[Bmw doubles]

I've had my F10 aggressively tuned now for over 2 years and it's approaching 80k! Reflashing for the track last week and we noticed I had lost almost 4psi at redline from the previous flash. Swapped out the old for a new, cut 1/8 off the hose for a clean reconnect and we recovered the 4psi loss at redline.

Lesson here. The diaphragm in the converter is going to get worn quickly if your running a tuned PWG setup. I think a tune requirement checklist should include changing the boost solenoid replacement on higher mileage cars.

[5soko]

Good idea for guys with alot of miles and or tuned for a long time... Was yours making noise? or just loss of boost?

[Bmw doubles]

Originally Posted by 5soko

Good idea for guys with alot of miles and or tuned for a long time... Was yours making noise? or just loss of boost?

Loss of boost on the top end due not controlling the wastegate properly

[burro_blasta]

Originally Posted by Bmw doubles

Loss of boost on the top end due not controlling the wastegate properly

My wgdc is at 100% at the top end and I'm ~3 psi lower than my tuner thinks I should be...a couple months ago, before starting custom tuning, I was at the same top end psi (still too low) but only at 60% wgdc...is that similar to what you were seeing when you say "not controlling the wastegate properly"?

[Thecastle]

Boost pressure by itself isn’t an indication of an issue. Boost pressure will vary on a vehicle, based on temperature, humidity, fuel quality, and etc. boost pressure is just a measure of resistance to airflow in your intake.

To know if you have an issue, look at mass air flow, timing in each cylinder, duty cycle, and pressure, and fuel trims.

If your car is showing high mass air flow and good timing it’s making power, regardless of boost. I

If your mass air flow is down, and your seeing a high duty cycle on the waste gate and normal for your tune a/f then you may have a bad boost solenoid. You have to log to figure out the problem,

[535_BiTurbo]

Originally Posted by Thecastle

Boost pressure by itself isn’t an indication of an issue. Boost pressure will vary on a vehicle, based on temperature, humidity, fuel quality, and etc. boost pressure is just a measure of resistance to airflow in your intake.

To know if you have an issue, look at mass air flow, timing in each cylinder, duty cycle, and pressure, and fuel trims.

If your car is showing high mass air flow and good timing it’s making power, regardless of boost. I

If your mass air flow is down, and your seeing a high duty cycle on the waste gate and normal for your tune a/f then you may have a bad boost solenoid. You have to log to figure out the problem,

[burro_blasta]

Thanks guys...situation is that, all else equal, as I've worked up to my fourth revision of a custom tune my top end has stayed at ~10psi but, as I went through revisions, my WGDC has gone from 60%ish, to 70s, to 80s, now at 100.

Tuner is concerned that WG is closing more but more boost is not resulting (again, all else equal across the logs then vs. now). Found/fixed some leaks but no change. Going to replace the boost solenoid and some vac lines this weekend as a bit of a hail mary, but also just a healthy thing to do now that I'm at 65k miles and tuning.

The other argument is that everything is fine, just the PWGs lose more boost at the top and I'm in Denver (altitude) so I'm even a bit lower than most. Still is weird that WG is now closing completely for the same psi as before but maybe that ~10psi is just my top end max, WG closed or not.

[harris69]

I had mine changed recently after my tuner suggested that boost onset was too strong and after seeing boost spikes in my logs. Ordered one from FCP and had my mechanic put it in. All has been good since then.

[Surly73]

My 4/2011 535xi has required a new pressure convertor almost every spring. I don't know if there's something about my climate or driving routine that puts it at risk but every spring when the weather starts getting nice since about 2014-2015 I hear the buzz when coming to a stop. At first only once in a while, working it's way up to every stop light.

It started late this year, a few weeks ago. This is my first replacement not under extended warranty and I already have the part from FCP. I'll just have to figure out just how to work this into their lifetime replacement deal - buy one more and just rotate annually with free replacements from here on out?

There doesn't seem to have been any update of the part that has helped since up until now they were coming straight from the dealer and should have had any updates etc... I'm just going from memory but there is another pressure convertor part# but I think the vehicle has to be 7/2011 (IIRC) or newer to use it so I can't. That one has been updated a couple of times from what I recall and perhaps later PWG cars won't suffer the annual failures I do.

EDIT to bring in real info. There's conflicting information in bimmercat and realoem about supercession, cut off dates etc... (I'm getting this a lot while looking for parts for my F10)

Bimmercat mentions 7/2011 production but a list of 3+ part changes. RealOEM only mentions a 6/2012 cutoff for the part change. I am stuck with 11747626351.

[burro_blasta]

That's the same part number I just ordered...my cars production date is 5/13. Good to know I should go for the other one of this one fails anytime soon.

Do you replace it yourself? Seems like it's going to be annoying getting the ratchet onto the lower bolt but otherwise nbd...any tips? I also ordered some silicon vacuum lines and am going to replace some of those while I'm in there.

[burro_blasta]

Was pretty straightforward to replace, as long as you have a deep 10mm socket for the bottom bolt. Still a pain to get into the tight spots but not a big deal.

Chickened out and didn't replace the vacuum line going to the wastegate...so tough to access it below the outlet, was worried I'd pull it off and not be able to reach down to get the new vacuum line back on the wastegate nipple...

[burro_blasta]

Logged some pulls with the new solenoid, now I'm getting a drive train malfunction and code 120308. Awesome