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Old 10-05-2009, 06:53 PM   #26
Shabib67
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id like to see how this compares to a true twin scroll setup, maybe something like full-race.
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Old 10-05-2009, 06:58 PM   #27
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Quote:
Originally Posted by fastnoypi View Post
interesting concept, i'd like to see some tuner data on the effects of possible increase in backpressure prior to the valve opening. The valve would have to be at a lower spring rate than the EWG spring when signaled off the same manifold boost source or a separate solenoid inbetween.
what kind of data do you want to see?

its not a "possible increase in backpressure".....it IS increased backpressure. But its a good increase in backpressure.

As people move up in turbo size all the piping is increased to accomodate high rpm hp......which in turn screws the low end because now the exhaust gases are trying to fill all these cavernous pipes before they can start spinning the turbine.
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Old 10-05-2009, 10:03 PM   #28
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Quote:
Originally Posted by Phatron View Post
why would someone run a twinscroll housing on a single scroll header?

wouldnt it be cheaper and easier (read less moving parts and possible points of failure) to just switch the turbine housing?

or just cut out the divider on the turbine?

to me this really isnt about single vs twin scroll.....but more about speeding up the exhaust gases at low rpm.

i'd like to see one of these on a single scroll turbine. Obviously it would never be shut, but partially closing it at low rpm should have this same effect, right?
How would shutting a valve and blocking the airflow to a single scroll turbine housing do anything beneficial? It wouldnt have a positive effect of any kind on a single scroll turbine.
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Old 10-05-2009, 10:09 PM   #29
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Quote:
Originally Posted by Leggy_09 View Post
How would shutting a valve and blocking the airflow to a single scroll turbine housing do anything beneficial? It wouldnt have a positive effect of any kind on a single scroll turbine.
no it's blocking one side(scroll) of the two; as it doesn't have enough exhaust gas at that low rpm(low boost as the valve to open the second scroll opens with boost) to be worth filling both scrolls as this would cause increased scavenging for the next exhaust pulse which causes interference(I think i'm using the correct term ) which is not good.

[/quote]

Last edited by CatfaceType-R; 10-05-2009 at 10:16 PM. Reason: *read this if you don't understand what the valve does*
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Old 10-05-2009, 11:36 PM   #30
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Quote:
Originally Posted by Leggy_09 View Post
How would shutting a valve and blocking the airflow to a single scroll turbine housing do anything beneficial? It wouldnt have a positive effect of any kind on a single scroll turbine.
Think what he is referring to is increasing the exhaust velocity on a single scroll turbo. In theory it would have an effect on that as well.

Man just been reading up more...simple design. Wastegate actuator that just opens a flap. Simple, easy and effective it seems.

Last edited by crashtke; 10-05-2009 at 11:56 PM.
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Old 10-05-2009, 11:46 PM   #31
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^^^ ding ding ding

imo it just doesnt seem like the 3-4" divider on a twin scroll housing would make this device benefit anymore......if it did we could just design the flange with a divider "insert" that would stick into the turbine.....just like one would be on a TS housing
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Old 10-05-2009, 11:50 PM   #32
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Quote:
Originally Posted by crashtke View Post
Think what he is referring to is increasing the exhaust velocity on a single scroll turbo. In theory it would have an effect on that as well.


it's less about pure velocity and more about good pulse waves being negated by the next incoming pulse(so cutting down on the pulastions is the goal of this valve or actuator should i say)

Last edited by CatfaceType-R; 10-05-2009 at 11:58 PM.
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Old 10-05-2009, 11:53 PM   #33
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Originally Posted by Phatron View Post
^^^ ding ding ding

imo it just doesnt seem like the 3-4" divider on a twin scroll housing would make this device benefit anymore......if it did we could just design the flange with a divider "insert" that would stick into the turbine.....just like one would be on a TS housing
Quote:
Twin scroll turbine housing. The TST housing derives its name from the geometry of the exhaust gas inlet into the turbine. Two different-sized scrolls are generally used, a primary and a secondary. Typically, the primary is open for low-speed operation, and both for high-speed use. This creates the ability of the TST to be a small A/R housing at low speeds and a large A/R at higher speeds.

TST designs are of merit in that they offer a better combination of low-speed response and high-end power. It would be difficult to configure the unit to control boost by effectively varying A/R. A wastegate is therefore still necessary to control boost pressure. Simplicity of the twin scroll turbine housing is its big selling point.

