dogfish246, I can't answer your specific question, but I did ask my local speed shop (with dyno) what are the common mistakes owners make, and exhaust mods are high on the list. This topic is sure to cause debates, but the bottom line to performance was intake and exhaust air velocity. Air velocity can be adjusted by changing intake and exhaust sizes, which moves the torque and related hp curve up and down the rpm scale. Having no back pressure does not mean maximum velocity. I'll use a ricer example. A Honda Si was dyno'ed with a modified exhaust (larger pipes from engine all the way back), and had actually lost power below 4000 rpm. Peak HP did increase, but it also moved up higher on the rpm scale. A lean condition was also occuring. The exhaust system was out of balance with the veleocity ability of the intake, cam and valves. Specific to a C4 L98, their is some room to improve exhaust velocity, but the intake system was designed for low to medium rpm velocity. So the reason you hear two answers is that it all depends what you are trying to do. For my L98, I need wide band torque for maximum performance because of the automatic and lower reving engine. Adding 10 more HP at 5000 rpm doesn't help me if I drop 10 HP at 2500 rpm. There are experts on this forum who can do a much better job of explaining the science behind all of this.
eddevil and much less hassle.
