Author Topic: Should we consider a BOV  (Read 11364 times)

July 24, 2008, 12:38:41 pm

Darkness_is_spreading

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Should we consider a BOV
« on: July 24, 2008, 12:38:41 pm »
I am wondering if I should connect a BOV to my 1.9 TD, I will be running my wastegate at around 20-22 psi and am worried that after loading the turbo up to 22 psi and letting off, the wastegate will let off but I will still have a fair amount of pressure in my intake and will have compressor surge.....  

If I tie the wastegate line into the BOV I could have them trigger at the same time Hypothetically and thus eliminate any surging....  

What do you guys think ?

I am trying to protect my built Hybrid turbo from early death, so I want to make sure every avenue is explored....  

I will also be running a seperate Thermostatic Controlled Oil Cooler, to help keep oil temps down because the turbos like to heat up our oil.


83 Jetta 1.9 T (Project Darkness)
88 Jetta 1.6 NA (Dead/Crushed)
92 Jetta 1.6 T (Sleepin)
96 Golf 1.9 T (Parts Car + Mexican Rust Bucket)

Reply #1July 24, 2008, 12:54:40 pm

gigaz2

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Should we consider a BOV
« Reply #1 on: July 24, 2008, 12:54:40 pm »
they have one in stock form, set to open at 0,7Bar

I see no problem in fitting one to open at say 25PSI, a few PSI more than your maximum boost, and a electric valve so it can only open when you let off the throttle.

if I were you, I would check first if it surges (a electric pressure switch set for 25+PSI and a buzzer/light) then deal with it.
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Reply #2July 24, 2008, 12:58:55 pm

saurkraut

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Should we consider a BOV
« Reply #2 on: July 24, 2008, 12:58:55 pm »
I've been running well over 20 PSI daily, and have yet to hear any comprossor surge.  Its a rock stock K24 with the waste gate vented to atmosphere.

The only downside I've had is spitting off the trailling edge of one turbine blade.

Have you heard any compressor stalls?

You have the k24/k26 hybrid right?

Hows it going?  I'm planning on doing the same soon, got a k26 sitting in my office.
'79 1.6TD RABBIT
'84 1.5TD RABBIT
'83 Diesel Westy
'86 Audi 5000 Turbo Quatro Wagon
92 Audi 100
'93 Eurovan
'82 Porsche 930

Reply #3July 24, 2008, 01:39:43 pm

Darkness_is_spreading

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.....
« Reply #3 on: July 24, 2008, 01:39:43 pm »
Alright so If I set the wastegate to open at 22 PSI I should be able to runthe turbo without fear of generating compressor surge......  

I believe compressor surge occurs when the waste gate is locked down ( or wastegate line plugged )and is not allowed to open, thus having the ability to hit 30 PSI

What about the stock BOV the connects to the intake manifold,  is that not the same priciple and must work in unicen with the wastegate to balaced out the boost between the exhust and intake.

We disable these items ( Broom stick mod and Wastegate line clamp)  and we are disabling any safety of overboosting/compressor surge......



So if we adjust the wastgate to open later, and tie the wastegate line to a BOV we can have them make the same boost as before and  have a safety net to protect from destruction......
83 Jetta 1.9 T (Project Darkness)
88 Jetta 1.6 NA (Dead/Crushed)
92 Jetta 1.6 T (Sleepin)
96 Golf 1.9 T (Parts Car + Mexican Rust Bucket)

Reply #4July 24, 2008, 01:43:06 pm

Dr. Diesel

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Should we consider a BOV
« Reply #4 on: July 24, 2008, 01:43:06 pm »
I had a k24 on a 1.6L making 35psi with nitrous. No surge. BOV's don't belong here.
I repair, maintain and modify VW's and BMW's.
Good work done at affordable rates. Welding and fabricating, too.
Performance Diesel Injection's Super Pump: gotta have one!

Reply #5July 24, 2008, 03:15:22 pm

zozep

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Should we consider a BOV
« Reply #5 on: July 24, 2008, 03:15:22 pm »
Quote from: "Dr. Diesel"
I had a k24 on a 1.6L making 35psi with nitrous. No surge. BOV's don't belong here.



Aw, but they sound so cool...  8)  :wink:
SOLD: 92 Jetta TD, Giles Pump set to 30 psi, MLS Head Gasket, ARP head studs, Huge eBay intercooler, blocked WG, FK suspension, 1.9L AAZ downpipe to 2.5 inch straight back.

Current: 2000 TDi, 01M :(  DG Full skid plate, Cat 2 micron Fuel Filter, Scanguage II, 4700kHIDs, DG RacePipe

Reply #6July 24, 2008, 03:55:11 pm

Vincent Waldon

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Should we consider a BOV
« Reply #6 on: July 24, 2008, 03:55:11 pm »
Quote from: "zozep"
Quote from: "Dr. Diesel"
I had a k24 on a 1.6L making 35psi with nitrous. No surge. BOV's don't belong here.



Aw, but they sound so cool...  8)  :wink:



No prob... get one of these... much simpler:

http://www.sunamiturbo.com/

(Nope, today is not April Fools Day)  ;-)
Vince

Edmonton, Alberta, Canada
2001 silver TDI Jetta Malone Stage 1.5 , 2001 blue TDI Jetta SBIII 216s Malone Stage 3, 1970 Bay Window bus

Gone but not forgotten: 1969/1971 Beetles, 1969/1974 Westies, 1979 Rabbit, 1986 TD Jetta, 1992 gas Jetta, 1994 TD Jetta

Reply #7July 24, 2008, 05:42:40 pm

Dr. Diesel

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Should we consider a BOV
« Reply #7 on: July 24, 2008, 05:42:40 pm »
JHMFC!
it's crazy the junk some people will put on their cars.

