Rennklinge Posted September 4 Report Share Posted September 4 Hello I'm having trouble setting the boost pressure on my BMW S50B30 Turbo. The engine is completely reinforced and the boost pressure pipes are sealed. The target is 220kPa. I couldn't get above 180kPa before, but now that I've changed the wastegate DC, I'm at 200kPa. The numbers from the wastegate DC are pretty high (70-80), although I see lower numbers in other wastegate DC examples. Can anyone help me or explain why I'm not reaching the target boost pressure? Or does anyone have an example of the closed loop with the BMW M50/S50 turbo engine? Ecu: Link G4 Engine: BMW S50B30 Turbo ( NON VANOS !! ) Turbo: Precision 6266 Wastegate: Precision 66 Blow Off: Precision 64 Exhaust: 76mm AN VOLT 5 = Exhaust Back Pressure THX Log 2-09-24 7;35;32 pm.llg s50b30280824.pcl Quote Link to comment Share on other sites More sharing options...
neil brown Posted September 4 Report Share Posted September 4 Boost leak Do a smoke test Quote Link to comment Share on other sites More sharing options...
Rennklinge Posted September 4 Author Report Share Posted September 4 I just did the boost pressure test, absolutely fine. No leak Smoke test: the only place where the smoke comes out is the MAC solenoid valve Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 5 Report Share Posted September 5 The boost solenoid is at 98%DC in your log so the ecu cant do anything further to increase boost. Assuming the spring is a suitable rate and adjusted correctly, you likely have a plumbing issue or a big leak. The most common 3 port external gate plumbing is as below. You may need a restrictor where shown if everything else looks ok. I've had a few cars come to me with the valve seat missing from the wastegate flange so this is always something I check if I didnt assemble myself. I have no experience with the PTE gates, but have had a couple of similar designs seize up before. Your boost leak test should have picked these up if done correctly however. Quote Link to comment Share on other sites More sharing options...
Rennklinge Posted September 5 Author Report Share Posted September 5 Thank you all.... Today, out of anger, I simply changed the wastegate spring from 9PSI to 18PSI. Now it goes up to 220kpa and holds it without any problems. The values of the wastegate DC are now very low (29=220kpa) @Adamw, should I install a restrictor and change back to a 9PSI spring or leave it as it is? (Exhaust back pressure at full load is around 120kpa) Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 8 Report Share Posted September 8 On 9/6/2024 at 8:21 AM, Rennklinge said: should I install a restrictor and change back to a 9PSI spring or leave it as it is? If you can acheive good control over the full pressure range you want then leave it alone. Quote Link to comment Share on other sites More sharing options...
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