# Forge Splitter valve help



## 85VR6GTI (Mar 15, 2007)

Hey guys, Just got the new splitter valve and installed it and im having some issues. i was wondering if any of you guys have had problems like this with this kind of valve.
The Issue: 
Well when recived it i didnt want to fart around with turning it to the engine all night so i placed it on the bench at work. (i work at a aircraft pnuematics repair station) an went to adjust the valve in for 16psi and i noticed the valve was leaking out of the outlet port for the recirc. Nothing coming out of the atmospheric. so i figured it would be harmless and was part of normal operation with this design. i installed it on the car and noticed i was only holding 10 lbs of boost under WOT. sometimes fluttering and getting upwards of 13. now my stock DV held 14 all day no flutter and was solid as a rock. kinda feeling like i wish i had never bought this thing.
so i went under the hood to check for boost leaks and couldnt find any tell tale signs or hear anything either when doing some load tests. i adjusted the valve till it was bottemed out to give it the most amount of spring load as possible to get the poppet to seal and all i got out of that was compressor surging and still only 10 lbs of boost.
has anyone needed to supply a more direct line from the manifold to the top of the poppet assembly to ensure enough pressure pushes down on the poppet to seal? or should i just send it back and get them to bench check it for leaks and ask them to send me a new one?
got a week ago so i think i have time to send it back.
much apperciate the input guys i am posting this on the 1.8t forum to, i just wanted a little TT support.
Davyd


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## A4 1.8 Turbo (Feb 28, 2005)

*Re: Forge Splitter valve help (85VR6GTI)*

isnt the stock boost level for a 225 13lbs? 
is there any reason you went with the splitter, vs. a standard recirculating? (other than the blow off sound) haha.....


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## HernTT (Nov 5, 2007)

*Re: Forge Splitter valve help (85VR6GTI)*

Stock boost level on a 225 is 11psi.
Seems like nothing but problems with having a BOV on the TT. Considered a ricey mod anyway. Just put a decent DV in and you won't have any problems at all.


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## A4 1.8 Turbo (Feb 28, 2005)

*Re: Forge Splitter valve help (HernTT)*

thats kinda what i was hinting at, but didnt want to be so straight! haha


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## 85VR6GTI (Mar 15, 2007)

stock is 14lbs not 11. Ko4 puts out more than the 180T


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## nvsbandit (Oct 2, 2007)

*Re: Forge Splitter valve help (HernTT)*

ive been lurking on the TT section







but ive had a few Forge peices and now i wont use anything but forge peices. just find a brand you like in the recirc and use it. i really liked forge because its fully customizable.


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## A4 1.8 Turbo (Feb 28, 2005)

*Re: Forge Splitter valve help (nvsbandit)*

im a bailey's guy! i guess it all comes to preference/individualized car


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## Blue TTop (Nov 21, 2003)

*Re: Forge Splitter valve help (A4 1.8 Turbo)*


_Quote, originally posted by *A4 1.8 Turbo* »_thats kinda what i was hinting at, but didnt want to be so straight! haha

x2
Forge does make a good DV. Bailey's is also good as are many others. Definitely no Honda "pshhhhhhht" on my TT.


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## nvsbandit (Oct 2, 2007)

*Re: Forge Splitter valve help (Blue TTop)*

i had the forge dual piston BOV on my saab. sounded gorgeous. i got so many compliments by people with way nicer cars. all the civic kids hated me...because they didnt have a turbo to do that with. haha


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## 85VR6GTI (Mar 15, 2007)

yeah this by far isnt any ricey sound. but i am thinking of just sending it back and getting another. This has to be leaking internally from high side to the compressor inlet.


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## cincyTT (May 11, 2006)

*Re: (85VR6GTI)*

since all the idiot "anti-bov" people cant seem to help, i will.
The splitter wont cause* ANY* ill effects. You need to install it in the opposite direction of the stock dv (pressure to bottom, side going to intake). In this direction you need more spring tension than the stock style. Just turn the top 7-10 more times and you should be fine. Also, the dv part recircs at idle, the bov will be closed. 
Dont let these AW conservatives tell you anything differnt. There are several dozen audis that i know of running a splitter or forge004 bov with 0 issues. Not everyone should be a mindless clone


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## TREFTTY (Jan 3, 2006)

*Re: (cincyTT)*


_Quote, originally posted by *cincyTT* »_There are several dozen audis that i know of running a splitter or forge004 bov with 0 issues.

I am one of them. I Love my splitter. Zero issues whatsoever. Go to forgemotorsport.com and it has the installation instructions with pictures. And like Cincy said, it is installed backwards. I have had 007, APR R1, Hyperboost, Turbosmart Dual port and stock. So just know that when I say that I like the splitter the best, that it is coming from actual experience. Not just another useless comment aimed at Cincy. If you dont want the sound then the APR R1 was my favorate. Hope this actually helps you out. http://****************.com/smile/emthup.gif 

_Quote, originally posted by *HernTT* »_Stock boost level on a 225 is 11psi.

