[darkpuppet]

haha.. the trying is the hardest part in the end.... stuff adds up quickly the more you try different things.

I agree that losing some of the backpressure will hurt your low-end torque numbers, and since the JRSC is pretty sparse on torque to begin with, I'm not sure if losing low-end torque is a good thing.

Now why would we be concerned with backpressure at low RPM? well, I think it's because the stock manifold, at lower RPM works more like a tuned pipe than a pressure-less sytem. At certain RPMs, the pulses generated by the backpressure help scavenge exhaust gasses, but ensure that your cylinder pressures are still maximized during the intake/combustion cycle.

By changing the exhaust, you decrease the backpressure, which improves the overall efficiency of the engine at higher RPM, but it hurts the scavenging effect at low RPM.. thus you lose low-range torque, but gain overall.

But you have bigger issues to worry about when it comes to your exhaust system.... you currently have some very aggressive cams on your car that could be hurting your cylinder pressures under boost and robbing you of valuable horsepower and midrange torque. I would look into that first before looking into an exhaust.

Once you maximize your gains with the current exhaust setup, you'll be able to gain more HP with a better exhaust, but you're ultimately going to hurt low-RPM torque numbers because high-flow exhausts are optimized for higher RPM ranges... what's good for flowing air/exhaust at high RPM could hurt the engine's breathability at low RPM...

just remember I didn't say anything about backpressure being good.. only that maximizing the efficiency of the exhaust is good.. but different sized exhausts maximize efficiencies for different flow characteristics which affect your power band at given points.

I think...