Help with boost issue with PS2 and other mods

[AndyW]

Need some help from the collective wisdom here.

I have an issue where the car *occasionally* doesn't make expected power at WOT (logs below). Seems to get worse as the car gets hot. As this was my first test day on the track with my new bits I would appreciate some help before I dive into anything. I really don't want to spend time, effort, or money on this without some thought. Interestingly, despite experiencing the boost issue I logged my fastest ever lap at Pacific Raceways!

Things on my suspect list are:

New WG
New GFB DV+ DV
Tune issue
HPFP
PCV

Car is 2012 135i N55 with 109K. Has a new PS2 with upgraded WG and DV as well as a new Fuel-it Stage 2 LPFP with Walbro 525. I also replaced the EKMP3 with the fuel pump.

All symptoms that are different from "normal" to me (for completeness, don't think all are related but hey...who knows).

The main symptom is that when going WOT (typically coming out of a turn on the track), boost will sometimes "stick" at 5-7#. Typical WOT throttle boost is 16# on this tune. So quantitatively, the car feels like it drops to NA but it's still pulling. I determined with some experimentation (and when it was safe to do on the track) that lifting the throttle for a second and reapplying full throttle would reset it. A related noise I am getting on lifting in general is a "whup whup whup", like letting air out of a balloon, sorta, which I presume is the DV? It appears to be coming from the drivers side so I presume it is coming out of the intake, which would also align with the DV being the source. Not sure if that is normal DV+ behavior with the race spring or not. The noise happens regularly on lift, even when I don't get the low boost symptom.

- Codes: Only codes the car is giving me right now are HPFP related and seem to be MHD related from reading forums. I am including them for completeness. Also, these are ghost codes and I would get them occasionally before the upgrade (would notice them when checking codes for another reason, no other symptoms)

2BDE Fuel high pressure on enabling of injection: pressure to low.

2BF0 High fuel pressure during or after the injection is released (2nd environmental condition sentence after time delay): Pressure too low (thx Google Translate!)

They only seem to ghost code at startup and rail pressure seems great on the track logs so I am not sure there is any relation to the boost problem. But I am also considering replacing the HPFP as well, just to be sure.

- Idle. The idle is more "stumbly" since the PS2 replacement, if that's a word, like if you have vacuum leak or very small PCV problem. I suspected PCV but every time I open the oil cap while running there is clearly vacuum. Considering replacing VC just to eliminate this as a possibility. I also have a little bit of concern in may be the new LPFP, but, unfortunately, there is no LP fuel pressure gauge on N55 like there is on N54.

- I track this car and the logs below were recorded on the track.

- Tune is an initial Wedge Performance tune specifically for PS2. Wedge is on vacation so I haven't heard back from him on this thoughts on this issue.

- Here is what I consider to be a decent 4th gear pull with this new setup (car was absolutely a blast except for the intermittent boost drop issue)

https://datazap.me/u/andyw/4th-gear-...mark=1984-2187

Everything seems in order. Throttle Max. Boost rises to boost target. WGDC goes up predictably, rail pressure good. Lambda does go down a bit, but I think that is good for max power.

Now, look at these two examples.

https://datazap.me/u/andyw/strange-b...551&mark=11395

Notice how boost doesn't track with target and actually start going *down* initially. WGDC also tracks *down* with a WOT, but that is actually consistent with the boost, I believe. And WGDC is what is electronically being *sent*, correct? I know of no sensor on the WG. So the car is actually telling itself to do this. Then, several seconds in, something "unsticks" and everything goes back to what I view as normal. One thing different on this log in the number and size of timing corrections...definitely needs some tuning work, but those corrections are also AFTER the boost issue. This log really makes me lean toward the DV+ being the problem.

https://datazap.me/u/andyw/strange-b...896&mark=11814

This is me feeling the car having an initial loss in power and playing with the throttle to correct. Notice that in this case...boost *target* also stays low, despite WOT, and then slowly starts to rise. WGDC also tracks *down* again. Then I come off throttle for just a blip, and boost becomes "unstuck" again. Very low timing corrections here. This log makes me think it may be a tune issue.

Anyway, would appreciate any advice or direction. Car feels awesome when the issue is not present.

[houtan]

Stuck looking at the logs on my phone for now. But in that last log, the tune is asking for much lower boost. Load request is much lower, boost target is lower, so your boost actual is lower. That seems it could be something in the flash to me. Have you tried reflashing the tune?

[AndyW]

Originally Posted by houtan

Stuck looking at the logs on my phone for now. But in that last log, the tune is asking for much lower boost. Load request is much lower, boost target is lower, so your boost actual is lower. That seems it could be something in the flash to me. Have you tried reflashing the tune?

Makes sense and worth a try, but my next track day isn't until the 8th when I can test again so I'll see what Wedge has to say when he gets back.

[iminhell1]

Clean air filter, get new one (larger), or try without one.
My best guess is a restriction at the filter itself.

[houtan]

What intake are you running?

[AndyW]

Originally Posted by iminhell1

Clean air filter, get new one (larger), or try without one.
My best guess is a restriction at the filter itself.

Thx. Air filter is brand new. BMS intake plus pure high flow elbow. Wouldn't an inlet restriction also be consistent in effect?

[AndyW]

Originally Posted by houtan

What intake are you running?

BMS with pure high flow elbow.