Nope it's 14.5 PSI, Nice try though http://****************.com/smile/emthup.gif 
1 bar translates to 14.5 psi.



_Modified by TREFTTY at 8:19 PM 1-13-2008_


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## cincyTT (May 11, 2006)

*Re: (TREFTTY)*

just to let you know, i ran the splitter and its now on my brothers 1.8t passat. My car is back running the forge004 bov w/o issues http://****************.com/smile/emthup.gif 
Facts > followers


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## A4 1.8 Turbo (Feb 28, 2005)

*Re: (cincyTT)*

why do people call them "blow up valves" then?? i know i tried to run an hks ssq once, and it didnt work toooo well. haha


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## cincyTT (May 11, 2006)

*Re: (A4 1.8 Turbo)*

because people use the wrong valves. And you wouldnt blow up the car, you would just stall it, after that, its gravitys problem








Basically any twin piston valve will work that flows what the turbo provides. For stock and small turbos, a forge 004 is perfect. For mid-large turbos, a tial 50mm bov is best.


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## nvsbandit (Oct 2, 2007)

*Re: (cincyTT)*

http://www.genuinesaab.com/cat...d=454
so that twin piston i had on my saab would work on a TT


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## A4 1.8 Turbo (Feb 28, 2005)

*Re: (cincyTT)*

yea right after it would blow off, my a4 used to stall!! then i went to forge 007 , then hyperboost


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## cincyTT (May 11, 2006)

*Re: (A4 1.8 Turbo)*


_Quote, originally posted by *nvsbandit* »_http://www.genuinesaab.com/cat...d=454
so that twin piston i had on my saab would work on a TT

yep. Its the same as mine but the 004 has the vac line on top.









_Quote, originally posted by *A4 1.8 Turbo* »_yea right after it would blow off, my a4 used to stall!! then i went to forge 007 , then hyperboost

Then it wasnt set right


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## HernTT (Nov 5, 2007)

*Re: Forge Splitter valve help (85VR6GTI)*

Since all the idiot anti-quality people that like chincy mods are pushing blow-up-valves........ please do your homework and go with a quality DV.
Especially don't listen to people that can't get along on the nicest forum of all (AW). Anyone not accepted there is really out in the weeds if you know what I mean.

_Quote, originally posted by *TREFTTY* »_
Nope it's 14.5 PSI, Nice try though 
1 bar translates to 14.5 psi.


Wrong!
1 atmosphere at sea level = 1-bar. A boost gauge factors this in. At zero on a Boost Gauge you are at 1atmostphere, which equals approx. 14.69psi. Stock boost at 11psi is approx. 1.75-bar at sea level.


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## A4 1.8 Turbo (Feb 28, 2005)

*Re: Forge Splitter valve help (HernTT)*


_Quote, originally posted by *HernTT* »_
Wrong!
1 atmosphere at sea level = 1-bar. A boost gauge factors this in. At zero on a Boost Gauge you are at 1atmostphere, which equals approx. 14.69psi. Stock boost at 11psi is approx. 1.75-bar at sea level. 


um.........i have not heard this calculation before....elaborate.....


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## TREFTTY (Jan 3, 2006)

*Re: Forge Splitter valve help (HernTT)*

Audi publishes the figure including atmospheric pressure as well - so according to Audi it's 2 bar.

http://forums.vwvortex.com/zer...52892


_Modified by TREFTTY at 9:16 PM 1-13-2008_


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## cincyTT (May 11, 2006)

*Re: Forge Splitter valve help (A4 1.8 Turbo)*

actually if want to get technical, the car is running 29.4psi. Check your manual and it will say 2bar.
As for bar/atmoshpere, it depends on who you ask, some measures claim 14.5 and others 14.7.
Man, you beat me!!!!


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## A4 1.8 Turbo (Feb 28, 2005)

*Re: Forge Splitter valve help (TREFTTY)*

ok got it now,,,,i was going to say, i've take 4 different levels of physics in college and never was i taught that, but i understand now what he's saying.....that post is much clearer that previously stated expl.


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## 85VR6GTI (Mar 15, 2007)

*Re: (cincyTT)*


_Quote, originally posted by *cincyTT* »_since all the idiot "anti-bov" people cant seem to help, i will.
The splitter wont cause* ANY* ill effects. You need to install it in the opposite direction of the stock dv (pressure to bottom, side going to intake). In this direction you need more spring tension than the stock style. Just turn the top 7-10 more times and you should be fine. Also, the dv part recircs at idle, the bov will be closed. 
Dont let these AW conservatives tell you anything differnt. There are several dozen audis that i know of running a splitter or forge004 bov with 0 issues. Not everyone should be a mindless clone 

Yeah i knew how to install it and after typing my previous statement i realized that the recirc would be venting. but it still doesnt explain how i am getting only 10lbs of boost with a few spikes up to 14. and turning it in more will only delay my valve even further and increase the surging. im going to switch it over to full recirc to see if it is just leaking out the atmosphric port, if thats the case i will jsut return it and ask for a new one that doesnt leak.


