One thing I did not that is a must is the two main coolant rubber hoses that feed the engine. Those DO fail. And it is bad when they do. As for the other vacuum lines, i just did a thorough visual inspection and ziptied the ones that were press fitted. It is one of those things where you could probably justify an insane amount of work "while you are in there" to the point of insanity. If you are to replace vacuum lines, maybe change just the ones needing an engine drop to replace and leak/smoke test.

 

I'm starting to think that a faulty n75 valve is what caused my engine failure. I ordered one so we'll see. Maybe this should be a regular maintenance item, they are cheap.

 

They do fail. I have never seen one cause over boost though. I had one fail on my S4. Typically they cause underboost. Or boost fluctuation. They are sprung to default to bypass boost pressure straight to the wastegates. You can verify by unplugging the N75. So then you are basically wastegate regulated. They would have to have seized not allowing any boost pressure to get to the wastegates. In which case you would see that by checking the valve while it is out.

 

ha, i cant recall the conversion btw the gauge and the psi so your continuing efforts at tweaking it are lost on me though you can have MY abnormally high boost levels! ( at least as the gauge sees them

which brings me to this

so not to waste time on a new thread! ( jump in anytime, bruno ..

i just replaced my maf as the car was idle fluctuating and this has not only cured that. but NOT my somewhat/occasional *over*boosting condition which i was sure were related ( spikes 1.4..and have seen even 1.5 on a 1.3 bar tune.. ) and while i don't suspect any vac leaks, i have not yet pressure tested ( soon ) and no codes.

so, can i ( and safe to? ) actually disconnect the n75 and run the car as a comparison in the same way one can simply unplug the maf and see if there's a difference in how it runs? i have always been under the impression that the n75 controls boost and i have checked my wg's ( 1.0 actuators ) and they are set properly. ( ar at least were.. ). i replaced my n75 along with a #16 cv a few years back, and wouldn't suspect they had gone bad so soon.

anyone? ( again, apologies bruno... )

 

How fast can you do it now? lol I need to take mine out for the first time..no lift.

 

exactly. mines tuned for 17-19 psi max boost. interestingly, although it's referred to as a "1.3 tune" when in all actuality, it's really a 1.1.5 at 7200 rpm.

so at what pressure should the n75 "hold", and for how long? if i have no leaks and wg's are within proper spec, should i assume the n75 is funky? it IS a cheap part. *something* is allowing overboost.

 

Can you? Yes. Should you? I probably wouldn't. Because if you are tuned the ECU may actually be controlling the boost curve for safety.