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LtKaos

By LtKaos,
in Western Australia

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LtKaos Apprentice

LtKaos

Posted
Posted

hey guys

i have been looking into this for quite a while, and im about ready to give up, i hear alot of cars having alot of flutter etc when changing gears etc...

and alot of people have been saying it the blow off valve, and alot of people are saying its turbo/compressor surge. just wondering which one it really is.. because hell i think it sounds cool, and would really like it on my r34. and if it is turbo surge, some also say its fine and some say it bad etc can anyone give me some more insight please?

any opinion and help woule be greatly appreciated

Conz

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mz.qiksky Explorer

mz.qiksky

Posted
Posted

It is compressor surge and is caused by the bov. When the bov doesnt open at the right time or doesnt open enough the compressed air flows back across the blades of the turbo and out of the air/pod filter. This is often because of the spring rate in bov. It is not good for the turbo because the blades can get damaged and break and go through the engine. The flutter may sound cool between gear changes but its not worth it.

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mz.qiksky Explorer

mz.qiksky

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The R34 has a nylon compressor wheel which makes them lighter and quicker to spool... yet weaker under high psi/temperature. They're only good for about 10psi and are probably one of the worst turbos to experience compressor surge with. You could get the factory turbo hi-flowed, where they replace the inlet and exhaust wheels with steel. But even so, I wouldn't recommend compressor surge on any turbo.

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mz.qiksky Explorer

mz.qiksky

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There's a few different forms of surge most common is when the throttle and bov are closed while boost is still in the system with no where to go and it back tracks to the comp wheel and trys to stall it while the turbine is still being driven making that lovely flutter sound which is very bad for the turbo. It puts over 100 lbs of load on the thrust bearing which only has a 2mm contact area in some cases and so they fail quickly.

The other type (shown in the video) is a mismatch of compressor wheel in relation to setup as in its outside its efficiency zone or surge limit and it cant grab air to make boost if it gets to bad it can have a servere enough effect to brake cranks or engine mounts.

Pretty much most blow valves on the market today are crap inducing surge when the stock one worked perfectly fine there is others ways to do systems that dont need a blow off valve - red top RB20's/rb30 VL

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Everlong-S13 Community Regular

Everlong-S13

Posted
Posted

This topic comes up once every couple of weeks, use the search function.

People are usually divided when it comes to whether turbo flutter is bad or not. Some people have been running fluttering turbo's for many years with no problem, others blow turbo's and quickly blame turbo flutter when it could have been many other reasons.

This is just my personal opinion, I have had a slight flutter on my ceramic turbo R34 at 12psi for 4 years now with no problem at all. I have read recently the smaller turbo's don't have the surface area that back pressure can damage as easy as larger turbos as the larger blades would be more susceptible to shear forces, but then others say the flutter in smaller turbos is dangerous. Whatever.

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syfon Veteran

syfon

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Posted

No one knows for 100% sure if it damages your turbo-charger. It is nothing more than a speculation.

All you have to do to get the sound is block off your blow-off valve. Instead of the air venting via the blow-off valve, it travels back through the intake across the blades of the turbine spinning forward. The resultant noise you hear is commonly referred to as flutter.

Don't listen to most of the tools here saying not to do it. If you like the sound, then do it. Nothing more than personal preference.

As stated, no-one can prove if it actually damages the turbine blades. XR6 Turbo Falcons do it from factory with nothing more than a pod-filter - you do not need to close the blow-off valve.

My brother had an R33 making 450rwhp, running a GT35R and a closed blow-off valve for the flutter sound. No problems ever reported there and that was over the course of 75,000km's.

It's quite simple; if you like the sound, do it.

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mz.qiksky Explorer

mz.qiksky

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I tell people not to listen to the tools who tell them its ok to do it on their cars which cost them xx thousand. But what do I know? I happen to get my information from people who rebuild turbo's for livings and not off google.

So what if it didnt happen on your car, it may happen on his. And if you want to be the idiot who told him it was ok, thats on you.

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gt35slider Explorer

gt35slider

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I tell people not to listen to the tools who tell them its ok to do it on their cars which cost them xx thousand. But what do I know? I happen to get my information from people who rebuild turbo's for livings and not off google.

So what if it didnt happen on your car, it may happen on his. And if you want to be the idiot who told him it was ok, thats on you.

good to know u get your info from people in the loop but gathering information and having it on your car is a different story, like i said, personal preference, your car do what you want!!!!!

his is stock, my set up was aftermarket and yes im the idiot who blocked my bov, BOO FU**ING WHO

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  • 4 weeks later...
immyishak Newbie

immyishak

Posted
Posted

Meh, BOV sounds are good for one thing and one thing only, creeping up to bus stops when school finishes and all them kiddies are standing around, then as u get closer, boost it hard and blow it off righttttttt next to the bus stops. Hks SSQV/ Turbosmart Supersonic <3

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