[Saif2018]

Originally Posted by CarAbuser

You seem to be proud about the fact you get worse mpg than a Dodge viper. It's really bad for the motor.

It's rare for the N54 to have rod bearing issues but when it does it's due to fuel dilution in the oil.

That's not it, lol proud about bad mpg

your making unrealistic claims which don't even match up with BMWs claims.

Yes rod bearings not so common but it does happen

[grahams]

Still without success on this issue.

Car is now flashed with standard IKMOS (1M) bin to remove any potential issues coming from mapped in throttle delay

Yesterday I hooked up a mity vac to the turbo wastegates and can see both fully close at the BMW spec on 200 mbar so am happy they are set correctly.

Something I haven't clocked before was the vacuum link hose between the two wastegate solenoids. Any marginal failure of 1 valve would impact both banks of turbos in the same way as the wastegate vacuum is shared.

Looking at some old logs the PID corrected base WGDC is being pulled down a significant amount to try and prevent overboost. Base WGDC and after PID seem to be closely aligned whilst bank 1 and 2 uniformly diverging. Can someone shed light on what the input and output of these values is?

my WOT LOG, very low WGDC and throttle closures
https://datazap.me/u/grahams/older-s...21-24-25-26-27
1m log higher WGDC and no throttle closures
https://datazap.me/u/sgagetti/bmw-1m...-24-28&solo=28

From a PWM project previously I recall that solenoid valves reach a point where a change in PWM toward the upper and lower limit of the valve no longer has a linear effect on the vacuum/boost it's controlling. With values down at 15% at times I expect this is very close and hence throttle closures as the car over boosts. The BMW literature implies the solenoid valves entirely control boost during WOT so there should be no throttle closures.

"When power is then demanded from the engine, the compressor can deliver the required boost pressure without any noticeable time lag. In the full-load situation, the boost pressure is maintained at a consistently high level when the maximum permissible torque is reached by a partial opening of the wastegate valves. In this way, the compressors are only ever induced to rotate at a speed which is called for by the operating situation.

The process of the wastegate valves opening removes drive energy from the turbine such that no further increase in boost pressure occurs, which in turn improves overall fuel consumption."

Summary: will replace solenoid valves and confirm vacuum canister effectiveness.

[grahams]

Unfortunately no resolution with new solenoids. At a loss with this car now and would appreciate any help with this issue.

Have done:
Vacuum lines
Boost solenoids
Cleaned TB
Cleaned valves
New plenum gaskets
New charge pipe O-Ring
No boost leaks
New turbos
New hpfp
New valve cover
Checked wastegates are set correctly
Vacuum canisters are effective

Summary of issue: car doesn't respond crisply to accelerator pedal input with light surging (amplified by jb4/MHD)

For example I pulled off a round about in 3rd about 3500rpm at partial throttle, proceeded to WOT, nothing happened and then about 1 second later the power snapped in, feeling very mechanical feeling. There is also light surging under partial throttle. No codes.

The car also experiences throttle closures on WOT due to slight overboost scenarios.
Bar downpipes and a charge pipe the car is standard with a 1M map (IKM0S)

My thoughts are:
Vanos solenoids
Throttle body
Diverter valves

To prevent throwing more money at the car does anyone know how to bench test these items?
Any additional items to check please let me know. I don't see any issues with fueling from my logs.

Latest WOT log
https://datazap.me/u/grahams/ikm0s-3...23-24-25-26-27

[Dave92N54]

Have you replaced the fuel pressure regulator on the driver side? It's known to cause a hesitation which I believe is visible in your rail pressure, you can see you go WOT, WGDC is flat and boost is on target, and rail pressure goes down just a tad and then shoots back to 2500 again, presumably when you feel the "power snapped back in". Just my initial thought.