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Location:
UK
Registered:
May 2002
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1JZ stock BOV.. normal sound?
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Sun, 30 November 2003 19:33
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hi all.. got a JZA70 auto.. quick question about normal operation of the stock BOV.
The car is an auto, im sure this makes a difference to the following.
Say im running perhaps 5psi boost, on release of the throttle to say 20% (when backing off or whatever) the BOV will release in multiple passes, ie it releases once, waits a split second, releases again, waits a split second, releses again, waits a split second etc etc .. you get the idea.. until all the pressure is released, getting gradually quieter each time. I cant get a sound file so heres a the best i can do...
'Psch...pssschh....pssssccccchhh ....pssssscccccchhhhh.....pssssscccccchhhhhhhhh' . Sometimes it does up to 15 times in the space of three or four seconds before it stops. Sometimes it even gets 'stuck' and carries on forever until i release the throttle completely, whereupon it sorts itself out.
On a high boost (say 12-15 psi) and a total foot off the throttle, it will release in one go.. a quick, short PSSSCCHHH burst.
Right.. is this normal operation? Could I have a nackered BOV and the repeated released be the turbos stalling? I've got stupidly expensive hybrids and dont want to nacker them.
Anyone? Remember this is an auto...
Cheers
adi
[Updated on: Sun, 30 November 2003 19:35]
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Registered:
March 2003
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Re: 1JZ stock BOV.. normal sound?
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Mon, 01 December 2003 01:33
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does the same on my auto 1jz.. sounds like an autobot transforming.
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Location:
Perth
Registered:
October 2002
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Re: 1JZ stock BOV.. normal sound?
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Mon, 01 December 2003 02:27
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Heya Hedgehog,
How are the hybrids going? They sound similar to the BB hybrids that GCG sell over here. About the same price as the Big Single - but bolt on replacements for the stock twins. What sort of power and response are they making? Good reading on the Seat-Of-Pants Meter? Are you using stock management & injectors with them?
Any info much appreciated!
cheers,
Justin
JZA61
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Location:
Sydney
Registered:
November 2003
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Re: 1JZ stock BOV.. normal sound?
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Mon, 01 December 2003 06:40
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yeah man that noise is normal... sik hey! If you can do it 15 times, it just means u have good throttle control  Its a 1j trademark.
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Location:
WA
Registered:
November 2003
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Re: 1JZ stock BOV.. normal sound?
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Mon, 01 December 2003 08:36
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yeh my mates 1j does it too. so i guess its normal. i like the sound aye..
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Location:
UK
Registered:
May 2002
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Re: 1JZ stock BOV.. normal sound?
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Mon, 01 December 2003 12:04
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lol.. yep the transformer thing pretty much sums it up..
I actually like the sound it makes, and it certainly gets you noticed.. i've just never heard it on another car. It's a bit strange when it gets 'stuck' though and seems like it will carry on forever... madeness... anyone know the technical explanation of whats happening during all this?
Celia-Sue
The Hybrids are going great so far... but i've only being running conservative boost of 1bar. I'm still pretty much stock apart from a few bits and pieces like rad and ATF cooler, but now the car is off the road for winter i'll be doing the 550's, 1.3map, SAFC or e-manage and intercooler. I wont ever be going over 1.3bar as being an auto the ECU situation will be a bit of a nightmare i think... (we'll see though).
As for power response.. like i say im only running at 1bar on stock IC but the didfference over stock is massive.. i get no positive boost until about 3000 rpm though, but by 4000 i get a massive shunt of power as they really liven up. I can plant my foot back at 5500 rpm and still get a huge shunt.
Theres a vid of the dash during a launch at www.jzasupra.com/supra2.avi , you can see what happens at 4000rpm. (ignore the appaling start, i cant make any positive boost below the stall point so my launches are awful until i can find a way to sort it, it also means i cant powerbrake). I back off at about 80mph... (PS the speed is in mph, not kmh)
Cheers
adi
[Updated on: Mon, 01 December 2003 12:25]
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Location:
Melbourne
Registered:
November 2003
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Re: 1JZ stock BOV.. normal sound?
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Mon, 01 December 2003 12:07
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Can't say from experience, but in games (I know I know) Supra RZs make a sort of tripple blow of sound. It could be something totaly different, or the game could be full of shit.
