Flutter Dump sound with out the danger

BlackMount · Jun 16, 2010

Soo Flutter Dump...

I'm trying to get the same sound with out the dangers.... Flutter dump from what I understand is when the BOV doesn't open when it should so the turbo "flutters" until it does causing that woopwoopwoopwoop sound

here's an example. I want to recreate the sound without the surge\danger?

YouTube - Sick Supra w/ Greddy Type-R BOV

JusMX141 · Jun 25, 2010

EclipticalGS said:
from what I understand some diesel engines didnt use BOV's??

....because diesels do not have throttle plates.

Lofty · Jun 25, 2010

EclipticalGS said:
buy an hx-35 and dont use a BOV, from what I understand some diesel engines didnt use BOV's?? Correct me if im wrong but theres a video on youtube where a kid is driving around with his hood open and claims he is NOT using any BOV what so ever.

He says 2 years and still going strong. Apparently ^^ its right there.

If you use an HX-35 it doesn't mean it's designed to surge. Surge kills turbos, there's no way around it. But have fun children. You need to understand how compressor surge works and why its bad.

Dert · Jun 26, 2010

92AWDTalonTSI said:
They do it by rerouting their MAF into the Intercooler system. Then add a 5-6 inch long pipe in front of your turbo and pop a filter onto it. Kind of hard to do on a DSM I'd imagine. The other way as I was reading is to use these: NSFW

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Remember to catch your pigeons your self and DON'T Buy those Chinese ripoffs.
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I borrowed the pics from Fastfours.com.au

wayfarer · Jun 26, 2010

How to make ## car DOSE, like a muzza

^How to make a dose pipe

In short, the argument is that it's not detrimental to your turbo, however it does slow it down when you get off the throttle. I wonder how this works with a DSMLink anti-lag...

ramsack · Jun 27, 2010

what would make it not detrimental to your turbo by having no BOV. i don't see the point of that. it's just like a blowthrough setup with no BOV and a short intake.

Zmann42087 · Jun 27, 2010

ramsack said:
if there is no pressure present in the piping, then air cannot be moving.

Air is most certainly still flowing as the compressor wheel is still spinning. Rather, pressure is not being built because when the BOV is open, there is no set volume in which the air is constrained to.

You can think of it in terms of the ideal gas law, PV=nRT. It's really just a balancing act between the parameters on either side of the equation. For instance, when the BOV is closed the intake system has a constant volume. So the increase in moles of gas (increase in "n" on right side of equation) as the turbo draws in air must be compensated for by one of the parameters on the left side. Because the volume is constant, the only option is for pressure to increase. On the other hand, when the BOV is open the volume of the intake system is essentially infinite, so the airflow from the turbo does not produce a pressure increase.

ramsack · Jun 27, 2010

i really don't agree. for this to be true the bov and IC pipes would have to not be a restriction, which is impossible. in math your theory works, but one of the first things we learn in science class is that in the real world, formulas can get you close, but not exact, because of friction and energy loss. nothing can be 100% efficient.

xxNocturnalxx · Mar 8, 2016

I know this is a old thread but it's most relative to my question. I have an evo 3 16g installed on a 4g61t and have been trying to get rid of my flutter issue. 1st I had a Greddy RS bov installed, it flutters bad when letting off the throttle lightly after boosting, if I let of the throttle fast it mostly goes out the bov with a little bit of flutter that can be heard. Mostly in 5th gear light throttling causes a lot of flutter, I can hear it very easily because the intake is mounted up near the throttle body (No room in the Colt). Next I installed an RZ bov then finally a NGR. The NGR is a little better, all bov's are completely on the soft setting (preload screw backed off). The NGR at least opens as low as 1psi. and opens at 15psi. but 5psi. with a soft throttle release cases mass flutter(SHSHSHSHSHshshshs). The bov is located on the drivers side of the front mount in the piping so it's fairly close to the turbo, I replaced the lines leading to intake manifold to rule a line collapse issue, will mounting the bov near throttle body give better results? Will this type of flutter cause any damage?

The car is tuned on linkV3 with a GM maf in the upper IC pipe.

1990TSIAWDTALON · Mar 8, 2016

Man that sounds like a BOV normally venting to me. Mine is vented to the atmosphere so I can here it all the time and it isn't hurting anything, its working. If you are on MAF then it should be recirculated to the intake since the MAF has already accounted for that air. I am on Speed Density so mine doesn't care. MY BOV is a crushed 1g unit and it "whoosh, whoosh, whoosh's" all the time. I run 30# boost so it is something I am used to hearing.

xxNocturnalxx · Mar 8, 2016

The flutter is what I'm worried about, a lot of flutter comes from the compressor at times. It's not the bov it self that's fluttering.