[Source- "Maximum Boost" by Corky Bell]
^^^^^ read me, so closing probably the high speed one until it's ready for it(has enough boost) makes it more efficient
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Old 10-06-2009, 12:00 AM   #34
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No I think he gets it, he is just wondering about the application of one of these on a big single scroll, speeding up exhaust velocity at lower rpms to help spool and opening up for big flow at higher rpms. It is a tangent, does not apply to twin scroll turbos.
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Old 10-06-2009, 12:01 AM   #35
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so....which twin scroll housings have different sized openings? and which ones have valves where only the "primary is open for low speed operation"?

it sounds like he's describing this device and not describing a ts housing.

can you post pics of different sized scrolls and pics of the primary and secondary scrolls and how the secondary is closed for low speeds?
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Old 10-06-2009, 12:05 AM   #36
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Quote:
Originally Posted by Phatron View Post
^^^ ding ding ding

imo it just doesnt seem like the 3-4" divider on a twin scroll housing would make this device benefit anymore......if it did we could just design the flange with a divider "insert" that would stick into the turbine.....just like one would be on a TS housing

I guess it could have that effect, but my concern is that with it being offset it would behave more like a blockage than it would to improve scavenging or increase gas velocity when the volume of gas is lower. It would probably work better for that purpose if you were altering the diameter of the port symmetrically, IE have a donut in the center that altered its diameter effectively increasing or decreasing the size of the port. Like a cone facing into the turbine housing that narrows and expands to act like a nozzle that would actually scavenge.... / \ -> | |

... instead of a block off plate that would still interrupt air flow even when fully open. This is of course incredibly complex and wouldnt provide an effective work/results ratio....

I could be wrong, of course, i just cant see how blocking 50% of the flow would be of benefit. The reason it could work on a twin scroll is that the geometry of the ports in the turbine housing are different, so the air moves through the larger diameter uppipe, hits the reducer, and then enters the turbine housing of the same diameter as the reducer where the scavenging process continues...... instead of flowing, hitting a block off wall, moving through the smaller port, and then expanding again to the larger diameter of the turbine housing.
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Old 10-06-2009, 12:05 AM   #37
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This works. Get one if you can spend the money on it.
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Old 10-06-2009, 12:10 AM   #38
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Quote:
Originally Posted by Leggy_09 View Post
instead of flowing, hitting a block off wall, moving through the smaller port, and then expanding again to the larger diameter of the turbine housing.
so on twin scroll housings the "divider" goes all the way to the turbine blade and never opens to a larger diameter?

the ones i've seen open into a larger diameter well before the turbine
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Old 10-06-2009, 12:13 AM   #39
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Quote:
Originally Posted by soon2bblackongold View Post
it's less about pure velocity and more about good pulse waves being negated by the next incoming pulse(so cutting down on the pulastions is the goal of this valve or actuator should i say)
this isnt even a factor in this situation because this valve is for NON twin scroll manifolds.

the only difference im proposing is the 3-4" divider thats on the twin scroll housing and not on the single scroll housing
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Old 10-06-2009, 12:13 AM   #40
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on a twin scroll housing, yeah, exactly. But thats how it would work on a single scroll housing....which is what I thought we were talking about? Reading fail?

The TS channel runs all the way to the turbine, but with a single scroll housing the gas would have to contract to get through the divider and then it would expand again in the turbine housing....
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Old 10-06-2009, 12:35 AM   #41
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Quote:
Originally Posted by Leggy_09 View Post
The TS channel runs all the way to the turbine,
pics please
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Old 10-06-2009, 12:37 AM   #42
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ok guy, you win. Buy it, bolt it up to your single port manifold and single scroll turbo and let us all know how it works out. :up:
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Old 10-06-2009, 12:46 AM   #43
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i just asked for a picture. when i search and look at the pics it looks like the divider stops well before the turbine....at least on some of them.

im not getting riled up or anything. do i need to end every post with

The reason twin scroll housings work is because of the separation of the exhaust pulses via the twin scroll manifold, correct?

Well....since that benefit is no longer there......

this valve is really no different than switching up pipe diameter

u make ur up pipe diameter smaller it will spool quicker but hurt ur top end.

u make ur up pipe diameter larger it will spool slower but increase ur top end.

am i really that wrong here? makes sense in my head. mr bud light agrees.

Last edited by Phatron; 10-06-2009 at 12:53 AM.
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Old 10-06-2009, 12:59 AM   #44
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Thats a small picture, but it shows how the turbine housing...

You may very well be correct on what happens when you change uppipes in a manner like you mentioned. Im asserting that using a simple block off plate trying to simulate an environment combing the best of both *may* yield undesirable results, because I dont think the scavenging effect you want will be there, because its not truly altering pipe diameter, its simply forcing air through an unnecessary port.

Last edited by Leggy_09; 10-06-2009 at 01:24 AM.
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Old 10-06-2009, 01:14 AM   #45
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Quote:
Originally Posted by Phatron View Post
when i search and look at the pics it looks like the divider stops well before the turbine....at least on some of them.
Here is another picture showing the divided channels.



