First I want to say that you actually have a very strong car for the mods you have. The next thing is the car posted made less HP than you and it had more mods than you. This means when you remove the biggest restriction in the whole system that is still in your car (The stock precats) your going to see awesome numbers. If you install downpipes in your car, I will be happy to dyno the result of a single pop vs dual after the downpipe install and I guarantee the gain will be greater than Justin's because your car is already stronger, allowing your car the breathe will show better results. The system is only as good as the smallest restriction in the system. Each part will add to the power, but the full gain of each part is not possible without the whole system being able to breathe. Jim Selin brought us a random car to test on. We did not do any magic and we did not look for some magic set of mods that would show some unreasonable gain that no one else could get. We simply dyno tested the car as is and made the change. We did 3 pulls before and 3 pulls after to make sure the results were repeatable, the result is the dyno chart posted. The car actually dyno tested weaker than a lot of others for his mods. This means that it is reasonable to think that most people that install a dual pop over a single pop with his mods should expect similar or better gains. Your car did not have the same mods as Justin's. Justin had 2.5" downpipes and this let air move out of the engine......Letting more air in will not have as much gain if you do not let the air out. Something else about a dyno chart is you do not want to look at only the peak number. You want to look at how large the area of the gain is and what the gains are in areas other than peak as well. You say you made just under 350 RWHP (With Precats) and the test car Justin only made only 335 PEAK power. Justin had a peak power gain of around 30, but more impressive was areas where he made over 40HP more as a large area improved in power and not just the peak power. I would bet you have a better gain than 17 in some areas and I would bet your making more power in a fairly large area with the dual pops even with precats. Adding dual pops works.
