From what I've read it's also RPM-dependent: the compressor blades are more likely to stall at lower RPMs, however its less of a problem if you get hear the flutter noise at lower RPMs as the damage will be negligible. If you still get the noise at high RPMs you may be damaging your turbo.

 

how much damage is hard to say though. mine makes that noise and has done so for while(i like it) and while the turbo is off at the moment i have inspected it and found it to be in as new condition, besides the grubby fingerprints on the housing. we run with some of my friends that have R33 GTST skylines that have been running with no BOV for as long as ive known them to have the cars, in one case 5 years now and his turbo is still in good condition. so in theory it sounds bad for the turbo but in reality it seems little damage is done

 

I reread what I typed and I actually have a turbo XS DV and I still have that noise. How large of a DV do I need? And just to reiterate, I have a DV, not a BOV.

Thanks
Tom

 

It depends. With adjustable tension BV/BOV's like for example the HKS ssqv, if you adjust them too tight then you are likely to hear surge often at anything but full boost. At partial throttle and only building say a couple psi, it's not that unusual to hear surge like that. It's much more apparent with bigger (laggier) turbos and stiffer wastegate springs. Just so everyone is on the same page, download this mp3 Link and pay attention to 00.05-00.06. That's what surge sounds like. The sound can be a bit different between large and small turbos but that's basically what it sounds like. AFAIK, Porsche never ran any bypass or blow-off valves on any of the 934/935/936/956/962/etc race cars.

 

That is definately the sound I get. The sound is the same with a stock DV and my aftermarket one.

Funny you mentioned laggier turbos, I have a pretty laggy turbo.

I'm planning on swapping out the turbo for one that spools up sooner in the future, but until then what can/should I do to avoid surge?

Thanks
Tom

 

i wouldnt worry about it, what you are getting is a form of induced surge. what i mean by this is that the turbo isnt causing the surge. you have a problem when it is the turbo, you know its the turbo when you are holding full throttle but the car is hesitating through out the rev range, also making that noise we are talking about at the same time. this for of surge is usually caused by the turbo running out of its compressor effeciency(usually too much boost, for the size of the exhaust housing and trim)

 

Derek Bell in the 956 at the Nurburgring ...

6mins 45secs - well worth a look CLICK HERE

 

While we're at it, here's a vid of Jurgen Barth in a 936 around La Sarthe website

 

off topic, hey porschefile, what turbo is on that RB26 in your avartar? is it a T51R or a T04Z. its HKS right

 

Hey anyone notice that Dereks car is Right hand drive also. See, we are correct 'down under'. Wonder where the shifter is as he takes his right hand off the wheel as if it's not quite tiptronic but he's certainly not grabbing a shifter down in the middle?

 

HKS T51R SPL. It made 710whp though not at full boost. It's rated at up to ~1000fwhp. The T51R series is basically the HKS equivalent to the Garrett Gt42r. The T04Z is similar sized to the Gt4088r. Here's the link to the R33 whose motor this is: Website

And here's a couple vids:

Vid 1
Vid 2

 

No bus stop style kink on the Mulsanne Straight in that video? When did they add the kink?

 

Many Porsche racecars were RHD (including for example 935 Moby Dick). Mostly it's because of the European circuits configuration.