Turbo Flutter

[Niteen Nadal]

Hi im really frustrated no mechanic knows how to make my ba turbo flutter I dont get it can't be that hard seriously! I love that fluttering sound. Does anyone here know what I have to do to the bov to get that sound?? please help thanks

[PTR_NITRO_FG]

The big doggz on here don't have time/cbf answering questions that have been asked literally hundreds of times over their decade of gracing this forum

Noobs like me can help....but then again do you really trust my opinion lol

I have no bov and shoved a flat ended bolt/screw thing into the BOV return line and then put a clamp on the end for safe measure (even though that's prob not necessary?) - then 'hid' the loose line near my abs unit.

Stock tune (but on a FG); been around 9 months+ and no limp mode for me....couple that with a growler (or any pod intake setup) plus the intake delete pipe...and you get some decent spool/flutter noise. Perfect amount for older blokes as with windows up there's not too much in cabin noise.....but will be going Plaz turbo side for more horny turbo noise

[arronm]

What are some areas where people often make errors modifying their turbo car?

"The classic blow-off valve.

"The blow-off valve is designed as an emissions control device for OE manufacturers. It came about when smaller engines made more and more power using larger turbochargers and bigger intercoolers. As you close the throttle, the build up of pressure and the larger volume inside the intake has to go somewhere; it can't go into the engine because the throttle is shut. Instead, it has to do a U-turn and it comes screaming out the airflow meter. That creates the 'gobble-goggle' sound.

"The gobble-gobble sound is something the public has grown to love.

"The airflow meter is not all that smart and does not realise the air is going in the wrong direction; it therefore measures the air twice (once going into the engine and again going out in the wrong direction). The computer now tips in twice as much fuel as what's required, making it run rich - making it not pass emissions.

"Therefore, manufacturers fit a blow-off valve - or a recirculation valve as they are actually called. A recirculation valve opens when it senses manifold vacuum, returning the air trapped at the throttle body to between the airflow meter and the turbocharger. As such, the airflow meter does not take a double reading - the car now passes emissions.

"Unfortunately, we've had people ringing up and wanting the "audible gear change alarm".

""What audible gear change alarm?" we ask. "You know, when the Sierras were running around and just when they went to change gear it used to go whoda-whoda-whoda" they tell us.

""No pal, that is the dump valve..."

"Some people do think that at the absolute upper extremes of boost levels - about 30-plus pounds - the blow-off valve does, somewhat, save the compressor wheel and shaft from trying to rotate backwards. It doesn't actually rotate backwards at all - all you're hearing is cavitation. What happens is, you've shut the throttle, the turbocharger is doing 100,000 rpm and now has a boost spike of 50 psi. Because it's working in a higher region than what it's designed for, it slips; it basically does a skid like a car tyre does when you dump the clutch. That's the noise you hear - the whoof-whoof-whoof is the air doing a skid."

Is there any performance gain to a blow-off valve?

"We've tested one on a manual gearbox performance car run at Winton Raceway. I think it was running 1 minute 40s back then, but it would lose 2 seconds a lap putting the gobble-gobble valve on. When you look at data acquisition, what you find is - as you change gear - the blow-off valve dumps all the pressure built up through the intercooler and pipes. It then goes back to zero manifold vacuum when you get back on the throttle, you have to build all that boost back up.

"The fact that people think that they keep the turbo spinning is a problem. The people that suggest this have never had an engine on the dyno and never had a turbo tacho in their hands. What people don't realise is, when you shut off the throttle, you shut off the air supply to the engine - this shuts off the exhaust gasses coming out of the engine. When there is no exhaust flow, there is no energy to keep the turbine spinning - the turbo slows down at an alarming rate.

"If you change gears at quite a good speed, you can actually get a boost spike on changes; if you're trying to hold a constant 30 pounds, when you do a racing change you'll get 32-33 pounds when you crack the throttle open again. If everything's working well, you've got a full head of stream waiting to go into the throttle as soon as it's opened.

"I've done this on a rally car and it was quicker through every timed section without a dump valve. You'll never hear a World Rally Car going pssshhht because they don't use a dump valve - you get the woof-woof-woof noise instead."

Busy today and on the iphone.

That write up came out of an interveiw with Simon Gishus of Nizpro.

