3071 surge

[prj]

I already wrote that 1.8 bar on stock engine is too much for 0.63 A/R housing.
You are overstressing the turbo and probably running high EGT's, because I can't imagine you will be able to run much more than 14 deg timing at redline with 0.63A/R hotside and 1.8 bar boost there.

Leave the spring alone - it seems perfectly fine if your car can actually manage to hold 1.8 bar to redline.

Going by the sound is also not the correct way. Post a log (graph) of boost vs RPM on the car, if boost does not oscillate when you hear the sound, then it's not surge.
By the looks of it, your car is perfectly healthy, just needs some mapping efforts.

[QuattroFever]

The stock turbo on a 1.5 bar chip gives WG flutter between 3 and 4k RPM or so also, hence asking. If you're running a stock spring, then it might be worth taking advice on an upgraded one.

I had a high boost high timing chipset from mrc on an all stock setup bar the exhaust and never heard anything quite like this.

It makes sense though, id like to make it adjustable like i had on my old 3b. A stud in the WG cap to adjust the tension.

[QuattroFever]

http://www.youtube.com/watch?v=pk3bInhF8Fw&feature=youtube_gdata_player

Thats the noise i get although not for as long.

[Thuppu]

The stock wastegate is adjustable if you pull off the small top cap.

[A80Avant]

I had a stock head on the setup I described. Just slightly lower compression.

[CS Q]

http://www.youtube.com/watch?v=17ZKxHV5Rzs

This is my car, and you can hear the flutter/chattering sound, on full throttel.
From 36 sek. and out.
Claus

[QuattroFever]

.

I already wrote that 1.8 bar on stock engine is too much for 0.63 A/R housing.
You are overstressing the turbo and probably running high EGT's, because I can't imagine you will be able to run much more than 14 deg timing at redline with 0.63A/R hotside and 1.8 bar boost there.

Leave the spring alone - it seems perfectly fine if your car can actually manage to hold 1.8 bar to redline.

Going by the sound is also not the correct way. Post a log (graph) of boost vs RPM on the car, if boost does not oscillate when you hear the sound, then it's not surge.
By the looks of it, your car is perfectly healthy, just needs some mapping efforts.

Missed this post. Using my phone. Will map some more boost in and get a log.

[A80Avant]

http://www.youtube.com/watch?v=17ZKxHV5Rzs
This is my car, and you can hear the flutter/chattering sound, on full throttel.
From 36 sek. and out.
Claus

that's excactly how surge sounds. Sometimes almost similar to a diverter valve flutter when on lift off.

[Audi_CQ]

that's excactly how surge sounds. Sometimes almost similar to a diverter valve flutter when on lift off.

That car belongs to a friend of mine and it sound like surge, but boost is completely stable I've observed a couple of 2.2's with GT35 that had surge at ~4000 and 1.8bar and there the boost was all over the place when surge occured.

[A80Avant]

mine sounded excactly like that with a movement of the needle only about 0.6bar. Sometimes its not that easy to notice on a gauge with a needle, and i was noticing it only on the logs.

[Audi_CQ]

mine sounded excactly like that with a movement of the needle only about 0.6bar. Sometimes its not that easy to notice on a gauge with a needle, and i was noticing it only on the logs.

Nothing is showing in the logs. Boost is steady all the way. The sound comes at ~5000 long after max boost is achived so can't be surge?

[prj]

After 5000 is not surge. When you get surge, the needle actually flutters back and forth.