[Dr777]

Hey all. I'm having some weird noise with my friends 335i n54. I just put in a engine cause last one was knocking and I was test driving it and around quarter throttle it makes a loud wailing sound

and if i go WOT it will feel like it has MASSIVE turbo lag followed by 30ff. I've checked for boost leaks and vaccum leaks and everything seems tight. So did I miss something or are the turbos kicking the bucket any help would be appreciated thanks

[Dr777]

bump

[Emilime75]

Noise, lag, 30ff...you checked for leaks and everything seemed tight...you sure about that? How did you check for leaks?

[Dr777]

Originally Posted by Emilime75

Noise, lag, 30ff...you checked for leaks and everything seemed tight...you sure about that? How did you check for leaks?

https://blog.protuningfreaks.com/2014/12/01/bmw-n54-30ff-underboost-code-boost-leak-testing-diy/
Did as the guide stated no air came out from anywhere else but the rear inlet. I tightened it afterwards noise was still there but even that wouldn't account for the 30ff code

[Emilime75]

Might just be a turbo then. Did you use the ones from the knocking motor? Were they having issues?

[Dr777]

Originally Posted by Emilime75

Might just be a turbo then. Did you use the ones from the knocking motor? Were they having issues?

Yeah I used the set from the old engine. I never really drove the car before taking out the motor my friend bought as is with the knocking engine.

[Dr777]

yeah the rear turbo was bad. It had some shaft play and would not spin straight. It was spinning in ovals best way I can think to describe it. I put new after market turbos and now it boosts fine with no issues