does your FM bov sound like a turkey - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Reply
 
 
 
LinkBack Thread Tools
Old 04-21-2007, 11:22 PM   #1
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Nov 2006
Location: Hartville, OH
Posts: 174
Total Cats: 0
Default does your FM bov sound like a turkey

i have a flyin miata bov, and it sounds silly? it is recirculated. any where from 1/2psi and up it sounds like a turkey gobble:gay: . is this normal for this bov? are these known to be not good. since it is recirculated i expected it to be silent. other than the noise it seems to work fine.
left field is offline   Reply With Quote
Old 04-21-2007, 11:31 PM   #2
Newb
 
Join Date: Feb 2007
Location: Charlotte, NC
Posts: 36
Total Cats: 0
Default

I could be wrong. But I think it's your waste gate rod. I know with GReddy kits like mine they're notorious for that turkey sound if you don't tighten the accuator rod.
Diver Dan is offline   Reply With Quote
Old 04-21-2007, 11:34 PM   #3
Senior Member
iTrader: (2)
 
SamS's Avatar
 
Join Date: Jun 2006
Location: Wisconsin
Posts: 1,254
Total Cats: 7
Default

The "turkey gobble" is often the sound of compressor surge from your bov not opening enough to relieve pressure from the charge piping. You could try lubricating your bov or loosening the spring to make it easier to open.
SamS is offline   Reply With Quote
Old 04-21-2007, 11:36 PM   #4
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,147
Total Cats: 6
Default

Where do you get your vacuum signal from? If you have a weak vac signal it won't open much either and could possibly "flutter". My tial, which has a really strong spring, blows off clean at just about any boost level(1-2psi)
cjernigan is offline   Reply With Quote
Old 04-21-2007, 11:42 PM   #5
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Nov 2006
Location: Hartville, OH
Posts: 174
Total Cats: 0
Default

1 rod is tight. 2 how can it surge a 1psi? i thought surge happens at high compressor speeds. 3 signal comes off of a tb vac port; i read this is best place.
left field is offline   Reply With Quote
Old 04-21-2007, 11:45 PM   #6
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,147
Total Cats: 6
Default

That's a good port to use I just wanted to make sure you weren't using a spider web of vac-t's for your signal.
Sounds like you need to clean and oil the valve and adjust the BOV spring tension.
cjernigan is offline   Reply With Quote
Old 04-21-2007, 11:48 PM   #7
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Nov 2006
Location: Hartville, OH
Posts: 174
Total Cats: 0
Default

only hundred miles on it.
left field is offline   Reply With Quote
Old 04-21-2007, 11:49 PM   #8
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: Nov 2006
Location: Hartville, OH
Posts: 174
Total Cats: 0
Default

spring can't be adjusted
left field is offline   Reply With Quote
Old 04-22-2007, 04:59 AM   #9
Senior Member
iTrader: (6)
 
Join Date: Mar 2005
Location: Sammamish, Washington
Posts: 1,396
Total Cats: 0
Default

Most the vacuum ports on the Miata intake manifold are too small to allow you to use a large enough vacuum line that will allow most blow off valves to function properly.
Kelly is offline   Reply With Quote
Old 04-24-2007, 08:42 PM   #10
Junior Member
 
Join Date: Dec 2006
Posts: 209
Total Cats: -1
Default

Ya same for me. I get compressor surge. That GFB BOV sucks ballz.
ak47bravo is offline   Reply With Quote
Old 04-24-2007, 09:26 PM   #11
Junior Member
iTrader: (1)
 
Join Date: Sep 2006
Posts: 464
Total Cats: 0
Default

Quote:
Originally Posted by left field View Post
1 rod is tight. 2 how can it surge a 1psi? i thought surge happens at high compressor speeds. 3 signal comes off of a tb vac port; i read this is best place.
It isn't surging, its fluttering. The valve is just opening and closing rapidly... probably. Does it happen at any amount of positive, does it happen at the beginning of the discharge or at the tail end? What size vacuum line and is there anything else sharing that source?
PAT! is offline   Reply With Quote
Old 04-24-2007, 10:05 PM   #12
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

does it really sound like turkey gobbling or wings fluttering? two very different conditions here....
Braineack is offline   Reply With Quote
Old 04-25-2007, 09:41 AM   #13
Senior Member
 