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Location:
Perth
Registered:
August 2003
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Re: 1JZ stock BOV.. normal sound?
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Mon, 01 December 2003 14:23
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yeah my friend got a auto 1g twin and everything he slows down it's blows i thought it was wierd but since it's auto
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Location:
Melbourne
Registered:
July 2002
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Re: 1JZ stock BOV.. normal sound?
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Tue, 02 December 2003 00:08
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You guys talking about intercooler shockwave?
Correct me if i'm wrong but that 'autobot transformer' noise is actually not from the blow off valve, but from the turbos (is heard through the air filter). When you boost, and shift, the thottle plate is closed but the turbo is still producing boost (cause its still spinning), the compressed air runs to the throttle plate and cause its closed, has to go back down the pipe work to the turbo. It hits the turbo blades in 'shockwaves' slowing the turbine down. The bi-product is the transformer noise which is heard out of the air filter.
Now, to get around this we install a BOV .. But, a BOV only operates under vaccuum. So when the thottle is still slightly open, the BOV stays shut, and we get this 'shockwave' effect happening onto the turbines.
This sound about right to everyone?
Cheers
Gaz
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Location:
UK
Registered:
May 2002
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Registered:
June 2002
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Re: 1JZ stock BOV.. normal sound?
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Tue, 02 December 2003 21:09
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Disconnect your BOV and see if it still does it/makes it worse.
It will under full boost throttle closing scenarios but see what it does under partial throttle.
I put a Atmo venting BOV on my EVO and it now makes the autobot noise because the spring (in the BOV) needs to have suffient preload that it doesn't 1. Get suck open by vacumn and 2. it doesn't get pushed open under boost.
My 1JZ makes the same noise, I think it is the turbos making enough boost to make the noise but not enough boost & vacumn (only partially closing the throttle) to open the BOV.
Should hurt the turbo's, it is more the 15psi then closing the throttle that hurts them without a BOV. I destroyed a Comp wheel in my old 323 GTX from having a jamed BOV and running 17psi.
The main problem with this was in older turbo when they didn't use Left hand threads on the comp wheel side, and this repeated stalling of the turbo would cause the nut to come undone = BAD
I'll shut up now after all that!!
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Registered:
March 2003
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Re: 1JZ stock BOV.. normal sound?
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Tue, 02 December 2003 23:18
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I don't even know if my stock BOV works!
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Location:
UK
Registered:
May 2002
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Re: 1JZ stock BOV.. normal sound?
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Wed, 03 December 2003 00:35
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I'm running 1bar, obvoiusly i dont want to damage them (especially considering they're virtually brand new hybrids).
It seem that this is common on all 1JZ's, but as to whether or not it is harming them or not is another matter. I can't see toyota making the engine virtually perfect and then leaving something like this open to fault.
I'll try disconnecting the BOV, do i do this by simply removing the vacuum pipe ? Presumably if it still makes the noise, then it is turbo stall as opposed to BOV noise?
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Location:
Melbourne
Registered:
July 2002
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Re: 1JZ stock BOV.. normal sound?
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Wed, 03 December 2003 01:12
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The autobot transformer noise is called 'intercooler shockwave'.. It only occurs on cars with intercoolers. Yes it is the turbos stalling.. If you didnt' have the intercooler, instead of the autobot noise, you would hear the reversal of turbo spool up.. hard to explain , here is the 'text' version of the sound :
spool up = woooooooooooooosssssssssshhhhhhhh
spool down = sssssssshhhhhhhooooooooowwwwwww
 man thats funny stuff haha..
with the intercooler , you get :
spool down = shhh hhhhh hoooo ooooo oowwww wwwwww
LOL..
Obviously it will cause damage to some extent, but i dont think its of major concern.
Cheers
Gaz
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Location:
UK
Registered:
May 2002
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Location:
Brisbane
Registered:
May 2002
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Re: 1JZ stock BOV.. normal sound?
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Wed, 03 December 2003 01:37
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Compressor surge is damaging to your turbos in the long term, but what you're describing could just as easily be BOV flutter which is completely harmless. I strongly doubt that a stock 1JZ with the stock BOV would experience compressor surge.
FWIW my 2JZ didn't do this with the stock BOV and still doesn't do it with my new RiceValve(tm).
