twin scroll turbo?
06-23-2003, 10:12 PM
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Re: twin scroll turbo? (94TealCivic)
http://www.automotiveforums.co....html
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A turbine section of a turbocharger with separate inlets for separate headers... e.g. a twin-scroll turbo could be used with two 3-1 headers (on a V-12, say).
I suppose they make for less exhaust restriction/backpressure
missed this one, the twin scroll is all about tuning, it keeps one exhaust pulse from reversing back to the head. Like a log manifold for example, shitty tuning since all the exhaust feeds into 1 log, a twin scroll lets a V6 or 8 stick 1 pair of header primaries into one side without worrying about the pulse from another reversing back up it, very good setup to use.
so it's basically like putting a turbo on the end of the first section of a header...
where it goes 4 into 2...
Quotes:
A turbine section of a turbocharger with separate inlets for separate headers... e.g. a twin-scroll turbo could be used with two 3-1 headers (on a V-12, say).
I suppose they make for less exhaust restriction/backpressure
missed this one, the twin scroll is all about tuning, it keeps one exhaust pulse from reversing back to the head. Like a log manifold for example, shitty tuning since all the exhaust feeds into 1 log, a twin scroll lets a V6 or 8 stick 1 pair of header primaries into one side without worrying about the pulse from another reversing back up it, very good setup to use.
so it's basically like putting a turbo on the end of the first section of a header...
where it goes 4 into 2...
06-26-2003, 10:50 AM
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Re: twin scroll turbo? (Neptune)
A twin scroll turbine is a method of having two different A/R's in a single turbine housing. A flapper door (or similar device) enables or disables a secondary port through which exhaust gasses can travel, thus increasing for decreasing the area of the turbine housing. This allows for quicker, more efficient spool up under the primary port, and more efficient high end power once the secondary port opens up.
This is a somewhat basic form of variable area turbine technology, the more advanced (and MUCH more expensive) form being Variable Area Turbine Nozzles. The only real draw back is the increased complexity and cost.
I believe that the STI is using a twin scroll turbine, but it may be the Evo. Someone please correct me if I'm wrong.
This is a somewhat basic form of variable area turbine technology, the more advanced (and MUCH more expensive) form being Variable Area Turbine Nozzles. The only real draw back is the increased complexity and cost.
I believe that the STI is using a twin scroll turbine, but it may be the Evo. Someone please correct me if I'm wrong.
07-03-2003, 10:13 PM
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Re: twin scroll turbo? (mamaboy)
Yeah, now that I think about it it makes more sense for the Evo to have it (although I did do some quick research to confirm it), based on Mitsubishi's in house production and Subaru's use of IHI units.
07-04-2003, 10:37 AM
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Re: twin scroll turbo? (johnisenglish)
Got any links of a more technical nature on this?
I'm only familiar with a "divided tang" style turbine, and the AR for each seperated runner is the same, not different. You see it a lot on T4 and the PS GTP38, and big diesel units. The tractor pull guys like to run them with one port blocked off so they can spool the huge compressor sides with relatively small engines.
I'm only familiar with a "divided tang" style turbine, and the AR for each seperated runner is the same, not different. You see it a lot on T4 and the PS GTP38, and big diesel units. The tractor pull guys like to run them with one port blocked off so they can spool the huge compressor sides with relatively small engines.
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07-04-2003, 10:44 AM
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Re: twin scroll turbo? (johnisenglish)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by johnisenglish »</TD></TR><TR><TD CLASS="quote">A twin scroll turbine is a method of having two different A/R's in a single turbine housing. A flapper door (or similar device) enables or disables a secondary port through which exhaust gasses can travel, thus increasing for decreasing the area of the turbine housing. This allows for quicker, more efficient spool up under the primary port, and more efficient high end power once the secondary port opens up.
</TD></TR></TABLE>
My understanding of the technical definition of twin scroll is simply a dual chamberered runner going to the turbine...basically paired up with the correct cylinders from the manifold to keep exhaust pulses consistently hitting the wheel. It's not going to vary a/r the way I see it, link me to some info if you could...
</TD></TR></TABLE>
My understanding of the technical definition of twin scroll is simply a dual chamberered runner going to the turbine...basically paired up with the correct cylinders from the manifold to keep exhaust pulses consistently hitting the wheel. It's not going to vary a/r the way I see it, link me to some info if you could...
07-04-2003, 11:16 AM
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Re: twin scroll turbo? (Prod)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Prod »</TD></TR><TR><TD CLASS="quote">
My understanding of the technical definition of twin scroll is simply a dual chamberered runner going to the turbine...basically paired up with the correct cylinders from the manifold to keep exhaust pulses consistently hitting the wheel. It's not going to vary a/r the way I see it, link me to some info if you could...</TD></TR></TABLE>
I'm pretty sure this is correct.
See how the exhaust flange on the header is divided? That's for a twin-scroll setup, keeps the exhaust pulses flowing evenly into the turbo for quicker spool and more power.
My understanding of the technical definition of twin scroll is simply a dual chamberered runner going to the turbine...basically paired up with the correct cylinders from the manifold to keep exhaust pulses consistently hitting the wheel. It's not going to vary a/r the way I see it, link me to some info if you could...</TD></TR></TABLE>
I'm pretty sure this is correct.
See how the exhaust flange on the header is divided? That's for a twin-scroll setup, keeps the exhaust pulses flowing evenly into the turbo for quicker spool and more power.
07-04-2003, 07:53 PM
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Re: twin scroll turbo? (boosted92)
From page 184 of Maximum Boost:
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="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 high speeds.
TST designs are of merit in that they offer a better combination of low-speed response and high-speed 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.
</TD></TR></TABLE>
Corkey Bell then goes on to talk about VATN turbos, which are ten thousand times cooler.
What you're describing, and what is shown in the picture is a dual tang inlet, which as said keeps different cylinder's exhaust pulses from clashing.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="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 high speeds.
TST designs are of merit in that they offer a better combination of low-speed response and high-speed 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.
</TD></TR></TABLE>
Corkey Bell then goes on to talk about VATN turbos, which are ten thousand times cooler.
What you're describing, and what is shown in the picture is a dual tang inlet, which as said keeps different cylinder's exhaust pulses from clashing.
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