Join Date: Mar 2007
Location: Denver, CO
Posts: 564
Total Cats: 0
Default

It flutters because when the throttle closes the valve opens, relieves some pressure, closes, turbo is still spooling down because it's ball bearing, pressure builds even as it slows, BOV opens again and etc. until the turbo is spooled down. A really good BOV for a street application, where boost is "low" (like less than 20psi), will have a multi-chamber design and lower port that you run another vacuum line to, this alleviates this problem. Don't know if the FM BOV has this but if it doesn't, it should.
jwarriner is offline   Reply With Quote
Old 04-25-2007, 10:12 AM   #14
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

It could be as simple as the adjustment screw is just too tight....

"fluttering" is best described as the piston opening and closing rapidly...when the piston has too much preload, the vacuum in the chamber allows it to open, but the boost pressure is not enough to keep it open, so it rapidly opens and closes, and it sounds like fluttering...

this is flutter: http://www.youtube.com/watch?v=Y4bZHpT-L38

"turkey gooble" or compressor surge is caused when the boost pressure is not released out of the valve. It instead is released out of the intake, but first causes the compressor wheel to spin in the opposite direction....this is the noise you hear, it's bad for the turbo and why you have a valve to begin with.

this is surge: http://www.youtube.com/watch?v=nTnUaBWXm88
Braineack is offline   Reply With Quote
Old 04-25-2007, 10:52 AM   #15
Junior Member
 
Join Date: Aug 2006
Location: Farmington Valley, CT
Posts: 147
Total Cats: 0
Default

Mechazawa is offline   Reply With Quote
Old 04-25-2007, 04:04 PM   #16
Junior Member
 
Join Date: Dec 2006
Posts: 209
Total Cats: -1
Default

Quote:
Originally Posted by Braineack View Post
It could be as simple as the adjustment screw is just too tight....

"fluttering" is best described as the piston opening and closing rapidly...when the piston has too much preload, the vacuum in the chamber allows it to open, but the boost pressure is not enough to keep it open, so it rapidly opens and closes, and it sounds like fluttering...

this is flutter: http://www.youtube.com/watch?v=Y4bZHpT-L38

"turkey gooble" or compressor surge is caused when the boost pressure is not released out of the valve. It instead is released out of the intake, but first causes the compressor wheel to spin in the opposite direction....this is the noise you hear, it's bad for the turbo and why you have a valve to begin with.



I loosened and tightened mine and it is the same either way. Mine sounds more like the surge video out of the two that braineack posted.
ak47bravo is offline   Reply With Quote
Old 04-25-2007, 04:07 PM   #17
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

Quote:
Originally Posted by ak47bravo View Post
I loosened and tightened mine and it is the same either way. Mine sounds more like the surge video out of the two that braineack posted.

it's your like this?

http://www.gofastbits.com/index.php?...b_option=basic
Braineack is offline   Reply With Quote
Old 04-25-2007, 04:14 PM   #18
Senior Member
 
Join Date: Mar 2007
Location: Denver, CO
Posts: 564
Total Cats: 0
Default

I'm really shocked by the DSM BOV's lack of prevalence in all the DIY setups. They can be had for anything from free, to $45 for a new one, will hold 18psi without so much as a leak and open normally every time. These **** ones that go on with a worm clamp make my skin crawl.
jwarriner is offline   Reply With Quote
Old 04-25-2007, 04:31 PM   #19
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,900
Total Cats: 1,792
Default

lots of people run them. and attach them with worm clamps.
Braineack is offline   Reply With Quote
Old 04-25-2007, 04:38 PM   #20
Elite Member
iTrader: (14)
 
Join Date: Mar 2006
Location: Edmonton, AB
Posts: 4,921
Total Cats: 0
Default

How does the method of attachement really matter in how it performs?
jayc72 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Buzzing from driver side of engine bay? (MS3 install) nick470 MEGAsquirt 7 06-16-2017 02:53 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM
why is my car running like pewp? (tune/datalog) itsMikey MSPNP 3 09-28-2015 07:40 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 03:32 AM.