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## rastta (Feb 22, 1999)

*Re: (85VR6GTI)*

The only reason to run a BOV is for the sound - since it really provides no benefit over a regular recirculating valve. I've probably seen people use about 100 different DV's, BOV, splitters over the years and quite frankly - if it aint producing any benefits - I just don't see the point. 
What you want to do is keep the turbo from getting any compressor surge and you want to ensure that your not running too rich. If you can tune a BOV to work and not run into those conditions - so be it. 
I just find it amusing that people will spend hours fooling around with something that should be set and forget.


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## cincyTT (May 11, 2006)

*Re: (85VR6GTI)*


_Quote, originally posted by *85VR6GTI* »_
Yeah i knew how to install it and after typing my previous statement i realized that the recirc would be venting. but it still doesnt explain how i am getting only 10lbs of boost with a few spikes up to 14. and turning it in more will only delay my valve even further and increase the surging. im going to switch it over to full recirc to see if it is just leaking out the atmosphric port, if thats the case i will jsut return it and ask for a new one that doesnt leak.

The valve CANT leak at idle. The port for the venting is higher and blocked off when the recirc part is open. You most likely still have the knob loose. There isnt a fixed amount of clicks, but people often start with 15+ clicks. Chipped cars are in the 20's


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## cincyTT (May 11, 2006)

*Re: ([email protected])*


_Quote, originally posted by *[email protected]* »_The only reason to run a BOV is for the sound - since it really provides no benefit over a regular recirculating valve. I've probably seen people use about 100 different DV's, BOV, splitters over the years and quite frankly - if it aint producing any benefits - I just don't see the point. 
What you want to do is keep the turbo from getting any compressor surge and you want to ensure that your not running too rich. If you can tune a BOV to work and not run into those conditions - so be it. 
I just find it amusing that people will spend hours fooling around with something that should be set and forget.
 
Its easier to run a bov where it should be on a passenger side TB and gives a less cluttered engine bay. If you have seen 100's of bovs, i can only think a 5 full bovs that will work and then a couple hybrids. The other 95 were people using the wrong valves.
I do not run rich. With the valve closed at idle, this problem is addressed
My forge004 is a set it and forget it valve










_Modified by cincyTT at 1:24 PM 1-15-2008_


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## rastta (Feb 22, 1999)

*Re: (cincyTT)*


_Quote, originally posted by *cincyTT* »_ 
Its easier to run a bov where it should be on a passenger side TB and gives a less cluttered engine bay. If you have seen 100's of bovs, i can only think a 5 full bovs that will work and then a couple hybrids. The other 95 were people using the wrong valves.
I do not run rich. With the valve closed at idle, this problem is addressed
My forge004 is a set it and forget it valve









_Modified by cincyTT at 1:24 PM 1-15-2008_

Intallations of BOV's and DV's - not the number of different valves. So in order to run the valved closed at idle - you aren't in a vacuum condition at idle?


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## cincyTT (May 11, 2006)

*Re: ([email protected])*


_Quote, originally posted by *[email protected]* »_
you aren't in a vacuum condition at idle? 

twin piston valves like the forge004 and tial 50mm keep the valve closed under vacuum unless there is pressure in the charge pipes


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## rastta (Feb 22, 1999)

*Re: (cincyTT)*


_Quote, originally posted by *cincyTT* »_
twin piston valves like the forge004 and tial 50mm keep the valve closed under vacuum unless there is pressure in the charge pipes









Under vacuum - there isn't pressure in the charge pipes though. Only time there is positive pressure in the charge pipes is under boost. So the valve is closed under both vacuum and boost conditions - until there is a transition during a throttle lift - whereby the valve opens under vacuum to vent to the atmosphere? So it would appear that there is threshold that needs to be crossed for the valve to vent under vacuum. I've known of a couple people that tried that valve but went back to the 006 (no 007 at the time), so i'm not that familiar with it.
How do you avoid the rich condition under vacuum - when the DV is typically recirculating the air back into the intake?


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## cincyTT (May 11, 2006)

*Re: ([email protected])*

Yes, your understanding is correct. The valve will release with as fast as any other valve with any amount of pressure, even 2-3psi. There was about a day where the car was a little rich after install and after that, adaptation cures all richness.
As for running rich, you wont since all the air is going into the intake at idle.
This is information, not pushing. Just because you dont like them doesnt mean they are "rice" or bad. Not to you Joe, these people know who they are.