IIRC, there is a difference between twin entry and twin scroll. I tried to search a little because its been years since Ive had them apart, but I really need to sleep. lol. At any rate, the early MR2 turbo used a ct26 "twin entry turbo" which, IIRC, used a divided manifold and a divided turbine housing to keep the pulses tuned heading into the turbine wheel, but the divider stopped before the wheel. A twin scroll, like the 3rd gen MR2 turbo 3sgte CT20B turbo (or a modern evo turbo) are twin scroll. the turbine housing has dual channels flowing around different parts of the turbine wheel to ensure even spread of gasses, like the picture above....

Someone may know more about that here, but I cant search for it any more tonight...

hope that helps.

Last edited by Leggy_09; 10-06-2009 at 01:20 AM.
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Old 10-06-2009, 01:43 AM   #46
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Quote:
Originally Posted by Phatron View Post
The reason twin scroll housings work is because of the separation of the exhaust pulses via the twin scroll manifold, correct?

Well....since that benefit is no longer there......

this valve is really no different than switching up pipe diameter

u make ur up pipe diameter smaller it will spool quicker but hurt ur top end.

u make ur up pipe diameter larger it will spool slower but increase ur top end.

am i really that wrong here? makes sense in my head. mr bud light agrees.
Twin scroll is good because of the pulse separation, yeah. But that's not relevant here. The only thing this has in common with a twin scroll turbo is that it requires an exhaust housing with the same divider. The principles of operation are entirely different.

I would expect this to provide zero benefit when used with a single scroll turbo - in fact I would expect it to just be a hindrance. That wouldn't be like putting your thumb over the end of a garden house. It would be like putting a half-cross-section restriction in the middle of your garden hose, halfway between the spigot and your hand. If you really insist on a garden hose analogy I could come up with one, but it would be a crappy analogy because the two scenarios are just not very analogous.

This is about having a turbo with half the usual AR for low-flow situations, which switches to full AR for high-flow situations. True VGT would give a continuous transition... this is pretty discrete, but the principle of operation is similar. (With the valve half-open you might get kinda half-small-AR-plus-half-big-AR performance but I'm not betting on it.)

When you wrote "got it" earlier I thought you had it... got it back again yet?

Some twin-scroll turbos use scrolls with different AR. None in the Subaru universe do, as far as I know. Those that do use different AR in each scroll do work similar to this device, in that the car uses one or both depending on the state of a valve.

There's a rumor that ATP is working on twin-scroll versions of their stock-location GT turbos. If that happens I'll switch from my current ATP3076 to the twin-scroll version of ATP's 35R, keeping my single-scroll header... but with a fork in UP, and a valve in one of the UPs. Same idea as this thing. I'd just drive the valve with an MBC.

Suppose they make it with a .8 AR housing... under 10psi I'd have a 35R with .4 AR so it would spool up a lot better than your average 35R. Over 10psi I'd have a 35R with .8 AR so it would run like a 35R should. Make sense yet? (I pulled the 10psi number out of my ass - it's a reasonable place to start testing but I have no reason to think it's actually the best place to make the switch.)
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Old 10-06-2009, 04:04 AM   #47
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twinscroll turbos keep the exhaust gasses seperate all the way from the head to throught the header, up the up pipe, and throught the turbo. the first time they actually contact is when they are coming out the turbine of the turbo
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Old 10-06-2009, 10:37 AM   #48
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This winter I may put my car under the knife again and get a borgwarner 362 ts ( whatever bw has that is equal or better to the 35r ts....) this thing doesn't get welded on to the uppipe or does it? This may get interesting, might as well go for it... Lol

Last edited by TDagen; 10-06-2009 at 10:49 AM.
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Old 10-06-2009, 11:28 AM   #49
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I'm curious to see how it compares to a true twinscroll setup. Both supra graph looks like a 300-325 rpm shift in spool.. I'd expect that much out of a good TS setup, with more midrange & top end power to boot.
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Old 10-06-2009, 11:29 AM   #50
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Quote:
Originally Posted by crashtke View Post
Think what he is referring to is increasing the exhaust velocity on a single scroll turbo. In theory it would have an effect on that as well.

Man just been reading up more...simple design. Wastegate actuator that just opens a flap. Simple, easy and effective it seems.

Quote:
Originally Posted by Phatron View Post
^^^ ding ding ding

imo it just doesnt seem like the 3-4" divider on a twin scroll housing would make this device benefit anymore......if it did we could just design the flange with a divider "insert" that would stick into the turbine.....just like one would be on a TS housing
The problem when using this with a single scroll turbo is that immediately after this valve the diameter of the flow path goes right back to what is was before the valve. The increase in gas velocity is only occurs as the gas passes the valves orifice. It overall velocity would actually be the same or slower than what is was pre-valve. Its conservation of energy and the same principle a venturi and orifice D/P plates work on. The gas velocity post valve has to be slower post valve if the diameter doesn't change and since you are not taking away a scroll you won't see any change in gas velocity
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