[pdubq]

Hey all... been capturing lots of logs to troubleshoot massive boost lag i've been experiencing on my 535... so thought i'd share logs and results here.

found a pretty awesome DIY diagnostic guide at 'the other' boosted N54 forum, as well as a good thread on adjusting the rear wastegate actuator rod to get rid of the rattle. Also people claming increase in PSI from doing that, and getting the boost to produce quicker.

After sending logs to SHiv, and getting his helpful advice .... THANKS SHIV!!... that wastegate was the suspect, I decided to approach that first, before looking for a leak. As I was making target boost, just very very slowly.

Anyways, I did call a few larger shops around San Diego.... (Independent in La Jolla, "You have 75k miles on her!? That's your problem, these turbos are only good for 60k, you need new turbos" over the phone.... wtf?..... others wouldn't even want to touch turbos for bolton replacement)... no one up for troubleshooting turbo.

seems like 335 owners had been able to get at the rear wastegate from under the hood... but on 535 it's too deep i think. Lucky i have my talented mechanic friend, Erik Rathmann... always up for a challenge. I was going there anyways to get my exhaust worked on, and thought it would be easier to check out the wastegate on the lift, thank God i looked with him. The rod is way up, behind the DP's, and some other tubing. He fabricated a custom 4mm crows foot (sacrificing some of his grandfathers old tools), and managed to get up there with a couple ratchet extensions and a ball-and-socket joint. This guy's got skills!

Anyways, seems like with 3 revolutions of the rod (clockwise wrt the tightening nut), the lag is virtually gone. I might adjust it a little further... but not sure.

I also noticed some funny behavior from the procede... i'll put in a different thread.

Here's before/after logs:

[TrollToll]

I know I am reviving an old thread, but has anyone else heard of this being done on a 535i? It is MUCH tighter than the 1 or 3.