BMS VW GTI JB4 info thread

[ZuMBLe]

I used the "nipple" that exits from behind the battery. I'm pretty sure this is one of the points you are looking at. I did this:
1. Punched a small slit in the rubber
2. I used small ziptie and ziptied a 10 or 12 inch ziptie to the head of the OBD cable. The long ziptie should be following the cable and the little ziptie should be holding the large ziptie to the cable like a collar.
3. Wrapped the OBD connector with electrical tape to protect it as it's being pulled through the grommet.
4. Push the 10 or 12 inch ziptie with the cable through the hole and look for it. You may have to try a few times. I've had the ziptie travel down instead of up in a few installs.
5. I patched the whole rubber grommet area with plumbers putty.

 

[robertinohio]

Noob / Novice feedback after installing this:
1. Install instructions should mention best places to route though the firewall. I think I used the same grommet as ZuMBLe (aka has a small nipple and close to an existing wire harness). However, I wonder if I should have used the grommet that was diamond shaped sitting by itself (might be used with manuals/clutch). See circle area in pic. If I used that one, I might have been able to buy a replacement grommet when selling so you can go back to factory. I have a DSG.

2. I wish someone would post how they secured the D cable. None of the videos show that part. They skip over it. I know this has to be secured so the extra cable doesn't get into the fan blades.

3. Best placement and mounting options for the JB4 itself.

Its not a difficult install, even for a novice like myself. The above items would have saved me time during the install. Hopefully this helps anyone getting ready to do this for the first time. I took out the battery which wasn't very hard. Routing the cables and connecting everything wasn't difficult either. Just take your time and practice on the JB4 harness first.

 

[Diggs24]

Noob / Novice feedback after installing this:
1. Install instructions should mention best places to route though the firewall. I think I used the same grommet as ZuMBLe (aka has a small nipple and close to an existing wire harness). However, I wonder if I should have used the grommet that was diamond shaped sitting by itself (might be used with manuals/clutch). See circle area in pic. If I used that one, I might have been able to buy a replacement grommet when selling so you can go back to factory. I have a DSG.

2. I wish someone would post how they secured the D cable. None of the videos show that part. They skip over it. I know this has to be secured so the extra cable doesn't get into the fan blades.

3. Best placement and mounting options for the JB4 itself.

Its not a difficult install, even for a novice like myself. The above items would have saved me time during the install. Hopefully this helps anyone getting ready to do this for the first time. I took out the battery which wasn't very hard. Routing the cables and connecting everything wasn't difficult either. Just take your time and practice on the JB4 harness first.

View attachment 162159

1. Use whichever one works.
2. Twist tie it onto itself (i.e. twist tie the 2 D plugs together. One has too much slack the other shouldn't and will keep slacker cable in place.
3. Shove in between battery and ECU.

 

[ZuMBLe]

Shove between battery and ECU for me also. I think that's the most secure and stealth place.

 

[GTI210]

I have a bad battery and will have to jumpstart my car to get to work tomorrow morning. I remember reading that that can fry the JB4. Is this accurate? And if so, I can just unplug the OBD plug and my JB4 should be fine right?

 

[goodvibes]

Don't know but I'd pull it completely unless George say different. It would have to do with voltage surges and that part would still be connected and powered.

 

[sprinks]

i've definitely jumped my car before with jb4 attached. ? If i were to take any precautions, i'd just unplug the box at the multipin connector.

 

[George Smooth]

I wouldnt be to concerned with jumping it. The JB4 runs on the 5V circuit so is relatively well protected from surges.

 

[dorkultra]

as for mounting the JB4, i used sticky back velcro and put it on top of the battery

 

[Ketheptis]

So I'm experiencing a serious lack of traction in 1st and second gear when running map 2 or 3. I'm on an 8.5" wheel width, 235 Extreme Contact DWS tires, in a non power package GTI.

I find I'm having to really ease into the power, keeping my RPM's below 3k until I'm over 25MPH or I get a lot of wheel slip. If I leave traction control fully enabled it triggers almost instantly. I'm not sure where to start with Map 6 to solve this.

 

[George Smooth]

So I'm experiencing a serious lack of traction in 1st and second gear when running map 2 or 3. I'm on an 8.5" wheel width, 235 Extreme Contact DWS tires, in a non power package GTI.

I find I'm having to really ease into the power, keeping my RPM's below 3k until I'm over 25MPH or I get a lot of wheel slip. If I leave traction control fully enabled it triggers almost instantly. I'm not sure where to start with Map 6 to solve this.

The boost per gear is global so will work in all the gears.
Starts by setting Max boost 1st to pull back power in 1st gear. The value you punch in is how much boost it will cut in psi. Starts with 5 that will cut 5psi and you can play with the value up or down till your traction is decent.

 

[sloopercat]

Looking at a dyno plot on these cars, it looks like full torque is on at 1500 and falls off around 4700. Is this a limitation on the turbo system or can the torque drop off be altered by changes in map 6? Car is plenty quick till it falls off the torque. Just increasing the height of the torque plateau is something I do not want as I want to stay on the stock clutch.

 

[DThissen]

Looking at a dyno plot on these cars, it looks like full torque is on at 1500 and falls off around 4700. Is this a limitation on the turbo system or can the torque drop off be altered by changes in map 6? Car is plenty quick till it falls off the torque. Just increasing the height of the torque plateau is something I do not want as I want to stay on the stock clutch.

I'd imagine you could tweak it a little bit, but the IS20 is a relatively small turbo and probably won't be able to push much more air. You could swap to an IS38, but you might sacrifice low end response for top end torque.

 

[DThissen]

Has anyone tried the new firmware? Firmware version is 60/86/5

 

[goodvibes]

Flashed it this afternoon. Map 3 intrigued me. Works great in my Alltrack.