[Ralph Wiggum]

Pretty average display folks. OP had asked a legit question. Considering he's not from this country and probably hasn't been a member for the last ten years a simple constructive answer would have been appropriate?

OP you have two options-

1. Block the outlet side of the valve and plug the hose the outlet side is normally connected to on the cross-over (the black piece atop the motor) and remove the small vacuum hose to the BOV and plug it.

2. (My preferred option) remove the BOV completely and block both hoses on the cross over Turbosmart actually make plugs to suit (TS-0205-2014) and then plug the small vac line.

The bov is under the Cross Over in the section marked by the Red box, the yellow Arrow Is the pressure side hose if you wish to block the bov using method 1 you need to plug the Other hose located under the crossover.

Don't expect huge flutter on stock boost though

TS Bov plugs

["Captain Retard"]

Hi im really frustrated no mechanic knows how to make my ba turbo flutter I dont get it can't be that hard seriously! I love that fluttering sound. Does anyone here know what I have to do to the bov to get that sound?? please help thanks

Ok friend, I have disconnected the BOV.

This is the hose you want to disconnect from the BOV.

Now my hose already had an unused T piece in it , so I just removed it.

Now you can just pull that hose off and make sure you block it off with a bolt or something or do what I did and put a bolt with the head cut off and connect both ends of the hose to it.

The reason I did this is so it looks stock after all it is an "emissions device"

Now for the results!

Pretty shyit really.

It was the middle of the day and it's pretty fuggin humid here at the moment, dare I say perfect Fijian weather.

Gave it about half throttle and changed gears (my car is a manual) ..... Couldn't hear any difference.

Gave it full throttle in 2nd and I changed gears and guess what .....nothing.... But it did miss fire and die. Now I might have hit the limiter but I never have before so not sure about it.

I gave it a few more goes and everything seemed normal but I'm buggered if I could hear any flutter or anything out of the ordinary.

Like I've mentioned before my car will flutter on cold mornings and it doesn't have to be full throttle or high revs, so I'll try it over the next couple of days and see what happens but so far not impressed.

TO BE CONTINUED....(that may piss off some but FiIC)

Yes DAGS I like using lots of full stops as well as exclamation marks

[PTR_NITRO_FG]

FFS Ralph....some of us did offer legit help :/

[Ralph Wiggum]

Meh.

[Niteen Nadal]

Thanks heaps Ralph been a great help n everyone else that is normal. u need to spread some of your positive energy on here that's all I was asking for man u have a nice day bro.

[discostig]

If by a long shot there is a tuner there that knows these cars, I say the best way is to up the boost on stock BOV system and still get flutter like me. Mine makes up to 5 or 6 "tu" sounds in a row if I really try. It just takes triple the stock boost levels (BF is 5 to 6 PSI, so 15 PSI) to make it flutter nicely is the problem. Can't do that on the cheap or bye bye motor :(

Take a good pic of your car somewhere nice and post it up so we can be jealous of having a T outside this country!!

Edited 09/12/14 04:40 AM by -Stever-

[barnz]

Ok friend, I have disconnected the BOV.

This is the hose you want to disconnect from the BOV.

Now my hose already had an unused T piece in it , so I just removed it.

Now you can just pull that hose off and make sure you block it off with a bolt or something or do what I did and put a bolt with the head cut off and connect both ends of the hose to it.

The reason I did this is so it looks stock after all it is an "emissions device"

Now for the results!

Pretty shyit really.

It was the middle of the day and it's pretty fuggin humid here at the moment, dare I say perfect Fijian weather.

Gave it about half throttle and changed gears (my car is a manual) ..... Couldn't hear any difference.

Gave it full throttle in 2nd and I changed gears and guess what .....nothing.... But it did miss fire and die. Now I might have hit the limiter but I never have before so not sure about it.

I gave it a few more goes and everything seemed normal but I'm buggered if I could hear any flutter or anything out of the ordinary.

Like I've mentioned before my car will flutter on cold mornings and it doesn't have to be full throttle or high revs, so I'll try it over the next couple of days and see what happens but so far not impressed.

TO BE CONTINUED....(that may piss off some but FiIC)

Yes DAGS I like using lots of full stops as well as exclamation marks

It may not be holding with the spring alone without pressure on the diaphragm, there is also a spike when you shut the throttle that could also force it open.