For a car that usually operates at 12-15 psi of turbo boost, 0-3 psi wasn’t doing our BMW 435i any favors on track.
One good thing about a large, catastrophic boost leak like this: It should be fairly easy to locate.
[What’s causing our BMW 435i’s boost problems?]
A few other assumptions would also guide our search. Since we had already upgraded …
Now take a paint marker and draw where its supposed to go on both sides so you can see really easy when it isn't positioned correctly.
theruleslawyer said:Now take a paint marker and draw where its supposed to go on both sides so you can see really easy when it isn't positioned correctly.
Look at that first picture again :)
Did you clean the oil off the inside of the silicone couplers? With a factory cam breather system the intake plumbing tends to get a coating of oil on the inside, and when the coupler blows off that oil gets transferred to the inside of the coupler where it's supposed to be sealing against the pipe. You don't want oil there because it lubricates the slip fit and makes it much easier for it to blow off against in the future.
Isopropyl alcohol does a pretty good job of cleaning the oil off.
In reply to codrus (Forum Supporter) :
For bonus points, use hairspray on the inside of the coupler when installing. Our silicone pipes have a special inner layer that's extra grippy and a minimum of joints, but back in the bad old days with many steel pipes and couplers the hairspray was the ticket.
Tip for Bimmerworld: formed silicone hoses are not expensive :) Although it looks like BMW uses some weird connections at the ends that make this unpalatable.
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