Originally Posted by phunk

We took the stock intake, no porting, to 818whp at ~17-18psi, which felt like we still had a fairly efficient and well matched combination. Perhaps it could have made another 30-40hp at the same boost with porting? That would be pretty wild... though I am skeptical; our turbo system still had plenty of headroom. Without knowing the test circumstances, I am guessing that if someone genuinely found 30HP in porting, they were possibly asking their turbo system for all its got. I dont believe we would have seen those results.

On the 818whp pull, the stock intake was showing no clear signs of becoming a restriction. This makes it difficult to estimate potential gains from changing to our intake. So far, it appears there would be virtually no gains at this point, even if our manifold had the potential to facilitate more airflow. When the existing resistence to airflow is so minimal, the potential reduction in that resistence is equally minimal. The boost levels were not choking us, so I dont imagine we would have found any worthwhile gains in swapping to our intake on that day.

I think we will need to increase the airflow volume a bit further first to find the point where the stock manifold has become a bottleneck. Until we find that point, there is no easy way to estimate when the potential of another manifold will come into play. I currently feel that up to the 800-900hp level, with a turbosystem ideally configured for that task, there will be little gain to find over the stock manifold.

In conclusion, we have no expectations of gains over a stock or ported manifold under the conditions we tested the stock manifold up to. We are crossing our fingers to merely do as well up to that point, and then continue to do well as we take things further than was possible with the stock engine and manifold.

Currently, It is my belief that (in turbocharged applications where the turbosystem is operating well within its efficiency) there is nothing to gain in changing the stock intake manifold out in an application that would not have burst it open. I think you would do that before you found it to be a bottleneck worth addressing, thus I question if it is even possible to demonstrate the potential gains if we will have to exceed the physical limitations of the stock manifold before we could find them.