it the faulty solenoid will most probably be what's causing the excessive lag berween 2500-4000 rpm. I've disabled the JB4 for now until I get it sorted.

The gains are so impressive for money (£330 delivered) it would be stupid not to buy a JB4

I already have

Another Mr.Vanos

Fair enough, must be an odd coincidence with another user. Sounds like a cracking bit of kit!

I've just had the VANOS solenoid replaced and I'm very please to report that I no longer have any noticeable lag.

The difference really is night and day. The throttle response is now instant right through the rev range, where as it before it only seemed to really pin you in you seat after 4k rpm. Now if you gun if in 1st or 2nd gear, the car has become very tail happy and almost caught me out

Dan, is it not worth uprating the intercooler? I thought that over 370-380bhp then the standard intercooler is under specced?

Jules.

No standard is fine for 380bhp. If I add aftermarket downpipes and a FMIC I should be seeing 420bhp-430bhp. The JB4 is a very popular mod. No other bolt on mods are needed. Meth is another very popular mod but I'm not entirely sure what meth is? To me, is sounds similar to nitrous which doesn't appeal to me.

Meth


When I had my solenoid replaced today at a BMW specialist, I asked how much it would be to fit down pipes and a FMIC. He said it's 4hrs work so £200 for fitting. I might consider it early next year.