can stock TIP cause surge at 75

[rfelker]

Car is stock except forge splitter. The dv not used as bov. Only other thing I have replaced is n75 in last 2 weeks. When going past 75 I get surge. Does stock tip collapse at that speed?

[coowhip]

The collapse of the TIP is not speed related, it is boost related. It won't have an affect if you are on stock tune.

[rfelker]

Well Im getting surge when letting off the gas at 75-80. and the way I understand it either collapsing the tip or bad dv correct?

[Timtheguru]

Do you have your N249 bypassed, and if not it's possible it has failed.

Start here and read on:

http://www.audizine.com/forum/showth...=1#post9378177

[rfelker]

No not bypassed. So bypassing it and no surge would tell me its bad correct? Any test in vag? thanks

[Timtheguru]

When the N249 fails it basically acts as though it is bypassed. So the only way to know is to replace the N249 (although there may be a code for failure), but before you start replacing...

1. Check for codes
2. Clear codes (after recording them, if there are any) and Align the throttle body (no matter what)
3. Pressure test and ensure you don't have any leaks post MAF, this could be charge side or non-charge side
4. Test diverter valve, test with pressure on both sides, then test with a socket and extension. With the socket and extension, press down the valve and then release, if the spring still works, then you're good. Be sure to put it back the same way you removed it, although probably ok, it just creates another variable.

[Quattro kev]

i don't think he's talking about compressor surge. Surge as in a loss of power or a buck?

[ShogunR32]

Well Im getting surge when letting off the gas at 75-80. and the way I understand it either collapsing the tip or bad dv correct?

You are experiencing compressor "stall" and not compressor surge. Compressor surge only happens when you are on the the throttle and the engine can not handle the amount of air being pushed in at the given RPM. I experienced real bad compressor surge with my old garrett 57 trim turbo with anything above 15psi. My guess is your diverter has something to do with it.

[Charles.waite]

How do you know you are getting surge? What is the symptom? Are the revs rising? Do you have a boost gauge?

[rfelker]

] Best way I can describe it is same as this video. And it only happens at 75 or above. Never had it until I replaced the n75 2 weeks ago. I did vag the car and no codes. also did a pressure test 2 weeks ago before I replaced the n75 and no leaks. Ill replace the n75 and clean the forge first and see if it resolves it.
http://www.youtube.com/watch?v=nCj6Spwl1CU