I have been having this issue ever since I put in bigger turbos on my car December of last year. Originally, I bought a set of used rb next gens to replace my perfectly working stock turbos. I took logs and noticed that I never held boost at higher rpms. I did smoke tests, pressure tests (by several different indy bmw shops), changed out my bov spring, boost solenoids, new vacuum lines, and even took it back to the guy who I had bought the turbos from to double check the installation as he went from rb next gens 15t to single turbo on his N54. Everything came back as if there was no leaks despite what my logs said.
One day, we (guy who sold and installed the turbos) were logging on the highway and the rear turbo shaft had snapped and there was lots of smoke coming out of the tail pipe. So maybe it was bad turbos that needed to be rebuilt you would think? I sent them back to Rob (excellent communication) for analysis and had them upgraded to next gen plus 17t. This took several months and again, had the guy put in the turbos in for me as he felt partially responsible for what had happened.
Fast forward to this day and I am still having the same issue on brand new, rebuilt turbos. Sorry for the long rant, but I felt like I needed to explain what I have been going through the past 10 months as it has not been easy (financially and mentally dealing with this). I am still not ready to throw in the towel as I want to tackle this issue and stick with my N54 for the next few years.
I also want to mention that I had an indy shop perform a compression test on the motor when I got my turbos rebuilt and all cylinders came back in the 180s.
When I was on stock turbos, I was custom tuned by Dimitri from BQtuning. Here is a log when I was on stock turbos: https://datazap.me/u/rnmevo9/bq-v2-log-1?log=0&data=4-21
When I got my used rb next gen 15t, I got a base map from bq and here is a log: https://datazap.me/u/rnmevo9/base-bqe45rb?log=0&data=4-20-21
After I blew up the turbos and had it rebuilt by Rob, I took another log and I am still having the same boost dropping off: https://datazap.me/u/rnmevo9/ng?log=0&data=3-22
My car is a 2007 335i with about 119k miles. My father was the original owner and then I bought the car from him so I know most of its history. My car has the following modifications currently:
RB next gen plus turbos
RB external pcv valve
Mhd custom tuned by BQ on e45
Vrsf relocated aluminum inlets
Vrsf downpipes
Vrsf charge pipe with tial bov (black spring)
Psp 900 intercooler
Psp external oil cooler
Psp aluminum outlets
Relocated 335d coolant tank
Fuel it stage 2 lpfp 525 pump
EOSpeed bpm4 lpfp controller
Index 12 injectors
Precision raceworks fuel filter assembly (waiting to be installed)
Spool hpfp overdrive (waiting to be installed)
Thank you for your time.
One day, we (guy who sold and installed the turbos) were logging on the highway and the rear turbo shaft had snapped and there was lots of smoke coming out of the tail pipe. So maybe it was bad turbos that needed to be rebuilt you would think? I sent them back to Rob (excellent communication) for analysis and had them upgraded to next gen plus 17t. This took several months and again, had the guy put in the turbos in for me as he felt partially responsible for what had happened.
Fast forward to this day and I am still having the same issue on brand new, rebuilt turbos. Sorry for the long rant, but I felt like I needed to explain what I have been going through the past 10 months as it has not been easy (financially and mentally dealing with this). I am still not ready to throw in the towel as I want to tackle this issue and stick with my N54 for the next few years.
I also want to mention that I had an indy shop perform a compression test on the motor when I got my turbos rebuilt and all cylinders came back in the 180s.
When I was on stock turbos, I was custom tuned by Dimitri from BQtuning. Here is a log when I was on stock turbos: https://datazap.me/u/rnmevo9/bq-v2-log-1?log=0&data=4-21
When I got my used rb next gen 15t, I got a base map from bq and here is a log: https://datazap.me/u/rnmevo9/base-bqe45rb?log=0&data=4-20-21
After I blew up the turbos and had it rebuilt by Rob, I took another log and I am still having the same boost dropping off: https://datazap.me/u/rnmevo9/ng?log=0&data=3-22
My car is a 2007 335i with about 119k miles. My father was the original owner and then I bought the car from him so I know most of its history. My car has the following modifications currently:
RB next gen plus turbos
RB external pcv valve
Mhd custom tuned by BQ on e45
Vrsf relocated aluminum inlets
Vrsf downpipes
Vrsf charge pipe with tial bov (black spring)
Psp 900 intercooler
Psp external oil cooler
Psp aluminum outlets
Relocated 335d coolant tank
Fuel it stage 2 lpfp 525 pump
EOSpeed bpm4 lpfp controller
Index 12 injectors
Precision raceworks fuel filter assembly (waiting to be installed)
Spool hpfp overdrive (waiting to be installed)
Thank you for your time.