I can tell you, my abovementioned K24, with a gated boost controller let out a hair raising wail every time I let off, even if only part throttle at mid rpm.
2.5" straight through exhaust, sounded like
BYYYOOOOOOOOOOOooooooo!!!

People who obviously had no interest in car stuff (women pushing baby carriages etc) turned to see what it was making this sound.

If you want cool sounds from your turbo car, skip the stupidity and give it a big exhaust!
I repair, maintain and modify VW's and BMW's.
Good work done at affordable rates. Welding and fabricating, too.
Performance Diesel Injection's Super Pump: gotta have one!

Reply #8July 24, 2008, 07:27:58 pm

VW_Commuter

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Should we consider a BOV
« Reply #8 on: July 24, 2008, 07:27:58 pm »
Dr Diesel is right about people looking around.  I know a lot of people look around when I'm driving the Silverado with the Duramax and pull away from a stop.  The turbo spooling is so loud since the turbo is on TOP of the engine and not buried down in the engine compartment that it sounds just like an 18-wheeler right next to you.

As libbybapa says, BOVs are for when the throttle plate shuts and you're still making +20PSI it will blow off pressure to keep the turbo from killing itself or blowing off any of your intake hoses.
Greg

'06 Golf TDI traded in for a '12 Jeep Rubicon (the Phatbox is available)
'91 Jetta TD, a work in progress (I'll do a build thread when I start in earnest)
'65 Notchback, a project not yet started

Reply #9July 24, 2008, 09:57:56 pm

CoolAirVw

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Should we consider a BOV
« Reply #9 on: July 24, 2008, 09:57:56 pm »
Quote from: "VW_Commuter"
As libbybapa says, BOVs are for when the throttle plate shuts and you're still making +20PSI it will blow off pressure to keep the turbo from killing itself or blowing off any of your intake hoses.


I assume everyone here knows that Diesels dont have Throttle plates and therefore they never slap shut, and therefore diesels dont need BOV's.  

The only reason I make this comment is because some Newbie might read this in the future and think that the above comment might mean that "BOV's are needed when the throttle plate shuts".

Obviously I'm stating the obvious.   :roll:  :o  :D
85 Jetta Turbo Diesel
75 Porsche 914
93 GMC Truck
99 Caravan <--wifes gotta drive something :)

Reply #10July 24, 2008, 10:28:19 pm

vanagonturbo

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Should we consider a BOV
« Reply #10 on: July 24, 2008, 10:28:19 pm »
ok so what happens then when going from full boost @ 4500 rpm (25PSI) to an idle? Is the engine still processing that much air? No. What happens to all that air? It gets stopped up and pressurizes the intake the wrong way. My car makes a fantastic warbling noise under these conditions, and I too am worried about shaft snappage.

Any other ideas? I dont like the idea of a switch that opens the valve on idle position because some of us let off the throttle while shifting to another gear. Not completely of course during accel but completely during decel. Even a DV would be better to keep performance up.

Reply #11July 24, 2008, 11:02:21 pm

vanagonturbo

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Should we consider a BOV
« Reply #11 on: July 24, 2008, 11:02:21 pm »
I totally understand the difference between the gasser need for a BOV and all that. But, the pump slows down to idle after letting off the throttle. Also, with the pump causing the engine to return to idle, doesnt that mean that the valves and pistons slow down?

As we all know, the engine is essentially a pump within itself. So if we slow the pump down then we are processing less air, no? Exhaust and intake alike.


The reason I am interested in this is because I believe I am getting a pretty fair amount of surge after letting off the throttle. Example, 1st gear pull to get to second, then WOT up to 4500 rpm and then let off the throttle. Hence the warbling noise. So if pressure could be vented  somehow that might alleviate stress on the turbo. I plan on using a gt25 on the next engine and I dont it to break the shaft. Especially @ 30+psi.

Reply #12July 24, 2008, 11:27:14 pm

andy2

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Should we consider a BOV
« Reply #12 on: July 24, 2008, 11:27:14 pm »
I have personally installed and test drove dodge diesel trucks with BOV's and they do make it easier on the turbo(s).I don't see any down sides to one being installed.The ones I've installed are from BD power and are called "Turbo Guard".I don't think that there is a real need for one when pushing 22 psi however.These devices are only really hepful for turbo(s) on diesel engines that produce say 35-40+psi.

Reply #13July 24, 2008, 11:47:18 pm

vanagonturbo

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« Reply #13 on: July 24, 2008, 11:47:18 pm »
yes, however, take into consideration the size of the turbo on the Dodge vs. the little tiny turbos that we have on the VWs.

Reply #14July 24, 2008, 11:52:53 pm

VW_Commuter

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Should we consider a BOV
« Reply #14 on: July 24, 2008, 11:52:53 pm »
Quote from: "CoolAirVw"
Quote from: "VW_Commuter"
As libbybapa says, BOVs are for when the throttle plate shuts and you're still making +20PSI it will blow off pressure to keep the turbo from killing itself or blowing off any of your intake hoses.


I assume everyone here knows that Diesels dont have Throttle plates and therefore they never slap shut, and therefore diesels dont need them.  

The only reason I make this comment is because some Newbie might read this in the future and think that the above comment might mean that "BOV's are needed when the throttle plate shuts".

Obviously I'm stating the obvious.   :roll:  :o  :D


I would hope that someone who owns a diesel would understand that they don't have a throttle plate and all power is controlled by amount of fuel injected, but maybe I'm wrong :|

Maybe I should have stated that diesels don't have throttle plates just to be more clear.
Greg

'06 Golf TDI traded in for a '12 Jeep Rubicon (the Phatbox is available)
'91 Jetta TD, a work in progress (I'll do a build thread when I start in earnest)
'65 Notchback, a project not yet started