viperbmw69
Active Member
Group I had some help identifying an issue. I have an aftermarket turbo on a L61 2.2 this engine is a fresh build with Forged Rods and Pistons. New Bearings. When I run the car the engine is very smooth and running fine. Once I get the RPM up to start building boost I get a noticeable knocking and all boost lost. Runs like crap and the knocking stays for a bit then stops and the engine runs smoothly again. I took the Turbo intake tube off the intake to check and the Engine is running perfectly fine even at high rpm. I did out of caution pull the plugs and Valve cover and the Engine is looking fine. I also took the intake and turbo off
Couple findings.
1. There is oil in the intake - Honestly this could have been there for a while I did not clean it.
2. This is an external Wastegate. Turbo and Wastegate are Ebay specials!!
3. The Turbo has NO play and spins smooth. I dont see anything obvious
4. I do think the oil Outlet is on the smaller side this is a 10AN fitting but the ID of the Adapters is 5/16 seems small.
5. I found a Oil restrictor underneath the Turbo Oil Inlet. The inlet flange itself has a very small hole and I believe this is an oil restriction hole in the flange so not sure why there is also another one under it. PICS attached
My Suspects
1. maybe the wastegate is not working properly and building to much boost then it flys open and dumps everything.... My boost gauge showing -21 boost I am not sure why it is showing negative reading.
I am thinking maybe the wastegate because the knocking sound goes away after a bit when the engine is idling. I did not get a chance to look at the wastegate pipe to see if it was exhausting during the knock.
2. Maybe a hidden turbo issue? The oil in the intake to me means the oil is not draining from the outlet fast enough.
Options I can think of
1. remove the manual boost controller and connect the Turbo to the wastegate direct and put a small PSI spring in the wastegate.
2. Replace the turbo and wastegate.
Couple findings.
1. There is oil in the intake - Honestly this could have been there for a while I did not clean it.
2. This is an external Wastegate. Turbo and Wastegate are Ebay specials!!
3. The Turbo has NO play and spins smooth. I dont see anything obvious
4. I do think the oil Outlet is on the smaller side this is a 10AN fitting but the ID of the Adapters is 5/16 seems small.
5. I found a Oil restrictor underneath the Turbo Oil Inlet. The inlet flange itself has a very small hole and I believe this is an oil restriction hole in the flange so not sure why there is also another one under it. PICS attached
My Suspects
1. maybe the wastegate is not working properly and building to much boost then it flys open and dumps everything.... My boost gauge showing -21 boost I am not sure why it is showing negative reading.
I am thinking maybe the wastegate because the knocking sound goes away after a bit when the engine is idling. I did not get a chance to look at the wastegate pipe to see if it was exhausting during the knock.
2. Maybe a hidden turbo issue? The oil in the intake to me means the oil is not draining from the outlet fast enough.
Options I can think of
1. remove the manual boost controller and connect the Turbo to the wastegate direct and put a small PSI spring in the wastegate.
2. Replace the turbo and wastegate.
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