Is JB4 and DCT on a N55 a bad idea?!

[135rampo]

Ive searched around the forum i have seen people running a JB4 on a n55 dct.
It seems some people have problems with the DCT and some don't?
Is there any reason or a year that this happens on?
Is there additional software i need to run a JB4 safely?

Ive searched alot but its always fairly vague.

Any one with direct experience would be great as burger say there is no issue untill i go bigger turbo but i have seen people with just a map having issues.

Rampo

[e36addict]

Most "issues" are firmware and adjustment issues. I had rough idle issues until I went ISO 5_5 and the car has run perfect since. Latest adjustment was bringing the auto shift boost redux down to 25 from 55 and the partial throttle shifting is buttery smooth now. Coupled with the Cobb back-end flash for the larger turbo and it's wonderful. I recommend it!

[135rampo]

Originally Posted by e36addict

Most "issues" are firmware and adjustment issues. I had rough idle issues until I went ISO 5_5 and the car has run perfect since. Latest adjustment was bringing the auto shift boost redux down to 25 from 55 and the partial throttle shifting is buttery smooth now. Coupled with the Cobb back-end flash for the larger turbo and it's wonderful. I recommend it!

So I need to do all that just to run a map with a cooler?

[houtan]

I have run the jb4 with and without the back end flash without issue. The main thing to do with the jb4 is take logs and post them on n54 tech in the support section.

The production date of your car will be the deciding factor whether or not you can flash the ecu. One of the reasons for flashing the ecu in conjunction with the jb4 is to increase the load signal being sent to the ecu if your DCT clutches start to slip. Typically, on a stock turbo FBO car you will not have this issue. Their has been some instances where the DCT clutches started slipping when FBO on the stock turbo, but I dont think this is the norm.

[135rampo]

Originally Posted by houtan

I have run the jb4 with and without the back end flash without issue. The main thing to do with the jb4 is take logs and post them on n54 tech in the support section.

The production date of your car will be the deciding factor whether or not you can flash the ecu. One of the reasons for flashing the ecu in conjunction with the jb4 is to increase the load signal being sent to the ecu if your DCT clutches start to slip. Typically, on a stock turbo FBO car you will not have this issue. Their has been some instances where the DCT clutches started slipping when FBO on the stock turbo, but I dont think this is the norm.

Sorry what is FBO?

Think i may go down the flash route as my car is late 2010

[ShocknAwe]

Originally Posted by 135rampo

Sorry what is FBO?

Think i may go down the flash route as my car is late 2010

Full Bolt On (modifications)

[Dilmorecg]

I have been running JB4+DP+Intake for about 6 months now 2011 N55 DCT and have no issues. Runs smooth, no problem shifting.

I think the issue is the DCT software update...if you dont have the newest you will get really bad lag when you slow down then try to accelerate.

[135rampo]

Originally Posted by Dilmorecg

I have been running JB4+DP+Intake for about 6 months now 2011 N55 DCT and have no issues. Runs smooth, no problem shifting.

I think the issue is the DCT software update...if you dont have the newest you will get really bad lag when you slow down then try to accelerate.

I just had mine updated.
I thought it made the clutches slip

[allies_jh]

Is there a way to check what software version you have for the DCT?

[houtan]

Originally Posted by Dilmorecg

I have been running JB4+DP+Intake for about 6 months now 2011 N55 DCT and have no issues. Runs smooth, no problem shifting.

I think the issue is the DCT software update...if you dont have the newest you will get really bad lag when you slow down then try to accelerate.

Drivability improvements from the SW update, like the lag when accelerating from a slow roll, are separate from drivability issues running the JB4 on a dct car (typically a slipping clutch). the clutches slip because the JB4 is intercepting the signals going to the DME. So at full boost, actual psi is at 18, but the DME is getting a signal that it is at 7 psi (just an example, not sure what the actual values are). Typically not an issue with the stock turbo at 18 psi. but 18 psi with a pure turbo stage 1 or 2 upgrade is much more power, which is where people starting experiencing slipping dct clutch. this is fixed by running the BMS back end flash, which ups the PSI values being sent to the DME when running the JB4. The higher values tell the DCT to apply more clamping force so the clutch does not slip. That is the way I understand it, may not be the exact way, but conceptually I believe that is what is happening.

[135rampo]

Originally Posted by houtan

Drivability improvements from the SW update, like the lag when accelerating from a slow roll, are separate from drivability issues running the JB4 on a dct car (typically a slipping clutch). the clutches slip because the JB4 is intercepting the signals going to the DME. So at full boost, actual psi is at 18, but the DME is getting a signal that it is at 7 psi (just an example, not sure what the actual values are). Typically not an issue with the stock turbo at 18 psi. but 18 psi with a pure turbo stage 1 or 2 upgrade is much more power, which is where people starting experiencing slipping dct clutch. this is fixed by running the BMS back end flash, which ups the PSI values being sent to the DME when running the JB4. The higher values tell the DCT to apply more clamping force so the clutch does not slip. That is the way I understand it, may not be the exact way, but conceptually I believe that is what is happening.

Thank you so if I got slip then removed the jb4 I would be fine? How do j get the dms back end flash?

[houtan]

Should be. BMS Back end flash is on n54 tech in the big turbo tuning sticky. A lot of information in that forum.

[mike@x-ph.com]

Originally Posted by 135rampo

Ive searched around the forum i have seen people running a JB4 on a n55 dct.
It seems some people have problems with the DCT and some don't?
Is there any reason or a year that this happens on?
Is there additional software i need to run a JB4 safely?

Ive searched alot but its always fairly vague.

Any one with direct experience would be great as burger say there is no issue untill i go bigger turbo but i have seen people with just a map having issues.

Rampo

Agree with Burger, you will have no problems unless you go with bigger turbos

[bmw0bsession]

I have 500+rwhp on my DCT no issues lol. You will be fine

[135rampo]

Originally Posted by bmw0bsession

I have 500+rwhp on my DCT no issues lol. You will be fine

from what i have seen people have had issues with JB4 with the clutches on a map and no bolt ons at all. That car only had around 10k miles on the clock too

[houtan]

I would say it's not the norm, but some people have reported Sipping clutches with no additional mods other than a jb4

[n54door]

It can slip past 450tq. FBO and E85 is enough to cause issues from what I've seen. Although, flashing the ECU with Cobb, MHD or BMS corrects the issue, the BMS flash is not something the avg Joe can do.

I screwed up my ECU when I tried to flash the BMS flash since my Laptop was not up to par (though it wasn't that old of a laptop ) Luckily I found someone local to recover my ECU.

MHD or Cobb would be your best bet for flashing the ECU. BMS requires a BT cable and a capable laptop, and lots of courage, and most of all, a backup plan if you screw it up like half of the people out there seem to. Just a word to the wise..

[houtan]

Originally Posted by n54door

BMS requires a BT cable and a capable laptop

Bummer about your ECU and glad you got it worked out.

Just an FYI, BMS does not require a BT cable and laptop to load their back end flash. It can be loaded using a cobb Accessport as well. Just load the map onto your accessport and flash just like any other tune. that's how I load it onto my car.

[n54door]

Originally Posted by houtan

Bummer about your ECU and glad you got it worked out.

Just an FYI, BMS does not require a BT cable and laptop to load their back end flash. It can be loaded using a cobb Accessport as well. Just load the map onto your accessport and flash just like any other tune. that's how I load it onto my car.

Agreed, Cobb is a safer option!

Wait for MHD though, should be out in a few weeks and their OTS maps are a league above Cobb OTS maps.