[MattPro]

Hey guys, just wanted to share this here. I was having an issue with the new JB4 where bank 2 would be @ ~18psi and bank one would hover around 14-15psi. Apparently, the BCM does not control both wastegates independently like the stock EMS does.

So my only option was really to adjust the wastegates. It isn't the easiest to do with the turbos installed. The bank 1 wastegate arm is almost impossible to adjust while installed on the car. So I opted to slightly loosen the bank 2 arm a bit. I could not get the rod to turn after loosening the locking nut, so I just backed off the nut until it reached the end of the threads then used it to turn the rod about 1 full revolution.

Now, bank 1 and 2 are at most 2psi apart. I'm going to repeat the process in a few days and hopefully I can get both banks evened out. The car definitely feels better after this (could be placebo). Took care of the turbo coolant lines while I was in there as well since mine were on their way out.

Definitely would consider this if you are in the same boat as me!

[747flyboy]

Matt I need your advise,

I am again swapping Turbo's to the larger Alpina's (MGT2260 from MGT2256) larger compressor section of 60mm. What do you suggest I tell the technician regarding number 2 bank pulling higher boost. What suggestion may you have since turbos are unmounted for equal bank boost with waste gates adjustment.

Joe

[MattPro]

Hey, sent this via PM as well but posting here in case anyone else comes across it and is curious:

Originally Posted by 747flyboy

Matt I need your advise,

I am again swapping Turbo's to the larger Alpina's (MGT2260 from MGT2256) larger compressor section of 60mm. What do you suggest I tell the technician regarding number 2 bank pulling higher boost. What suggestion may you have that the turbos are unmounted to adjust waste gates.

Joe

At the minimum, I would recommend that they apply the same vacuum to both wastegates and ensure that they actuate the same amount. If not, adjust them slightly. However, the difference in boost could come from many different sources and not just the turbos.

So the best thing to do would be try to ensure the wastegates operate the same, and then do some pulls and get some datalogs. I started with a ~3 psi difference, got it down to ~2 after the first adjustment, and had to do two more to get them almost exactly even. Since there's no set method, what I did was follows:

You can only get to the wastegate on bank two with the turbos installed. So first, I counted the exposed threads on each wastegate arm. Then I tried to lengthen the bank 2 wastegate to expose the same amount of threads as the first. My original readings were 20 threads exposed on bank 1, and 18 on bank two. After two more adjustments, my final readings are 18 on bank one and 23 on bank two and the boost in each bank is almost dead even. Since the JB4 just essentially manually actuates the wastegates after the DME does as much as it can every car will be different and there's no way to know for sure how much to adjust them. Once you have them adjusted, any small change to your setup could sadly put them out of adjustment. This is a limitation with the JB4 hardware as it actuates both wastegates the same amount.

As a note: lengthening the wastegate will reduce the boost when the JB4 starts controlling the wastegates, and shortening it will increase the boost. So either make increase or decrease the boost on the 2nd turbo to match the first, then adjust your JB4 duty bias values for map 7 as required to make sure you get up to target or stay at target.

Hope that was all clear, sorry there isn't a clear answer or procedure so I just wanted to explain everything I have found out and done to make mine work.

[m5james]

While different engines/turbos, there are YouTube videos on how to adjust the wastegate arms, preload, etc that I found quite informative. Now I just need to install JB4 so I can see if mine are different since I've yet to find a location to install a manual boost gauge.

[MattPro]

Originally Posted by m5james

While different engines/turbos, there are YouTube videos on how to adjust the wastegate arms, preload, etc that I found quite informative. Now I just need to install JB4 so I can see if mine are different since I've yet to find a location to install a manual boost gauge.

I wish our manifolds weren't so hard to get to, I would like an accurate boost reading. The JB4 and people who run boost gauges on the charge pipes are just reading charge pressure which isn't the actual pressure in the manifold. Good enough for what it is but I'm really curious to see what the actual manifold pressure is at certain times.

[m5james]

I don't know many of the differences between the N63 and S63, but the S63 reads pressure from the intercoolers. I do agree that in the manifold would be better...other than accessibility to replace the sensor, I'm curious as to why BMW didn't install them there.

[MattPro]

Originally Posted by m5james

I don't know many of the differences between the N63 and S63, but the S63 reads pressure from the intercoolers. I do agree that in the manifold would be better...other than accessibility to replace the sensor, I'm curious as to why BMW didn't install them there.

It gets really confusing because BMW does have 2 sensors in there as well. I'm guessing those are used along with the MAFs for load calculation, but I haven't brushed up on my technical manual for our family of engines in a while. I do know that the ones in the intercoolers are just for controlling the charging system (these are the ones that the piggybacks intercept to increase boost). It's crazy to think our engines have 2 MAF sensors and 4 MAP sensors haha.

[m5james]

To make it even more confusing, the S63 doesn't even have MAF sensors, but the N63* and S63* does.

[m5james]

Hey, MattPro. I've got my JB4 up and running but I get an odd overboost condition when I try going over 21psi. I was just curious what you were using to read the differences of the two pressures before I take my own advice and adjust the wastegates.

[badblack550xi]

Originally Posted by m5james

Hey, MattPro. I've got my JB4 up and running but I get an odd overboost condition when I try going over 21psi. I was just curious what you were using to read the differences of the two pressures before I take my own advice and adjust the wastegates.

adjust wastegates manual as close as possible.

[m5james]

Using a vacuum gauge? I'm just curious how Matt was seeing differences in boost between each turbo.