Twinscroll turbos?
07-28-2008, 05:40 AM
#3
yea you would need a manifold with 1&4 and 2&3 together and separated till the turbo flange. only then will a twin scroll properly work. you will also need to get 2 wastegates or an internal for this to work properly also.
07-28-2008, 07:16 AM
#4
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Originally Posted by jzz30,Jul 28 2008, 05:40 AM
yea you would need a manifold with 1&4 and 2&3 together and separated till the turbo flange. only then will a twin scroll properly work. you will also need to get 2 wastegates or an internal for this to work properly also.
I'm gonna talk to my local shop/welder/tuner that turbos a load of Hondas all the time.
07-28-2008, 08:48 AM
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Twin Scroll setups allow for the quick spool of a smaller turbo, with the top end of a larger turbo. I think it has a smaller wheel that spools up quicker, and one that takes over once the small one "runs out" of its efficiency range... not sure about the physics / mechanics of it, but that is what I read about the concept... sounds like it was designed for a high-winding engine to give torque down low without sacrificing top end.
John
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07-28-2008, 01:42 PM
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You can run twinscrolls with one wastegate (with a separator plate between the two pipes from the two pairs of runners). They provide better response and give the exhaust a different note slightly. They pair up cylinders that are firing at the same time and separate the exhaust gases all the way up til it hits the exhaust wheel.
For reference on my old subaru, there were two turbos, the vf30 and vf34 (same size, but the 34 was ball bearing and the vf30 was thrust bearing). The VF34 had 200-400 rpms faster spool up than the VF30. The twinscroll variants of the VF30 and VF34 were the VF37 and the VF36 (with the vf36 being the same size as the vf37, except being ball bearing). All of these turbos mentioned are the same size (to my knowledge, the exhaust sides of the twinscroll were slightly larger physically due to the extra material, but had same volume).
When getting tuned, the tuner mentioned that my twinscroll vf37 (non ball-bearing) spooled around 300-400 rpms sooner than vf34's (ball-bearing single scroll) which draws the conclusion that the vf37 spools 500-800 rpms sooner than its single-scroll counterpart, the vf30. Of course there are many variables to take into consideration when factoring boost response (manifold design,intercooler flow, etc) but still valid as this tuner has tuned many vf30 and vf34 setups.
For reference on my old subaru, there were two turbos, the vf30 and vf34 (same size, but the 34 was ball bearing and the vf30 was thrust bearing). The VF34 had 200-400 rpms faster spool up than the VF30. The twinscroll variants of the VF30 and VF34 were the VF37 and the VF36 (with the vf36 being the same size as the vf37, except being ball bearing). All of these turbos mentioned are the same size (to my knowledge, the exhaust sides of the twinscroll were slightly larger physically due to the extra material, but had same volume).
When getting tuned, the tuner mentioned that my twinscroll vf37 (non ball-bearing) spooled around 300-400 rpms sooner than vf34's (ball-bearing single scroll) which draws the conclusion that the vf37 spools 500-800 rpms sooner than its single-scroll counterpart, the vf30. Of course there are many variables to take into consideration when factoring boost response (manifold design,intercooler flow, etc) but still valid as this tuner has tuned many vf30 and vf34 setups.
07-28-2008, 01:47 PM
#10
The difference is that the exhaust pulses are (partially) separated until they hit the turbine wheel. The turbine wheels are the exact same size.
Tim
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