As one increases boost with ECU software or with external controllers on vehicles that tolerate that, flow restrictions become more important. So there is a need to reduce intake and exhaust restrictions. The downpipe goes from the turbo the rear of the engine and this has the cat converter(s) in it. A low restriction DP will typically be 3" and have a single cat converter instead of the the two smaller stock ones.

The snorkel tube from the air filter box to top center behind the grill can be replaced with a larger less restrictive unit. With higher flow rates the stock intercooler becomes a problem, but this is not easily changed and is expensive. One can replace the air box with an open filter in its "fender" location in front of the RH tire.

Flow restrictions make the turbo work harder and thus increases intake and exhaust temperatures. High temperatures can make the ECU retard timing to avoid knock. When the turbo is working harder, the wastegate is more closed and this increases the pressure in the exhaust manifold. This pressure is what provides power to the turbine. In many OEM setups, at 15PSI of boost, one should expect to see something around 30PSI of pressure in the exhaust manifold. That implies very high temperatures for the plugs, valves and pistons. Also, these high pressures mean there is more gas in the combustion chamber at the end of the exhaust stroke. That gas then expands and reduces the amount of fuel and air that can be taken in during the intake stroke. The T7 mass flow targeted boost then makes the turbo work even harder to overcome that, and the temperatures and exhaust pressures go even higher. All of this negative synergy can payoff in your favour when reducing these restrictions and then you get compounding benefits instead of compounding pressures and temperatures.

• 2001 Aero Stage 2 or 3 upgrade?, Quahog, Sat, 11 Feb 2006 11:21:08
  • Re: 2001 Aero Stage 2 or 3 upgrade?, Dean, Sun, 12 Feb 2006 10:28:50 <-- Viewing This Message
  • I've been looking to ask this, too. Maptun specifically, StoneMan, Sun, 12 Feb 2006 06:13:09
  • Re: 2001 Aero Stage 2 or 3 upgrade?, Aero~0657, Sat, 11 Feb 2006 12:39:32
    • Re: 2001 Aero Stage 2 or 3 upgrade?, Brooks G, Sat, 11 Feb 2006 15:06:06
      • Yes, I agree but I'll take what I can get :¬) n/m, Aero~0657, Sat, 11 Feb 2006 21:27:27

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