29/04/2026
Turbo sizing isn’t just about making power — it’s about how and where that power is delivered.
On our Elusive Racing DC2R Time Attack car, every component is chosen with purpose. We’ve leaned into a twin scroll turbo setup to maximise response without sacrificing top-end — exactly what you need when every corner exit and straight matters.
By properly managing exhaust flow through the turbine, we’re able to:
• Improve response out of corners
• Reduce back pressure at high RPM
• Broaden the usable powerband
That’s the difference between a fast car… and a competitive one.
This is what helped us put it together when it counted — P1 in Clubsprint at WTAC 2018 with a 1:38.7 🏆
Real engineering. Real results.
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Turbo sizing is always a balancing act between choosing a turbo that offers great response or one that offers great power at high rpm. While the compressor side of the turbo is important, it’s the turbine side that drives the compressor and if we choose a small turbine wheel we end up with great response but high exhaust back pressure which strangles top end performance. If we choose a larger turbine wheel we reduce exhaust pressure and increase exhaust flow, but also reduce the energy available to drive the compressor wheel which hurts response and increases lag.
It’s certainly not a new technology, but twin scroll turbine housings are one way where we can get the best of both worlds. By taking advantage of the firing order of the engine (the order in which the exhaust gas exits the cylinders), and delivering the exhaust gas in an optimised way to the two individual scrolls of the turbine housing, we can reduce exhaust back pressure without sacrificing response. Of course there’s limits to this and if you think that you can fit a twin scroll EFR 9180 to your 2 litre 4 cylinder and have full boost by 2500 rpm you’re going to be very disappointed. On an application like Time Attack however, a twin scroll turbocharger can offer a wider power band and better response without choking high rpm performance. The downside however is that the exhaust manifold and wastegate integration become more complex with this style of turbo.
