Yes another compressor surge thread.

[RichX]

I've been ignoring it for months .. Has zero negative effect when the car is coming on boost, just a sound.

Long term, who knows, but suspect is has very very little impact to the turbo.

Mine only does it in 4th when i floor it without chaging into 3rd.

[wannabox]

Originally Posted by RichX

I've been ignoring it for months .. Has zero negative effect when the car is coming on boost, just a sound.

Long term, who knows, but suspect is has very very little impact to the turbo.

Mine only does it in 4th when i floor it without chaging into 3rd.

Yep thats me too . I actually like the sound hehe.

[jungleboy]

I'm not totally 100% on this, feel free to correct.

Doesn't the stock ECU have a target boost table(Boost against RPM and engine load) that can be adjusted. If you find the cells in this table you experience surge and set these values lower, it will open the wastegate to prevent the turbo pumping more air than the engine can flow. But I'm unsure whether the wastegate will even operate if surging occurs during low boost conditions.....If that's the case, then either deal with it or get cams.

But yeah, just my thoughts.

[WRP10]

You can tune out compressor surge to an extent, after that youre stuck with it

The two best ways i looked at to alleviate the problem was an external gate (which is also mad fun) or just getting a dump pipe with a splitter in it, ended up going with the latter and the problems all fixed

I think like 350 from RMS or something

[RUSSGT]

BXT was gettin this really bad on his xt forrie. So he put the p20 rear housing in his vf34 and its fine now.

[RichX]

Originally Posted by RUSSGT

BXT was gettin this really bad on his xt forrie. So he put the p20 rear housing in his vf34 and its fine now.

Which lines up with what Mister Two said about increasing flow in the exhaust housing.

[BXT]

My problem was not compressor surge originally with the VF34....it was a lack of boost control due to boost creep which was caused by the wastegate not being able to flow enough to control boost. It turned out I had one of the VF34's that had the very sharp edge leading to the wasetgate port which caused gases to race past the wastegate hole and continue on to keep spooling the turbo.



The RED area was my problem as it was very sharp.....the P20 was obviously bigger but that RED edge was smoothed & rounded from the factory.....so that together with the increased capacity of the P20 solved any creep issues.

In saying all that though, I actually do have compressor surge at low rpms which is more noticeable in 4th and a little in 3rd...and like some of you have said, its caused by the turbo creating more boosted air than the engine can ingest at a given rpm.....my wastegate hole under the penny was also ported out larger so I don't think surging is a wastegate flow problem in most cases, its more that the target boost the tuner is setting is achievable but unfortunately the engine is unable to ingest it and as jungleboy suggested bigger cams and/or porting the heads will help get rid or compressor surge as heads & cams are usually the biggest restriction on any turbo engine. (besides an OEM exhaust)

[SSjCosmo]

I'm gonna pull the vacuum line off my atmo BOV that's attached to my TMIC so that it's silent to get it over the pits.. I'm guessing i'm gonna get some killer compressor surge? :|

[Jim621]

No, you may explode your engine though..

why dont you borrow, or just buy a stock BOV for trips over the pits?

Steve.

[Elrico]

All you do is take you BOV vacum line off your throttlebody and plug with with a screw, tie it away out of sight, out of mind. It'll make an avg noise but if only left for a little while, will be ok. Think about it, VL turbos came from factory with no BOV. They made a horrible flutter lol.