Porting and Forced Induction

[CobraSix]

Okay, working with KStang with making a MPFI manifold and setting up some engines to run the MPFI with forced induction.

My question, looking at flow numbers of the OZ250 head, CI's head, and crossflow heads. They all show significant improvement in flow through porting. Is there as much to be gained if forced induction is used? I could understand that when running off boost you'd get better performance but once you boost is created is there any large benefit?

I'm looking to make around 350BHP from a MPFI 200 (between 10-14 psi). Was just wondering if its worth the time, effort, or money to port for a FI engine?

 

[Does10s]

Slade,
We had our CI head ported a few years ago and it made a HUGE difference! We dropped almost 2 tenths in just the 60' times. I totally didn't expect that. I expected more top end power (which we got too!) but the torque we gained in the 2500-3500 range was just amazing!
Now this was with the Holley 450 of course.

It is always worthwhile to port the head. The more power you can make in N/A trim, then it's that much better at 10lbs. of boost.
Later,
Will

 

[Kstang]

For porting where are the biggest gains? Would you need to take it to a specialist? is this something you can do your self? I have done a very small bit on my mazda when removing the VTCS but that was really just smoothing out the ledges the butterflies sat on. Would any engine shop that does v8 porting know how to do it on the 6?

 

[CNC-Dude]

The main difference in a ported N/A head and a ported forced induction head are the intake/exhaust flow ratios. The N/A head usually has a 75% ratio, and the forced induction generally has an 80-85% ratio. Keep in mind that some heads cant even achieve the 75% ratio, so you can only do what you can with those heads. Still any improvement is considered a gain.