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WERK I WERK I is offline
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Join Date: Jan 2003
Location: Wisconsin
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Originally Posted by kenikh View Post
Dave, is the issue simply that only one reference was cited and that you need hard, empirical evidence or that you think twin scroll technology is without merit?

I think we'll all agree that anything that allows an engine to optimize intake and exhausg velocity gas velocity throughout the rev range is goodness. While I haven't read any PhD these or industry papers on twin scroll technology and variable valve train management, the overwhelming practice of these technologies by massively capitalized companies who make their money by selling optimized solutions tells the story.

The newest turbo engines from the big boys are all going twin scroll on single turbos with variable valve systems. Having talked to camgrinder at length on the effect of lobe spacing, overlap and limiting exhaust duration/lift low in the RPM band to increase boost response was an eye opening conversation.

The best minds with the deepest pockets betting the farm on these technologies are enough for me, especially since my ability to dissect the math isn't there. I accept E=MC^2 not because I can dissect the equation, but because I can understand the intuitive bases for this and also see that nuclear weapons work. I accept these automotive technologies for the same reasons.

The Mitsubishi Evo X and Bimmer turbos are the equivalent of 'the bomb' in the automotive context.
Thanks for your input. That's exactly what I was asserting. To use the BMW engine as an example of an efficient twin scrolling exhaust system, grossly over simplifies what BMW accomplished. It's an "apples and oranges" scenario. The BMW engine has direct injection, a more efficient combustion chamber design, variable valve timing, higher compression, PLUS twin scrolling exhaust manifold/turbochargers. It's remarkable the torque this engine produces below former boss has one in his 1 Series and that thing is a rocket!!!

But let's keep in mind that engine is producing 100 horsepower per liter and most of us are already beyond that. Twin scrolling will produce more efficiency at low engine speeds, but there is no advantage to twin scrolling when an engine achieves higher engine speeds (above 3000RPM, for instance).
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Old 06-07-2010, 02:49 PM
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