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Location:
northern beaches
Registered:
August 2002
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: external wastegate with two vacuum line connections?
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Sun, 19 June 2005 11:21
 
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"Usually" there is an inlet that connects to the compressor housing and the other goes to the controller valve!
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Location:
northern beaches
Registered:
August 2002
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Re: external wastegate with two vacuum line connections?
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Sun, 19 June 2005 11:34
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so the connection that feeds to the top of the diaphragm connects to the compressor housing and the one that feeds to the underside of the diaphragm connects to the bleed valve/boost controler?
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: external wastegate with two vacuum line connections?
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Sun, 19 June 2005 11:41
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I do believe thats how they work. Certainly is on my CT20B.
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Location:
northern beaches
Registered:
August 2002
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Re: external wastegate with two vacuum line connections?
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Sun, 19 June 2005 11:55
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hmm well the dato has been running with the top line not conected to anything and the lower connection that feeds to underneath the diaphragm connected to the bleed valve? doesent that mean the bleed valve is doing nothing?
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: external wastegate with two vacuum line connections?
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Sun, 19 June 2005 12:02
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I'm not exactly sure what is the inlet or outlet on that waste gate. The connection that is currently being used could be the inlet from the compressor housing. So having the control valve in series with this line will still make the waste gate fully operational.
The second connection is meant to give much finer boost control.
So if you remove the control valve from where it is now and put it on that second connection, it will give better control.
Does that make sense?
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: external wastegate with two vacuum line connections?
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Sun, 19 June 2005 12:05
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This might help:
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Location:
Canberra
Registered:
May 2002
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Location:
northern beaches
Registered:
August 2002
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Re: external wastegate with two vacuum line connections?
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Sun, 19 June 2005 12:15
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yea i understand the wastegate concept, just found a cut-away pic of an external gate along with an exploded view, think im sorted now.
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: external wastegate with two vacuum line connections?
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Sun, 19 June 2005 12:20
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| TE72_Turbo wrote on Sun, 19 June 2005 22:08 |
NO NO NO NO NO!! You definately do not want to hook the fitting on top of the diaphragm directly to a boost source, this will ensure that the wastegate valve cannot lift off its seat (cause effectively you are pushing it into the seat, not lifting it off!), so that you will get as much boost as the turbo can produce!! 
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I do believe that some waste gates operate this way with a bleed system. HKS?
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Location:
northern beaches
Registered:
August 2002
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Location:
sunny coast, qld
Registered:
October 2002
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Re: external wastegate with two vacuum line connections?
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Mon, 20 June 2005 02:32
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Option 2 is what Celicamad told me to do when fitting my Hiperboost with external wastegate. Unfortunately car isn't tuned yet so can't comment on how much boost it is running like this.
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Location:
Canberra
Registered:
June 2003
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Re: external wastegate with two vacuum line connections?
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Mon, 20 June 2005 03:47
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The top port sits on the vac side of the diaphram ie you need vac for it to open. It is there purely for cruise situations to open the wastegate and allow the exhaust gases a freer path out...ie don't have to go thru the exhaust wheel.
Good for emissions and maybe fuel economy. I have never actually seen anyone bother to hook this port up...certainly not in a performance application.
Remember, externals gates feature on a lot of factory turbo cars and trucks so the aftermarket has just copied their design. Not all aftermarket external gates run the dual port simply for the reason that 99% of users don't or won't use it.
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Location:
Canberra
Registered:
May 2002
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Re: external wastegate with two vacuum line connections?
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Mon, 20 June 2005 05:59
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So on yours Justen, do you just bleed off air from the port below the diaphragm to get the desired boost level (like a conventional internal gate bleeder)?
Ever tried the second option? I'd be interested to hear some results as to whether it actually does give more accurate boost adjustment/control.
Cheers
Phil
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Toymods Vice President
Location:
Sydney
Registered:
May 2002
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Re: external wastegate with two vacuum line connections?
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Mon, 20 June 2005 06:05
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Some electronic boost controllers are setup so the solenoid feeds boost to the top port on the external gate then close the solenoid to increase the pressure differential across the diaphram to limit the boost.
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Location:
Canberra
Registered:
June 2003
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Re: external wastegate with two vacuum line connections?
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Mon, 20 June 2005 22:47
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That would decrease the pressure differential across the diaphram josh but i understand what you were trying to explain.
I don't use that no, just the bottom port and currently with no bleed as 13psi from the 10psi wastegate spring in plenty. When i had the 6psi spring i used a bleed and could get any boost level no probs.
I can't see why feeding boost to the top port would be any more accurate and i can see a big prob if the solenoide to that port fails in the open position...if you feed full boost to both ports you only have exhaust back pressure to counter the spring pressure and open the gate...you will suffer massive overboost.
I have never seen anyone use both ports for a perf gain so more i can't say...it may deliver a benefit but i can't see how and would like to see some real world results.
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Location:
sunny coast, qld
Registered:
October 2002
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Re: external wastegate with two vacuum line connections?
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Mon, 20 June 2005 23:11
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I will let you guys know how mine behaves when it is getting tuned on Friday as mine is setup using both ports.