JPuehl mentioned this looked like a "commanded WG" vs a PID tune and said you knew more about that. I admit to being ignorant of either approach. I am sure this will all be resolved when Ken gets back and flips some software value and fixes it. I am really hoping it's tune related...would like to not have to work on the car for a while and just be able to play with it!

[JPuehl]

Originally Posted by AndyW

Thx. Air filter is brand new. BMS intake plus pure high flow elbow. Wouldn't an inlet restriction also be consistent in effect?

I run the same intake and inlet you do at 22/26# with no problems, it's not an intake problem. You did mention this was only rev 1 of your tune so maybe before making changes just see how the logs of the next rev look.

[DWN-N-OUT]

You mentioned you have the the DV+ with the optional spring installed, my guess is that's what causing your issue. Your problems seem to line up with the ones mentioned in this thread and he solved it by removing the spring.

https://f30.bimmerpost.com/forums/sh....php?t=1516956

[dtla1]

Did you also upgrade the DCT Flywheel?
Don't remember the exact symptoms of Pure Stg 2 + OE Flywheel, but it had to do with misfires IIRC?

[AndyW]

Originally Posted by DWN-N-OUT

You mentioned you have the the DV+ with the optional spring installed, my guess is that's what causing your issue. Your problems seem to line up with the ones mentioned in this thread and he solved it by removing the spring.

https://f30.bimmerpost.com/forums/sh....php?t=1516956

Interesting. That does sound like what is happening to me.

[AndyW]

Originally Posted by dtla1

Did you also upgrade the DCT Flywheel?
Don't remember the exact symptoms of Pure Stg 2 + OE Flywheel, but it had to do with misfires IIRC?

No, flywheel replacement is planned for the winter.... No misfires.

[AndyW]

I'll hold off changing anything until my tuner has a crack at it...

[AndyW]

Current theory is what I will refer to as "pre-limp" mode where the car cuts power based on coolant, oil, or trans temp. I need to log torque limit parameters to figure out which one. My past track day I was definitely in the coolant temp zone for this (maxed at 248F, pre-limp is 242-255F). Oil was 262F (pre-limp is 300-314F). Only one I don't know is trans but it got to 255F and my tuner suspects it is the culprit. Thinking about getting a secondary trans cooler as the trans would be drawing up the coolant temp as well.

[AndyW]

Some interesting data.

Here is a log on a hot day last year. This was before CSF Rad, before PS2, before race FMIC. However, I found a period of similar boost behavior in the log. I don't remember it being dramatic at the time but I was also noticing high IAT's and expecting less performance since it was so hot.

https://datazap.me/u/andyw/tnia-ridg...zoom=3129-8880

The plot thickens...if this was occurring before all my upgrades, it's likely not the upgrades. It has to be the car doing some kind of protective action. Can't wait til the 2nd when I can log TQ Lim parameters and hopefully finally get an answer!

Tempted to upgrade to 25 row Setrabs and add a Transmission cooler anyway...

[AndyW]

So. it's definitely not anything mechanical I added. Car ECU is reducing the power via TQ Lim 1, 2 and 3.

https://datazap.me/u/andyw/4th-gear-...zoom=4749-4809

Car was running awesome, until a coolant hose ruptured or became disconnected and let all the magic blue fluid out. Will put it on the lift this weekend to figure it out. I just replaced thermostat, pump, and recently replaced all the hoses so hope it is something simple, like a hose to the pump slipped off or something.

[AndyW]

So, I added a 13 row Setrab between the DCT outlet and the water/DCT cooler. I stuck it in front of the FMIC and viola! No temp issues today at all. Granted it was 15 degrees cooler but the trans cooler also pulled down the coolant temps nicely. I think this problem is solved.

[mKilgore]

Are you also running one of the larger volume billet trans covers?

[AndyW]

Originally Posted by mKilgore

Are you also running one of the larger volume billet trans covers?

Yes. A slon.

[cup4leafs]

Did you figure this out?

I had issues with the GFB DV when using MHD.

After a lot of messing around trying to find the issue, I found that uninstalling the MHD completely fixed my boost issues.

It seems that MHD does not play well with the GFB DV.

I am running the JB4 just fine but no MHD anymore.

2011 335xi
M-Sport
6MT
BMS intake
VRSF Catless DP
VRSF charge pipe
JB4

[wheela]

I was having similar problems as OP, where sometimes at WOT it would happen (but usually not). I was suspecting it was an extreme traction control intervention, so started driving with it off. In almost 2 years of driving with it off, it hasn't happened. When it would happen it would be scary, for example being stuck in the slow lane, and punching it to enter the fast lane and the engine revs up, but no power... And just like OP, the only way to get power back when it happens is to completely let off the gas - not something you want to do after pulling out into traffic.
I did catch it on a log once on a pull on a particular time when I had forgotten to turn traction control off. If your logging torque limiters you'll see them trip along with throttle plate and boost interventions. Doesn't make sense since i'm x-drive and can't light up the tires, but for some reason every now and then the traction control thinks all hell is breaking loose (when it isn't) and starts cutting power. Now I only leave traction control on if it's raining or driving in the snow.

Edit: first noticed on stock tune w/ stock parts. Now i'm mhd 2+, catless DP, intercooler, and chargepipe, and it will still happen if I don't turn off traction control.

[AndyW]

This ended up being TQ limiting due to temps. Bigger coolers and all is well.