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## rastta (Feb 22, 1999)

*Re: (cincyTT)*


_Quote, originally posted by *cincyTT* »_Yes, your understanding is correct. The valve will release with as fast as any other valve with any amount of pressure, even 2-3psi. There was about a day where the car was a little rich after install and after that, adaptation cures all richness.
As for running rich, you wont since all the air is going into the intake at idle.
This is information, not pushing. Just because you dont like them doesnt mean they are "rice" or bad. Not to you Joe, these people know who they are.


Interesting. Then the spring rates of the dual pistons are what is the key to making this work and the ability of the ECU to adapt. I wonder if the thresholds for adaptation for the 180 and 225 are different or it's simply the valve's threshold under vacuum conditions that allow it to work undervacuum and not run rich.


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## cincyTT (May 11, 2006)

*Re: ([email protected])*

the adaptations should be the same.
The forge comes with a spring kit like the 007. tial does the same thing but bases it off vacuum, not psi.
adaptation takes like a day or 2 (milage based) to get use to the change.
I have seen a few people like you discribed installing a bov and just as fast removed it w/o ever giving adaptation a chance to work. I have also seen people try to install single piston bovs and dont understand why they stall after shifts (same will happen with a splitter 100% bov).


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## rastta (Feb 22, 1999)

*Re: (cincyTT)*


_Quote, originally posted by *cincyTT* »_the adaptations should be the same.
The forge comes with a spring kit like the 007. tial does the same thing but bases it off vacuum, not psi.
adaptation takes like a day or 2 (milage based) to get use to the change.
I have seen a few people like you discribed installing a bov and just as fast removed it w/o ever giving adaptation a chance to work. I have also seen people try to install single piston bovs and dont understand why they stall after shifts (same will happen with a splitter 100% bov).









Are there one or two springs? 
Yeah - that's probably true although there is a great amount of variations in idle mix conditions depending on what software you are running - although all within stock specifications. I know my GIAC runs richer than most.


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## cincyTT (May 11, 2006)

*Re: ([email protected])*

There is 2 springs and a single piston. Basically
vac nipple - secondary spring (holds piston closed under idle) - piston - primary spring (the same as other valves).
For those that dont know, they can lean/richen idle with lemmiwinks or unisettings.


_Modified by cincyTT at 3:04 PM 1-15-2008_


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## Blue TTop (Nov 21, 2003)

*Re: ([email protected])*


_Quote, originally posted by *[email protected]* »_The only reason to run a BOV is for the sound - since it really provides no benefit over a regular recirculating valve.
I just find it amusing that people will spend hours fooling around with something that should be set and forget.

Joe - I could not agree more. If you go through the hassle of setting it up to actually work, what have you gained (other than the sound)? Maybe just to say you could do it.


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## cincyTT (May 11, 2006)

*Re: (Blue TTop)*


_Quote, originally posted by *Blue TTop* »_
Joe - I could not agree more. If you go through the hassle of setting it up to actually work, what have you gained (other than the sound)? Maybe just to say you could do it.

wow, you expressed your opinions already and after joe and i made this a positive thread you have to come back and dump on it again. Nice








Its not for you, we got that.


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## 85VR6GTI (Mar 15, 2007)

*Re: (cincyTT)*


_Quote, originally posted by *cincyTT* »_
wow, you expressed your opinions already and after joe and i made this a positive thread you have to come back and dump on it again. Nice








Its not for you, we got that.

Thanks for that, makes it reassuring that i can actually post question on this forum and actually get some answers.
Well i opened the Valve up to see if i could see anything wrong with it and when i did couldn't see anything wrong. So i put it back together re-installed it srove around for a day or two and bam running at 14lbs finally and i even need to turn the spring down to allow it to react a little quicker.
cant understand that.







Oh and adaption is quicker made when you pull the battery cables off and let it sit for a while and then reconnect. lets the car learn from scratch.


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## cincyTT (May 11, 2006)

*Re: (85VR6GTI)*

glad your up and running finally. I actally took mine apart within an hour of getting the package.


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## rastta (Feb 22, 1999)

*Re: (85VR6GTI)*


_Quote, originally posted by *85VR6GTI* »_
Thanks for that, makes it reassuring that i can actually post question on this forum and actually get some answers.
Well i opened the Valve up to see if i could see anything wrong with it and when i did couldn't see anything wrong. So i put it back together re-installed it srove around for a day or two and bam running at 14lbs finally and i even need to turn the spring down to allow it to react a little quicker.
cant understand that.







Oh and adaption is quicker made when you pull the battery cables off and let it sit for a while and then reconnect. lets the car learn from scratch.

Chances are that the piston wasn't seated correctly in the O-rings causing the problem. Very common with piston DV's. So when you take it apart - nothing looks wrong - because the problem only presents itself when you reassemble it.


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