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TheOtherDave™ · 08-26-2005, 01:45 PM

You know, the Group B Lancia Integrale S4 used a compound turbo / supercharger system.

But given the design of modern intermediate-sized turbos [like Garrett's GT28RS], I wonder if it's truly necessary.

Using the SR20DET as an comparison to VW's new 2.0T, the GT28RS can be spooled by 2800rpm and flow enough air to make about 350hp.

---
And on a related note, yes, a lot of petrol's energy is wasted as heat, but a turbo helps recover a considerable amount of energy from the exhaust stream. The supercharger OTOH, places a parasitic load on the engine that increases with RPM.
So again, you wonder, why bother?

08-26-2005, 01:45 PM	#6 (permalink)
TheOtherDave™ Upright Location: The Left Lane	You know, the Group B Lancia Integrale S4 used a compound turbo / supercharger system. But given the design of modern intermediate-sized turbos [like Garrett's GT28RS], I wonder if it's truly necessary. Using the SR20DET as an comparison to VW's new 2.0T, the GT28RS can be spooled by 2800rpm and flow enough air to make about 350hp. --- And on a related note, yes, a lot of petrol's energy is wasted as heat, but a turbo helps recover a considerable amount of energy from the exhaust stream. The supercharger OTOH, places a parasitic load on the engine that increases with RPM. So again, you wonder, why bother?