I started porting my stock '05-'06 Type-S exhaust manifold. You can see the ridge right inside the flange. I'm using a double cut carbide burr to grind away the ridge. The last three pictures are the result of the grinding work.
Yeah, I have time and sort of enjoy doing it, to be honest...Yeah seems like alot of work for minimal gains. If you've got the time and patience, more power to ya!
Uhhhhhhn he just did you dirty impI generally don't deign to respond to what I consider ignorant trash talk, but since you did ask and since this sub-forum is comprised of folks of higher intellectual caliber than most others in this forum, I'll respond for their benefit, if nothing else.
I'm a mechanical engineer, and I perform 1D hydraulic flow analyses for a living. I have looked at a lot of aftermarket designs (and have purchased and installed them as well) and see that if there is any sort of improvement (not always the case), it generally comes with some sort of trade-off (reliability, cost, comfort, NVH, or it simply shifts the peak power to a different point). These are compromises I am not willing to make. I happen to think Honda has some exceptionally good engineering practices, and that to make more power without compromising is to take advantage of the few inefficiencies (mostly due to manufacturing processes) that are present.