1990TSIAWDTALON · Mar 8, 2016

That sounds like compressor surge and no that's not good its hard on the turbo. How is shaft play. OH JUSTIN....please chime in LOL

. Way way more knowledgeable than me.

chrysler kid · Mar 8, 2016

You would want to try to wiggle the little bolt in the middle of the turbo left and right and in and out to see how much shaft play is happening to see if there is any major damage that could be happening.

If your ngr bov is on the softest setting and you have the vacuum line to the bov hooked from a source on the intake manifold everything is working properly.

The flutter noise is normal under partial throttle, all these aftermarket bov's are designed to make a noise under full pressure, partial pressure bov release does make a flutter noise because the bov is designed to make noise at a certain pressure so it releases the pressure as several pulses causing the flutter noise.

JusMX141 · Mar 8, 2016

I currently have a Greddy S valve on my daily because the piping is flanged as such and fitment of anything else would be quite difficult....and it flutters like hell if I mash it in a higher gear then roll out of the throttle- I can't make it go away. I've tried one spring, two springs, replacing the diaphragm, adjustment screw all over the place. It does it so bad that it will interrupt the airflow over the MAS because the valve is recirculated and cause the car to cut out.

The only conclusion I've drawn is that Greddy valves are garbage and I don't know why people want them so badly. I'm modding a 1G valve to fit it again like when I had the stock piping and adapter in place as soon as I get some free time.

chrysler kid · Mar 8, 2016

JusMX141 said:
I currently have a Greddy S valve on my daily because the piping is flanged as such and fitment of anything else would be quite difficult....and it flutters like hell if I mash it in a higher gear then roll out of the throttle- I can't make it go away. I've tried one spring, two springs, replacing the diaphragm, adjustment screw all over the place. It does it so bad that it will interrupt the airflow over the MAS because the valve is recirculated and cause the car to cut out.

The only conclusion I've drawn is that Greddy valves are garbage and I don't know why people want them so badly. I'm modding a 1G valve to fit it again like when I had the stock piping and adapter in place as soon as I get some free time.

The bend in the recirc hose should reduce that, or the recirc fitting on your intake might be at an bad angle maybe? if you ran a stock non moded 2g rubber intake your problem might go away. But I do get your point about the type s

My $20 fake ebay type s with the screw all the way out will make no noise on a full throttle release and will whistle under partial throttle. Turn the screw in two full rotations and it will whistle and flutter like a regular type s. I've never had any drive ability issues decelerating in gear after a partial throttle bov release but I'm just a tiny t25

Mello · Mar 8, 2016

I have no flutter issue with my real Greddy type S either. But I use both ports, run with 1 spring & my adjuster screw is all the way out. Also no problem holding boost. My car sounds like Darth Vader.

chrysler kid · Mar 9, 2016

A type s should whistle. If your bov is purple and sounds like Darth Vader it needs to be rebuild

Mello · Mar 9, 2016

No rebuilding my BOV would be stupid. It's in as new condition as my new NGR. This would be like rebuilding a brand new motor & using the same new parts. Complete stupidity.

chrysler kid · Mar 9, 2016

Mello said:
No rebuilding my BOV would be stupid. It's in as new condition as my new NGR. This would be like rebuilding a brand new motor & using the same new parts. Complete stupidity.

Yeah your blow off valve has a damaged diaphragm if it sounds like Darth vader.

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It's like if you bought a new engine and it had a spun bearing and I told you it had a spun bearing, and you told me it can't have a spun bearing because it's a new engine but it really had a spun bearing.

A type S has a whistle. I don't care if you bought it brand new or not, if yours sounds like darth vader it is not operating correctly.

xxNocturnalxx · Mar 10, 2016

I'm starting to think it's more of a greddy/nrg issue because I've tried everything and the only way I can get the compressor to not surge is let off the throttle slowly. I guess I'm going to try a ssqv or tial next and see what happens. I haven't checked for shaft play yet..

xxNocturnalxx · Mar 10, 2016

Here's why I can hear the surge loud and clear..

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Flutter Dump sound with out the danger

BlackMount

JusMX141

Lofty

Dert

wayfarer

ramsack

Zmann42087

ramsack

xxNocturnalxx

1990TSIAWDTALON

xxNocturnalxx

1990TSIAWDTALON

chrysler kid

JusMX141

chrysler kid

Mello

chrysler kid

Mello

chrysler kid

xxNocturnalxx

xxNocturnalxx

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