Whistling/leaking noise? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

xXKoukiXx · 07-01-2013, 09:39 PM

Every time I hit boost and then let off the gas, my car makes a whistling noise following the sound of my BOV. Could this be a leak?

Here is a video:

whistling - YouTube

You may need to turn up the sound to hear it. The sound starts at :06

Also, my vac pressure is -22, as you can see in the vid. Is this normal?
Thanks

nield13 · 07-02-2013, 07:23 AM

is there a loss of power? just sounds like your bov closing to me, could be wrong

cotbu · 07-02-2013, 11:05 AM

You BOV is slow reacting
You should be pulling more vac than that when letting off the throttle, my guess is the gauge is maxed or you have a leak. At the end of the video sounds like you applied brakes and the gauge still read -22 although I have no idea if your gauge reads in mmhg, inhg or whatever just an observation.

xXKoukiXx · 07-02-2013, 12:23 PM

Thanks for the replies.

Quote:

Originally Posted by nield13

is there a loss of power? just sounds like your bov closing to me, could be wrong

It does feel a little slower...

Quote:

Originally Posted by cotbu

You BOV is slow reacting
You should be pulling more vac than that when letting off the throttle, my guess is the gauge is maxed or you have a leak. At the end of the video sounds like you applied brakes and the gauge still read -22 although I have no idea if your gauge reads in mmhg, inhg or whatever just an observation.

What do you mean the gauge is maxed out?. The units for the vacuum should be in [inhg].

*blksylv* · 07-02-2013, 12:26 PM

my greddy type s used to do the same thing, it was really slow to close no matter now much i adjusted it but i later found that the welds around the flange were leaking lol

xXKoukiXx · 07-02-2013, 12:30 PM

Quote:

Originally Posted by blksylv

my greddy type s used to do the same thing, it was really slow to close no matter now much i adjusted it but i later found that the welds around the flange were leaking lol

Ok thanks. What method would you suggest for diagnosing leaks? I am skeptical about spraying soapy water around my engine because there is a lot of wiring everywhere, which I don't want to short out.

ultimateirving · 07-02-2013, 12:34 PM

Quote:

Originally Posted by xXKoukiXx

Ok thanks. What method would you suggest for diagnosing leaks? I am skeptical about spraying soapy water around my engine because there is a lot of wiring everywhere, which I don't want to short out.

Boost leak presure tester, Build one.

cotbu · 07-02-2013, 01:15 PM

Quote:

Originally Posted by xXKoukiXx

What do you mean the gauge is maxed out?. The units for the vacuum should be in [inhg].

C'mon, maxed out, gauge means the highest number the gauge reads! Look in your gauge manual.
Is the max vacuum reading 22inhg?. If so, than if you pull 25inch during decel it would probably only read 22inhg.

Vacuum gauges vary in their readings, I look for at least a 30inhg vacuum gauge.
Decel Vacuum is stronger than idle vacuum.
Unless you have a cam upgrade, then it's way more stronger.

xXKoukiXx · 07-02-2013, 01:20 PM

Quote:

Originally Posted by cotbu

C'mon, maxed out, gauge means the highest number the gauge reads! Look in your gauge manual.
Is the max vacuum reading 22inhg?. If so, than if you pull 25inch during decel it would probably only read 22inhg.

Vacuum gauges vary in their readings, I look for at least a 30inhg vacuum gauge.
Decel Vacuum is stronger than idle vacuum.
Unless you have a cam upgrade, then it's way more stronger.

I see. I am pretty sure the gauge reads lower than -22...

07-01-2013, 09:39 PM	#1
xXKoukiXx Leaky Injector Join Date: Aug 2011 Location: seattle Posts: 86 Trader Rating: (0) Feedback Score: 0 reviews	Whistling/leaking noise? Every time I hit boost and then let off the gas, my car makes a whistling noise following the sound of my BOV. Could this be a leak? Here is a video: whistling - YouTube You may need to turn up the sound to hear it. The sound starts at :06 Also, my vac pressure is -22, as you can see in the vid. Is this normal? Thanks

07-02-2013, 11:05 AM	#3
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 47 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	You BOV is slow reacting You should be pulling more vac than that when letting off the throttle, my guess is the gauge is maxed or you have a leak. At the end of the video sounds like you applied brakes and the gauge still read -22 although I have no idea if your gauge reads in mmhg, inhg or whatever just an observation. __________________ LoverTechnologies "Half Broken Things!"

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07-02-2013, 07:23 AM	#2
nield13 Leaky Injector Join Date: Aug 2009 Location: Narnia(sarnia) Age: 30 Posts: 102 Trader Rating: (2) Feedback Score: 2 reviews	is there a loss of power? just sounds like your bov closing to me, could be wrong