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I supported Toymods
Location:
Perth, WA
Registered:
May 2003
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Location:
sunny coast, qld
Registered:
October 2002
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Re: external wastegate with two vacuum line connections?
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Tue, 02 August 2005 09:30
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is that a conventional bleed valve or a restricter like the norgen valve in general talk? I had mine setup like that and it was over boosting hardcore.
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I supported Toymods
Location:
Perth, WA
Registered:
May 2003
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Re: external wastegate with two vacuum line connections?
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Tue, 02 August 2005 10:42
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we'll see how i go.
apparently this is the PROPER way to setup up an external gate with a manual boost controller(bleed valve).
its a GFB(Go fast bits) bleed valve
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Registered:
July 2005
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Re: external wastegate with two vacuum line connections?
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Tue, 02 August 2005 12:01
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If you want higher boost do this. Its what i do and it has worked at 25psi quite well.
1.Run boost from the comp cover to the bottom of the gate.
2.Run boost from plenum with bleed valve inline to the top of the gate
3. Wind the bleed valve out all the way(bleeding the max amount) out and work your way in till the boost starts to increase.
I guarantee it will work
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I supported Toymods
Location:
Perth, WA
Registered:
May 2003
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Re: external wastegate with two vacuum line connections?
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Tue, 02 August 2005 13:07
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hmm
i did a quick search on google and so far all i've found is teeing off the boost cource and running a line to each nipple on the gate
(same as in the pics)
would this have the same effect as running a line from the inlet manifold(vacuum source) to the top nipple on the gate
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Registered:
July 2005
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Re: external wastegate with two vacuum line connections?
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Tue, 02 August 2005 13:15
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| ae95 wrote on Tue, 02 August 2005 23:07 |
hmm
i did a quick search on google and so far all i've found is teeing off the boost cource and running a line to each nipple on the gate
(same as in the pics)
would this have the same effect as running a line from the inlet manifold(vacuum source) to the top nipple on the gate
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that will have no effect. it will be even pressure on each side of the diaphragm so it is effectively nothing,will be like running no boost pressure at all.
the way i explained works well because the top signal is always a few psi lower than the bottom signal.so its enough to open the valve but not enough to over ride it:)
just trust me on this one lol.
leigh
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Registered:
July 2005
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Re: external wastegate with two vacuum line connections?
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Tue, 02 August 2005 13:20
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i setup my mates rb25/gt35r/45mm turbosmart gate like this, he was getting gate creep at 20psi with a 14 spi spring.
he was bleeding to the bottom of the diaphragm only and in higher gears the boost was all over the place.
set your up like i said and let me know how good it works 
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: external wastegate with two vacuum line connections?
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Tue, 02 August 2005 13:26
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| JustenGT4 wrote on Tue, 21 June 2005 08:47 |
I can't see why feeding boost to the top port would be any more accurate
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the theory comes from the error in controlling pressures etc.. the higher the pressure/forces, the lower the error will be and it should be more reproducible...
basically, rather than bleeding off the lower port pressure, resulting in a smaller force on the diaphragm vs spring, you have higher forces both above and below... this should allow more accurate adjustment because the same change in the amount of bleed results in a smaller change in wastegate movement?
something like that.....
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I supported Toymods
Location:
Perth, WA
Registered:
May 2003
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Location:
sunny coast, qld
Registered:
October 2002
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Re: external wastegate with two vacuum line connections?
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Tue, 02 August 2005 22:33
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| rb30 boy wrote on Tue, 02 August 2005 22:01 |
If you want higher boost do this. Its what i do and it has worked at 25psi quite well.
1.Run boost from the comp cover to the bottom of the gate.
2.Run boost from plenum with bleed valve inline to the top of the gate
3. Wind the bleed valve out all the way(bleeding the max amount) out and work your way in till the boost starts to increase.
I guarantee it will work
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If the top line on the wastegate is equal to the same pressure as the bottom line how is the wastegate going to open? That is what happened with mine. It didn't! Was running 23psi before I let off and would have continued.
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Location:
Adelaide
Registered:
June 2002
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Re: external wastegate with two vacuum line connections?
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Wed, 03 August 2005 02:40
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Supplying regulated pressure to the top port of the gate as well is the most accurate way of controlling boost. Using any form of bleed system to the lower port induces boost spiking as the response time of the gate is significantly decreased the higher the boost level used. The slowed response is due to the mass flow required through the system (and the finite time required for the system to fill) to achieve the pressure reduction to the gate actuator. These sort of boost spikes are what boost controllers tune out by preempting the spike and opening the gate earlier than it would otherwise to prevent overshoot due to slow response.
A completely sealed boost control system gives the fastest possible response.
If you have an 8psi gate, and supply a REGULATED 2 psi to the top of the diaphragm, the will be ZERO gate creep until 2psig is achieved. Once at 2PSIG the gate will commence creeping, and will be fully opeb at 10psig (ie 8+2=10).
Moral of story-use regulated pressure to the top port to control boost on an external gate-NOT a bleed system to the lower (main) port. The lower port bleed type set-up may work, but a top port bleed system set-up correctly works better hands down.
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