Subaru twin scroll turbo unit - STi ver 8
07 November 2002, 09:34 AM
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Interesting stuff -- Volvo has used Mitsu twin-scroll turbos on its T4 and its light-pressure turbo cars for years, and they're well known for wide torque spread and almost zero lag.
Had a T4 myself for a while and lag was hard to find
Had a T4 myself for a while and lag was hard to find
07 November 2002, 03:34 PM
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The twin scroll turbo enables excellent low to mid response aswell as top end power. How does it work ? The twin scroll entry point has one chamber closed off at low to medium rev's in order to obtain a higher air speed through the smaller than normal passageway. The result is very effective in reducing turbo lag. At a pre-determined engine speed the second intake chamber of the comes 'on-line' to add full boost. The result is effortless performance.......
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07 November 2002, 05:55 PM
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I understood that twin scroll turbine housings worked (on 4cyl) by allowing the cylinders to be paired of in such a manner that there would be no interference and "reversion"? problems between cylinders.
I heard of a recent system which staged use of seperate scrolls, but I am pretty sure that the traditional function of twin scroll turbine housings is to cancel out inteference that would otherwise occur between certain cylinders in a traditional header setup.
I heard of a recent system which staged use of seperate scrolls, but I am pretty sure that the traditional function of twin scroll turbine housings is to cancel out inteference that would otherwise occur between certain cylinders in a traditional header setup.
07 November 2002, 06:09 PM
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For those like me that didn't know how twin scroll turbos work:
"Its secret lies in the utilization of a system known as 'twin scroll technology'. Two separate exhaust manifolds, each of which serve two cylinders generate pressure pulses which accelerate the turbine more effectively than the conventional turbo. Combined with relatively low charge-air pressure, the special exhaust manifolds endow the engine with characteristics reminiscent of substantially more powerful conventional engines but with the added benefit of lower fuel consumption."
Want those headers too, and a new hybrid twin-scroll turbo .....
"Its secret lies in the utilization of a system known as 'twin scroll technology'. Two separate exhaust manifolds, each of which serve two cylinders generate pressure pulses which accelerate the turbine more effectively than the conventional turbo. Combined with relatively low charge-air pressure, the special exhaust manifolds endow the engine with characteristics reminiscent of substantially more powerful conventional engines but with the added benefit of lower fuel consumption."
Want those headers too, and a new hybrid twin-scroll turbo .....
08 November 2002, 01:46 PM
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Chiark
The WRX I saw at the Paris Motorshow had the standard up pipe design (with cat) and so was not a twin scroll unit.
Full production cars may differ, but I expect this technology will be reserved for the STi.
Full torque achieved at 2800
That's going to upset laggy STi7 owners
The WRX I saw at the Paris Motorshow had the standard up pipe design (with cat) and so was not a twin scroll unit.
Full production cars may differ, but I expect this technology will be reserved for the STi.
Full torque achieved at 2800
That's going to upset laggy STi7 owners
08 November 2002, 02:09 PM
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just hope this new extractors fit (or can be modified to fit) the older EJ20K and EJ205 engines ..... ..... but probably the price of this new turbo must be $$$ 
Carlos H.
..... ..... but probably the price of this new turbo must be $$$ Carlos H.
08 November 2002, 02:26 PM
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Full torque at 2,800 rpms ??? awesome !!!!! Imagine what a decat will do 2,500 rpms ??????
The new STi-8 must be a Evo killer with that torque stat ? I think the best the Evo ever had was the EVO V with full torque at 3,000 rpms, Evo VII is 3,500 I think ? STI-7 4,000
Cheers,
Ray
2,500 rpms ??????The new STi-8 must be a Evo killer with that torque stat ? I think the best the Evo ever had was the EVO V with full torque at 3,000 rpms, Evo VII is 3,500 I think ? STI-7 4,000
Cheers,
Ray
08 November 2002, 03:00 PM
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Nick
Looked at it myself already
and the wrx does not have twinscroll[img]images/smilies/mad.gif[/img]
Can not find any info on STI Wagon.
Perhaps we should put up a request list and forward to subaru
Could always modify the standard wagon though, i sure it wont take long for someone to crack how to do it.
Looked at it myself already
and the wrx does not have twinscroll[img]images/smilies/mad.gif[/img]Can not find any info on STI Wagon.
Perhaps we should put up a request list and forward to subaru
Could always modify the standard wagon though, i sure it wont take long for someone to crack how to do it.
08 November 2002, 05:05 PM
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Nathan, £26995 for the fully loaded version, but Ian is getting me a price for one with the adjustable diff. It seems the adjustable diff version also has an automatic mode that does it all for you, or you can select a setting which overides it.
The spec list on the apexjapan site doesn't look right though. The compression ratio is unchanged, so is the stroke, but those are definitely high compression pistons in the pictures.
The spec list on the apexjapan site doesn't look right though. The compression ratio is unchanged, so is the stroke, but those are definitely high compression pistons in the pictures.