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Location:
Melbourne
Registered:
July 2002
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Re: 1JZ stock BOV.. normal sound?
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Wed, 03 December 2003 01:38
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Well i'm sure toyota would design their turbos to be able to cope with some back pressure on the turbine blades. Its not just 1JZ's that do this.. Its any car that has a turbo and an intercooler.. 2JZ does it aswell. You cant' really get around it. Unless you fit a weaker BOV that will open on smaller vaccum (ie. not a completely closed throttle). Which is what i did to my 1JZ.. but the BOV pretty much goes off every movement of the throttle, gets a bit annoyin.. i ended up tentioning my BOV right up, which meant i would only get the BOV to open on a totally closed throttle, which in turn meant if the thorttle wasn't completely closed, i'd get the intercooler shockwave noise. My turbos lasted for 12 months like this on my 1JZ. They blew up for different reasons in the end aswell..
Hope this helps.
Gaz
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Registered:
June 2002
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Re: 1JZ stock BOV.. normal sound?
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Wed, 03 December 2003 03:28
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mrsoopra:
You still get that noise on non IC'd engines also, My friends Subaru Leone race car did it, it was alot more obvious with higher boost because the compressor would stall from a higher speed.
The 2JZ won't make the sound because it has a different (same style as the 7M-GTE one) BOV to the 1JZ. Funily enough the VVTi 1JZ'd have the same BOV as the TT ones, so there must not be any thing wrong with the design or its operation. That is if it is the BOV fluttering.
I wouldn't worry about it at all as long as it goes well!!
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Location:
Melbourne
Registered:
July 2002
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Re: 1JZ stock BOV.. normal sound?
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Wed, 03 December 2003 03:37
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Ok take a stock CA18DET 180sx/Silvia (thats the 1.8 turbo) for example.. It doesn't have a blow off valve at all.. unless its installed aftermarket. If you fit a pod style filter to it, you get that shockwave noise.. with NO blow off valve at all.
explanations??
I'm not saying i'm right or anything. This is just from my experiences.
I dont see how a blow off valve can make a 'fluttering' noise.. as it is just a hole in the compressor piping. The only way to get that sound is for air to travel back through the compressor blades.. Its like if you have a desk fan and blow into it, you will hear your breath 'flutter'..
Gaz
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Location:
Brisbane
Registered:
May 2002
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Re: 1JZ stock BOV.. normal sound?
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Wed, 03 December 2003 03:43
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Like I said, the "shockwave noise" (which is called compressor surge) can sound similar to BOV flutter, but they're not the same thing.
BOV flutter occurs when the BOV opens and closes several times in rapid succession due to fluctuating pressure in the manifolds. It usually happens when the BOV has a fairly weak spring.
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Location:
UK
Registered:
May 2002
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Location:
Balranald
Registered:
May 2002
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Re: 1JZ stock BOV.. normal sound?
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Thu, 04 December 2003 10:38
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My 1JZ does that noise too...love it.
A mate has a CA18 Silvia and he put a Turbosmart Type 2 BOV on and it does that noise too...but much louder. And then another mate at the time had a TX3 and he wanted to make that noise so he bought the same thing and it doesn't. Someone told us that the one that makes the noise is broken...the spring is stuffed.
I have no idea about them but just putting this up to let you guys know.
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Location:
Brunswick, W.A.
Registered:
December 2003
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Re: 1JZ stock BOV.. normal sound?
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Thu, 04 December 2003 12:36
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my 1jz does that psch psch psch sound aswell. but mine is a manual so it doesn't just happen with autos but mine doesn't stay open  hehe lucky me
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Registered:
March 2003
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Location:
Sydney
Registered:
November 2003
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Re: 1JZ stock BOV.. normal sound?
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Thu, 04 December 2003 15:44
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jeez....
NORBIES RIGHT ... the rest of u are wrong.
Thanks for coming... happy fluttering.
*IT WILL DO NO DAMAGE*
1J Blow of valve says...
*** Will i open will i close, will i open will i close, ***
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Location:
Wollongong
Registered:
May 2002
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Re: 1JZ stock BOV.. normal sound?
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Thu, 04 December 2003 23:42
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My factory one used to do it all the time. I never worried about it. Sounded normal to me.
I've changed the BOV now (unrelated issue) and just get a single pshhht.
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